tag:theconversation.com,2011:/ca/topics/volcanic-eruptions-5825/articles
Volcanic eruptions – The Conversation
2024-02-21T13:13:10Z
tag:theconversation.com,2011:article/223209
2024-02-21T13:13:10Z
2024-02-21T13:13:10Z
Earth’s early evolution: fresh insights from rocks formed 3.5 billion years ago
<figure><img src="https://images.theconversation.com/files/576464/original/file-20240219-24-5de047.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Barberton Makhonjwa Mountains look peaceful today - but 3.5 billion years ago the earth there was roiled by volcanoes. </span> <span class="attribution"><span class="source">Instinctively RDH/Shutterstock</span></span></figcaption></figure><p>Our Earth is <a href="https://www.amnh.org/exhibitions/darwin/the-world-before-darwin/how-old-is-earth#:%7E:text=Today%2C%20we%20know%20from%20radiometric,have%20been%20taken%20more%20seriously.">around 4.5 billion years old</a>. Way back in its earliest years, vast oceans dominated. There were frequent volcanic eruptions and, because there was no free oxygen in the atmosphere, there was no ozone layer. It was a dynamic and evolving planet.</p>
<p>Scientists know all of this – but, of course, there are still gaps in our knowledge. For instance, while we know what kind of rocks were being formed on different parts of the planet 3.5 billion years ago, we are still understanding which geological processes drove these formations. </p>
<p>Luckily the answers to such questions are available. Evidence is preserved in ancient volcanic and sedimentary rocks dating back to the <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/archean-eon#:%7E:text=Thus%2C%20the%20Archean%20Eon%20is,continental%20plates%20began%20to%20form.">Archaean age</a>, between 4 billion and 2.5 billion years ago.</p>
<p>These rocks are found in the oldest parts of what are today the continents, called cratons. Cratons are pieces of ancient continents that formed billions of years ago. Studying them offers a window into how processes within and on the surface of Earth operated in the past. They host a variety of different groups of rocks, including greenstones and granites.</p>
<p>One example is the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0012825222000782">Singhbhum Craton</a>, in the Daitari Greenstone Belt in the state of Odisha in eastern India. This ancient part of the Earth’s crust has been found in previous research to date back to 3.5 billion years ago. The craton’s oldest rock assemblages are largely volcanic and sedimentary rocks also known as greenstone successions. Greenstones are rock assemblages made up mostly of sub-marine volcanic rocks with minor sedimentary rocks. </p>
<p>My research team and I recently published <a href="https://www.sciencedirect.com/science/article/pii/S0301926823000372">a study</a> in which we compared the Singhbhum Craton to cratons in South Africa and Australia. We chose these sites because they preserve the same kinds of rocks, in the same condition (not intensely deformed or metamorphosed), from the same time period – about 3.5 billion years ago. They are the best archives to study early Earth surface processes.</p>
<p>Our key findings were that explosive-style volcanic eruptions were common in what are today India, South Africa and Australia around 3.5 billion years ago. These eruptions mostly occurred under oceans, though sometimes above them.</p>
<p>Understanding these early Earth processes is vital for piecing together the planet’s evolutionary history and the conditions that may have sustained life during different geological epochs. This kind of research is also a reminder of the ancient geological wonders that surround us – and that there is much more to discover to understand the story of our planet.</p>
<h2>The research</h2>
<p>We sampled some rocks from the Singhbhum Craton so we could study them in our laboratory. Existing data from the same site, as well as sites in South Africa and India, were used for comparison purposes.</p>
<p>Our detailed field-based studies were complemented by <a href="https://link.springer.com/referenceworkentry/10.1007/978-94-007-6326-5_193-1">uranium-lead (U-Pb) radiometric-age dating</a>. This common and well-established method provides information as to when a magma crystallised; in other words, it tells us when a rock formed. In this way we were able to establish key geological timelines to illustrate what processes were underway and when.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-the-discovery-of-a-small-continental-fragment-in-the-indian-ocean-matters-72314">Why the discovery of a small continental fragment in the Indian Ocean matters</a>
</strong>
</em>
</p>
<hr>
<p>We also found that the geology of this area shares stark similarities with the greenstone belts documented in South Africa’s <a href="https://www.sciencedirect.com/science/article/abs/pii/S0301926816300663">Barberton</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S1342937X11002504?via%3Dihub">Nondweni</a> areas and the <a href="https://www.nature.com/articles/375574a0">Pilbara Craton</a> in western Australia. </p>
<p>Most particularly, all these areas experienced widespread submarine mafic – meaning high in magnesium oxide – volcanic eruptions between 3.5 and 3.3 billion years ago, preserved as pillowed lava and komatiites.</p>
<p>This differs from silicic (elevated concentration of silicon dioxide) volcanism, which research <a href="https://www.sciencedirect.com/science/article/abs/pii/S0040195100000585">has shown</a> was prevalent around 3.5 billion years ago.</p>
<p>These findings enrich our understanding of ancient volcanic and sedimentary processes and their significance in the broader context of Earth’s geological as well as biological evolution.</p>
<h2>Our planet’s formative years</h2>
<p>Our discoveries are pivotal for several reasons. First, they offer a clearer picture of Earth’s early tectonic activities during the Archaean times, contributing to our understanding of the planet’s formative years. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/four-ways-that-fossils-are-part-of-everyday-life-199193">Four ways that fossils are part of everyday life</a>
</strong>
</em>
</p>
<hr>
<p>Second, the Singhbhum Craton’s unique geological features, including its greenstone belts, provide invaluable information about Earth’s surface and atmospheric processes. This is crucial for hypothesising early habitable conditions and the emergence of life on Earth. </p>
<p>Additionally, comparing the Singhbhum Craton with similar cratons in South Africa and Australia allows us to construct a more comprehensive model related to geological processes that operated during the Archaean. This can help to shed light on ancient geodynamic processes that were prevalent across different parts of the young Earth.</p>
<p>This research emphasises the need for further exploration into the geological history of ancient cratons worldwide. Understanding these early Earth processes is vital for piecing together the planet’s evolutionary history and the conditions that may have sustained life.</p><img src="https://counter.theconversation.com/content/223209/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaganmoy Jodder received funding from the DSI-NRF Centre of Excellence (CoE) for Integrated Mineral and Energy Resource Analysis (CIMERA) and Genus DSI-NRF Centre of Excellence in Palaeosciences.</span></em></p>
Cratons are pieces of ancient continents that formed billions of years ago.
Jaganmoy Jodder, Post-doctoral researcher, University of the Witwatersrand
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/222512
2024-02-20T23:26:55Z
2024-02-20T23:26:55Z
A botanical Pompeii: we found spectacular Australian plant fossils from 30 million years ago
<figure><img src="https://images.theconversation.com/files/576662/original/file-20240220-28-l9zg5j.jpg?ixlib=rb-1.1.0&rect=39%2C65%2C8544%2C5709&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Details of a silicified fern fossil.</span> <span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span></figcaption></figure><p>The Australian continent is now geologically stable. But volcanic rocks, lava flows and a contemporary landscape dotted with extinct volcanoes show this wasn’t always the case.</p>
<p>Between 40 and 20 million years ago – during the <a href="https://www.britannica.com/science/Tertiary-Period">Eocene to Miocene epochs</a> – there was widespread volcano activity across eastern Australia. In places such as western Victoria and the Atherton Tablelands in Queensland, it was even more recent.</p>
<p>Erupting volcanoes can have devastating consequences for human settlements, as we know from Pompeii in Italy, which was buried by ash when Mount Vesuvius erupted in 79 CE. But ash falls and lava flows can also entomb entire forests, or at least many of the plants within them. </p>
<p>Our studies of these rare and unique plant time capsules are revealing exquisitely preserved fossil floras and new insights into Australia’s botanical history. This new work is published <a href="https://authors.elsevier.com/a/1idT5,UYEnjl1W">in the journal Gondwana Research</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A landscape with snow crested mountain in the background and ash layers covering plants next to a road" src="https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This is what volcanoes can do to landscapes – super-heated gasses from the 2011–12 eruption of Puyehue-Cordon Caulle Volcano in Argentina killed the forest. After ten years, the forest has started to regrow.</span>
<span class="attribution"><span class="source">Andrew Rozefelds</span></span>
</figcaption>
</figure>
<h2>Remarkable preservation</h2>
<p>The most common volcanic rocks are basalts. The rich red soils derived from them are among the most fertile in Australia.</p>
<p>But the rocks in which fossils occur are buried under basalts or other volcanic rock, and are called silcretes – the name indicates their origins are from silica-rich groundwaters. Silica is the major constituent of sand, and familiar to most of us as quartz. </p>
<p>What makes the silcrete plant fossils so fascinating is the superfine preservation of plant material. This includes fine roots and root nodules, uncurling fern fronds and their underground stems, the soft outer bark of wood, feeding traces and <a href="https://www.amentsoc.org/insects/glossary/terms/frass/">frass</a> (powdery droppings) of insects, and even the delicate tissues and anatomy of fruits and seeds.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of clearly visible fern leaves and fragments made up of amber coloured stone" src="https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The foliage of a <em>Pteridium</em> fern, preserved in silcrete in exceptional detail.</span>
<span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span>
</figcaption>
</figure>
<p>For this fine preservation to occur, first there needs to be a rapid burial, like that from a volcanic eruption. Then, there has to be an abundant source of silica — a condition met when the volcanic rocks began to weather. </p>
<p>The process where silica infills and preserves plant structures is referred to as “<a href="https://en.wikipedia.org/wiki/Silicification">silicification</a>” or “permineralisation”. When plant material is buried, it provides acidic conditions that are ideal for this to happen. </p>
<p>And the process need not take millions of years. Overseas studies of plants <a href="https://doi.org/10.2110/palo.2012.p.12-064r">in hot springs</a> or undertaken <a href="https://doi.org/10.2110/palo.2012.p.12-064r">in the laboratory</a> have shown that some types of silica will quickly infiltrate wood and plant tissues.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a rocky amber and white material with bubble-like shapes within" src="https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This is a cross-section of the stem (rhizome) of a silicified fern, showing its characteristic anatomy.</span>
<span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span>
</figcaption>
</figure>
<h2>Why are these plant fossils significant?</h2>
<p>Because of their rapid entombment by the volcanoes, we can be sure the plants were in situ (that is, their original location) and were actively growing. This means we can gain detailed information about the make-up of these past plant communities.</p>
<p>In other areas where plant fossils might accumulate – such as river deltas – we can never be sure how far the bits of plants were carried, and whether they were from different types of vegetation.</p>
<p>Silicification not only preserves plants, but also leaf litter on the forest floor and even the underlying soil containing roots and root nodules. The fossil plants that are preserved at different sites varies, indicating the presence of distinct plant communities. </p>
<p>The abundance of seeds and fruits at one site near Capella, in central Queensland, even indicated to us that the local volcanic eruptions are likely to have occurred in summer or early autumn during the fruiting season.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A detailed folded shape of a seed encased in orange-amber rock" src="https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This cross-section of a silicified native grape seed shows its complex internal structure which is typical of the seeds of this family.</span>
<span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span>
</figcaption>
</figure>
<p>The extraordinary preservation of these fossils allows us to compare them with modern plants. In turn, this means we can accurately identify them.</p>
<p>The ferns include fronds and underground stems (rhizomes) of the familiar bracken fern (<em>Pteridium</em>). We have also found the distinctive seeds and lianas of the grape family (Vitaceae), along with evidence of insect damage in the wood. Two sites also had evidence of palms.</p>
<p>While there have been few previous studies on silcrete plants, we have revealed new insights into the history of the modern Australian flora.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a bright green pointy leaved fern with sun shining from behind it" src="https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A modern bracken fern found in Queensland – the clear successor of the ferns found in the silcrete rocks.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fern-north-queensland-rainforest-australia-2400181713">AustralianCamera/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Volcanoes shaped plant communities</h2>
<p>Volcanic activity both destroys and modifies existing plant communities. It also provides new substrates for plants to colonise.</p>
<p>Several sites contained ferns – this may be because they are among the first living plants to colonise new volcanic terrains via their tiny wind-borne spores. For instance, <a href="https://doi.org/10.2307/2937282">it has been documented</a> that bracken ferns were pioneer plants of the barren cone of the <a href="https://theconversation.com/krakatoa-is-still-active-and-we-are-not-ready-for-the-tsunamis-another-eruption-would-generate-147250">famous Krakatoa volcano</a> after its eruption in 1883.</p>
<p>But the diversity of seeds and fruits at another site suggests that an existing forest was buried by volcanic activity. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A star shaped impression embedded in an orange-amber rock" src="https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This star-shaped fruit, seen in cross section here, is currently being studied and is likely to be a species new to science.</span>
<span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span>
</figcaption>
</figure>
<p>Researchers have suggested that the key factors responsible for the evolution of the Australian fauna and flora during the Cenozoic period (the last 66 million years) were predominantly climate and environmental change. It happened, in part, due to the movement of the Australian continental plate northwards.</p>
<p>But the broad-scale volcano activity that occurred in eastern Australia during the Cenozoic has rarely been invoked as a key driver of such changes. </p>
<p>So remarkably preserved, the silcrete plant fossils are now providing startling new insights into the history of some groups of Australian plants and the vegetation types in which they grew. </p>
<hr>
<p><em>The author would like to acknowledge co-author Raymond Carpenter from the University of Adelaide who contributed to this article.</em></p><img src="https://counter.theconversation.com/content/222512/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Rozefelds receives funding from the Herman Slade Foundation and Churchill Trust, Australia.</span></em></p>
Millions of years ago, widespread volcano eruptions in eastern Australia buried entire forests. Today, these time capsules reveal stunningly fossilised plants.
Andrew Rozefelds, Adjunct Assoc Professor Central Queensland University and Principal Curator Geosciences Queensland Museum, CQUniversity Australia
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/220193
2023-12-19T21:59:56Z
2023-12-19T21:59:56Z
Volcanic eruption lights up Iceland after weeks of earthquake warnings − a geologist explains what’s happening
<p>Lava erupted through a fissure in Iceland’s Reykjanes Peninsula on Dec. 18, 2023, shooting <a href="https://en.vedur.is/about-imo/news/a-seismic-swarm-started-north-of-grindavik-last-night">almost 100 feet (30 meters)</a> in the air in its early hours.</p>
<p>Icelanders had been anticipating an eruption in the area for weeks, ever since a <a href="https://en.vedur.is/about-imo/news/a-seismic-swarm-started-north-of-grindavik-last-night">swarm of thousands of small earthquakes</a> began on Oct. 23 northeast of the fishing town of Grindavík, signaling volcanic activity below. </p>
<p>In the days that followed those first rumblings, a series of small rifts opened under the town, breaking streets, rupturing utility lines and tilting houses. GPS stations detected the <a href="https://en.vedur.is/about-imo/news/earthquake-activity-in-fagradalsfjall-area">ground sinking and rising</a> over a large area.</p>
<p>Geologists from the <a href="https://en.vedur.is/about-imo/news/a-seismic-swarm-started-north-of-grindavik-last-night">Icelandic Met Office</a> interpreted the events as evidence that a basalt dike – pressurized magma that forces its way into a fracture – had intruded under Grindavík. The activity there had tapered off by early December, but 2.5 miles (4 kilometers) north of town, the ground under the <a href="https://www.verkis.com/projects/energy-production/geothermal-energy/nr/936">Svartsengi</a> geothermal power plant was moving.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566683/original/file-20231219-19-6waspp.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows the location of the fissure." src="https://images.theconversation.com/files/566683/original/file-20231219-19-6waspp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566683/original/file-20231219-19-6waspp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566683/original/file-20231219-19-6waspp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566683/original/file-20231219-19-6waspp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566683/original/file-20231219-19-6waspp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566683/original/file-20231219-19-6waspp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566683/original/file-20231219-19-6waspp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The location of the fissure where magma erupted starting Dec. 18, 2023, a few miles from the town of Grindavík and just east of Svartsengi power plant and ajacent Blue Lagoon thermal spa.</span>
<span class="attribution"><a class="source" href="https://en.vedur.is/about-imo/news/a-seismic-swarm-started-north-of-grindavik-last-night">Icelandic Met Office</a></span>
</figcaption>
</figure>
<p>The ground had dropped 10 inches (25 centimeters) as the basalt dike filled, but then it began to rise in a broad dome, indicating that magma was reinflating and repressurizing the magma chamber. The result was the nearby eruption on Dec. 18.</p>
<p>If the fissure continues to propagate to the south, or if a large volume of lava erupts, the evacuated town of Grindavík, with a population of around 3,500, may be in danger. The lava could also spill to the northwest toward the power plant, although the utility built rock walls to try to divert lava flows.</p>
<figure class="align-center ">
<img alt="An aerial photo shows the lights of Grindavík and glow of the eruption very nearby." src="https://images.theconversation.com/files/566707/original/file-20231219-25-zfbj7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566707/original/file-20231219-25-zfbj7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566707/original/file-20231219-25-zfbj7a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566707/original/file-20231219-25-zfbj7a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566707/original/file-20231219-25-zfbj7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566707/original/file-20231219-25-zfbj7a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566707/original/file-20231219-25-zfbj7a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The evacuated town of Grindavík and a nearby geothermal power plant are still at risk.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-evacuated-icelandic-town-of-grindavik-is-seen-as-smoke-news-photo/1860420658?adppopup=true">Viken Kantarci/AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>Iceland is known as “the land of fire and ice” for a reason. Its residents have learned over centuries to live with its overactive geology.</p>
<p>The reason for Iceland’s volcanism has two parts: One has to do with what geologists unimaginatively <a href="https://oceanexplorer.noaa.gov/facts/volcanic-hotspot.html">call a hot spot</a>, and the other involves giant tectonic plates that are pulling apart beneath the island. As <a href="https://scholar.google.com/citations?user=r8FqGBEAAAAJ&hl=en">a geologist</a>, I study both.</p>
<h2>Life on the edge of two tectonic plates</h2>
<p>When <a href="https://www.iris.edu/hq/inclass/animation/plate_tectonic_theorya_brief_history">plate tectonic theory</a> was emerging in the 1960s, geologists realized that many volcanoes are located in zones where tectonic plates meet. Tectonic plates are gigantic chunks of Earth’s rigid outer layer that carry both continents and oceans and are constantly in motion. They <a href="https://www.usgs.gov/media/images/tectonic-plates-earth">cover the planet</a> like large pieces of a spherical jigsaw puzzle.</p>
<p>Many of these volcanoes are in subduction zones, like the Pacific’s <a href="https://education.nationalgeographic.org/resource/plate-tectonics-ring-fire/">Ring of Fire</a>, where thinner oceanic plates slowly sink into <a href="https://education.nationalgeographic.org/resource/mantle/">Earth’s mantle</a>. These are the postcard stratovolcanoes like Mount Fuji, in Japan, or Mount Rainier, outside of Seattle. Because of their high gas content, they tend to erupt catastrophically, shooting ash high into the atmosphere with the energy of nuclear bombs, as <a href="https://www.usgs.gov/volcanoes/mount-st.-helens/science/1980-cataclysmic-eruption">Mount St. Helens did in 1980</a>.</p>
<p>A second, typically quieter kind of volcano forms <a href="https://oceanexplorer.noaa.gov/facts/mid-ocean-ridge.html">where plates pull apart</a>.</p>
<p>The volcanic activity near Grindavík is directly related to this kind of plate tectonic motion. The mid-Atlantic ridge between the Eurasian and North American plates cuts right through that part of the island.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559688/original/file-20231115-22-mdyae8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows where the earthquakes are taking place in a southwest peninsula and where the tectonic plates meet." src="https://images.theconversation.com/files/559688/original/file-20231115-22-mdyae8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559688/original/file-20231115-22-mdyae8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=780&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559688/original/file-20231115-22-mdyae8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=780&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559688/original/file-20231115-22-mdyae8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=780&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559688/original/file-20231115-22-mdyae8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=980&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559688/original/file-20231115-22-mdyae8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=980&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559688/original/file-20231115-22-mdyae8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=980&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Iceland sits atop the meeting of two tectonic plates, the North American to the west and Eurasian to the east, indicated by the red line crossing the island. The maps show the earthquake swarms on Nov. 12-14, 2023.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/an-infographic-titled-iceland-prepares-for-volcanic-news-photo/1782148842?adppopup=true">Yasin Demirci/Anadolu via Getty Images</a></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559732/original/file-20231115-27-7uf0ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows details of midocean ridges looking like seams on a baseball as they wind through the major oceans." src="https://images.theconversation.com/files/559732/original/file-20231115-27-7uf0ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559732/original/file-20231115-27-7uf0ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=330&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559732/original/file-20231115-27-7uf0ky.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=330&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559732/original/file-20231115-27-7uf0ky.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=330&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559732/original/file-20231115-27-7uf0ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=415&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559732/original/file-20231115-27-7uf0ky.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=415&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559732/original/file-20231115-27-7uf0ky.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=415&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In the 1950s, cartographer Marie Tharp used echo soundings gathered by ships to develop the first map showing the ocean floor in detail. It clearly revealed the mid-ocean ridges. This hand-painted version of her map includes annotations showing hot spot tracks related to movement of the plates.</span>
<span class="attribution"><a class="source" href="https://www.loc.gov/">Heinrich C. Berann via Library of Congress; annotations by Jaime Toro</a></span>
</figcaption>
</figure>
<p>In fact, at <a href="https://guidetoiceland.is/connect-with-locals/jorunnsg/ingvellir-national-park">Thingvellir National Park</a> you can literally walk between the two tectonic plates. You can see the topographic scars of the rift in the long, linear valleys that extend to the northeast from Grindavík. They align with the swarms of earthquakes, the <a href="https://en.vedur.is/about-imo/news/bigimg/4511?ListID=0">ground deformation</a>, and the fissure eruption of 2023.</p>
<p>Where plates pull away from each other, the underlying mantle rises toward the surface to fill the gap, carrying its heat with it and moving into an area of lower pressure. Those <a href="https://www.e-education.psu.edu/rocco/node/1988">two processes</a> cause melting at depth and volcanic activity at the surface.</p>
<p>This is the <a href="https://en.wikipedia.org/wiki/Sheeted_dyke_complex">same process that creates new oceanic crust</a> underwater at mid-ocean ridges. After the magma solidifies as basalt rock, it will look like vertical walls intruded into the surrounding area.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566733/original/file-20231219-19-4i4dgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The uplift is in a large area that includes a nearby power plant and the Blue Lagoon thermal spa." src="https://images.theconversation.com/files/566733/original/file-20231219-19-4i4dgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566733/original/file-20231219-19-4i4dgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=552&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566733/original/file-20231219-19-4i4dgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=552&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566733/original/file-20231219-19-4i4dgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=552&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566733/original/file-20231219-19-4i4dgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=694&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566733/original/file-20231219-19-4i4dgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=694&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566733/original/file-20231219-19-4i4dgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=694&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A map shows the uplift of the ground (bright red) north of Grindavík prior to the Dec. 18, 2023, eruption, as well as the extent of the new lava flow (black).</span>
<span class="attribution"><a class="source" href="https://en.vedur.is/">Icelandic Met Office</a></span>
</figcaption>
</figure>
<h2>Sitting on a hot spot</h2>
<p>In Iceland, the large volcanoes in the interior also <a href="https://doi.org/10.1016/j.epsl.2013.02.022">appear to be over a mantle plume</a>, <a href="https://theconversation.com/where-mauna-loas-lava-is-coming-from-and-why-hawaiis-volcanoes-are-different-from-most-195633">similar to Hawaii</a>.</p>
<p>This kind of volcano typically erupts basalt lava, which melts at very high temperature and tends to flow easily. Eruptions are generally not explosive because the runny lava allows gases to escape. </p>
<p>Exactly what causes hot material to rise at hot spots is still debated, but the most commonly accepted idea is that they are caused by plumes of super-heated rock that originate at the transition <a href="https://doi.org/10.1126/science.349.6252.1032">between Earth’s metallic core and rocky mantle</a>. Hot spots are a mechanism for the Earth to give off some of its <a href="https://www.sciencealert.com/earth-s-insides-are-cooling-faster-than-we-thought-and-it-will-mess-things-up">internal heat</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Hl1gfV-TdU0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How hot spots develop. Video by Volcano Museum.</span></figcaption>
</figure>
<p>Typically, fissure eruptions are not explosive. However, when lava that is 1,800 degrees Fahrenheit (about 1,000 degrees Celsius) hits water, the flash to steam can cause explosions that can scatter ash over a larger area. </p>
<h2>A silver lining of Iceland’s volcanoes</h2>
<p>Living in an active volcanic area has some advantages, particularly for energy.</p>
<p>Iceland derives 30% of its electricity from geothermal sources that use underground heat to drive turbines and produce power. It’s almost like a controlled version of a lava flow hitting the sea, and it helps make Iceland <a href="https://www.volts.wtf/p/whats-the-deal-with-iceland#details">one of the cleanest economies on earth</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559465/original/file-20231114-21-f3fk7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People sit in an eggshell-blue lake surrounded by black lava rocks. Steam rises in the background." src="https://images.theconversation.com/files/559465/original/file-20231114-21-f3fk7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559465/original/file-20231114-21-f3fk7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=758&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559465/original/file-20231114-21-f3fk7c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=758&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559465/original/file-20231114-21-f3fk7c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=758&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559465/original/file-20231114-21-f3fk7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=953&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559465/original/file-20231114-21-f3fk7c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=953&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559465/original/file-20231114-21-f3fk7c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=953&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Iceland has a lot of natural hot springs, but its Blue Lagoon has an unusual origin linked to geothermal energy.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/people-swimming-on-hot-spring-near-mountain-during-daytime-jTeQavJjBDs">Photo by Jeff Sheldon on Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.verkis.com/projects/energy-production/geothermal-energy/nr/936">Svartsengi</a> hydrothermal plant uses the underground heat from the same magma chamber that is now erupting to provide hot water for several thousand homes, plus 75 megawatts of electricity.</p>
<p>That power plant is also part of the reason the <a href="https://www.bluelagoon.com/">Blue Lagoon</a> is so popular. When the power plant was built in 1976, the plan was to discharge its still hot wastewater into an adjacent low area, expecting that it would seep into the ground. However, the geothermal water was loaded with dissolved silica, which became solid minerals when the water cooled, creating an impermeable layer. A small lake began to form.</p>
<p>Because of its high silica content, the water in this lake is a spectacular blue color that inspired the creation of the geothermal spa. The Blue Lagoon is one of the top tourist attractions in the country.</p>
<p>Now the Blue Lagoon is at risk: Sometimes the volcano gives, sometimes it takes away.</p>
<p><em><a href="https://theconversation.com/pourquoi-leruption-volcanique-en-islande-na-rien-dune-surprise-les-explications-dun-geologue-220292">Lire en français</a></em></p>
<p><em>This is an updated version of an <a href="https://theconversation.com/volcanic-iceland-is-rumbling-again-as-magma-rises-a-geologist-explains-eruptions-in-the-land-of-fire-and-ice-217671">article published Nov. 15, 2023</a>.</em></p><img src="https://counter.theconversation.com/content/220193/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaime Toro works for West Virginia University. In the past, he has received funding from NSF, USGS and DOE.
</span></em></p>
Iceland is known as ‘the land of fire and ice’ for a reason.
Jaime Toro, Professor of Geology, West Virginia University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/214309
2023-10-02T15:01:31Z
2023-10-02T15:01:31Z
Glaciers can give us clues about when a volcano might erupt
<figure><img src="https://images.theconversation.com/files/550281/original/file-20230926-23-2qa2o3.jpg?ixlib=rb-1.1.0&rect=0%2C588%2C4000%2C2396&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/skier-snowy-volcano-niseko-hokkaido-japan-2139353883">Mayumi.K.Photography/Shutterstock</a></span></figcaption></figure><p>Globally, there is about one volcano erupting <a href="https://volcanoes.usgs.gov/vsc/file_mngr/file-153/FAQs.pdf">each week</a>. Volcanic unrest kills an average of <a href="https://doi.org/10.1186/s13617-017-0067-4">500 people every year</a> and costs the global economy roughly US$7 billion (£5.7 billion). With <a href="https://www.sciencedirect.com/science/article/abs/pii/S1464286702000025#:%7E:text=Using%20recently%20compiled%20databases%20of,during%20the%20last%2010%2C000%20years.">one in 20 people</a> living somewhere at risk of volcanic activity, every effort that can be made to improve the monitoring of volcanoes is important. </p>
<p>This is especially true for volcanoes covered by glaciers – <a href="https://doi.org/10.1016/j.gloplacha.2020.103356">roughly 18%</a> of all volcanoes on Earth. When these erupt, the consequences can be among the deadliest of all natural disasters. </p>
<p>The Nevado del Ruiz volcano in Colombia killed nearly 25,000 people in 1985 when its eruption caused the near-instantaneous melting of overlying glacier ice and snow, forming a deadly mix of water and eruptive material (mostly ash and gas) that hurtled down a populated valley at incredible speed. Glaciers on volcanoes are not only dangerous, they make monitoring volcanoes from the ground and from above using satellites particularly tricky.</p>
<figure class="align-center ">
<img alt="A mountainous scene with a large smoking crater covered in snow." src="https://images.theconversation.com/files/550278/original/file-20230926-29-z15x8u.png?ixlib=rb-1.1.0&rect=0%2C0%2C799%2C501&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550278/original/file-20230926-29-z15x8u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=377&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550278/original/file-20230926-29-z15x8u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=377&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550278/original/file-20230926-29-z15x8u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=377&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550278/original/file-20230926-29-z15x8u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550278/original/file-20230926-29-z15x8u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550278/original/file-20230926-29-z15x8u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The crater of Nevado del Ruiz in 2023.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Nevado_del_Ruiz#/media/File:Volcan_Nevado_del_Ruiz-2023.png">Portal Servicio Geológico Colombiano</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Fortunately, in <a href="https://doi.org/10.1130/G51411.1">a new study</a>, we found that these glaciers can offer clues about what’s happening to the volcano below. This could help improve the monitoring of volcanoes that might erupt in the future.</p>
<h2>Hotting up</h2>
<p>Research has tentatively revealed that volcano temperatures change over time and <a href="https://www.nature.com/articles/s41561-021-00705-4">increase towards an eruption</a>. In some cases, these changes can be recorded over several years before visible unrest begins. It’s possible to monitor this via satellite, but the signal can be masked by clouds or disrupted by the ice or snow sitting on top of a volcano.</p>
<figure class="align-center ">
<img alt="A volcano spewing ash, seen from a distant grassland." src="https://images.theconversation.com/files/550283/original/file-20230926-25-rlduxr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550283/original/file-20230926-25-rlduxr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550283/original/file-20230926-25-rlduxr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550283/original/file-20230926-25-rlduxr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550283/original/file-20230926-25-rlduxr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550283/original/file-20230926-25-rlduxr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550283/original/file-20230926-25-rlduxr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Vaporised snow and ash combine during eruptions of ice-clad volcanoes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/karimskiy-volcano-volcanic-eruption-kamchatka-ash-468722087">LukaKikina/Shutterstock</a></span>
</figcaption>
</figure>
<p>Although thought to move very slowly, glaciers are quite dynamic. These rivers of ice flow faster or slower depending on what’s happening in their environment. This may come as no surprise – most glaciers around the world are now shrinking due to rising global temperatures, and many will soon disappear.</p>
<p>But glaciers are sensitive to other changes too. For example, if a volcano’s temperature increases over time, the glacier sitting on it will melt faster and shrink to higher elevations. We thought this shrinking might indicate that something is brewing in the volcano below, so we analysed the elevation of 600 glaciers that either sat on or near (between 1km and 15km) 37 ice-clad volcanoes in South America using computer models. </p>
<figure class="align-center ">
<img alt="A volcano with an ice-covered summit seen from a distance." src="https://images.theconversation.com/files/550277/original/file-20230926-15-6d5e4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550277/original/file-20230926-15-6d5e4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550277/original/file-20230926-15-6d5e4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550277/original/file-20230926-15-6d5e4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550277/original/file-20230926-15-6d5e4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550277/original/file-20230926-15-6d5e4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550277/original/file-20230926-15-6d5e4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ice-clad Cotopaxi volcano in the Andes mountains, Ecuador.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cotopaxi-volcano-appears-clouds-light-snow-484202014">Ecuadorpostales/Shutterstock</a></span>
</figcaption>
</figure>
<p>Normally, elevation does not vary much from glacier to glacier within the same climate region. But our results showed that, in some cases, glacier elevation progressively decreases with distance from a volcano. In other words, glaciers further from a volcano tended to reach further down the mountain valley that hosted them.</p>
<p>The drop in glacier elevation moving away from a volcano can be as much as 600 metres. This is bigger than what we would expect to see with natural variation alone, especially for the relatively small glaciers we investigated. </p>
<h2>A sign from below</h2>
<p>Glaciers sitting on volcanoes are typically confined to higher elevations (230 metres higher, on average) compared with those nearby. Most importantly, our study showed that this difference is linked to measured volcanic temperatures: volcanoes with higher measured temperatures hosted glaciers at particularly high elevations.</p>
<p>This is really exciting because it paves the way for using glaciers to improve volcano monitoring. If the elevation of a glacier on top of a volcano changes over a short period (five to ten years, say), and the speed of this change cannot be attributed to climate change, it might signal a forthcoming period of volcanic unrest.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/bylTVZFQOsE?wmode=transparent&start=1" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Glaciers sitting on volcanoes act as icy thermometers in volcano monitoring. This insight could help create early-warning systems capable of reducing the deadliness of erupting ice-clad volcanoes.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 20,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/214309/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matteo Spagnolo receives funding from NERC and the Leverhulme Trust. </span></em></p><p class="fine-print"><em><span>Brice Rea receives funding from NERC. </span></em></p><p class="fine-print"><em><span>Iestyn Barr receives funding from the Leverhulme Trust and NERC </span></em></p>
Like icy thermometers, glaciers overlying volcanoes shift according to temperature changes below.
Matteo Spagnolo, Professor of Geography and the Environment, School of Geosciences, University of Aberdeen
Brice Rea, Professor of Geography, University of Aberdeen
Iestyn Barr, Reader in Physical Geography, Manchester Metropolitan University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/206977
2023-07-13T12:38:33Z
2023-07-13T12:38:33Z
Living near the fire – 500 million people worldwide have active volcanoes as neighbors
<figure><img src="https://images.theconversation.com/files/536136/original/file-20230706-25-u2xrop.jpg?ixlib=rb-1.1.0&rect=11%2C0%2C3778%2C2506&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Indonesia's Mount Merapi spews lava during an eruption on May 23, 2023. Over 250,000 people live nearby.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/indonesias-mount-merapi-one-of-the-worlds-most-active-news-photo/1257370107">DEVI RAHMAN/AFP via Getty Image</a></span></figcaption></figure><p>The thought of living near an active volcano probably sounds like an unimaginable risk to you – and rightly so. An active volcano is never safe and can turn a <a href="https://www.usgs.gov/volcanoes/mount-st.-helens/1980-cataclysmic-eruption">forested hillside into a lifeless wasteland in a matter of seconds</a>. From <a href="https://www.usgs.gov/programs/VHP/pyroclastic-flows-move-fast-and-destroy-everything-their-path">molten avalanches of rock</a> to <a href="https://volcanoes.usgs.gov/volcanic_ash/mount_st_helens_health.html">razor-sharp lung-shredding ash</a>, volcanoes threaten people’s lives and property. </p>
<p>Yet <a href="https://www.preventionweb.net/news/newsletter-xviii-jrc-study-assesses-global-human-population-living-proximity-active-volcanoes">500 million people</a> worldwide live and work under the shadow of active volcanoes. As a geologist who’s studied many volcanoes over the years, I’ve come to realize it’s naïve to ask, “Why don’t these people just move to less risky places?”</p>
<p>Their motivations range widely. For some, strong cultural beliefs and traditions keep them in place. For others, volcanoes offer significant economic opportunity. For the most vulnerable, poverty traps them in dangerous locations. </p>
<p>Whatever the reason, many people’s lives and welfare are so intimately linked with a volcano, moving elsewhere is unthinkable. </p>
<h2>Centers of identity</h2>
<p>Numerous cultures and Indigenous peoples <a href="https://www.usgs.gov/observatories/hvo/news/volcano-watch-strong-ties-between-volcanoes-and-religion">revere volcanoes</a> as places of worship, ritual and tradition that are celebrated for their power over fertility, life and sustenance. </p>
<p><a href="https://www.nationalgeographic.com/travel/article/climbing-mount-fuji">For a number of religious traditions</a>, <a href="https://www.worldhistory.org/Mount_Fuji/">Mount Fuji</a> in Japan is a place where ancestral spirits congregate. It has been a <a href="https://www.taylorfrancis.com/chapters/edit/10.4324/9781315676272-23/mount-fuji-history-spiritual-realm-means-preservation-toshihiko-ono-tetsuro-hongo-kiyotatsu-yamamoto-naoya-furuta">symbolic and sacred site of pilgrimage for centuries</a>. Every summer, <a href="https://www.statista.com/statistics/729744/mount-fuji-mountaineer-number-japan/">thousands of people ascend</a> through the clouds to reach the summit. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/536370/original/file-20230707-15-6jry4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A group of people gather at a precipice, throwing flower petals and a chicken into the void." src="https://images.theconversation.com/files/536370/original/file-20230707-15-6jry4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536370/original/file-20230707-15-6jry4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536370/original/file-20230707-15-6jry4i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536370/original/file-20230707-15-6jry4i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536370/original/file-20230707-15-6jry4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536370/original/file-20230707-15-6jry4i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536370/original/file-20230707-15-6jry4i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A worshipper throws a chicken into the crater of Mount Bromo as an offering to the gods during the Yadnya Kasada festival in Probolinggo, East Java, Indonesia.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/IndonesiaHinduFestival/6206d79160dc4253a1829025987fb9b2">AP Photo/Trisnadi</a></span>
</figcaption>
</figure>
<p>For the Tenggerese people on Java, <a href="https://volcano.si.edu/volcano.cfm?vn=263310">Mount Bromo</a> is a deeply sacred site – the abode of gods. Every year they hike up the volcano carrying agricultural products and livestock to be sacrificed during the <a href="https://www.nytimes.com/2021/11/08/travel/yadnya-kasada-volcano-ritual.html">Yadnya Kasada festival</a>. Pilgrims gather at the rim to express gratitude and seek blessings with prayer, chanting and sacred offerings. </p>
<p>In Ecuador, the Quechua people follow a <a href="https://www.encyclopedia.com/literature-and-arts/language-linguistics-and-literary-terms/language-and-linguistics/quechua">religion that combines pre-Columbian and Catholic elements</a>. Local people see the <a href="https://volcano.si.edu/volcano.cfm?vn=352080">Tungurahua volcano</a> as a <a href="https://www.sapiens.org/culture/tungurahua/">familiar but unpredictable matriarch</a> who can offer support and guidance. </p>
<h2>Economic opportunity</h2>
<p>The land surrounding volcanoes often offers significant economic opportunity.</p>
<p>Volcanic soils are <a href="https://doi.org/10.1016/B978-0-12-385938-9.00072-9">among the most fertile in the world</a>. They contain essential minerals and nutrients such as iron, magnesium, calcium, potassium, phosphorus and trace elements that are <a href="https://thedailyfarming.com/farming/what-crops-grow-best-in-volcanic-soil/">essential for plant growth</a>. They also have high organic matter content, good pH balance, high porosity and strong water retention, making them <a href="https://doi.org/10.1016/B978-0-12-385938-9.00072-9">ideal for agriculture</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/536130/original/file-20230706-22749-l28s65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A mature woman leans against a stone wall with banana trees in the background." src="https://images.theconversation.com/files/536130/original/file-20230706-22749-l28s65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536130/original/file-20230706-22749-l28s65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536130/original/file-20230706-22749-l28s65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536130/original/file-20230706-22749-l28s65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536130/original/file-20230706-22749-l28s65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536130/original/file-20230706-22749-l28s65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536130/original/file-20230706-22749-l28s65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The owner of a small banana farm watches as ash comes from the Cumbre Vieja volcano in the Canary island of La Palma, Spain, on Oct. 6, 2021.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/isabel-marãa-who-owns-a-small-piece-of-land-where-she-news-photo/1235764706">Marcos Moreno/Anadolu Agency via Getty Images</a></span>
</figcaption>
</figure>
<p>In addition, volcanic terrains often create unique microclimates that are ideal for growing high-value crops such as <a href="https://www.wineenthusiast.com/basics/advanced-studies/volcanic-soils-wine-science/">grapes</a>, coffee and <a href="https://www.echocommunity.org/en/resources/f3e66825-d4ff-4038-85c1-11cf3b468224">bananas</a>.</p>
<p>Striking landscapes, unique geological features and the thrill of proximity <a href="https://www.usgs.gov/observatories/hvo/news/volcano-watch-mount-fuji-workshop-focused-how-manage-tourism-active">draw tourists to active volcanoes worldwide</a>. Visitors to sites like the <a href="https://earth.google.com/web/search/Bromo,+Area+Gunung+Bromo,+Podokoyo,+Pasuruan+Regency,+East+Java,+Indonesia/@-7.94249345,112.9530122,2156.2657602a,5671.73576521d,35y,0h,45t,0r/data=CrcBGowBEoUBCiUweDJkZDYzN2FhYWI3OTRhNDE6MHhhZGE0MGQzNmVjZDJhNWRkGdnB0godxR_AIRjs4Sb-PFxAKkpCcm9tbywgQXJlYSBHdW51bmcgQnJvbW8sIFBvZG9rb3lvLCBQYXN1cnVhbiBSZWdlbmN5LCBFYXN0IEphdmEsIEluZG9uZXNpYRgCIAEiJgokCagitvMQb0RAEahkXx0MZURAGUO61niw4SxAISXcEg68uSxAKAI">Bromo Tengger Semeru National Park</a> on Java, <a href="https://www.usgs.gov/volcanoes/kilauea">Mount Kilauea in Hawaii</a> and
<a href="https://whc.unesco.org/en/list/1427/">Mount Etna</a> on the island of Sicily can <a href="https://www.nationalgeographic.com/travel/article/is-volcano-tourism-safe">boost local economies</a> and significantly enhance the livelihoods of residents. </p>
<p>Volcanic landscapes can also offer <a href="https://www.nature.com/articles/s41598-018-33206-3">rich mineral resources</a> such as gold, silver, amethyst and more. For example, the rich volcanic landscape around El Misti in southern Peru is valued for its <a href="https://www.mining-technology.com/projects/cerro-verde-copper-molybdenum-mine/">industrially mined copper and other metals</a>. </p>
<p>On Java, in Indonesia, <a href="https://volcano.si.edu/volcano.cfm?vn=263350">miners still excavate</a> bright yellow <a href="https://www.bbc.com/future/article/20190109-sulphur-mining-at-kawah-ijen-volcano-in-indonesia">sulfur deposits from the active Kawah Ijen</a> volcano crater floor using simple hand tools. They then <a href="https://www.youtube.com/watch?v=E0WT1HtB-Sc">carry the heavy blocks up the volcano’s steep walls to its rim</a>.</p>
<p>Such extraction can stimulate economic growth and create jobs, <a href="https://www.reuters.com/world/americas/peru-declares-state-emergency-restore-copper-production-cuajone-mine-2022-04-20/">but often the wealth is exported</a> and lost to local communities that struggle financially.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/536118/original/file-20230706-25-rkjej2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of an old woman's hand holding a cluster of tomatoes covered in ash." src="https://images.theconversation.com/files/536118/original/file-20230706-25-rkjej2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536118/original/file-20230706-25-rkjej2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536118/original/file-20230706-25-rkjej2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536118/original/file-20230706-25-rkjej2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536118/original/file-20230706-25-rkjej2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536118/original/file-20230706-25-rkjej2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536118/original/file-20230706-25-rkjej2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A farmer shows her tomatoes after a 2023 Mount Merapi eruption at Tlogolele village, Indonesia.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/farmer-shows-tomatoes-in-her-fields-after-mount-merapi-news-photo/1248214796">Bram Selo/Xinhua via Getty Images</a></span>
</figcaption>
</figure>
<h2>Low-cost land</h2>
<p>Not everyone who lives next to a volcano does so by choice. Poverty can push and trap people there.</p>
<p>At <a href="https://volcano.si.edu/volcano.cfm?vn=263250">Mount Merapi in Indonesia</a> and <a href="https://volcano.si.edu/volcano.cfm?vn=273030">Mount Mayon in the Philippines</a>, two of the world’s most active volcanoes, subsistence farmers live and work on the steep slopes. Because they live closest to the eruption sites, these communities are particularly vulnerable, making rapid evacuation unlikely.</p>
<p>In 2010, <a href="https://web.archive.org/web/20101202120048/http://www.thejakartapost.com/news/2010/11/18/death-toll-fromindonesia039s-volcano-climbs-275.html">250 people were killed by searing gas clouds</a> during an eruption of Mount Merapi. Despite the tragedy, many people who did survive stayed put because leaving their crops behind would mean financial ruin. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534905/original/file-20230629-27-ra1933.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scientific mapping of the area around El Misti -- detailing areas most at risk for various types of volcanic destruction." src="https://images.theconversation.com/files/534905/original/file-20230629-27-ra1933.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534905/original/file-20230629-27-ra1933.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=793&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534905/original/file-20230629-27-ra1933.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=793&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534905/original/file-20230629-27-ra1933.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=793&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534905/original/file-20230629-27-ra1933.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=997&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534905/original/file-20230629-27-ra1933.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=997&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534905/original/file-20230629-27-ra1933.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=997&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A hazard zone map for El Misti in Peru shows probable paths of destruction.</span>
<span class="attribution"><a class="source" href="https://volcano.si.edu/volcano.cfm?vn=354010">Smithsonian Institution Global Volcanism Program, Courtesy of Cobeñasa and others</a></span>
</figcaption>
</figure>
<p>As scientists get better at <a href="https://www.usgs.gov/programs/VHP">predicting eruptions and likely paths of destruction</a>, sometimes the danger of volcanoes can be mitigated with good communication and solid <a href="https://www.cdc.gov/disasters/volcanoes/before.html">evacuation plans</a>. Even so, life beside a volcano is a complex interplay of risk and reward – and one many cannot avoid.</p><img src="https://counter.theconversation.com/content/206977/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Kitchen does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
For some people, it’s a choice based on cultural beliefs or economic opportunities provided by the volcano. Other times it’s less a choice than the only option.
David Kitchen, Associate Professor of Geology, University of Richmond
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/207031
2023-07-05T20:05:49Z
2023-07-05T20:05:49Z
Volcano eruptions are notoriously hard to forecast. A new method using lasers could be the key
<figure><img src="https://images.theconversation.com/files/534721/original/file-20230629-28-952crh.jpg?ixlib=rb-1.1.0&rect=105%2C169%2C4298%2C2738&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/etna-eruption-sicily-lava-nature-1560571136">Shutterstock</a></span></figcaption></figure><p>When you hear news reports about volcanoes spewing lava and ash, you may worry about the people nearby. In fact, almost one in ten people around the world <a href="https://www.cambridge.org/core/books/global-volcanic-hazards-and-risk/global-volcanic-hazard-and-risk/E0B20AB275CDB097BF802665DD6DA9A6">live within 100 kilometres of an active volcano</a>. For those living close to volcanoes, farming on their fertile soils, or visiting their spectacular landscapes, it is crucial to understand the drivers of eruption. </p>
<p>Why is the volcano erupting? How will the eruption evolve? When will it finish?</p>
<p>Our <a href="http://www.science.org/doi/10.1126/sciadv.adg4813">new research</a> published today in Science Advances applies laser technology to read into the chemical composition of erupted magma over time. </p>
<p>Because the chemistry of magmas affects their fluidity, explosivity and hazard potential, our work could help future monitoring and forecasting of the evolution of volcanic eruptions. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-cant-we-predict-when-a-volcano-will-erupt-53898">Why can't we predict when a volcano will erupt?</a>
</strong>
</em>
</p>
<hr>
<h2>Untangling the chemistry of erupted melt</h2>
<p>Magma – molten rock – is composed of liquid (known as “melt”), gas and crystals that grow as the temperature of the magma drops during its journey up to Earth’s surface.</p>
<p>When the magma erupts to become a lava flow, it will release the gas (which contains water vapour, carbon dioxide, sulphur dioxide and other compounds) and cool down into a volcanic rock. This rock contains crystals cooled slowly inside the volcano, embedded in a finer rock matrix cooled rapidly at the surface.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/534728/original/file-20230629-27-cuhqv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black background with colourful crystals in it" src="https://images.theconversation.com/files/534728/original/file-20230629-27-cuhqv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/534728/original/file-20230629-27-cuhqv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=962&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534728/original/file-20230629-27-cuhqv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=962&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534728/original/file-20230629-27-cuhqv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=962&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534728/original/file-20230629-27-cuhqv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1209&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534728/original/file-20230629-27-cuhqv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1209&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534728/original/file-20230629-27-cuhqv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1209&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microscope view of lava erupted on October 24 2021 at La Palma, with large colourful crystals in a fine-grained black rock matrix which we analyse via laser. The image is in cross-polarised transmitted light (5mm scale bar).</span>
<span class="attribution"><span class="source">A. MacDonald</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>As a result, volcanic rocks can <a href="https://theconversation.com/there-she-blows-the-internal-magma-filter-that-prompts-ocean-island-volcanoes-to-erupt-167358">look a bit like “rocky road” chocolate</a>. The <a href="https://theconversation.com/volcano-crystals-could-make-it-easier-to-predict-eruptions-90558">crystals</a> formed in the guts of the volcano are excellent archives of the run-up to eruption. However, the crystals can get in the way when we want to focus on the melt that carries them to the surface, and how the melt properties vary throughout the eruption. </p>
<p>To isolate the melt signal, we used an ultraviolet laser, similar to the ones used for eye surgery, to blast the rock matrix between larger crystals.</p>
<p>We then analysed the laser-generated particles by <a href="https://www.britannica.com/science/mass-spectrometry">mass spectrometry</a> to determine the chemical composition of the volcanic matrix. The method allows for a rapid chemical analysis.</p>
<p>This provides a faster and more detailed measure of melt chemistry and its evolution over time, compared to traditional analysis of the entire rock, or to painstaking separation of matrix and crystal fragments from crushed rock samples. Even if we call the crystals “large”, they are often as small as a grain of salt (or up to a chickpea in size if you are lucky!) and difficult to remove. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-pulse-of-a-volcano-can-be-used-to-help-predict-its-next-eruption-117005">The 'pulse' of a volcano can be used to help predict its next eruption</a>
</strong>
</em>
</p>
<hr>
<h2>A destructive disaster in the Canary Islands</h2>
<p>Our study focused on the <a href="https://en.wikipedia.org/wiki/2021_Cumbre_Vieja_volcanic_eruption">2021 eruption at La Palma</a>, the most destructive volcanic eruption on historical record in the Canary Islands.</p>
<p>From September to December 2021, a total of 160 million cubic metres of lava covered more than 12 square kilometres of land. It destroyed more than 1,600 homes, forced the evacuation of more than 7,000 people and generated losses of more than <a href="https://ec.europa.eu/regional_policy/en/newsroom/news/2022/03/22-03-2022-eu-solidarity-eur5-4-million-of-advance-payments-to-spain-following-the-volcanic-eruption-in-la-palma">€860 million</a> (AU$1.4 billion). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534724/original/file-20230629-21-uph29m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial photo of houses with a river of lava flowing in between" src="https://images.theconversation.com/files/534724/original/file-20230629-21-uph29m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534724/original/file-20230629-21-uph29m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534724/original/file-20230629-21-uph29m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534724/original/file-20230629-21-uph29m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534724/original/file-20230629-21-uph29m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534724/original/file-20230629-21-uph29m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534724/original/file-20230629-21-uph29m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Drone image of a lava flow from the 2021 La Palma eruption (December 4 2021, houses for scale).</span>
<span class="attribution"><span class="source">Instituto Geologico y Minero de Espana</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We analysed lava samples collected systematically by our collaborators in Spain throughout the three months of eruption. These are precious samples as we know their exact eruption day, and many of the sampling sites are now covered by later lavas from the eruption. </p>
<p>Using the laser-powered method, we could see variations in lava chemistry linked to changes in earthquakes and sulphur dioxide emissions, as well as eruption style and the resulting hazards. This included a change from thick lavas that acted as a bulldozer at the start of the eruption, to runny lavas that created rapid <a href="https://twitter.com/i_ameztoy/status/1665062180713103362?s=20">lava rivers</a> and lava tunnels later in the eruption.</p>
<p>We also found a key change in lava chemistry about two weeks before the eruption ended, which suggests cooling of the magma due to a dropping magma supply.</p>
<p>Similar changes could be monitored as a signal of eruption wind-down in future eruptions around the world. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534729/original/file-20230629-23-v10rmi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/534729/original/file-20230629-23-v10rmi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534729/original/file-20230629-23-v10rmi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534729/original/file-20230629-23-v10rmi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534729/original/file-20230629-23-v10rmi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534729/original/file-20230629-23-v10rmi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534729/original/file-20230629-23-v10rmi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534729/original/file-20230629-23-v10rmi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Early lavas from the 2021 La Palma eruption were voluminous and blocky, acting as a hot ‘bulldozer’ (September 22 2021, traffic sign for scale).</span>
<span class="attribution"><span class="source">JJ Coello Bravo</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Forecasting volcanic activity</h2>
<p>We cannot prevent volcanoes from erupting, and we cannot yet travel inside them <a href="https://en.wikipedia.org/wiki/Journey_to_the_Center_of_the_Earth">like French sci-fi author Jules Verne once envisioned</a>. But <a href="https://www.usgs.gov/programs/VHP/comprehensive-monitoring-provides-timely-warnings-volcano-reawakening">volcano monitoring</a> has improved enormously in the last few decades to allow us to indirectly ‘peek into’ volcanoes and better forecast their activity.</p>
<p>Our work aims to provide a laboratory tool for testing volcanic samples collected during future eruptions. The goal is to read into the evolution of eruptions, to understand why they start and when they will end. </p>
<p>With <a href="https://volcano.si.edu/">about 50 volcanoes erupting</a> at any given time around the world, you will soon see another volcano erupting in the news. This time, you can consider the importance of volcano science to improve our understanding of how volcanoes work and what drives them to erupt, to protect the people around them. </p>
<hr>
<p><em>Correction: an earlier version of this article stated the 2021 La Palma eruption released 160 cubic metres of lava. The correct figure is 160 million cubic metres.</em></p><img src="https://counter.theconversation.com/content/207031/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Teresa Ubide works for The University of Queensland. She receives funding from the Australian Research Council, AuScope-NCRIS, and The University of Queensland. </span></em></p><p class="fine-print"><em><span>Alice MacDonald is a PhD Student at The University of Queensland and receives a RTP PhD Stipend from UQ. </span></em></p><p class="fine-print"><em><span><a href="mailto:jack.mulder@adelaide.edu.au">jack.mulder@adelaide.edu.au</a> receives funding from the Australian Research Council, AuScope-NCRIS, The University of Adelaide. </span></em></p>
One in ten people around the world live near an active volcano. Understanding the drivers of eruptions is crucial.
Teresa Ubide, Associate Professor - Igneous Petrology/Volcanology, The University of Queensland
Alice MacDonald, PhD Student, The University of Queensland
Jack Mulder, Lecturer, University of Adelaide
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/204905
2023-05-08T20:11:01Z
2023-05-08T20:11:01Z
Supercomputers have revealed the giant ‘pillars of heat’ funnelling diamonds upwards from deep within Earth
<figure><img src="https://images.theconversation.com/files/524817/original/file-20230508-27-u0wox4.jpg?ixlib=rb-1.1.0&rect=32%2C24%2C5359%2C3564&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Most diamonds are formed deep inside Earth and brought close to the surface in small yet powerful volcanic eruptions of a kind of rock called “kimberlite”. </p>
<p>Our <a href="https://www.nature.com/articles/s41561-023-01181-8">supercomputer modelling</a>, published in Nature Geoscience, shows these eruptions are fuelled by giant “pillars of heat” rooted 2,900 kilometres below ground, just above our planet’s core.</p>
<p>Understanding Earth’s internal history can be used to target mineral reserves – not only diamonds, but also crucial minerals such as nickel and rare earth elements. </p>
<h2>Kimberlite and hot blobs</h2>
<p>Kimberlite eruptions leave behind a characteristic deep, carrot-shaped “pipe” of kimberlite rock, which often contains diamonds. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0012821X17307124">Hundreds of these eruptions</a> that occurred over the past 200 million years have been discovered around the world. Most of them were found in Canada (178 eruptions), South Africa (158), Angola (71) and Brazil (70).</p>
<p><iframe id="FbdgL" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/FbdgL/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Between Earth’s solid crust and molten core is the mantle, a thick layer of slightly goopy hot rock. For decades, geophysicists have used computers to study how the mantle slowly flows over long periods of time. </p>
<p>In the 1980s, <a href="https://www.sciencedirect.com/science/article/pii/0012821X84900438">one study showed</a> that kimberlite eruptions might be linked to small thermal plumes in the mantle – feather-like upward jets of hot mantle rising due to their higher buoyancy – beneath slowly moving continents. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/volcanoes-diamonds-and-blobs-a-billion-year-history-of-earths-interior-shows-its-more-mobile-than-we-thought-179673">Volcanoes, diamonds, and blobs: a billion-year history of Earth's interior shows it's more mobile than we thought</a>
</strong>
</em>
</p>
<hr>
<p>It had <a href="https://www.nature.com/articles/230042a0">already been argued</a>, in the 1970s, that these plumes might originate from the boundary between the mantle and the core, at a depth of 2,900km.</p>
<p>Then, in 2010, <a href="https://www.nature.com/articles/nature09216">geologists proposed</a> that kimberlite eruptions could be explained by thermal plumes arising from the edges of two deep, hot blobs anchored under Africa and the Pacific Ocean.</p>
<p>And last year, <a href="https://theconversation.com/volcanoes-diamonds-and-blobs-a-billion-year-history-of-earths-interior-shows-its-more-mobile-than-we-thought-179673">we reported that</a> these anchored blobs are more mobile than we thought.</p>
<p>However, we still didn’t know exactly how activity deep in the mantle was driving kimberlite eruptions.</p>
<h2>Pillars of heat</h2>
<p>Geologists assumed that mantle plumes could be responsible for igniting kimberlite eruptions. However, there was still a big question remaining: how was heat being transported from the deep Earth up to the kimberlites?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/524728/original/file-20230506-35349-epn7ao.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524728/original/file-20230506-35349-epn7ao.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=494&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524728/original/file-20230506-35349-epn7ao.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=494&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524728/original/file-20230506-35349-epn7ao.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=494&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524728/original/file-20230506-35349-epn7ao.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=621&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524728/original/file-20230506-35349-epn7ao.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=621&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524728/original/file-20230506-35349-epn7ao.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=621&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A snapshot of the global mantle convection model centred on subduction underneath the South American plate.</span>
<span class="attribution"><span class="source">Ömer F. Bodur</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>To address this question, we used <a href="https://nci.org.au">supercomputers</a> in Canberra, Australia to create three-dimensional geodynamic models of Earth’s mantle. Our models account for the movement of continents on the surface and into the mantle over the past one billion years. </p>
<p>We calculated the movements of heat upward from the core and discovered that broad mantle upwellings, or “pillars of heat”, connect the very deep Earth to the surface. Our modelling shows these pillars supply heat underneath kimberlites, and they explain most kimberlite eruptions over the past 200 million years. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/524816/original/file-20230508-23-g6oon7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524816/original/file-20230508-23-g6oon7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=303&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524816/original/file-20230508-23-g6oon7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=303&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524816/original/file-20230508-23-g6oon7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=303&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524816/original/file-20230508-23-g6oon7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=381&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524816/original/file-20230508-23-g6oon7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=381&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524816/original/file-20230508-23-g6oon7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=381&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A schematic representation of Earth’s heat pillars and how they bring heat to kimberlites, based on output from our geodynamic model.</span>
<span class="attribution"><span class="source">Ömer F. Bodur</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The model successfully captured kimberlite eruptions in Africa, Brazil, Russia and partly in the United States and Canada. Our models also predict previously undiscovered kimberlite eruptions occurred in East Antarctica and the Yilgarn Craton of Western Australia. </p>
<figure>
<iframe src="https://player.vimeo.com/video/824007338" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Earth’s “pillars of heat” in a global mantle convection model can be used to predict kimberlite eruptions. Credit: Ömer F. Bodur.</span></figcaption>
</figure>
<p>Towards the centre of the pillars, mantle plumes rise much faster and carry dense material across the mantle, which may explain chemical differences between kimberlites in <a href="https://www.nature.com/articles/s41561-023-01181-8">different continents</a>.</p>
<p>Our models do not explain some of the kimberlites in Canada, which might be related to a different geological process called “plate subduction”. We have so far predicted kimberlites back to one billion years ago, which is the current limit of <a href="https://www.sciencedirect.com/science/article/abs/pii/S0012825220305237">reconstructions of tectonic plate movements</a>.</p><img src="https://counter.theconversation.com/content/204905/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ömer Bodur was supported by funding from the Australian Research Council and from De Beers.</span></em></p><p class="fine-print"><em><span>Nicolas Flament receives funding from the Australian Research Council and from De Beers.</span></em></p>
The volcanic eruptions that bring diamonds to Earth’s surface are driven by ‘pillars of heat’ stretching deep inside the planet.
Ömer F. Bodur, Honorary Fellow, University of Wollongong
Nicolas Flament, Associate Professor, University of Wollongong
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/195704
2023-05-01T12:10:20Z
2023-05-01T12:10:20Z
What causes volcanoes to erupt?
<figure><img src="https://images.theconversation.com/files/501671/original/file-20221218-11129-2abr3x.jpg?ixlib=rb-1.1.0&rect=7%2C0%2C4985%2C3323&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An aerial view of the Mauna Loa volcano, which erupted on the island of Hawaii in December 2022.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/in-an-aerial-view-lava-erupts-from-the-mauna-loa-volcano-on-news-photo/1245459430?phrase=Mauna%20Loa%20volcano%202022&adppopup=true">Andrew Richard Hara/Getty Images News</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>What causes volcanoes to erupt? – Avery, age 8, Los Angeles</strong></p>
</blockquote>
<hr>
<p>On Nov. 27, 2022, Mauna Loa – the world’s largest active volcano – <a href="https://www.usgs.gov/observatories/hvo/news/volcano-watch-mauna-loa-reawakens-0">erupted on the island of Hawaii</a>. For days, fountains of lava, boiling at more than 2,000 degrees Fahrenheit (1,100 degrees Celsius), spewed upward and flowed down the mountain’s sides. </p>
<p>For tens of millions of people around the world, the videos were a mesmerizing sight. Then, a few weeks later, the eruption ended. Fortunately, there were no known deaths, and no major property damage. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/F0tmu-zaXig?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Mauna Loa is the world’s largest active volcano.</span></figcaption>
</figure>
<p>About a week later, Mount Semeru in East Java, Indonesia, <a href="https://volcano.si.edu/volcano.cfm?vn=263300">erupted a mix of ash, gas and hot rocks</a>. The plumes rose a mile above the mountain’s summit. Thousands <a href="https://www.pbs.org/newshour/world/new-eruption-of-indonesias-mt-semeru-unleashes-lava-river-volcanic-ash">living in the vicinity were evacuated</a>; many wore masks to protect themselves from the ash-filled air. Mount Semeru has continued to erupt for months.</p>
<p>I am a geologist who <a href="https://scholar.google.com/citations?user=4Q8uMqUAAAAJ&hl=en&oi=ao">studies minerals in volcanic rocks</a>. I want to learn more about what causes volcanoes to erupt. Millions of people <a href="https://www.discovery.com/exploration/People-Live-Near-Active-Volcanoes">live near an active volcano</a> – that is, one of the 1,328 volcanoes worldwide that have <a href="https://volcano.si.edu/faq/index.cfm?question=activevolcanoes">erupted over the past 12,000 years</a>. </p>
<p>At any given time, 20 to 50 of these <a href="https://volcano.si.edu/gvp_currenteruptions.cfm">active volcanoes are erupting</a>. The proximity of people and buildings makes it important to study volcanoes and understand the hazards. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502804/original/file-20230102-22-tpygfq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photograph of the city of Naples, Italy, with Mount Vesuvius in the background." src="https://images.theconversation.com/files/502804/original/file-20230102-22-tpygfq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502804/original/file-20230102-22-tpygfq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=370&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502804/original/file-20230102-22-tpygfq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=370&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502804/original/file-20230102-22-tpygfq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=370&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502804/original/file-20230102-22-tpygfq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=465&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502804/original/file-20230102-22-tpygfq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=465&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502804/original/file-20230102-22-tpygfq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=465&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mount Vesuvius, about 6 miles east of Naples, Italy, is still an active volcano. In A.D. 79, Vesuvius erupted and destroyed the city of Pompeii.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/travelling-in-italy-royalty-free-image/906204248?phrase=volcanoes%20mount%20vesuvius&adppopup=true">Antonio Busiello/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>How volcanoes blow their stacks</h2>
<p>The center of the Earth is <a href="https://earthhow.com/inside-earth-crust-core-mantle/">called the core</a>; the next layer up is the mantle; the outermost layer is the crust. </p>
<p>Over time, <a href="https://kids.kiddle.co/Magma">magma</a> – which is melted rock mixed with gas and mineral crystals – accumulates in an underground chamber beneath the volcano. The magma at Mauna Loa forms when a <a href="https://www.cbsnews.com/news/where-does-mauna-loa-lava-come-from/">hot mantle plume</a> – think of a conveyor of heat – partly melts rock in the mantle. </p>
<p>The volcano is essentially an <a href="https://www.natgeokids.com/uk/discover/geography/physical-geography/volcano-facts/">opening that lets magma out</a> onto the surface of the Earth. Once released from the volcano, the magma is called lava. </p>
<p>In the months leading to its eruption, scientists noted <a href="https://www.usgs.gov/observatories/hvo">increased earthquakes and a bulging of Mauna Loa</a>, like a balloon being inflated. These signs suggested that more magma was making its way upward, because pressure from rising magma can expand the sides of a volcano and cause rocks to shift and break, which leads to earthquakes.</p>
<p>Typically, for an eruption to occur, enough magma must <a href="https://www.usgs.gov/programs/VHP/about-volcanoes">accumulate in the chamber under the volcano</a>. Then something needs to trigger the eruption. That could be an injection of new magma into the chamber, a buildup of gases within the volcano, or a landslide that removes material from the top of a volcano.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/XLF_lMY2gu8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The eruption on Mount Semeru forced an evacuation of nearly 2,000 nearby residents.</span></figcaption>
</figure>
<h2>Types of volcanoes</h2>
<p>Mauna Loa is a <a href="https://study.com/academy/lesson/shield-volcano-facts-lesson-for-kids.html#:%7E">shield volcano</a>, built up over thousands of years through lava eruptions. Its sides slope gently downward in all directions. </p>
<p>But Mount Semeru is different – it’s a <a href="https://study.com/academy/lesson/composite-volcano-facts-lesson-for-kids.html#:%7E">composite volcano</a>, also known as a stratovolcano, with steep sides that come to a point at the top, like an upside-down sugar cone. </p>
<p>Semeru’s most recent eruption started when heavy rains <a href="https://www.cnn.com/2021/12/08/asia/indonesia-mount-semeru-volcano-eruption-cimate-intl/index.html">washed away rocks near the top of the volcano</a>. That allowed gas to escape – and ash to start erupting. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517451/original/file-20230324-24-crlmkn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A motorbike, and the ground around it, covered in ash." src="https://images.theconversation.com/files/517451/original/file-20230324-24-crlmkn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517451/original/file-20230324-24-crlmkn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517451/original/file-20230324-24-crlmkn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517451/original/file-20230324-24-crlmkn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517451/original/file-20230324-24-crlmkn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517451/original/file-20230324-24-crlmkn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517451/original/file-20230324-24-crlmkn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">After the eruption at Mount Semeru, nearby villages were covered in volcanic ash.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/motorbike-is-covered-with-volcanic-ashes-after-mount-semeru-news-photo/1237024024?adppopup=true">Bayu Novanta/Xinhua News Agency via Getty Images</a></span>
</figcaption>
</figure>
<h2>The dangers</h2>
<p>Many hazards are associated with erupting volcanoes: lava flows, acidic gases, ash and <a href="https://www.usgs.gov/observatories/cascades-volcano-observatory/lahars-most-threatening-volcanic-hazard-cascades#:%7E">lahars</a>, which are dangerous flows of water, ash and rock that <a href="https://www.usgs.gov/programs/VHP/lahars-move-rapidly-down-valleys-rivers-concrete">run miles down the steep slopes of volcanoes</a>, sometimes <a href="https://www.usgs.gov/programs/VHP/lahars-move-rapidly-down-valleys-rivers-concrete#:%7E">at over 100 miles per hour</a>. The force of lahars can move huge boulders and destroy bridges and buildings. </p>
<p>Mount Semeru’s recent eruption <a href="https://www.usgs.gov/programs/VHP/ashfall-most-widespread-and-frequent-volcanic-hazard">covered nearby villages with ash</a> – tiny particles of rock that can go deep into lungs, causing irritation and making it hard to breathe. </p>
<p>As falling ash accumulates, it can smother crops, contaminate water supplies and trigger the collapse of buildings. Newly fallen dry ash weighs <a href="https://mil.wa.gov/asset/5ba4200a0b533#:%7E:text=Ash%20accumulates%20like%20heavy%20snowfall,Wet%20ash%20is%20slippery.">10 to 20 times more than snow</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/3Jxeh-yAXek?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Below the surface, Earth is always moving and changing.</span></figcaption>
</figure>
<p>Generally, scientists don’t try to stop volcanoes from erupting. They are a natural part of the Earth. But monitoring volcanoes is critical. People need an early warning of an eruption <a href="https://www.usgs.gov/programs/VHP/understanding-volcanic-hazards-can-save-lives">so they can move out of harm’s way</a>. </p>
<p>While we cannot predict the exact time of an eruption, scientists are learning more about what causes them, and how to protect people who live near them. </p>
<p>What’s critical: warning systems for lahars, planned evacuation routes in areas threatened by volcanoes, and excellent communication between the scientists at volcanic monitoring stations and government agencies who can let people know when a volcano is about to go. </p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/195704/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rachel Beane receives funding from Bowdoin College and the National Science Foundation. She is affiliated with the Harpswell Heritage Land Trust. </span></em></p>
As they shape the Earth, volcanoes inspire and terrify humans.
Rachel Beane, Professor of Natural Sciences, Bowdoin College
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/196636
2022-12-19T21:11:09Z
2022-12-19T21:11:09Z
Mauna Loa eruption in Hawaii: How to stay safe while visiting volcanoes
<figure><img src="https://images.theconversation.com/files/501423/original/file-20221215-18-r2vi12.jpg?ixlib=rb-1.1.0&rect=17%2C22%2C2977%2C1971&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">People watch and record images of lava from the Mauna Loa volcano on Dec. 1, 2022 near Hilo, Hawaii.</span> <span class="attribution"><span class="source">(AP Photo/Gregory Bull)</span></span></figcaption></figure><p>On Nov. 27, the Big Island of Hawaii’s Mauna Loa volcano — the largest active volcano in the world — <a href="https://www.nytimes.com/video/us/100000008659677/mauna-lao-hawaii-volcano-erupts.html">erupted for the first time in 38 years</a>. This eruption was very special because Mauna Loa historically erupts very frequently, every six years on average.</p>
<p>As the director of <a href="https://www.yorku.ca/cifal/">CIFAL York</a>, Canada’s first hub for <a href="https://unitar.org/about">the United Nations Institute for Training and Research (UNITAR)</a>, I recently attended the <a href="https://unitar.org/about/offices-training-centres-around-world/cifal-global-network">global CIFAL directors’ meeting</a> in Honolulu, Hawaii organized by UNITAR and CIFAL Honolulu.</p>
<p>As a disaster and emergency management professor with research interest in volcanoes, I had planned to tour the Big Island, which is <a href="https://www.skylinehawaii.com/blog/the-most-active-volcanoes-on-the-hawaiian-islands">home to some of the most active volcanoes in the world</a>, including Kilauea, Hualalai, Kohala and Mauna Loa. To my amazement, my visit coincided with <a href="https://www.usgs.gov/volcanoes/mauna-loa/mauna-loa-eruption-webpage">Mauna Loa’s eruption</a>. </p>
<p>It took me two attempts to finally get a glimpse of the eruption. My first attempt on Dec. 3 was thwarted because of low visibility, caused by clouds covering the volcano, and a lack of parking availability on side roads. Some of the side roads were temporarily converted to one-way streets to divert traffic away from the busy, but orderly, main highway near the volcano summit. </p>
<figure class="align-center ">
<img alt="Glowing lava flows from an erupting volcano" src="https://images.theconversation.com/files/501228/original/file-20221215-14-ffyghb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501228/original/file-20221215-14-ffyghb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501228/original/file-20221215-14-ffyghb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501228/original/file-20221215-14-ffyghb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501228/original/file-20221215-14-ffyghb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501228/original/file-20221215-14-ffyghb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501228/original/file-20221215-14-ffyghb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mauna Loa erupting on Dec. 5, 2022 as seen from Hilo, Hawaii.</span>
<span class="attribution"><span class="source">(Ali Asgary)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>My second attempt was successful. I departed from my hotel in the town of Hilo at 2 a.m. and arrived at the nearest open side road, as close to the eruption site as possible. The sky was clear, and the beautiful and glowing reddish volcano plumes were visible as far as Hilo.</p>
<h2>Hazard tourism</h2>
<p>The Hawaii Volcanoes National Park and volcanic eruptions <a href="https://www.nps.gov/havo/learn/news/economy.htm">attract many tourists</a>, including scientists, nature photographers and the public, from all over the world. Some of the recorded human impacts of volcanic eruptions in the Big Island are <a href="http://npshistory.com/morningreport/incidents/havo.htm">attributed to hazard tourism</a>. </p>
<p>Hazard tourism refers to touristic activities that occur near historical or existing natural or technological hazard sites, or disaster-impacted areas. <a href="https://doi.org/10.1007/s12371-022-00691-y">Volcano tourism is one of the most popular types of hazard tourism</a> and involves the observation, photography and study of active volcanoes and their geological and natural phenomena. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/where-mauna-loas-lava-is-coming-from-and-why-hawaiis-volcanoes-are-different-from-most-195633">Where Mauna Loa’s lava is coming from – and why Hawaii’s volcanoes are different from most</a>
</strong>
</em>
</p>
<hr>
<p><a href="https://www.bgs.ac.uk/discovering-geology/earth-hazards/volcanoes/eruption-styles/">Volcanic eruptions can either be explosive or effusive</a>. Unlike explosive volcanoes that shoot ash and magma up into the atmosphere, most Hawaiian eruptions — including the Mauna Loa — are known for their <a href="https://www.nps.gov/articles/000/hawaiian-style-eruptions.htm">nonexplosive and effusive nature</a>. This means they have less direct human impacts in the form of injuries and fatalities.</p>
<p>During their eruptions, effusive volcanic eruptions create large volumes of lava that flow slowly downhill into the surrounding environment. These flows can damage vegetation, infrastructure such as roads, and properties. </p>
<p>While Hawaiian volcanoes do not produce ash, they produce a huge amount of <a href="https://www.usgs.gov/faqs/what-vog-how-it-related-sulfur-dioxide-so2-emissions">volcanic smog, also known as vog</a>. It contains sulphur dioxide, which can cause fatal health risks to humans, especially for those with respiratory illnesses.</p>
<h2>Safety procedures</h2>
<p>My visit happened during low season, but seeing as we are approaching the holiday spike, more people are expected to visit Hawaii in the coming days — the Big Island in particular. Managing visitors will be a significant task for authorities. </p>
<p>When volcanic eruptions happen, <a href="https://dod.hawaii.gov/hiema/about-the-agency/">emergency managers</a> have an additional task of managing hazard tourism. These include managing the tourist crowds trying to get as close as possible to the eruption sites.</p>
<figure class="align-center ">
<img alt="Cars parked on either side of a road at night time" src="https://images.theconversation.com/files/501424/original/file-20221215-24-432u6u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501424/original/file-20221215-24-432u6u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501424/original/file-20221215-24-432u6u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501424/original/file-20221215-24-432u6u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501424/original/file-20221215-24-432u6u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501424/original/file-20221215-24-432u6u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501424/original/file-20221215-24-432u6u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Motorists make their way along as people search for a vantage point of the erupting Mauna Loa volcano, on Dec. 2, 2022, near Hilo, Hawaii.</span>
<span class="attribution"><span class="source">(AP Photo/Gregory Bull)</span></span>
</figcaption>
</figure>
<p>To reduce the risks to visitors, authorities in the Big Island implement several measures when eruptions happen. <a href="https://www.travelweek.ca/news/qa-hawaii-tourism-authority-answers-questions-about-the-mauna-loa-eruption/">These measures include</a> restricting parking on certain segments of nearby highways, closing roads and trails that are subject to lava flow and other volcanic hazards, providing information to visitors, and continuous monitoring of the eruption activities.</p>
<p>The main goal for authorities is allowing visitors to watch volcanic activity safely. While this requires planning from the local and state authorities in Hawaii, it also requires close co-operation and attention of visitors to safety procedures and high levels of preparedness. </p>
<h2>How visitors can be prepared</h2>
<p>It is very important for tourists to properly prepare for excursions to see volcanic eruptions. Visitors should allocate sufficient time for their visit and expect delays, depending on how busy the roads and the sites are.</p>
<p>Tourists should understand and follow the traffic and all safety guidelines and roles throughout their visits. They should wear adequate footwear for rough grounds, clothing for chilly and windy weather at night, and carry emergency kits including flashlights for when it gets dark. </p>
<figure class="align-center ">
<img alt="A column of orange smoke billows from the mouth of a volcano. A stream of yellow-orange lava flows down the side of it." src="https://images.theconversation.com/files/501425/original/file-20221215-26-wc0zrj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501425/original/file-20221215-26-wc0zrj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501425/original/file-20221215-26-wc0zrj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501425/original/file-20221215-26-wc0zrj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501425/original/file-20221215-26-wc0zrj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501425/original/file-20221215-26-wc0zrj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501425/original/file-20221215-26-wc0zrj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Lava erupts from Hawaii’s Mauna Loa volcano on Nov. 30, 2022, near Hilo, Hawaii.</span>
<span class="attribution"><span class="source">(AP Photo/Gregory Bull)</span></span>
</figcaption>
</figure>
<p>Visiting natural hazard sites poses risks to visitors. Some of these hazards are visible, like vog, and some invisible, <a href="https://bigislandhikes.com/hazards">like cooled lava tubes</a> that can collapse when walked on, or <a href="https://doi.org/10.1007/11157_2015_14">invisible but toxic gases</a>.</p>
<p>Studies show that, unfortunately, <a href="https://www.earthmagazine.org/article/danger-paradise-hidden-hazards-volcano-geotourism/">most people visiting such sites are not properly prepared</a>. Watching this amazing and spectacular natural phenomenon will be a once-in-a-lifetime experience for many people, but visitors should understand the potential risks of exposure to volcanic hazards and prepare themselves for visiting such sites.</p><img src="https://counter.theconversation.com/content/196636/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ali Asgary does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
It’s very important for tourists to understand the risks of visiting volcanic sites and properly prepare themselves for excursions to see volcanic eruptions.
Ali Asgary, Professor, Faculty of Liberal Arts & Professional Studies, York University, Canada
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/195633
2022-11-30T13:44:16Z
2022-11-30T13:44:16Z
Where Mauna Loa’s lava is coming from – and why Hawaii’s volcanoes are different from most
<figure><img src="https://images.theconversation.com/files/498437/original/file-20221201-6346-syova6.jpeg?ixlib=rb-1.1.0&rect=2568%2C1769%2C2083%2C1338&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Magma fountains through a fissure on Mauna Loa, becoming lava, on Nov. 30, 2022.
</span> <span class="attribution"><a class="source" href="https://www.usgs.gov/media/images/november-30-2022-mauna-loa-fissure-3"> K. Mulliken/USGS</a></span></figcaption></figure><p><em>Hawaii’s Mauna Loa, the world’s largest active volcano, began sending up <a href="https://www.usgs.gov/volcanoes/mauna-loa/mauna-loa-eruption-webpage">fountains of glowing rock</a> and spilling lava from fissures as its first eruption in <a href="https://www.usgs.gov/volcanoes/mauna-loa">nearly four decades</a> began on Nov. 27, 2022.</em> </p>
<p><em>Where does that molten rock come from?</em></p>
<p><em>We asked <a href="https://scholar.google.com/citations?user=a7D-WawAAAAJ&hl=en">Gabi Laske</a>, a geophysicist at the University of California-San Diego who led one of the first projects to map the deep plumbing that feeds the Hawaiian Islands’ volcanoes, to explain.</em> </p>
<h2>Where is the magma surfacing at Mauna Loa coming from?</h2>
<p>The magma that comes out of Mauna Loa comes from a series of magma chambers found between about 1 and 25 miles (2 and 40 km) below the surface. These magma chambers are only temporary storage places with magma and gases, and are not where the magma originally came from.</p>
<p>The origin is much deeper in <a href="https://pubs.usgs.gov/gip/dynamic/inside.html">Earth’s mantle</a>, perhaps more than 620 miles (1,000 km) deep. Some scientists even postulate that the magma comes from a <a href="https://www.usgs.gov/observatories/hvo/news/volcano-watch-exploring-deep-source-hawaiian-volcanoes">depth of 1,800 miles (2,900 km)</a>, where the mantle meets Earth’s core.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/498078/original/file-20221129-14-85b5yv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/498078/original/file-20221129-14-85b5yv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498078/original/file-20221129-14-85b5yv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=318&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498078/original/file-20221129-14-85b5yv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=318&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498078/original/file-20221129-14-85b5yv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=318&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498078/original/file-20221129-14-85b5yv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=400&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498078/original/file-20221129-14-85b5yv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=400&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498078/original/file-20221129-14-85b5yv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=400&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An illustration suggests what Hawaii’s mantle plume might look like.</span>
<span class="attribution"><span class="source">Joel E Robinson/USGS</span></span>
</figcaption>
</figure>
<p>Earth’s crust is made up of tectonic plates that are slowly moving, at about the same speed as a fingernail grows. Volcanoes typically occur where these plates either move away from each other or where one pushes beneath another. But volcanoes can also be in the middle of plates, as Hawaii’s volcanoes are <a href="https://www.usgs.gov/media/images/pacific-plate-boundaries-and-relative-motion">in the Pacific Plate</a>.</p>
<p>The crust and mantle that comprise the Pacific Plate cracks at different places as it moves northwestward. Beneath Hawaii, magma can move upward through the cracks to feed different volcanoes on the surface. The same thing happens at Maui’s Haleakala, <a href="https://www.usgs.gov/volcanoes/haleakal%C4%81">which last erupted</a> about 250 years ago.</p>
<h2>How does molten rock travel from deep in Earth’s mantle, and what exactly is a mantle plume?</h2>
<p>Scientists hypothesize that the mantle is not made of uniform rock. Instead, <a href="https://doi.org/10.1038/s41561-019-0368-9">differences in the type</a> of mantle rock make it melt at <a href="https://openoregon.pressbooks.pub/earthscience/chapter/4-1-magma-and-how-it-forms/">different temperatures</a>. Mantle rock is solid at some places, while it starts to melt at other places.</p>
<p>The partially molten rock becomes buoyant and ascends toward the surface. The ascending mantle rock is what makes a mantle plume. Because the overlying pressure lessens as the rock ascends, it melts more and more, and eventually collects in the magma chamber. If a large enough opening exists at the surface, and enough volcanic gases have collected in the magma chamber, the magma is forced to the surface in a volcanic eruption.</p>
<figure class="align-center ">
<img alt="A cross section of the earth shows two potentially sources for the mantle plume, one starting much deeper and flowing a squiggly route as seismic imaging suggests." src="https://images.theconversation.com/files/498109/original/file-20221129-20-2d4cyv.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498109/original/file-20221129-20-2d4cyv.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498109/original/file-20221129-20-2d4cyv.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498109/original/file-20221129-20-2d4cyv.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498109/original/file-20221129-20-2d4cyv.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498109/original/file-20221129-20-2d4cyv.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498109/original/file-20221129-20-2d4cyv.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The origin of the magma may be more than 620 miles deep, and some scientists have suggested it could come from a depth of 1,800 miles, where the mantle meets Earth’s core.</span>
<span class="attribution"><span class="source">Gabi Laske</span></span>
</figcaption>
</figure>
<p>Seismic imaging by research teams I’m involved with has shown that Hawaii’s mantle plume <a href="https://doi.org/10.1126/science.1180165">comes from deep inside the mantle</a>.</p>
<p>But the plume is not a straight pipe as some concept figures suggest. Instead, it has <a href="https://doi.org/10.1038/ngeo1878">twists and turns</a>, originally coming from the southeast, but then turning toward the west of Hawaii as the plume reaches into the shallower mantle. Cracks in the Pacific Plate then channel the magma upward toward the magma chamber beneath the island of Hawaii.</p>
<h2>Why does Hawaii typically see less dramatic eruptions than other locations?</h2>
<p>Hawaii is in the middle of an oceanic plate. In fact, it is the most isolated volcanic hot spot on Earth, far away from any plate boundary.</p>
<p>Oceanic magma is very different from continental magma. It has a different chemical composition and flows much more easily. So, the magma is <a href="https://geowiki.ucsd.edu/sio15/topics/topic09.html">less prone to clog volcanic vents</a> on its ascent, which would ultimately lead to more explosive volcanism.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/9DUexRQfNBA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Thermal imaging shows the Mauna Loa eruption, which began around 11:30 p.m. local time on Nov. 27, 2022. Temperatures are in Celsius. USGS.</span></figcaption>
</figure>
<h2>How do scientists know what is happening under the surface?</h2>
<p>Volcanic activity is monitored with many different instruments.</p>
<p>The perhaps simplest to understand is GPS. The way scientists use GPS is different from that of everyday life. It can detect minuscule movements of a few centimeters. On volcanoes, any upward movement on the surface detected by GPS indicates that something is pushing from underneath.</p>
<p>Even more sensitive are <a href="https://www.usgs.gov/programs/VHP/tiltmeters-and-strainmeters-measure-subtle-changes-ground-slope-and-shape-volcanoes">tiltmeters</a>, which are in essence the same as bubble levels that people use to hang pictures on a wall. Any change in the tilt on a volcano slope indicates that the volcano is “breathing,” again because of magma moving below.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/498080/original/file-20221129-14-pr28xg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of the island of Hawaii, showing Mauna Loa and the lava flow paths since the late 1800s. There have been several eruptions and they tend to follow two routes." src="https://images.theconversation.com/files/498080/original/file-20221129-14-pr28xg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498080/original/file-20221129-14-pr28xg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=776&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498080/original/file-20221129-14-pr28xg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=776&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498080/original/file-20221129-14-pr28xg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=776&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498080/original/file-20221129-14-pr28xg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=976&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498080/original/file-20221129-14-pr28xg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=976&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498080/original/file-20221129-14-pr28xg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=976&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mauna Loa has a history of eruptions. Here’s where the lava tends to go.</span>
<span class="attribution"><a class="source" href="https://www.usgs.gov/volcanoes/mauna-loa/geology-and-history">USGS</a></span>
</figcaption>
</figure>
<p>A very important tool is watching for seismic activity.</p>
<p>Volcanoes like Hawaii’s are monitored with a large network of seismographs. Any movement of magma below will cause tremors that are picked up by the <a href="https://www.usgs.gov/programs/VHP/networks-multiple-seismometers-are-necessary-adequately-monitor-volcanoes">seismometers</a>. A few weeks before the eruption of Mauna Loa, scientists noticed that the tremors came from ever shallower depths, indicating that magma was rising and an eruption might be imminent. This <a href="https://apnews.com/article/science-hawaii-kilauea-mauna-loa-14f7596e22b08a44600caa5f185b5b18">allowed scientists to warn the public</a>.</p>
<p>Other ways that volcanic activity is monitored includes chemical analysis of gases coming out <a href="https://www.usgs.gov/news/earthword-fumarole">through fumaroles</a> – holes or cracks through which volcanic gases escape. If the composition changes or activity increases, that’s a pretty clear indication that the volcano is changing.</p><img src="https://counter.theconversation.com/content/195633/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gabi Laske receives funding from the National Science Foundation. </span></em></p>
A scientist who led one of the first projects to map the Hawaiian Islands’ deep volcanic plumbing explains what’s going on under the surface as Mauna Loa erupts.
Gabi Laske, Professor of Geophysics, University of California, San Diego
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/189524
2022-09-22T19:51:23Z
2022-09-22T19:51:23Z
We can use drones to get inside and learn more about active, gassy volcanoes
<figure><img src="https://images.theconversation.com/files/485137/original/file-20220916-1799-a2tkgw.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5208%2C3875&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An overhead shot of a volcano crater in east Java, Indonesia.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Volcanic eruptions cannot be predicted with 100 per cent certainty. However, details about an upcoming eruption can be estimated using the hot and smelly gases a volcano produces. </p>
<p>These gases provide clues about the timing, duration or severity of upcoming eruptions which can help local authorities decide if and when the surrounding communities need to be evacuated. </p>
<p>On average, there are <a href="https://volcano.si.edu/">up to 50 volcanoes</a> actively erupting on the planet at any given time. Many of these volcanoes are more likely to be spewing hot gases — like steam and carbon dioxide — than lava. Collecting these gases is key to understanding the mysterious ways of volcanoes, but it can be dangerous.</p>
<p>Now, <a href="https://doi.org/10.30909/vol.03.01.67114">drones are making it safer</a> and easier than ever before.</p>
<h2>Gassy volcanoes</h2>
<p>For the better part of the last decade, I have been visiting such gassy volcanoes regularly to catch them just before, during or after an eruption. </p>
<p>I have worked with other scientists and engineers to <a href="https://eos.org/science-updates/drones-swoop-in-to-measure-gas-belched-from-volcanoes">measure volcanic gases</a> with a variety of devices attached to drones. </p>
<p>Our latest research uses drones to <a href="https://doi.org/10.1016/j.jvolgeores.2022.107639">capture volcanic carbon dioxide at Poás volcano in Costa Rica</a>. We measured the isotopes of carbon in this carbon dioxide and discovered a pattern in the way these chemical fingerprints change during different stages of activity.</p>
<h2>Unique carbon makeup</h2>
<p>Carbon dioxide is everywhere: in the air we exhale, in vehicle exhaust — and dissolved in magma. At volcanoes, it escapes from magma to the surface through cracks and hydrothermal systems (like the geysers in Yellowstone National Park), by seeping through the soil or by puffing out in a plume of gas. </p>
<p>By obtaining a sample of this <a href="https://doi.org/10.2138/rmg.2013.75.11">volcanic carbon</a>, we can measure the stable carbon isotopic ratio, a unique chemical makeup which reflects the source and pathway the CO2 took to the surface. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/485139/original/file-20220916-8280-bzy2aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a plume of smoke emerges from a hole in the ground" src="https://images.theconversation.com/files/485139/original/file-20220916-8280-bzy2aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/485139/original/file-20220916-8280-bzy2aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/485139/original/file-20220916-8280-bzy2aj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/485139/original/file-20220916-8280-bzy2aj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/485139/original/file-20220916-8280-bzy2aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/485139/original/file-20220916-8280-bzy2aj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/485139/original/file-20220916-8280-bzy2aj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Underground pressure forces gas and smoke out of the ground in the geysers in Yellowstone National Park.</span>
<span class="attribution"><span class="source">(Donna Elliot/Unsplash)</span></span>
</figcaption>
</figure>
<p>Each volcano around the world produces a unique range of these <a href="https://doi.org/10.1126/science.aan5049">carbon isotopes</a> which change when the volcanic system changes. </p>
<p>However, it took a long time to collect each sample when researchers needed to hike down into a crater, putting them at risk each second they remained in the danger zone. With the evolution of unoccupied aerial systems (UAS, also known as drones), researchers have started sending these machines into the danger areas.</p>
<h2>Employing drones</h2>
<p>To do this, we used switches and electronics parts to connect gas sensors to the onboard communications systems of the UAS. The volcanic CO2 would be sucked in through a series of tubing with the help of a pump and sensors that would send a signal back to the pilot when we entered the gas plume. With the flick of a switch on the remote control, the pilot could choose — from a safe distance — when and where to collect the gas sample. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/484123/original/file-20220912-1707-5fe5og.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4898%2C3226&q=45&auto=format&w=1000&fit=clip"><img alt="A drone landed in front of smoke" src="https://images.theconversation.com/files/484123/original/file-20220912-1707-5fe5og.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4898%2C3226&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/484123/original/file-20220912-1707-5fe5og.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/484123/original/file-20220912-1707-5fe5og.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/484123/original/file-20220912-1707-5fe5og.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/484123/original/file-20220912-1707-5fe5og.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/484123/original/file-20220912-1707-5fe5og.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/484123/original/file-20220912-1707-5fe5og.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A drone equipped to sample volcanic gas captures carbon dioxide.</span>
<span class="attribution"><span class="source">(Fiona D'Arcy)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We arrived in Costa Rica in April 2019 with our shiny new drone set-up, which we launched at the rim of Poás volcano and which crashed almost immediately. Thankfully, our team whipped up a quick solution for our second drone — a pump and switch hanging from the drone in a laundry bag. It worked flawlessly.</p>
<p>To avoid further losses, we got up close to the crater and flew our assembly directly above it. Later that day, we looked at the stable isotopes of carbon in our drone samples and in the samples we took from the ground. After we accounted for the mixing with the regular air in the drone samples, the two results were strikingly similar. Our drone assembly worked!</p>
<h2>A pattern emerges</h2>
<p>When we started compiling our data with all the carbon isotopes measured at Poás volcano in the past, we noticed a trend in how the balance of isotopes shifted when the volcano was behaving differently. </p>
<p>During eruptive phases, when Poás was making wet explosions releasing extra hot, sulfur-rich gas, the isotopes of carbon slipped down to lighter values. Meanwhile, during quieter phases <a href="https://doi.org/10.1016/j.jvolgeores.2021.107297">when the volcano was sealed</a>, the isotopic balance rose to heavier values. </p>
<p>With this new insight, we could look back even further and stitch together our data with <a href="https://doi.org/10.1007/978-3-319-02156-0_10">isotope data from older activity</a>. We saw that this pattern was repeating itself, with the carbon isotopes alternating between heavy an light values over the last 20 years of activity at Poás. There were relatively heavy values when the volcano was sealed and there were relatively light values when the volcano was open. </p>
<p>We now have a blueprint of what warning signals to look for in future isotopes of carbon sampled at this volcano when it’s gearing up to erupt.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1298020478691549190"}"></div></p>
<h2>Future research</h2>
<p>Thanks to drones, we captured the first CO2 from Poás volcano since 2014. Volcanic gases sampled before our work were all taken by hand by brave volcano scientists climbing down into the crater of Poás. These expeditions were few and far between. </p>
<p>We hope that with the onset of gas-capturing drones, carbon dioxide at volcanoes <a href="https://doi.org/10.1126/sciadv.abb9103">can start to be sampled more frequently</a>. This will fill the gaps in the timeline and help us understand and forecast eruptions.</p><img src="https://counter.theconversation.com/content/189524/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fiona D'Arcy receives funding from the Vanier Canada Graduate Scholarships (Vanier CGS). </span></em></p>
Drones can be used to collect gas samples from active volcanoes, where it is too dangerous for researchers. This data can be then used to predict the frequency and severity of eruptions.
Fiona D'Arcy, PhD candidate in Earth Sciences, McGill University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/178037
2022-05-09T19:59:55Z
2022-05-09T19:59:55Z
How a volcanic bombardment in ancient Australia led to the world’s greatest climate catastrophe
<figure><img src="https://images.theconversation.com/files/458057/original/file-20220414-20-lr2alr.jpg?ixlib=rb-1.1.0&rect=116%2C63%2C6965%2C3472&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Artwork by Katrina Kenny © 2022</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Some 252 million years ago the world was going through a tumultuous period of rapid global warming. </p>
<p>To understand what caused it, scientists have looked to one particular event in which a volcanic eruption in what is now Siberia spewed huge volumes of greenhouse gas into the atmosphere.</p>
<p>However, there is evidence the climate was already changing before this. </p>
<p>Sea surface temperatures had increased by more than 6–8°C in the hundreds of thousands of years leading up to the Siberian outpouring. Temperatures increased again after it, so much so that 85–95% of all living species eventually went extinct.</p>
<p>The eruption in Siberia obviously made a mark on the planet, but experts remained puzzled about what caused the initial warming before it. </p>
<p>Our research reveals Australia’s own ancient volcanoes played a big role. Prior to the event in Siberia, catastrophic eruptions in northern New South Wales spewed volcanic ash across the east coast.</p>
<p>These eruptions were so large they initiated the world’s biggest ever climate catastrophe — the evidence for which is now hidden deep in Australia’s thick piles of sediment.</p>
<h2>Ancient volcanoes</h2>
<p>Our study, <a href="https://www.nature.com/articles/s41561-022-00934-1">published today</a> in Nature, confirms eastern Australia was shaken by repeated “super eruptions” between 256 and 252 million years ago.</p>
<p>Super eruptions are different to the more passive Siberian event. These catastrophic explosions spewed massive amounts of ash and gasses high into the atmosphere. </p>
<p>Today we see evidence of this in light-coloured layers of volcanic ash in sedimentary rock. These layers are found across huge areas of NSW and Queensland, all the way from Sydney to near Townsville. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/449143/original/file-20220301-19-vzgy5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Ash layers in coal measures" src="https://images.theconversation.com/files/449143/original/file-20220301-19-vzgy5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449143/original/file-20220301-19-vzgy5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449143/original/file-20220301-19-vzgy5i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449143/original/file-20220301-19-vzgy5i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449143/original/file-20220301-19-vzgy5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449143/original/file-20220301-19-vzgy5i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449143/original/file-20220301-19-vzgy5i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Thick pile of coal with multiple light coloured ash layers that represent volcanic eruptions sourced from the New England region and now in the Sydney basin.</span>
<span class="attribution"><span class="source">Ian Metcalfe</span></span>
</figcaption>
</figure>
<p>Our study has identified the source of this ash in the New England region of NSW, where the eroded remnants of volcanoes are preserved. </p>
<p>Though erosion has removed much of the evidence, the now innocuous-looking rocks are our record of terrifying eruptions. The thickness and spread of the ash produced is consistent with some of the largest volcanic eruptions known.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/449146/original/file-20220301-21-ynsjff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Eroded volcanoe" src="https://images.theconversation.com/files/449146/original/file-20220301-21-ynsjff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449146/original/file-20220301-21-ynsjff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449146/original/file-20220301-21-ynsjff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449146/original/file-20220301-21-ynsjff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449146/original/file-20220301-21-ynsjff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449146/original/file-20220301-21-ynsjff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449146/original/file-20220301-21-ynsjff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Eroded remnants of the volcanoes in the New England region of NSW.</span>
<span class="attribution"><span class="source">Tim Chapman</span></span>
</figcaption>
</figure>
<h2>How big were the super eruptions?</h2>
<p>At least 150,000 km³ of material erupted from the northern NSW volcanoes over four million years. This makes them similar to the supervolcanoes of Yellowstone in the United States and Taupo in New Zealand. </p>
<p>To put it into perspective, the 79AD eruption of Mt Vesuvius, which obliterated the Italian city of Pompeii, produced just 3–4km³ of rock and ash. And the deadly Mt St Helens eruption in 1980 was about 1km³. </p>
<p>The Australian eruptions would have repeatedly covered the <em>entire</em> east coast in ash — metres thick in some places. And a massive outpouring of greenhouse gases would have triggered global climate change. </p>
<h2>Environmental devastation</h2>
<p>Ancient sedimentary rocks provide us with a timeline of the environmental damage caused by the eruptions. Ironically, the evidence is preserved in coal measures.</p>
<p>Today’s coal deposits in eastern Australia show ancient forests used to cover much of this land. After the super eruptions, however, these forests were abruptly terminated in a series of bushfires over some 500,000 years, 252.5–253 million years ago.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-australias-geology-gave-us-an-abundance-of-coal-and-a-wealth-of-greentech-minerals-to-switch-to-173988">How Australia's geology gave us an abundance of coal – and a wealth of greentech minerals to switch to</a>
</strong>
</em>
</p>
<hr>
<p>Typically the plant matter accumulated in swamps and was then buried under sediments. The burial process provided heat and pressure which enabled the conversion of the plant matter into coal. </p>
<p>Without the forests, there was no plant matter to accumulate. The ecosystem collapsed and most animals became extinct. </p>
<p>The subsequent eruptions in Siberia only exaggerated the devastation started by Australia’s supervolcanoes.</p>
<p>And this collapse of ecosystems was not limited to Australia, either. The catastrophic event affected all of the ancient continents. It had a substantial influence on the evolution of life — which eventually led to the rise of the dinosaurs. </p>
<p>Australia’s super eruptions were a key marker of change in the ancient world. As we look to achieving a more habitable climate in the future, who knew the clues to environmental catastrophe lay buried beneath our feet?</p>
<hr>
<p><em>Acknowledgement: we would like to thank our colleague Phil Blevin from the Geological Survey of New South Wales for his contribution to this work.</em></p><img src="https://counter.theconversation.com/content/178037/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Timothy Chapman has received funding from Australia Research Council. He is affiliated with the University of New England. </span></em></p><p class="fine-print"><em><span>Ian Metcalfe is an Adjunct Professor at the University of New England and has received both Australian Research Council and industry grants for research on the Permian-Triassic boundary and end-Permian mass extinction.</span></em></p><p class="fine-print"><em><span>Luke Milan is staff at the University of New England and has received funding from the Australian Research Council in the past. </span></em></p>
Research has found evidence in NSW for one the most devastating series of volcanic eruptions known.
Timothy Chapman, Postdoctoral Fellow in Geology, University of New England
Ian Metcalfe, Adjunct Professor, University of New England
Luke Milan, University of New England
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/175247
2022-01-23T19:09:15Z
2022-01-23T19:09:15Z
5 ways climate change increases the threat of tsunamis, from collapsing ice shelves to sea level rise
<figure><img src="https://images.theconversation.com/files/441876/original/file-20220121-9541-as4ejs.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C2983%2C1986&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The enormous eruption of the underwater volcano in Tonga, Hunga Tonga-Hunga Ha'apai, triggered a <a href="https://www.reuters.com/business/environment/tonga-volcano-generates-tsunami-us-tsunami-monitor-said-2022-01-15/">tsunami</a> that reached countries all around the Pacific rim, even causing a <a href="https://apnews.com/article/oil-spills-business-tonga-peru-trending-news-3a92a17e2101945afcb22f5eb5bfb2ad?utm_campaign=SocialFlow&utm_source=Twitter&utm_medium=AP">disastrous oil spill</a> along 21 beaches in Peru. </p>
<p>In Tonga, waves about 2 metres high were recorded before the sea level gauge failed, <a href="https://twitter.com/ConsulateKoT/status/1483384039826464768/photo/1">and waves of up to 15m</a> hit the west coasts of Tongatapu Islands, ‘Eua, and Ha’apai Islands. Volcanic activity could continue for weeks or months, but it’s hard to predict if or when there’ll be another such powerful eruption.</p>
<p>Most tsunamis are caused by earthquakes, but a <a href="http://tsunami.org/what-causes-a-tsunami/">significant percentage</a> (about 15%) are caused by landslides or volcanoes. Some of these may be interlinked – for example, landslide tsunamis are often triggered by earthquakes or volcanic eruptions. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1482437044785889286"}"></div></p>
<p>But does <a href="https://www.un.org/en/climatechange/what-is-climate-change">climate change</a> also play a role? As the planet warms, we’re seeing more <a href="https://www.usgs.gov/faqs/how-can-climate-change-affect-natural-disasters">frequent and intense</a> storms and cyclones, the melting of glaciers and ice caps, and sea levels rising.
Climate change, however, doesn’t just affect the atmosphere and oceans, it affects the Earth’s crust as well. </p>
<p><a href="https://www.reuters.com/article/us-climate-geology-idUSTRE58F62I20090916">Climate-linked</a> geological changes can increase the incidence of earthquakes and volcanic eruptions which, in turn, can exacerbate the threat of tsunamis. Here are five ways this can happen.</p>
<h2>1. Sea level rise</h2>
<p>If greenhouse gas emissions remain at high rates, the average global sea level is <a href="https://www.ipcc.ch/srocc/chapter/chapter-4-sea-level-rise-and-implications-for-low-lying-islands-coasts-and-communities">projected to rise</a> between 60 centimetres and 1.1m. <a href="https://www.un.org/sustainabledevelopment/wp-content/uploads/2017/05/Ocean-fact-sheet-package.pdf">Almost two thirds</a> of the world’s cities with populations over five million are at risk.</p>
<p>Rising sea levels not only make coastal communities more vulnerable to flooding from storms, but also tsunamis. Even modest rises in sea level will dramatically increase the frequency and intensity of flooding when a tsunami occurs, as the tsunami can travel further inland. </p>
<p>For example, <a href="https://www.science.org/doi/10.1126/sciadv.aat1180">a 2018 study</a> showed only a 50 centimetre rise would double the frequency of tsunami-induced flooding in Macau, China. This means in future, smaller tsunamis could have the same impact as larger tsunamis would today.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1483741932970983428"}"></div></p>
<h2>2. Landslides</h2>
<p>A warming climate can increase the risk of both submarine (underwater) and aerial (above ground) landslides, thereby increasing the risk of local tsunamis. </p>
<p>The <a href="https://www.nrdc.org/stories/permafrost-everything-you-need-know">melting of permafrost</a> (frozen soil) at high latitudes decreases soil stability, making it more susceptible to erosion and landslides. More <a href="https://climate.nasa.gov/news/2951/climate-change-could-trigger-more-landslides-in-high-mountain-asia/">intense rainfall</a> can trigger landslides, too, as storms become more frequent under climate change. </p>
<p><a href="https://www.usgs.gov/faqs/how-do-landslides-cause-tsunamis#:%7E:text=Tsunamis%20are%20large%2C%20potentially%20deadly,a%20result%20of%20submarine%20earthquakes.&text=Tsunamis%20can%20be%20generated%20on,a%20rapidly%20moving%20underwater%20landslide.">Tsunamis can be generated</a> on impact as a landslide enters the water, or as water is moved by a rapid underwater landslide. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/waves-from-the-tonga-tsunami-are-still-being-felt-in-australia-and-even-a-50cm-surge-could-knock-you-off-your-feet-175056">Waves from the Tonga tsunami are still being felt in Australia – and even a 50cm surge could knock you off your feet</a>
</strong>
</em>
</p>
<hr>
<p>In general, tsunami waves generated from landslides or rock falls dissipate quickly and don’t travel as far as tsunamis generated from earthquakes, but they can still lead to huge waves locally.</p>
<p>In Alaska, US, glacial retreat and melting permafrost has exposed unstable slopes. In 2015, this melting caused a landslide that sent 180 million tonnes of rock into a narrow fjord, <a href="https://www.nature.com/articles/s41598-018-30475-w">generating a tsunami reaching 193m high</a> – one of the highest ever recorded worldwide. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/441884/original/file-20220121-8856-1regaso.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/441884/original/file-20220121-8856-1regaso.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441884/original/file-20220121-8856-1regaso.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441884/original/file-20220121-8856-1regaso.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441884/original/file-20220121-8856-1regaso.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441884/original/file-20220121-8856-1regaso.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441884/original/file-20220121-8856-1regaso.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441884/original/file-20220121-8856-1regaso.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scientists survey damage from a megatsunami in Taan Fiord that had occurred in October, 2015 after a massive landslide.</span>
<span class="attribution"><span class="source">Peter Haeussler, United States Geological Survey Alaska Science Center/Wikimedia</span></span>
</figcaption>
</figure>
<p>Other areas at risk include <a href="https://www.sciencedirect.com/science/article/pii/S0921818121000849">northwest British Columbia</a> in Canada, and the Barry Arm in Alaska, where an <a href="https://dggs.alaska.gov/hazards/barry-arm-landslide.html">unstable mountain slope</a> at the toe of the Barry Glacier has the potential to fail and <a href="https://www.woodwellclimate.org/wp-content/uploads/2020/05/Letter-to-Stakeholders_-Barry-Arm-Landslide-Final.pdf">generate a severe tsunami</a> in the next 20 years.</p>
<h2>3. Iceberg calving and collapsing ice shelves</h2>
<p>Global warming is accelerating the <a href="https://www.businessinsider.com.au/chasing-ice-glacier-calving-climate-change-2014-10?r=US&IR=T">rate of iceberg calving</a> – when chunks of ice fall into the ocean.</p>
<p>Studies predict large ice shelves, such as the Thwaites Glacier in Antarctica, will <a href="https://news.climate.columbia.edu/2021/12/17/crucial-antarctic-glacier-likely-to-collapse-much-earlier-than-expected/">likely collapse</a> in the next five to ten years. Likewise, the Greenland ice sheet is <a href="https://climate.nasa.gov/news/3062/warming-seas-are-accelerating-greenlands-glacier-retreat/">thinning and retreating</a> at an alarming rate.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/441878/original/file-20220121-8497-jjkh3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Iceberg near ship" src="https://images.theconversation.com/files/441878/original/file-20220121-8497-jjkh3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441878/original/file-20220121-8497-jjkh3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441878/original/file-20220121-8497-jjkh3d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441878/original/file-20220121-8497-jjkh3d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441878/original/file-20220121-8497-jjkh3d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441878/original/file-20220121-8497-jjkh3d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441878/original/file-20220121-8497-jjkh3d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Icebergs colliding with the seafloor can trigger underwater landslides.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>While much of the current research focus is on the sea level risk associated with melting and collapse of glaciers and ice sheets, there’s also a <a href="https://nhess.copernicus.org/articles/12/415/2012/">tsunami risk</a> from the calving and breakup process. </p>
<p>Wandering icebergs can trigger <a href="https://www.nature.com/articles/s41561-021-00767-4">submarine landslides and tsunamis</a> thousands of kilometres from the iceberg’s original source, as they hit unstable sediments on the seafloor.</p>
<h2>4. Volcanic activity from ice melting</h2>
<p>About 12,000 years ago, the last glacial period (“ice age”) ended and the melting ice triggered a dramatic <a href="https://eprints.lancs.ac.uk/id/eprint/32995/2/Tuffen_PTRSL.pdf">increase in volcanic activity</a>.</p>
<p>The correlation between climate warming and more volcanic eruptions isn’t yet well constrained or understood. But it may be related to <a href="https://pubs.er.usgs.gov/publication/70182772">changes in</a> stress to the Earth’s crust as the weight of ice is removed, and a phenomenon called “<a href="http://people.rses.anu.edu.au/lambeck_k/pdf/152.pdf">isostatic rebound</a>” – the long-term uplift of land in response to the removal of ice sheets. </p>
<p>If this correlation holds for the current period of climate warming and melting of ice in high latitudes, there’ll be an increased risk of volcanic eruptions and associated hazards, including tsunamis.</p>
<h2>5. Increased earthquakes</h2>
<p>There are a number ways climate change can increase the frequency of earthquakes, and so increase tsunami risk. </p>
<p>First, the weight of ice sheets may be <a href="https://royalsocietypublishing.org/doi/10.1098/rsta.2010.0031">suppressing fault movement and earthquakes</a>. When the ice melts, the isostatic rebound (land uplift) is accompanied by an increase in earthquakes and fault movement as the crust adjusts to the loss of weight. </p>
<p>We may have seen this already in <a href="http://www.geotimes.org/oct04/NN_glacier.html">Alaska</a>, where melting glaciers reduced the stability of faults, inducing many small earthquakes and <a href="https://www.sciencedirect.com/science/article/pii/S0921818104000487?casa_token=BGo_KzIOuJkAAAAA:UHyQvV-tvVulwAfvOFPJILcG2206iyZhOM9TCVS_VAh0UdLimWrfu_NJRTHJVtwlKBL0cfA">possibly the magnitude 7.2 St Elias earthquake</a> in 1979.</p>
<p>Another factor is low air pressure associated with storms and typhoons, which studies have also shown can trigger earthquakes in areas where the Earth’s crust is already under stress. Even relatively small changes in air pressure can trigger fault movements, as <a href="https://www.nature.com/articles/nature08042">an analysis</a> of earthquakes between 2002 and 2007 in eastern Taiwan identified. </p>
<h2>So how can we prepare?</h2>
<p>Many mitigation strategies for climate change should also include elements to improve tsunami preparedness. </p>
<p>This could include incorporating projected sea level rise into tsunami prediction models, and in building codes for infrastructure along vulnerable coastlines. </p>
<p>Researchers can also ensure scientific models of climate impacts include the projected increase in earthquakes, landslides and volcanic activity, and the increased tsunami risk this will bring.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-causes-a-tsunami-an-ocean-scientist-explains-the-physics-of-these-destructive-waves-175213">What causes a tsunami? An ocean scientist explains the physics of these destructive waves</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/175247/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jane Cunneen does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Climate change doesn’t just affect the atmosphere and the oceans, it affects the Earth’s crust as well.
Jane Cunneen, Adjunct Research Fellow, Curtin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/175407
2022-01-23T13:45:22Z
2022-01-23T13:45:22Z
Why the Tonga volcano cued tsunami warnings for the North American Pacific coast
<figure><img src="https://images.theconversation.com/files/442034/original/file-20220121-17-1okcqhy.jpg?ixlib=rb-1.1.0&rect=0%2C11%2C4000%2C2646&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Beachgoers watch waters rise during a tsunami advisory on a beach in Santa Cruz, Calif.</span> <span class="attribution"><span class="source">(AP Photo/Nic Coury) </span></span></figcaption></figure><p>On Jan. 15, a tsunami warning went out to residents of British Columbia and the west coast of the United States. The warning was issued <a href="https://www.emergencyinfobc.gov.bc.ca/tsunami-advisory-bc-jan15/">after the eruption of the Hunga-Tonga-Hunga-Ha'apai volcano in Tonga</a> in the Southwest Pacific.</p>
<p>Tsunami literally means “<a href="http://itic.ioc-unesco.org/index.php?option=com_content&view=article&id=1162">harbour wave</a>” in Japanese — a tsunami comprises a series of waves separated by 10 to 60 minutes. While wind waves reach a maximum height and later crash, a tsunami wave is a massive water mass moving with great height and speed, bringing debris and boulders from the bottom of the ocean with it. The force of this water wall can have enough force to knock down an adult, move cars and destroy buildings that aren’t tsunami-proof.</p>
<p>Tsunamis are generated when great masses of water move suddenly and with great force, such as the seafloor elevating quickly, as in an earthquake, landslide or <a href="https://doi.org/10.1007/s11069-013-0822-8">volcanic eruption</a>. Ten years ago, <a href="https://doi.org/10.1007/s00024-014-0775-1">an earthquake in Haida Gwaii, B.C.</a>, resulted in <a href="https://www.earthquakescanada.nrcan.gc.ca/recent/2012/20121028.0304/index-en.php">the evacuation of areas as far away as Hawaii due to the threat of a tsunami</a>.</p>
<h2>Tonga eruption</h2>
<p>The massive underwater eruption of the <a href="https://apogeospatial.com/the-story-of-hunga-tonga-hunga-haapai-island-in-the-kingdom-of-tonga/">volcanic island Hunga-Tonga-Hunga-Ha'apai</a> contained a level of force only seen once every 1,000 years, creating the conditions for a tsunami that could travel across the Pacific Ocean.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-the-volcanic-eruption-in-tonga-was-so-violent-and-what-to-expect-next-175035">Why the volcanic eruption in Tonga was so violent, and what to expect next</a>
</strong>
</em>
</p>
<hr>
<p><a href="https://www.whoi.edu/oceanus/feature/mid-atlantic-ridge-volcanic-processes/">There are many underwater volcanoes, that constantly erupt, such as those in the mid-Atlantic ridge</a>. Most volcanic eruptions near or underwater generate waves only noticeable to measuring instruments. </p>
<p>What made the eruption in Tonga different? Usually, magma is released from these volcanoes slowly, which allows the water to provide insulation and cool the outer surface of the magma. And although the Hunga Tonga-Hunga Ha'apai has had other eruptions in the past decades, these haven’t reached the level of explosivity and energy this one presented. <a href="https://eos.org/science-updates/new-volcanic-island-unveils-explosive-past">Past eruptions in 2014 and 2009 were related to the sides of the volcano</a>, while this 2022 eruption most likely was the the “centre” of the volcano — the caldera — collapsing.</p>
<h2>Travelling waves</h2>
<p>Tsunami alerts may be issued even if the eruption or earthquake occurs on the other side of the world. The waves produced by an earthquake or eruption in this case may <a href="http://www.tulane.edu/%7Esanelson/Natural_Disasters/tsunami.htm">travel through the ocean with a speed of roughly 890 km/hr</a> (assuming an average ocean depth of six kilometres). For comparison, that is <a href="https://modernairliners.com/boeing-787-dreamliner/boeing-787-dreamliner-specs/">the same speed of a Boeing 787 Dreamliner on a transcontinental flight</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1482449815019659269"}"></div></p>
<p>On the open sea, the waves are fast but their height is hardly distinguishable. When approaching shallower waters near the coasts, the speed of the wave decreases, but its height increases. Changing depths of the ocean floor allow the crests of the waves to increase in energy and height as they get closer to the coast. This is why tsunamis are so hazardous at the coasts — a wall of water moving towards the coast can quickly reach heights from tens of centimetres to tens of metres. One of the highest heights recorded was in 2011, <a href="https://www.ncei.noaa.gov/news/day-2011-japan-earthquake-and-tsunami">when a tsunami wave reached 40 metres high in Japan</a>.</p>
<p>In the case of the waves generated by the eruption in Tonga, some coasts were hit with waves that were <a href="http://www.ioc-sealevelmonitoring.org/station.php?code=hilo">one metre high in Hilo, Hawaii</a>, and <a href="https://www.japantimes.co.jp/news/2022/01/16/national/japan-tsunami-tonga-volcano/">up to two metres in Japan</a>, where conditions allow for waves to reflect. </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CYxAbpsvS80/?utm_source=ig_embed\u0026ig_rid=af50925c-7984-4a1c-a3f2-d62d6947531f","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>For people 9,000 kilometres away from an eruption — like the west coast of continental North America — there is plenty of time to send alerts and prepare. On Vancouver Island and Haida Gwaii, authorities requested that people stay in place and not head to the shores. Tsunami waves may not always occur with great force, but shallow coastlines may flood.</p>
<p>With the threat of tsunamis on the B.C. coast produced by the Tonga explosion, authorities had time to prepare and notify residents. But unlike volcanic explosions, earthquakes are far more difficult to forecast, and often do not provide advance notice.</p>
<h2>Tsunami preparation</h2>
<p>Tsunami alerts activate an emergency response, and when the threat is not realized, it produces an opportunity to assess how people respond in advance of potentially more devastating events, <a href="https://www.cbc.ca/news/canada/british-columbia/haida-gwaii-earthquake-tsunami-evacuation-1.5745739">like a closer eruption or a significant earthquake</a>.</p>
<p>While B.C.’s tsunami advisory was lifted, tsunamogenic earthquakes — those that may result in tsunamis — are a threat in locations <a href="https://www.nationalgeographic.org/article/plate-tectonics-ring-fire/">situated on the Ring of Fire, around the coasts of the Pacific Ocean</a>.</p>
<p>For people living on coastal areas at risk of tsunamis, the B.C. government recommends that they <a href="https://www.emergencyinfobc.gov.bc.ca/resources/">stay away from the shoreline during advisories and follow any emergency instructions</a>.</p><img src="https://counter.theconversation.com/content/175407/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cindy Mora-Stock does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Tsunamis can be generated by underwater volcanic explosions thousands of miles away. The Jan. 15 explosion in Tonga resulted in tsunami advisories for British Columbia and all along the U.S. west coast.
Cindy Mora-Stock, Postdoctoral Research Associate, Earth Science Department and Statistics and Actuarial Sciences Department, Western University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/175408
2022-01-21T15:01:56Z
2022-01-21T15:01:56Z
Underwater volcanoes: how ocean colour changes can signal an imminent eruption
<p>The scale of a recent volcano eruption took the people of Tonga by surprise. Scientists monitoring the submarine volcano, Hunga Tonga-Hunga Ha'apai, were likewise caught off-guard, failing to foresee an explosion which would unleash <a href="https://apnews.com/article/tonga-volcano-eruption-impact-whats-next-01288e5ecc43aa9a9bf3bc2803efd7e2">a Pacific-wide tsunami</a>.</p>
<p>The scale of the eruption was hailed as a “<a href="https://edition.cnn.com/2022/01/17/opinions/tonga-volcano-eruption-tsunami-lessons/">once in a millenium</a>” event by one scientist. It hurled gasses and ash over 39km <a href="https://www.space.com/tonga-volcano-eruption-wont-cool-climate">into the atmosphere</a> – comparable to that ejected from Mount Pinatubo in 1991 – and generated a shock wave that was <a href="https://www.sciencemediacentre.co.nz/2022/01/17/tonga-undersea-eruption-and-tsunami-expert-reaction/">heard in New Zealand</a> and detected <a href="https://twitter.com/WMO/status/1482487745167691783?s=20">as far away as Switzerland</a>. </p>
<p>Scientists estimate that the blast may have been the loudest terrestrial event since the <a href="https://www.npr.org/2022/01/18/1073800454/nasa-scientists-estimate-tonga-blast-at-10-megatons?t=1642717816702">eruption of Krakatoa in 1883</a>, while an organisation which monitors nuclear tests went so far as to <a href="https://www.gpb.org/news/2022/01/21/nuclear-test-monitor-calls-tonga-volcano-blast-biggest-thing-weve-ever-seen">declare</a> it “the biggest thing we have ever seen”.</p>
<p>The volcano had been active a few times in recent years, with moderate eruptions that only amounted to <a href="https://volcano.si.edu/volcano.cfm?vn=243040">local disturbance</a>. The lack of warning for an event this large left many wondering if there might be other volcanoes beneath the ocean similarly primed to blow.</p>
<p>To study volcanoes and interpret whether they’re likely to erupt, scientists mount them with different kinds of measuring equipment. Seismometers help them detect small tremors caused by magma moving under the ground, while gas samplers and thermal cameras can be used to track changes in gas concentrations and temperature as magma ascends from the depths.</p>
<p>It’s rarely acknowledged, however, that most volcanic activity on Earth occurs beneath the sea. Submarine volcanoes are pretty much ubiquitous in all of the world’s major oceans and it’s estimated that <a href="https://volcano.oregonstate.edu/submarine">75%</a> of the Earth’s magma output comes from mid-ocean ridges.</p>
<p>To make things trickier, many known submarine volcanoes are found far from land, and being underwater prevents scientists from observing any changes by conventional means. So how do we monitor them?</p>
<p>Scientists have managed to install equipment that detects tell-tale tremors on the sea bed before. This research has helped reveal the <a href="https://www.nature.com/articles/ngeo1490">seismic precursors</a> of a submarine eruption – the signs that one is imminent – similar to what scientists had already documented in volcanoes on land. Installing this equipment does not come cheap though, and it’s not possible to do it everywhere. </p>
<p>An impending eruption can be detected in subtle temperature increases on the volcanic surface. For submarine volcanoes, these are harder to spot. The heat signatures of submarine volcanoes will only ever be visible at the sea surface if a volcano is in shallow water and already erupting hot lava. At that point, it’s too late to warn anybody.</p>
<p>To really find out what submarine volcanoes are up to, it helps to zoom out. Way out.</p>
<h2>Monitoring from space</h2>
<p>Satellite observations allow scientists to regularly view vast areas of the ocean surface, helping them note any changes. On numerous occasions, scientists have spotted <a href="https://eos.org/science-updates/satellite-sleuthing-detects-underwater-eruptions">floating rafts of pumice</a> which can be traced back to submarine eruptions that might otherwise have gone undetected. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/wildfires-volcanoes-and-climate-change-how-satellites-tell-the-story-of-our-changing-world-100415">Wildfires, volcanoes and climate change: how satellites tell the story of our changing world</a>
</strong>
</em>
</p>
<hr>
<p>But this only allows us to identify eruptions after they have happened – it doesn’t help us stay a step ahead of underwater volcanoes.</p>
<p>Recent scientific advances can, however. In the <a href="https://www.jstage.jst.go.jp/article/kazan/38/3/38_KJ00003457971/_pdf">early 1990s</a>, Japanese scientists investigated a long-noted phenomenon: the strange discolouration of the ocean near submarine volcanoes off the island of Iōjima. They determined that it was caused by precipitates of silicon, iron and aluminium oxides emitted by underwater volcanic activity. </p>
<p>Later work confirmed that a higher proportion of iron precipitates produces a yellow-brown hue, while higher proportions of aluminium or silicon result in <a href="http://www.kazan-g.sakura.ne.jp/E/index.html">a white colour</a>. Scientists <a href="https://www.mdpi.com/2073-4441/13/8/1100/htm#B13-water-13-01100">revisited these findings</a> during submarine eruptions around another volcanic Japanese island, Nishinoshima. In satellite photographs of Earth’s surface, the ocean was seen to turn varying shades of yellow, brown and green, depending on the ratio of silicon to iron and aluminium. </p>
<figure class="align-center ">
<img alt="A rocky seafloor with streams of bubbles emanating from it." src="https://images.theconversation.com/files/441991/original/file-20220121-23-16jbp93.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441991/original/file-20220121-23-16jbp93.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441991/original/file-20220121-23-16jbp93.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441991/original/file-20220121-23-16jbp93.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441991/original/file-20220121-23-16jbp93.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441991/original/file-20220121-23-16jbp93.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441991/original/file-20220121-23-16jbp93.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Bubbles rise from the seafloor near an active volcano in Indonesia.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/bubbles-rise-seafloor-near-active-volcano-659122135">Ethan Daniels/Shutterstock</a></span>
</figcaption>
</figure>
<p>With this finding, scientists discovered that the colour of the ocean began to change about a month before the submarine volcano erupted. This suggests that ocean colour may be a reliable precursor of underwater volcanic activity. And, given this insight, there is every possibility that in the future, automated systems could analyse satellite images of the ocean in volcanic regions for signs of an impending eruption.</p>
<p>The destruction wrought by the submarine eruption of Hunga Tonga-Hunga Ha'apai appears to be intense. The tsunami that followed obliterated coastal areas of Tonga and even caused <a href="https://www.independent.co.uk/news/world/australasia/tonga-volcano-peru-women-drowning-b1994501.html">deaths</a> thousands of miles away in Peru. Ash coated the island, destroying crops and shutting down transport networks.</p>
<p>Had an early warning been available, perhaps on the scale of weeks as <a href="https://www.mdpi.com/2073-4441/13/8/1100/htm#B13-water-13-01100">research suggests</a> might be possible one day, it would have let people on Tonga stock up on food and water and evacuate vulnerable regions. This <a href="https://www.newscientist.com/article/2304822-volcano-eruption-in-tonga-was-a-once-in-a-millennium-event/">once in a millennium</a> tragedy might at least stimulate further research into monitoring and predicting the ever-present hazard of submarine volcanic eruptions.</p><img src="https://counter.theconversation.com/content/175408/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Blackett does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Monitoring volcanoes is a bit trickier when they’re deep under the ocean’s surface.
Matthew Blackett, Reader in Physical Geography and Natural Hazards, Coventry University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/175048
2022-01-17T05:50:01Z
2022-01-17T05:50:01Z
The Tonga volcanic eruption has revealed the vulnerabilities in our global telecommunication system
<p>In the wake of a violent volcanic eruption in Tonga, much of the communication with residents on the islands remains at a standstill. In our modern, highly-connected world, more than 95% of global data transfer occurs along fibre-optic cables that criss-cross <a href="https://www.navy.gov.au/media-room/publications/semaphore-02-12">through the world’s oceans</a>. </p>
<p>Breakage or interruption to this critical infrastructure can have catastrophic local, regional and even global consequences. This is exactly what has happened in Tonga following Saturday’s volcano-tsunami disaster. But this isn’t <a href="https://www.jstor.org/stable/24862155">the first time</a> a natural disaster has cut off critical submarine cables, and it won’t be the last.</p>
<p>The video below shows the incredible spread of submarine cables around the planet – with more than 885,000 kilometres of cable laid down since 1989. These cables cluster in narrow corridors and pass between so-called critical “choke points” which leave them vulnerable to a number of natural hazards including volcanic eruptions, underwater landslides, earthquakes <a href="https://brill.com/view/book/edcoll/9789004260337/B9789004260337_012.xml">and tsunamis</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/6dkiqJ_IZGw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Animation of spread of global submarine cable network between 1989 and 2023.</span></figcaption>
</figure>
<h2>What exactly has happened in Tonga?</h2>
<p>Tonga was only connected to the <a href="https://www.adb.org/documents/tonga-tonga-fiji-submarine-cable-project-0">global submarine telecommunication network in the last decade</a>. Its islands have been heavily reliant on this system as it is more stable than other technologies such as satellite and fixed infrastructure. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-the-volcanic-eruption-in-tonga-was-so-violent-and-what-to-expect-next-175035">Why the volcanic eruption in Tonga was so violent, and what to expect next</a>
</strong>
</em>
</p>
<hr>
<p>The situation in Tonga right now is still fluid, and certain details have yet to be confirmed – but it seems one or more volcanic processes (such as the tsunami, submarine landslide or other underwater currents) have snapped the 872km long fibre-optic cable connecting Tonga to the rest of the world. The cable system was not switched off or disconnected by the authorities. </p>
<p>This has had a massive impact. Tongans living in Australia and New Zealand <a href="https://www.abc.net.au/news/2022-01-17/sydney-tongan-community-struggles-to-reach-family-after-tsunami/100759686">can’t contact their loved ones to check on them</a>. It has also made it difficult for Tongan <a href="https://www.abc.net.au/news/2022-01-17/tonga-volcano-surveillance-flights-tsunami-warning-damage/100760394">government officials</a> and emergency services to communicate with each other, and for local communities to determine aid and recovery needs. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1482483452687839232"}"></div></p>
<p>Telecommunications are down, as are regular internet functions – and outages keep disrupting online services, making things worse. Tonga is particularly vulnerable to this type of disruption as there is only <a href="http://www.fiberatlantic.com/system/W6qDg">one cable</a> connecting the capital Nuku'alofa to Fiji, which is more than 800km away. No inter-island cables exist.</p>
<h2>Risks to submarine cables elsewhere</h2>
<p>The events in Tonga once again highlight how fragile the global undersea cable network is and how quickly it can go offline. In 2009, <a href="https://nhess.copernicus.org/articles/9/605/2009/nhess-9-605-2009.pdf">I coauthored a study</a> detailing the vulnerabilities of the submarine telecommunications network to a variety of natural hazard processes. And nothing has changed since then.</p>
<p>Cables are laid in the shortest (that means cheapest) distance between two points on the Earth’s surface. They also have to be laid along particular geographic locations that allow easy placement, which is why many cables are clustered in choke points. </p>
<p>Some good examples of choke points include the Hawaiian islands, the Suez Canal, Guam and the Sunda Strait in Indonesia. Inconveniently, these are also locations where major natural hazards tend to occur.</p>
<p>Once damaged it can takes days to weeks (or even longer) to repair broken cables, depending on the cable’s depth and how easily accessible it is. At times of crisis, such outages make it much harder for governments, emergency services and charities to engage in recovery efforts.</p>
<p>Many of these undersea cables pass close to or directly over active volcanoes, regions impacted by tropical cyclones and/or active earthquake zones. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/441004/original/file-20220117-23-1e5gmmf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="https://blog.apnic.net/2021/01/13/how-critical-are-submarine-cables-to-end-users/" src="https://images.theconversation.com/files/441004/original/file-20220117-23-1e5gmmf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441004/original/file-20220117-23-1e5gmmf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=352&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441004/original/file-20220117-23-1e5gmmf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=352&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441004/original/file-20220117-23-1e5gmmf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=352&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441004/original/file-20220117-23-1e5gmmf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=443&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441004/original/file-20220117-23-1e5gmmf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=443&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441004/original/file-20220117-23-1e5gmmf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=443&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tonga is connected to the rest of the world via a global network of submarine cables.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/441005/original/file-20220117-19-jexwm9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/441005/original/file-20220117-19-jexwm9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441005/original/file-20220117-19-jexwm9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=295&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441005/original/file-20220117-19-jexwm9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=295&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441005/original/file-20220117-19-jexwm9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=295&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441005/original/file-20220117-19-jexwm9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=370&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441005/original/file-20220117-19-jexwm9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=370&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441005/original/file-20220117-19-jexwm9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=370&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In this map you can see the global plate tectonic boundaries (dashed lines) where most volcanic eruptions and earthquakes occur, approximate cyclone/hurricane zone (blue lines) and locations of volcanic regions (red triangles). Significant zones where earthquakes and tsunami occur are marked.</span>
<span class="attribution"><a class="source" href="https://nhess.copernicus.org/articles/9/605/2009/">Author provided</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In many ways, Australia is also very vulnerable (as is New Zealand and the rest of the world) since we are connected to the global cable network by a very small number of connection points, from just Sydney and Perth. </p>
<p>In regards to Sydney and the eastern seaboard of Australia, we <a href="https://link.springer.com/article/10.1007/s10346-019-01223-6">know large underwater landslides have occurred off the coast of Sydney in the past</a>. Future events could damage the critical portion of the network which links to us.</p>
<h2>How do we manage risk going forward?</h2>
<p>Given the vulnerability of the network, the first step to mitigating risk is to undertake research to quantify and evaluate the actual risk to submarine cables in particular places on the ocean floors and to different types of natural hazards. For example, tropical cyclones (hurricanes/typhoons) occur regularly, but other disaster such as earthquakes and volcanic eruptions happen less often.</p>
<p>Currently, there is little publicly available data on the risk to the global submarine cable network. Once we know which cables are vulnerable, and to what sorts of hazards, we can then develop plans to reduce risk. </p>
<p>At the same time, governments and the telecommunication companies should find ways to diversify the way we communicate, <a href="https://www.hindawi.com/journals/wcmc/2019/6243505/">such as by using more satellite-based systems</a> and other technologies.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/undersea-internet-cables-connect-pacific-islands-to-the-world-but-geopolitical-tension-is-tugging-at-the-wires-167968">Undersea internet cables connect Pacific islands to the world. But geopolitical tension is tugging at the wires</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/175048/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dale Dominey-Howes receives funding from the Australian Research Council, National Disaster Resilience Program and Global Resilience Partnership. </span></em></p>
Future events could damage the critical portion of the undersea network which links to Australia.
Dale Dominey-Howes, Professor of Hazards and Disaster Risk Sciences, University of Sydney
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/175035
2022-01-15T20:04:22Z
2022-01-15T20:04:22Z
Why the volcanic eruption in Tonga was so violent, and what to expect next
<p>The Kingdom of Tonga doesn’t often attract global attention, but a <a href="https://www.rnz.co.nz/international/pacific-news/459572/underwater-volcano-hunga-tonga-hunga-ha-apai-erupts-again">violent eruption of an underwater volcano</a> on January 15 has spread shock waves, quite literally, around half the world. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1482259999724535809"}"></div></p>
<p>The volcano is usually not much to look at. It consists of two small uninhabited islands, Hunga-Ha’apai and Hunga-Tonga, poking about 100m above sea level 65km north of Tonga’s capital Nuku‘alofa. But hiding below the waves is a massive volcano, around 1800m high and 20km wide.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/440948/original/file-20220115-27-82tzyq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of the massive underwater volcano next to the Hunga-Ha’apai and Hunga-Tonga islands." src="https://images.theconversation.com/files/440948/original/file-20220115-27-82tzyq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440948/original/file-20220115-27-82tzyq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=658&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440948/original/file-20220115-27-82tzyq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=658&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440948/original/file-20220115-27-82tzyq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=658&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440948/original/file-20220115-27-82tzyq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=827&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440948/original/file-20220115-27-82tzyq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=827&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440948/original/file-20220115-27-82tzyq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=827&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A massive underwater volcano lies next to the Hunga-Ha’apai and Hunga-Tonga islands.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The Hunga-Tonga-Hunga-Ha'apai volcano has erupted regularly over the past few decades. During events in 2009 and 2014/15 hot jets of magma and steam exploded through the waves. But these eruptions were small, dwarfed in scale by the January 2022 events.</p>
<p>Our <a href="https://eos.org/science-updates/new-volcanic-island-unveils-explosive-past">research</a> into these earlier eruptions suggests this is one of the massive explosions the volcano is capable of producing roughly every thousand years. </p>
<p>Why are the volcano’s eruptions so highly explosive, given that sea water should cool the magma down?</p>
<p>If magma rises into sea water slowly, even at temperatures of about 1200°C, a thin film of steam forms between the magma and water. This provides a layer of insulation to allow the outer surface of the magma to cool. </p>
<p>But this process doesn’t work when magma is blasted out of the ground full of volcanic gas. When magma enters the water rapidly, any steam layers are quickly disrupted, bringing hot magma in direct contact with cold water. </p>
<p>Volcano researchers call this “fuel-coolant interaction” and it is akin to weapons-grade chemical explosions. Extremely violent blasts tear the magma apart. A chain reaction begins, with new magma fragments exposing fresh hot interior surfaces to water, and the explosions repeat, ultimately jetting out volcanic particles and causing blasts with supersonic speeds. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-pulse-of-a-volcano-can-be-used-to-help-predict-its-next-eruption-117005">The 'pulse' of a volcano can be used to help predict its next eruption</a>
</strong>
</em>
</p>
<hr>
<h2>Two scales of Hunga eruptions</h2>
<p>The 2014/15 eruption created a volcanic cone, joining the two old Hunga islands to create a combined island about 5km long. We visited in 2016, and discovered these historical eruptions were merely <a href="https://eos.org/science-updates/new-volcanic-island-unveils-explosive-past">curtain raisers to the main event</a>. </p>
<p>Mapping the sea floor, we discovered a hidden “caldera” 150m below the waves. </p>
<figure class="align-center ">
<img alt="A map of the seafloor shows the volcanic cones and caldera." src="https://images.theconversation.com/files/440944/original/file-20220115-19-nplel8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440944/original/file-20220115-19-nplel8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=660&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440944/original/file-20220115-19-nplel8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=660&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440944/original/file-20220115-19-nplel8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=660&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440944/original/file-20220115-19-nplel8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=829&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440944/original/file-20220115-19-nplel8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=829&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440944/original/file-20220115-19-nplel8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=829&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A map of the seafloor shows the volcanic cones and massive caldera.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The caldera is a crater-like depression around 5km across. Small eruptions (such as in 2009 and 2014/15) occur mainly at the edge of the caldera, but very big ones come from the caldera itself. These big eruptions are so large the top of the erupting magma collapses inward, deepening the caldera. </p>
<p>Looking at the chemistry of past eruptions, we now think the small eruptions represent the magma system slowly recharging itself to prepare for a big event.</p>
<p>We found evidence of two huge past eruptions from the Hunga caldera in deposits on the old islands. We matched these chemically to volcanic ash deposits on the largest inhabited island of Tongatapu, 65km away, and then used radiocarbon dates to show that big caldera eruptions occur about ever 1000 years, with the last one at AD1100. </p>
<p>With this knowledge, the eruption on January 15 seems to be right on schedule for a “big one”. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-white-island-erupted-and-why-there-was-no-warning-128550">Why White Island erupted and why there was no warning</a>
</strong>
</em>
</p>
<hr>
<h2>What we can expect to happen now</h2>
<p>We’re still in the middle of this major eruptive sequence and many aspects remain unclear, partly because the island is currently obscured by ash clouds. </p>
<p>The two earlier eruptions on December 20 2021 and January 13 2022 were of moderate size. They produced clouds of up to 17km elevation and added new land to the 2014/15 combined island.</p>
<p>The latest eruption has stepped up the scale in terms of violence. The ash plume is already about 20km high. Most remarkably, it spread out almost concentrically over a distance of about 130km from the volcano, creating a plume with a 260km diameter, before it was distorted by the wind. </p>
<p><img src="https://cdn.theconversation.com/static_files/files/1920/2022-01_volcano_jan_13_ash%281%29.gif?1642274062" width="100%"></p>
<p>This demonstrates a huge explosive power – one that cannot be explained by magma-water interaction alone. It shows instead that large amounts of fresh, gas-charged magma have erupted from the caldera.</p>
<p>The eruption also produced a <a href="https://www.theguardian.com/world/2022/jan/15/tonga-tsunami-warning-as-volcano-erupts-at-sea">tsunami throughout Tonga</a> and neighbouring Fiji and Samoa. Shock waves traversed many thousands of kilometres, were seen from space, and recorded in New Zealand some 2000km away. Soon after the eruption started, the sky was blocked out on Tongatapu, with ash beginning to fall.</p>
<p>All these signs suggest the large Hunga caldera has awoken. Tsunami are generated by coupled atmospheric and ocean shock waves during an explosion, but they are also readily caused by submarine landslides and caldera collapses.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1473857092364771336"}"></div></p>
<p>It remains unclear if this is the climax of the eruption. It represents a major magma pressure release, which may settle the system. </p>
<p>A warning, however, lies in geological deposits from the volcano’s previous eruptions. These complex sequences show each of the 1000-year major caldera eruption episodes involved many separate explosion events. </p>
<p>Hence we could be in for several weeks or even years of major volcanic unrest from the Hunga-Tonga-Hunga-Ha'apai volcano. For the sake of the people of Tonga I hope not.</p><img src="https://counter.theconversation.com/content/175035/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shane Cronin receives funding from The University of Auckland Faculty of Science to study the 2014-2015 Hunga eruption.</span></em></p>
The eruption is akin to a weapons-grade chemical explosion, and there could be several weeks or even years of major volcanic unrest to follow.
Shane Cronin, Professor of Earth Sciences, University of Auckland, Waipapa Taumata Rau
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/170919
2022-01-03T13:42:00Z
2022-01-03T13:42:00Z
Why can’t we throw all our trash into a volcano and burn it up?
<figure><img src="https://images.theconversation.com/files/435952/original/file-20211206-141213-f6fuq.jpg?ixlib=rb-1.1.0&rect=49%2C0%2C5472%2C3645&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lava flows from a fissure in the aftermath of eruptions from the Kilauea volcano on Hawaii's Big Island, May 22, 2018. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/lava-flows-from-a-fissure-in-the-aftermath-of-eruptions-news-photo/962057980">Andrew Richard Hara/Ena Media Hawaii via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>Why can’t we throw all our trash into a volcano and burn it up? – Georgine T.</strong></p>
</blockquote>
<hr>
<p>It’s true that lava is hot enough to burn up some of our trash. When Kilauea erupted on the Big island of Hawaii in 2018, the lava flows were <a href="https://www.usgs.gov/media/images/lava-temperatures-were-about-2000-degrees-fahrenheit">hotter than 2,000 degrees Fahrenheit (1,100 Celsius)</a>. That’s hotter than <a href="https://solarsystem.nasa.gov/planets/venus/overview/">the surface of the planet Venus</a>, and hot enough to melt many rocks. It’s also as hot as waste incinerators, which usually burn garbage at <a href="https://www3.epa.gov/ttnchie1/mkb/documents/fthermal.pdf">1,800 to 2,200 F</a> (1,000-1,200 C). </p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>But not all lavas are the same temperature. The eruptions in Hawaii produce a type of lava called <a href="https://volcanoes.usgs.gov/vsc/glossary/basalt.html">basalt</a>. Basalt is much hotter and more fluid than the lavas that erupt at other volcanoes, like the thicker <a href="https://volcanoes.usgs.gov/vsc/glossary/dacite.html">dacite lava</a> that erupts at Mount St. Helens in Washington state. For example, the 2004-2008 eruption at Mount St. Helens produced a lava dome with surface temperatures less than about 1,300 F (704 C). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/435957/original/file-20211206-21-16nxx9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Infographic on number and location of U.S. volcanoes" src="https://images.theconversation.com/files/435957/original/file-20211206-21-16nxx9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/435957/original/file-20211206-21-16nxx9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/435957/original/file-20211206-21-16nxx9j.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/435957/original/file-20211206-21-16nxx9j.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/435957/original/file-20211206-21-16nxx9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/435957/original/file-20211206-21-16nxx9j.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/435957/original/file-20211206-21-16nxx9j.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">There are 161 volcanoes in 14 U.S. states and territories. Scientists monitor them and warn nearby communities if they see signs that a volcano may erupt.</span>
<span class="attribution"><a class="source" href="https://www.usgs.gov/media/images/us-one-earths-most-volcanically-active-countries">USGS</a></span>
</figcaption>
</figure>
<p>Beyond temperature, there are other good reasons not to burn our trash in volcanoes. First, although lava at 2,000 degrees F can melt many materials in our trash – including food scraps, paper, plastics, glass and some metals – it’s not hot enough to melt many other common materials, including <a href="https://www.americanelements.com/meltingpoint.html">steel, nickel and iron</a>. </p>
<p>Second, there aren’t many volcanoes on Earth that have lava lakes, or bowl-like craters full of lava, that we could dump trash into. Of all of the thousands of volcanoes on Earth, scientists know of only <a href="https://www.bbc.co.uk/newsround/48856373">eight with active lava lakes</a>. They include <a href="https://www.usgs.gov/media/images/new-usgs-video-about-k-laueas-summit-eruption-now-online">Kilauea</a>, <a href="https://volcano.si.edu/volcano.cfm?vn=390020">Mount Erebus in Antarctica</a> and <a href="https://volcano.si.edu/volcano.cfm?vn=223030">Nyiragongo in the Democratic Republic of the Congo</a>. Most active volcanoes have craters filled with rocks and cooled lava, like <a href="https://www.usgs.gov/volcanoes/mount-st-helens/lava-flows-mount-st-helens">Mount St. Helens</a>, or with water, like <a href="https://www.usgs.gov/media/images/crater-lake-caldera-wizard-island-cinder-cone-and-lava-flows">Crater Lake in Oregon</a>. </p>
<p>The third problem is that dumping trash into those eight active lava lakes would be a very dangerous job. Lava lakes are covered with a crust of cooling lava, but just below that crust they are molten and intensely hot. If rocks or other materials fall onto the surface of a lava lake, they will break the crust, disrupt the underlying lava and cause an explosion. </p>
<p>This happened at Kilauea in 2015: Blocks of rock from the crater rim fell into the lava lake and caused a big explosion that <a href="https://www.usgs.gov/media/videos/rockfall-and-explosion-halemaumau-crater">ejected rocks and lava up and out of the crater</a>. Anyone who threw garbage into a lava lake would have to run away and dodge flaming garbage and lava.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/w8IaG2U65Is?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An eruption from the Cumbre Vieja volcano on the Spanish island of La Palma on Sept. 30, 2021, produced clouds of toxic gas.</span></figcaption>
</figure>
<p>Suppose it was possible to dump trash safely into a lava lake: What would happen to the trash? When plastics, garbage and metals burn, they release a lot of toxic gases. Volcanoes already give off tons of toxic gases, including sulfur, chlorine and carbon dioxide. </p>
<p>Sulfur gases can create acidic fog, which we call “vog,” for “volcanic fog.” It can <a href="https://www.usgs.gov/observatories/hawaiian-volcano-observatory/volcanic-gas">kill plants and cause breathing problems for people nearby</a>. Mixing these already-dangerous volcanic gases with other gases from burning our trash would make the resulting fumes even more harmful for <a href="https://www.usgs.gov/media/images/lava-breakouts-access_road">people and plants near the volcano</a>. </p>
<p>Finally, many indigenous communities view nearby volcanoes as sacred places. For example, Halema’uma’u crater at Kilauea is considered the home of Pele, the native Hawaiian goddess of fire, and the area around the crater is <a href="https://www.hawaii.com/discover/culture/pele/">sacred to native Hawaiians</a>. Throwing trash into volcanoes would be a huge insult to those cultures.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/170919/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emily Johnson receives funding from the U.S. Geological Survey </span></em></p>
Volcanoes might seem like nature’s incinerators, but using them to burn up trash would be dangerous and disrespectful to indigenous people who view them as sacred.
Emily Johnson, Research Geologist, US Geological Survey
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/173240
2021-12-07T02:52:04Z
2021-12-07T02:52:04Z
Mount Semeru’s deadly eruption was triggered by rain and storms, making it much harder to predict
<p>The eruption of Mount Semeru in Indonesia on Saturday tragically claimed the lives of <a href="https://bnpb.go.id/berita/-update-lebih-dari-900-personel-gabungan-lakukan-operasi-penanganan-darurat-paska-erupsi-semeru-">22 people</a>, with another 22 still missing and 56 injured. More than <a href="https://twitter.com/BNPB_Indonesia/status/1467877286586171394?s=20">5,000 people</a> have been affected by the eruption, and more than 2,000 people have taken refuge at 19 evacuation points. </p>
<p>Saturday’s eruption produced an ash plume that reached 15km into the atmosphere, along with hot <a href="https://www.nationalgeographic.org/encyclopedia/pyroclastic-flow/">pyroclastic flows</a> – dense, fast-moving clouds of solidified lava, ash and gas. Volcanic mudflows called <a href="https://www.usgs.gov/natural-hazards/volcano-hazards/lahars-move-rapidly-down-valleys-rivers-concrete">lahars</a> also tumbled down the volcano’s steep slopes. Heavy ash blanketed nearby villages and plunged some areas into temporary darkness.</p>
<p>Several villages have been buried in up to 4 metres of volcanic material and debris, more than 3,000 buildings have been damaged, and Gladak Perak Bridge, which connected Lumajang with the nearby city of Malang, has collapsed.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1467088826304630785"}"></div></p>
<p>The Volcano Observatory Notice for Aviation (VONA) has since <a href="https://magma.vsi.esdm.go.id/vona/">reported</a> further pyroclastic flows travelling down the the volcano’s slopes, and ash plumes reaching 4.5km above its summit. There are also reports of lava flows at the summit crater.</p>
<p>Mt Semeru is one of the most active volcanoes in Java, with activity taking place in 74 of the past 80 years. The volcano’s current eruptive phase began in <a href="https://volcano.si.edu/volcano.cfm?vn=263300#November2021">2014</a>, with frequent emissions of ash plumes to hundreds of metres above the crater, pyroclastic flows and glowing lava avalanches.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/436002/original/file-20211207-19-12fid3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/436002/original/file-20211207-19-12fid3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/436002/original/file-20211207-19-12fid3g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/436002/original/file-20211207-19-12fid3g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/436002/original/file-20211207-19-12fid3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/436002/original/file-20211207-19-12fid3g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/436002/original/file-20211207-19-12fid3g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Buildings and infrastructure buried by volcanic material and debris from the eruption of Mt Semeru (source BNPB Twitter).</span>
</figcaption>
</figure>
<h2>Unexpected larger-scale eruption</h2>
<p>But Saturday’s eruption was, unexpectedly, much larger than the ongoing background of activity. The Head of the Geological Agency of the Ministry of Energy and Mineral Resources, Eko Budi Lelono, said a thunderstorm and persistent rain had eroded part of the volcano’s <a href="https://volcano.oregonstate.edu/lava-domes">lava dome</a> – a “plug” of solidified lava at the summit. This caused the dome to collapse, triggering the eruption. </p>
<p>Lava dome collapse is a common trigger of volcanic eruptions, and has been behind some of the deadliest eruptions in history. Collapse of the unstable dome of solidified lava is rather like taking the top off a fizzy drink bottle, depressurising the system and triggering an eruption. Lava domes sometimes collapse under their own weight as they grow, or they can be weakened by external weather conditions, as was evidently the case at Mt Semeru.</p>
<p>The fact that Saturday’s eruption was triggered by an external factor, rather than conditions inside the volcano, would have made this event harder to forecast. </p>
<p>Volcano monitoring typically relies on signs of increased unrest inside a volcano. Increased earthquake activity can be a sign that magma is moving around beneath the ground. Another warning sign is a change in the temperature or type of gases emitted. Sometimes, small changes in the shape of the volcano or lava dome can be detected on the ground or from satellites.</p>
<p>Another fatal, hard-to-predict explosive eruption <a href="https://theconversation.com/why-white-island-erupted-and-why-there-was-no-warning-128550">happened in 2019</a> at Whakaari (White Island) in New Zealand. That event was thought to have been driven by an explosion of pressurised steam rather than by magma, which made it challenging to predict.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-white-island-erupted-and-why-there-was-no-warning-128550">Why White Island erupted and why there was no warning</a>
</strong>
</em>
</p>
<hr>
<h2>Living with active volcanoes</h2>
<p>As the world’s population grows, more and more people are living close to active volcanoes. According to one estimate, <a href="https://www.mdpi.com/2220-9964/8/8/341">more than a billion people</a> (14% of people on the planet) live within 100km of an active volcano.</p>
<p>In Indonesia, more than 70% of the population live within 100km of one or more of the country’s 130 active volcanoes – that’s a staggering 175 million people. More than <a href="https://www.cambridge.org/core/books/global-volcanic-hazards-and-risk/populations-around-holocene-volcanoes-and-development-of-a-population-exposure-index/8CAD59A8B0CE1DF9FD72FEE7DD3CAF7F">8.6 million</a> Indonesians live within 10km of an active volcano – well within range of deadly pyroclastic flows.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/under-the-volcano-predicting-eruptions-and-coping-with-ash-rain-32899">Under the volcano: predicting eruptions and coping with ash rain</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/436000/original/file-20211207-142574-1lspy5e.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/436000/original/file-20211207-142574-1lspy5e.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=383&fit=crop&dpr=1 600w, https://images.theconversation.com/files/436000/original/file-20211207-142574-1lspy5e.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=383&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/436000/original/file-20211207-142574-1lspy5e.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=383&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/436000/original/file-20211207-142574-1lspy5e.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=481&fit=crop&dpr=1 754w, https://images.theconversation.com/files/436000/original/file-20211207-142574-1lspy5e.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=481&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/436000/original/file-20211207-142574-1lspy5e.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=481&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Active volcanoes monitored by the Indonesian Center for Volcanology and Geological Hazard Mitigation (CVGHM). Curent eruptive activity is noted by the erupting volcano symbols at Mt Merapi (orange) and Mt Semeru (yellow) in Java.</span>
</figcaption>
</figure>
<p>The fertile soils typically found near volcanoes mean these communities need to balance their livelihoods with the risks. Keeping an eye on dozens of active volcanoes poses a continuous challenge to Indonesia’s volcano monitoring and disaster management authorities.</p><img src="https://counter.theconversation.com/content/173240/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Heather Handley receives funding from the Australian Research Council. She is Co-Founder of Women in Earth and Environmental Sciences Australasia (WOMEESA) and Co-Founder of the Earth Futures Festival. Heather is Governing Councillor of the Geological Society of Australia.</span></em></p>
The eruption in East Java that claimed 22 lives on Saturday was likely triggered by weather conditions rather than by internal unrest inside Mount Semeru, which would have been easier to monitor.
Heather Handley, Adjunct Associate Professor, Monash University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/166342
2021-08-23T09:05:58Z
2021-08-23T09:05:58Z
When Greenland was green: rapid global warming 55 million years ago shows us what the future may hold
<figure><img src="https://images.theconversation.com/files/417345/original/file-20210823-27-9hufpg.JPG?ixlib=rb-1.1.0&rect=17%2C17%2C3976%2C2976&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Milo Barham</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Frozen northeast Greenland seems an unlikely place to gain insight into our ever-warming world. Between 50 million and 60 million years ago, however, the region was a different place.</p>
<p>Back then Greenland had a subtropical climate befitting of its name. It was host to volcanic activity that restructured the land and ocean connections and drove rapid warming.</p>
<p>The abrupt global warming event 56 million years ago, known as the Paleocene-Eocene Thermal Maximum (PETM), is often used as a worrying analogue for our current climate crisis. </p>
<p>Our research, published today in <a href="https://doi.org/10.1038/s43247-021-00249-w">Communications Earth and Environment</a>, provides crucial details about the event — with a focus on Greenland’s role in it. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/volcanic-emissions-caused-the-warmest-period-in-past-56m-years-new-study-82354">Volcanic emissions caused the warmest period in past 56m years – new study</a>
</strong>
</em>
</p>
<hr>
<h2>Lessons from Earth’s past</h2>
<p>About 56 million years ago, increased volcanic activity resulted in the eruption of huge volumes of molten rock, in a vast area surrounding what would eventually become Iceland. Underground, the magma essentially “cooked” sediments rich in organic material, converting the stored carbon into gas.</p>
<p>This led to trillions of tonnes of greenhouse gases being released into the atmosphere. It drove an increase in ocean acidity and a rise in global temperatures to the tune of 5-8°C. </p>
<p>The environmental and ecological consequences were immense. Mass extinctions and animal migrations took place over just a few thousand years. Fast-forward to the release of the latest <a href="https://www.ipcc.ch/">Intergovernmental Panel on Climate Change</a> report, and there has never been a greater need to understand Earth’s climate systems.</p>
<p>The geological record provides an opportunity to learn from past climate events that occurred on a timescale far longer than human lifespans or any written history. </p>
<p>Most importantly, it could forewarn us of the outcomes of Earth’s current climate upheaval which is unfolding much more rapidly.</p>
<h2>Greenland’s exotic land</h2>
<p>Northeast Greenland is the world’s largest national park, and one of the most remote and unexplored areas on the planet. </p>
<p>For our study, we set out to map the environmental evolution and geographic response to volcanic activity throughout the PETM event in northeast Greenland. Volcanic activity has been identified as the “smoking gun” for what drove the PETM warming. </p>
<p>Greenland also acted as a gatekeeper for the once-narrow seaway that connected the Arctic and Atlantic oceans (before movement of the tectonic plates opened the Atlantic more fully). </p>
<p>Greenland therefore played a significant role in regulating climate-critical ocean connections. These channels control the distribution of heat, dissolved gasses such as oxygen and carbon dioxide, nutrients and moisture in the atmosphere.</p>
<figure class="align-center ">
<img alt="Outlook across empty snowy mountains and valleys at sunset" src="https://images.theconversation.com/files/417021/original/file-20210819-17-1gtzwca.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/417021/original/file-20210819-17-1gtzwca.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/417021/original/file-20210819-17-1gtzwca.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/417021/original/file-20210819-17-1gtzwca.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/417021/original/file-20210819-17-1gtzwca.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/417021/original/file-20210819-17-1gtzwca.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/417021/original/file-20210819-17-1gtzwca.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Midnight sunset in the pristine northeast Greenland wilderness.</span>
<span class="attribution"><span class="source">Milo Barham</span></span>
</figcaption>
</figure>
<p>Our international team of geologists carefully mapped sediments and lava flows onshore in northeast Greenland, and in rock cores extracted from the nearby sea bed.</p>
<p>We identified and dated various microscopic plant and plankton fossils, which provided detailed information about the environment they would have lived in. This was combined with findings gleaned from tracing the echoes of sound waves under the seabed. </p>
<p>By measuring how sound waves are reflected by buried sediment, we mapped the thickness and development of the geological layers. This revealed how the landscape, now partly covered by ocean, evolved over time.</p>
<p>With this, we carefully resurrected an image of northeast Greenland as it was between 47 and 63 million years ago.</p>
<h2>A hotter, wetter planet</h2>
<p>We discovered that around the time of the PETM, volcanic uplift turned deeper marine environments around northeast Greenland into shallow estuaries, rivers and vegetated swampy floodplains.</p>
<figure class="align-center ">
<img alt="Layers of fossil leaves" src="https://images.theconversation.com/files/417023/original/file-20210819-27-1qqdyt6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/417023/original/file-20210819-27-1qqdyt6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=217&fit=crop&dpr=1 600w, https://images.theconversation.com/files/417023/original/file-20210819-27-1qqdyt6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=217&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/417023/original/file-20210819-27-1qqdyt6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=217&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/417023/original/file-20210819-27-1qqdyt6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=273&fit=crop&dpr=1 754w, https://images.theconversation.com/files/417023/original/file-20210819-27-1qqdyt6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=273&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/417023/original/file-20210819-27-1qqdyt6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=273&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some carbonised fossil leaf impressions in finely laminated sediment, retrieved from the Wollaston Forland peninsula in northeast Greenland.</span>
<span class="attribution"><span class="source">Jussi Hovikoski</span></span>
</figcaption>
</figure>
<p>Around 56 million years ago lava began erupting across the region, building volcanic rock piles hundreds of metres high. As successive lava flows emerged, the hot, wet climate of the time eventually caused the surface to break down into a red soil called laterite. </p>
<figure class="align-center ">
<img alt="Geologist inspecting a cliff section exposing a volcanic sequence with evidence for subaerial eruptions in a tropical climate." src="https://images.theconversation.com/files/417022/original/file-20210819-19-lx6t0v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/417022/original/file-20210819-19-lx6t0v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/417022/original/file-20210819-19-lx6t0v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/417022/original/file-20210819-19-lx6t0v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/417022/original/file-20210819-19-lx6t0v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/417022/original/file-20210819-19-lx6t0v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/417022/original/file-20210819-19-lx6t0v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dr Steven Andrews inspecting the boundary between successive lava flows in Wollaston Forland in northeast Greenland. The faint red band directly above the geologists head represents the eruption surface of a lava flow that was broken down into laterite by the hot wet climate.</span>
<span class="attribution"><span class="source">Milo Barham</span></span>
</figcaption>
</figure>
<p>Our data from northeast Greenland are consistent with broader Arctic greenhouse reconstructions of the time. Both paint a picture of lush, swampy woodlands inhabited by cold-blooded reptiles, primates and hippo-like beasts unlike anything you’d see in today’s cooler world.</p>
<h2>Ocean gateways and land bridges</h2>
<p>Our work also reconstructs seabed uplift, and the emergence of large areas of land from the ocean. This is important as it would have caused a severe obstruction of the seaway that separated Greenland and Norway.</p>
<p>Such blockages are bad news. We know from the geological record that if critical ocean circulation stops, it can lead to <a href="https://eos.org/research-spotlights/explaining-ocean-acidification-patterns-during-ancient-warming">dangerously acidic</a> and <a href="https://theconversation.com/the-ocean-is-losing-its-breath-and-climate-change-is-making-it-worse-66192">oxygen-starved oceans</a>, as well as enhanced climate disturbance. </p>
<p>That said, when the flow of water between the Atlantic and Arctic was constricted because of emerging land during the PETM, there was more opportunity for plants and animals to move around. The continental connection allowed species to migrate into cooler climates and escape the effects of the warming.</p>
<figure class="align-center ">
<img alt="schematic reconstruction of arctic paleogeography showing faunal migration, volcanic regions and impeded ocean circulation" src="https://images.theconversation.com/files/417218/original/file-20210820-25-1pexame.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/417218/original/file-20210820-25-1pexame.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=322&fit=crop&dpr=1 600w, https://images.theconversation.com/files/417218/original/file-20210820-25-1pexame.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=322&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/417218/original/file-20210820-25-1pexame.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=322&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/417218/original/file-20210820-25-1pexame.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=404&fit=crop&dpr=1 754w, https://images.theconversation.com/files/417218/original/file-20210820-25-1pexame.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=404&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/417218/original/file-20210820-25-1pexame.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=404&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This schematic diagram of the Arctic 50 to 60 million years ago shows how volcanic uplift would have narrowed the seaway between Greenland and Norway, restricting ocean exchange and consequently boosting flora and fauna migration.</span>
<span class="attribution"><span class="source">modified from Ron Blakey (2021) - https://doi.org/10.4138/atlgeol.2021.002 and Jussi Hovikoski et al. (2021) - https://doi.org/10.1038/s43247-021-00249-w</span></span>
</figcaption>
</figure>
<h2>Back to the future</h2>
<p>Today’s environments have been largely broken up by human activity through agriculture and urbanisation, which gives species under environmental stress less opportunity to move elsewhere to survive any change.</p>
<p>And although we’re still some way from matching the overall volume of greenhouse gas emissions released during the PETM, today’s emission rates are rising <a href="https://www.sciencedaily.com/releases/2019/02/190220112221.htm">almost ten times faster</a>. Our ecosystems are already displaying signs of destabilisation.</p>
<p><a href="https://theconversation.com/climate-change-is-slowing-atlantic-currents-that-help-keep-europe-warm-94930">Recent studies</a> have warned of weakening ocean circulation, which may lead to climatic tipping points. Without urgent intervention, the unfolding climate and ecological crisis could prove to be a far greater burden than the world can bear. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/satellites-reveal-ocean-currents-are-getting-stronger-with-potentially-significant-implications-for-climate-change-159461">Satellites reveal ocean currents are getting stronger, with potentially significant implications for climate change</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/166342/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Milo Barham works is a Senior Lecturer at Curtin University. He has received funding from industry partners and state geoscience bodies. He is affiliated with the Timescales of Mineral Systems Group and The Institute of Geoscience Research at Curtin University. </span></em></p><p class="fine-print"><em><span>Jussi Hovikoski works as a Senior Scientist at the Geological Survey of Denmark and Greenland. He has received funding from GEUS, Greenland authorities and industry. </span></em></p><p class="fine-print"><em><span>Michael B.W. Fyhn works as Senior Scientist for the Geological Survey of Denmark and Greenland (GEUS). He receives funding from GEUS, Greenlandic Authorities and industry. </span></em></p>
Greenland’s conditions were once similar to those of a greenhouse. Volcanoes swelled the land, constricted seaways and gigatonnes of greenhouse gases were released into the atmosphere.
Milo Barham, Senior Lecturer, Curtin University
Jussi Hovikoski, Senior scientist, Geological Survey of Denmark and Greenland
Michael B.W. Fyhn, Geological Survey of Denmark and Greenland
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/164299
2021-08-16T12:09:09Z
2021-08-16T12:09:09Z
How a volcano and flaming red sunsets led an amateur scientist in Hawaii to discover jet streams
<figure><img src="https://images.theconversation.com/files/414701/original/file-20210804-13508-4zcdw5.jpg?ixlib=rb-1.1.0&rect=17%2C14%2C1001%2C491&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The eruption of Krakatoa in 1883 sent volcanic dust and gases circling the Earth, creating spectacular sunsets captured by artists.</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa#/media/File:Houghton_71-1250_-_Krakatoa,_twilight_and_afterglow.jpg">William Ashcroft via Houghton Library/Harvard University</a></span></figcaption></figure><p>On the evening of Sept. 5, 1883, people in Honolulu witnessed a spectacular sunset followed by a period of extended twilight described as a “<a href="https://evols.library.manoa.hawaii.edu/bitstream/10524/14502/1/1883092201.pdf#page=4">singular lurid after sunset glow</a>.” There were no signs of anything else out of the ordinary, but these exceptional twilight glows returned each morning and evening over the following weeks.</p>
<p>Among the mystified Honolulu citizens was 56-year-old <a href="https://archive.org/details/reminiscencesofo00bish/page/4/mode/2up">Rev. Sereno Edwards Bishop</a>, who in his varied career in Hawaii had been a chaplain, school principal and surveyor, and who had a keen interest in science. Over the subsequent weeks and months, the exceptional twilight glows occurred around the whole globe. Remarkably, as scientists first grappled with understanding the origin of the twilight glows, Bishop’s efforts would lead to the first convincing explanation. </p>
<figure class="align-right ">
<img alt="Profile photo of Bishop with a beard and glasses and wearing a suit" src="https://images.theconversation.com/files/411159/original/file-20210714-25-yq4tfb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/411159/original/file-20210714-25-yq4tfb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=718&fit=crop&dpr=1 600w, https://images.theconversation.com/files/411159/original/file-20210714-25-yq4tfb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=718&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/411159/original/file-20210714-25-yq4tfb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=718&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/411159/original/file-20210714-25-yq4tfb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=903&fit=crop&dpr=1 754w, https://images.theconversation.com/files/411159/original/file-20210714-25-yq4tfb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=903&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/411159/original/file-20210714-25-yq4tfb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=903&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rev. Sereno Edwards Bishop (1827–1909)</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Sereno_Edwards_Bishop#/media/File:Sereno_E._Bishop.jpg">Wikipedia</a></span>
</figcaption>
</figure>
<p>His discoveries led to scientific investigations of the winds high above the ground and ultimately yielded information that today is used to <a href="https://link.springer.com/article/10.1007/s00382-008-0379-5">forecast weather over extended periods</a>.</p>
<p>I am a <a href="http://iprc.soest.hawaii.edu/users/kph/">meteorologist</a> in Hawaii who helped revive appreciation of <a href="https://www.tandfonline.com/doi/full/10.1080/07055900.2011.639736">Bishop’s seminal contribution</a> to the scientific exploration of the upper atmosphere.</p>
<h2>A volcanic eruption half a world away</h2>
<p>Today we know that the 1883 glows were caused by the sun below the visible horizon illuminating a mist of <a href="https://skyandtelescope.org/observing/volcanoes-turn-twilights-purple/">small liquid droplets in the atmosphere</a> high above the ground.</p>
<p>The mist was made of sulfuric acid droplets that were formed by reactions of the massive amounts of sulfur dioxide gas produced by the explosive eruption of Mount Krakatoa close to the equator in Indonesia on Aug. 27, 1883. The eruption sent the droplets high into the atmosphere, where the winds transported them around the world. They spread gradually, and it was November before people in <a href="http://www.simonwinchester.com/krakatoa">London</a> began to notice the glow.</p>
<p>Much later, scientists observed <a href="http://www.dewbow.co.uk/glows/sunset5.html">similar effects</a> after the June 1991 <a href="https://pubs.usgs.gov/pinatubo/self/">eruption of Mount Pinatubo in the Philippines</a>. The material Pinatubo injected into the upper atmosphere could be followed in detail with satellite observations, and their connection with spectacular sunsets and twilight glows was <a href="https://pubs.usgs.gov/pinatubo/self/">clearly established</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/414683/original/file-20210804-27-qb2zwz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414683/original/file-20210804-27-qb2zwz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=863&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414683/original/file-20210804-27-qb2zwz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=863&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414683/original/file-20210804-27-qb2zwz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=863&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414683/original/file-20210804-27-qb2zwz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1085&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414683/original/file-20210804-27-qb2zwz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1085&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414683/original/file-20210804-27-qb2zwz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1085&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sketches of twilight and afterglow on one evening in 1883 in London following the Krakatoa eruption.</span>
<span class="attribution"><span class="source">William Ashcroft via Houghton Library/Harvard University</span></span>
</figcaption>
</figure>
<p>In 1883, Bishop had no idea that there had been a volcanic eruption until the San Francisco newspapers arrived. Very quickly, he formulated a hypothesis that he published as <a href="https://evols.library.manoa.hawaii.edu/bitstream/10524/14502/1/1883092201.pdf#page=4">a letter</a> in his <a href="https://evols.library.manoa.hawaii.edu/bitstream/10524/14502/1/1883092201.pdf">local newspaper</a>.</p>
<p>“I am disposed to conjecture that some very light element among the vapors of the Java eruptions has continued at a very great height in the atmosphere, and has been borne … across the Pacific into this region,” Bishop wrote.</p>
<p>He realized that he could connect the eruption to the glowing skies most credibly by gathering reports of the first appearance of the glows elsewhere and tracking the initial spread of the “vapor” from Krakatoa. Bishop continued his letter: “I earnestly invite, in behalf of science, all shipmasters and mates to publish what they may have observed at sea.”</p>
<p>Bishop assembled a dozen such reports over the first three weeks after the eruption and was able to show that the “vapor” that produced the glows had moved westward from Krakatoa, along the equator to reach Honolulu 10 days later. This implied that there was a wind high in the atmosphere blowing steadily with an extreme speed that, at ground level, is seen only in hurricanes.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/414682/original/file-20210804-13-1iv4fpx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414682/original/file-20210804-13-1iv4fpx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414682/original/file-20210804-13-1iv4fpx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414682/original/file-20210804-13-1iv4fpx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414682/original/file-20210804-13-1iv4fpx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=321&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414682/original/file-20210804-13-1iv4fpx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=321&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414682/original/file-20210804-13-1iv4fpx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=321&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Tracking the red sunsets following the Krakatoa eruption. The stars mark the initial reports and dates of seeing the exceptional twilight colors in 1883.</span>
</figcaption>
</figure>
<p>Bishop <a href="https://ia800604.us.archive.org/25/items/afw8023.0001.001.umich.edu/afw8023.0001.001.umich.edu.pdf#page=122">published his observations</a> in <a href="https://onlinebooks.library.upenn.edu/webbin/serial?id=hawaiianmonthly">The Hawaiian Monthly</a>, concluding that there was “a vast stream of smoke due west with great precision along a narrow equatorial belt with an enormous velocity, around the globe.”</p>
<h2>The equatorial jet stream</h2>
<p>Bishop called the motion of the volcanic aerosol a “smoke stream.” In fact, the equatorial winds transporting the aerosol were the first discovery of what meteorologists now call a jet stream. </p>
<p>A half-century would pass before the experiences of pilots flying at heights of several miles revealed the <a href="http://scihi.org/wiley-post-jetstream/">existence of the extratropical jet streams</a> lower down in the atmosphere that are now familiar from TV newscasts. Jet streams are strong, typically narrow bands of wind. The more familiar lower atmospheric jet streams move weather systems in the middle latitudes from west to east. By contrast, Bishop’s jet stream circles the equator at high altitudes and actually can blow from east to west.</p>
<p>Bishop’s work opened further exploration of the equatorial jet stream that culminated in the <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/JZ066i003p00813">1961 discovery</a> that the equatorial jet stream varied from strong east winds to strong west winds roughly every other year. This so-called <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/1999RG000073">Quasi-biennial Oscillation</a> has been shown to <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2009JD011737">connect with weather near the ground</a>, particularly in Europe and the North Atlantic, a fact that is now routinely <a href="https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/quasi-biennial-oscillation">exploited in making long range forecasts for the weather</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5wCq2Y9CB6Y?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Bishop’s contribution was <a href="https://archive.org/details/eruptionkrakato00whipgoog/page/n18/mode/2up">acknowledged</a> by the <a href="https://archive.org/details/eruptionkrakato00whipgoog/page/n12/mode/2up">scientists who first followed him,</a> and he won a prize from New York’s Warner Observatory in a contest for <a href="https://www.nature.com/articles/045422a0">essays explaining the post-Krakatoa glows</a>. Bishop even merited a brief <a href="https://journals.ametsoc.org/downloadpdf/journals/mwre/37/2/1520-0493_1909_37_47b_dsb_2_0_co_2.pdf">obituary</a> in an American meteorological science journal.</p>
<p>Bishop, who was the son of missionaries, could also be a divisive figure in Hawaii. He supported the U.S. annexation of the islands, and his religious views opposed some native Hawai'ian traditions, <a href="http://www.ulukau.org/elib/cgi-bin/library?e=d-0voicesofeden-000Sec--11en-50-20-contact-book--1-010escapewin&a=d&d=D0.18&toc=0">such as the hula dance</a>. His contributions to science were largely forgotten in the 20th century.</p>
<p>An international scientific committee’s celebration of the <a href="https://www.sparc-climate.org/meetings/qbo60-celebrating-60-years-of-discovery-within-the-tropical-stratosphere/">60th anniversary of the Quasi-biennial Oscillation discovery</a> is an opportunity to <a href="http://iprc.soest.hawaii.edu/users/kph/zoom_0.mp4">remember Bishop</a> and his discovery.</p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=youresmart">You can read us daily by subscribing to our newsletter</a>.]</p><img src="https://counter.theconversation.com/content/164299/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Hamilton does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
The Rev. Sereno Edwards Bishop mobilized ship captains to track the extraordinary sunsets appearing around the world after Krakatau erupted in 1883.
Kevin Hamilton, Emeritus Professor of Atmospheric Sciences, University of Hawaii
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/161176
2021-06-02T20:06:32Z
2021-06-02T20:06:32Z
Photos from the field: the stunning crystals revealing deep secrets about Australian volcanoes
<figure><img src="https://images.theconversation.com/files/403875/original/file-20210601-13-1kcoq9j.jpg?ixlib=rb-1.1.0&rect=36%2C84%2C3989%2C3024&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This isn't a painting or a stained-glass window — it's a microscope image of light shining through the Earth's mantle. </span> <span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span></figcaption></figure><p><em>Environmental scientists see flora, fauna and phenomena the rest of us rarely do. In this series, we’ve invited them to share their unique <a href="https://theconversation.com/au/topics/photos-from-the-field-92499">photos from the field</a>.</em></p>
<hr>
<p>Volcanic activity is a constant global threat. It’s estimated over <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiIqcmkyfLwAhWK4zgGHWPiDGkQFjADegQIBhAD&url=https%3A%2F%2Fwww.mdpi.com%2F2220-9964%2F8%2F8%2F341%2Fpdf&usg=AOvVaw2smkdZhL8rlzzyfjwu8sgV">1 billion people</a> live within the potential, direct impact range of volcanic eruptions. </p>
<p>Just recently, lava flows from the eruption of <a href="https://theconversation.com/mount-nyiragongos-volcano-why-its-unique-and-treacherous-161847">Mount Nyiragongo</a>, a volcano in the Democratic Republic of Congo, killed <a href="https://www.unicef.org/press-releases/280000-children-face-displacement-because-drc-volcano-threat">32 people</a>, with many more missing. Tens of thousands of people have been forced to flee the city of Goma.</p>
<p>This shows why understanding more about the inner workings of volcanoes is critical to improve the safety of those living in their shadows. </p>
<p>As a volcano scientist, my research takes me across Australia and all over the world. But sometimes, the most stunning revelations actually occur in the lab.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403883/original/file-20210602-21-kqs7gu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Heather Handley wearing a gas mask" src="https://images.theconversation.com/files/403883/original/file-20210602-21-kqs7gu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403883/original/file-20210602-21-kqs7gu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403883/original/file-20210602-21-kqs7gu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403883/original/file-20210602-21-kqs7gu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403883/original/file-20210602-21-kqs7gu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403883/original/file-20210602-21-kqs7gu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403883/original/file-20210602-21-kqs7gu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Heather Handley at Ambrym volcano in Vanuatu, wearing a mask due the hazardous volcanic gases present.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>I take a microscopic look at volcanic rocks and fragments of the Earth’s mantle to estimate just how fast molten rock (magma) moves from deep in the Earth to the surface. This can help us prepare for future eruptions. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403880/original/file-20210602-25-8j69md.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403880/original/file-20210602-25-8j69md.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403880/original/file-20210602-25-8j69md.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403880/original/file-20210602-25-8j69md.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403880/original/file-20210602-25-8j69md.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403880/original/file-20210602-25-8j69md.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403880/original/file-20210602-25-8j69md.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403880/original/file-20210602-25-8j69md.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A slice of the Earth’s mantle under a microscope, and the colourful crystals it reveals. Different types of crystals (minerals) and different orientations of the same minerals produce the range in colours seen when cross-polarised light passes through them.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Australia’s fiery past — and future</h2>
<p>Since the demise of the dinosaurs to recent human settlement, magmatic activity has left behind a trail of volcanoes stretching over 4,000 kilometres down Australia’s eastern margin, forming one of the world’s most extensive volcanic belts. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-volcanic-history-is-a-lot-more-recent-than-you-think-58766">Australia's volcanic history is a lot more recent than you think</a>
</strong>
</em>
</p>
<hr>
<p>The last mainland eruptions took place at Mount Gambier and Mount Schank in South Australia around 5,000 years ago, a mere blink of a geological eye. </p>
<p>These eruptions were witnessed by local Aboriginal people and incorporated into oral traditions that have been passed down for hundreds of <a href="https://www.sciencedirect.com/science/article/abs/pii/S1871101416300826">generations</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/NjkBETUXGWo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">View from the crater of Mount Schank volcano, one of the youngest volcanoes in Australia. Credit Heather Handley.</span></figcaption>
</figure>
<p>Based on the time since the last eruption, there are potentially two active volcanic regions in mainland Australia: in the northeast (southwest of Cairns) and southeast (from Melbourne across into South Australia).</p>
<p>The Mount Gambier and Mount Schank volcanoes are two of more than 400 volcanoes in the <a href="https://volcano.oregonstate.edu/faq/how-volcano-defined-being-active-dormant-or-extinct">active</a> southeast region called the Newer Volcanics Province, which has been active for at least the last 4.5 million years. </p>
<p>It’s considered likely there’ll be a future eruption in this province, but it’s not known when or where exactly the eruption will be.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403882/original/file-20210602-25-1cwzwps.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Volcanic eruption" src="https://images.theconversation.com/files/403882/original/file-20210602-25-1cwzwps.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403882/original/file-20210602-25-1cwzwps.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403882/original/file-20210602-25-1cwzwps.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403882/original/file-20210602-25-1cwzwps.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403882/original/file-20210602-25-1cwzwps.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403882/original/file-20210602-25-1cwzwps.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403882/original/file-20210602-25-1cwzwps.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Yasur volcano in Vanuatu, one of the most active volcanoes on the planet.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403884/original/file-20210602-25-xk8lg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403884/original/file-20210602-25-xk8lg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403884/original/file-20210602-25-xk8lg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403884/original/file-20210602-25-xk8lg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403884/original/file-20210602-25-xk8lg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403884/original/file-20210602-25-xk8lg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403884/original/file-20210602-25-xk8lg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403884/original/file-20210602-25-xk8lg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The volcanic deposits of Ohakune volcano in New Zealand. The different coloured layers represent variations in eruption style and explosive power.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>So how much warning time might we have?</h2>
<p>To answer this question, we have to unravel the secrets held by past eruptions, now locked away in the erupted rocks and the crystals within them.</p>
<p>Our first clue is that many of the dark black volcanic rocks that erupted in the Newer Volcanics Province (and others) contain chunks of green rock, called peridotite. </p>
<p>These dense green rock fragments are, in fact, pieces of the Earth’s upper mantle that were plucked out by the rising magma and carried all the way to the surface from depths of greater than 30 or 40 kilometres below our feet. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/403527/original/file-20210531-21-1j4tpr0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403527/original/file-20210531-21-1j4tpr0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=502&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403527/original/file-20210531-21-1j4tpr0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=502&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403527/original/file-20210531-21-1j4tpr0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=502&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403527/original/file-20210531-21-1j4tpr0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=630&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403527/original/file-20210531-21-1j4tpr0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=630&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403527/original/file-20210531-21-1j4tpr0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=630&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A black volcanic bomb from Mount Noorat volcano in the Newer Volcanics Province containing peridotite xenoliths — green fragments of the Earth’s upper mantle.</span>
<span class="attribution"><span class="source">Heather Handley</span></span>
</figcaption>
</figure>
<p>These fragments can sink back down through the liquid rock during its ascent, like a pebble dropped into a cylinder of honey. So in order to reach the surface, the rising magma had to move fast — likely taking just a few days from the source.</p>
<h2>Volcanic crystal balls</h2>
<p>In the same way <a href="https://theconversation.com/we-found-a-secret-history-of-megadroughts-written-in-tree-rings-the-wheatbelts-future-may-be-drier-than-we-thought-160526">tree rings</a> can tell you about what the climate was like when the tree grew, the crystals within volcanic rocks and the mantle fragments they carry preserve memories of the environment on their upward journey through the Earth.</p>
<p>In the photo below, you can see how cross-polarised light passing through the mantle rock reveals a mosaic of colourful crystals. The darker part is the enclosing volcanic rock. </p>
<p>This thin slice of rock is just 30 microns in thickness, about half the thickness of a typical human hair.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/403535/original/file-20210531-21-m4nyfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403535/original/file-20210531-21-m4nyfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=365&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403535/original/file-20210531-21-m4nyfz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=365&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403535/original/file-20210531-21-m4nyfz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=365&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403535/original/file-20210531-21-m4nyfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=459&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403535/original/file-20210531-21-m4nyfz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=459&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403535/original/file-20210531-21-m4nyfz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=459&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Microscope image of a rock from Mount Quincan volcano in the Atherton Volcanic Province, Queensland.</span>
<span class="attribution"><span class="source">Heather Handley</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403886/original/file-20210602-15-14p85v5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403886/original/file-20210602-15-14p85v5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403886/original/file-20210602-15-14p85v5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403886/original/file-20210602-15-14p85v5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403886/original/file-20210602-15-14p85v5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403886/original/file-20210602-15-14p85v5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403886/original/file-20210602-15-14p85v5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403886/original/file-20210602-15-14p85v5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A section of lava from Mount Gambier, the youngest volcano in Australia. The larger crystals grew before the smaller crystals, which formed near or at the surface.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403896/original/file-20210602-17-147g5xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403896/original/file-20210602-17-147g5xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403896/original/file-20210602-17-147g5xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403896/original/file-20210602-17-147g5xw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403896/original/file-20210602-17-147g5xw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403896/original/file-20210602-17-147g5xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403896/original/file-20210602-17-147g5xw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403896/original/file-20210602-17-147g5xw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Using a microscope to look at thin sections of volcanic rocks.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Now let’s take a look through a scanning electron microscope at the border where the mantle crystals make contact with the now-solidified magma.</p>
<p>In the two photos below, you can see the rim of the crystals has become lighter in colour, which means it changed its chemical composition. This is so it could adapt to its new magma environment on ascent in a process called <a href="https://www.nature.com/articles/s43017-020-0038-x">diffusion</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403970/original/file-20210602-15-1fr3cn7.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403970/original/file-20210602-15-1fr3cn7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403970/original/file-20210602-15-1fr3cn7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403970/original/file-20210602-15-1fr3cn7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403970/original/file-20210602-15-1fr3cn7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403970/original/file-20210602-15-1fr3cn7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403970/original/file-20210602-15-1fr3cn7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403970/original/file-20210602-15-1fr3cn7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The dark grey expanse is the mantle fragment. It has a light coloured rim due to its interaction with the rising magma. On the right, bits of mantle crystals are breaking off.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403971/original/file-20210602-13-wk9ucs.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403971/original/file-20210602-13-wk9ucs.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403971/original/file-20210602-13-wk9ucs.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403971/original/file-20210602-13-wk9ucs.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403971/original/file-20210602-13-wk9ucs.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403971/original/file-20210602-13-wk9ucs.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403971/original/file-20210602-13-wk9ucs.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403971/original/file-20210602-13-wk9ucs.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A crystal fragment (130 microns in width) from a peridotite mantle within a volcanic rock from Mount Gambier. The light grey rim has a different chemical composition to the darker area inside.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We use the sharpness of this chemical boundary to estimate how long mantle fragments sat in the magma before the rock erupted. </p>
<p>In other words, the minimum time magma took to travel from source to surface — an eruption warning time.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-volcanoes-erupt-98251">Curious Kids: Why do volcanoes erupt?</a>
</strong>
</em>
</p>
<hr>
<p>I can also use the chemistry and shapes of crystals that grew within the magma itself to map out the plumbing system beneath the volcano — the route magma takes to the surface.</p>
<p>The photos below show some of the different shapes crystals can form as the magma rises to the surface, cooling along the way. The spiky and skeleton-shaped crystals grow when the rising magma cools fast and by a large degree.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403972/original/file-20210602-23-1ci4mz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403972/original/file-20210602-23-1ci4mz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403972/original/file-20210602-23-1ci4mz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403972/original/file-20210602-23-1ci4mz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403972/original/file-20210602-23-1ci4mz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403972/original/file-20210602-23-1ci4mz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403972/original/file-20210602-23-1ci4mz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403972/original/file-20210602-23-1ci4mz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The small (5 to 10 microns in size), spikier crystals are clear in this image. The black areas are holes from trapped gas bubbles.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403973/original/file-20210602-25-bju3zt.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403973/original/file-20210602-25-bju3zt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403973/original/file-20210602-25-bju3zt.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403973/original/file-20210602-25-bju3zt.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403973/original/file-20210602-25-bju3zt.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403973/original/file-20210602-25-bju3zt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403973/original/file-20210602-25-bju3zt.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403973/original/file-20210602-25-bju3zt.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Skeleton-shaped olivine crystal in a volcanic rock from Mount Gambier. 500 microns in width.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403885/original/file-20210602-17-1l6qhsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403885/original/file-20210602-17-1l6qhsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403885/original/file-20210602-17-1l6qhsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=554&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403885/original/file-20210602-17-1l6qhsv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=554&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403885/original/file-20210602-17-1l6qhsv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=554&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403885/original/file-20210602-17-1l6qhsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=696&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403885/original/file-20210602-17-1l6qhsv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=696&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403885/original/file-20210602-17-1l6qhsv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=696&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The same volcanic crystal, but through a regular microscope.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>And we’re finding so far that individual volcanoes in the Newer Volcanics Province can take strikingly different pathways to the surface. This could result in varying eruption warning times. </p>
<h2>Australia isn’t prepared</h2>
<p>With likely maximum warning times of some past eruptions in Australia on the order of days, it’s worth considering how prepared we are for future eruptions — and not just from within Australia. If the global pandemic has taught us anything, it’s to expect the unexpected. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403895/original/file-20210602-13-rn6nr8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403895/original/file-20210602-13-rn6nr8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403895/original/file-20210602-13-rn6nr8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403895/original/file-20210602-13-rn6nr8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403895/original/file-20210602-13-rn6nr8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403895/original/file-20210602-13-rn6nr8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403895/original/file-20210602-13-rn6nr8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403895/original/file-20210602-13-rn6nr8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microscopic view of a mantle fragment brought to the surface during a volcanic eruption at Mount Quincan in the Atherton Volcanic Province, Queensland.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403892/original/file-20210602-27-rd0lyo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/403892/original/file-20210602-27-rd0lyo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403892/original/file-20210602-27-rd0lyo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403892/original/file-20210602-27-rd0lyo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403892/original/file-20210602-27-rd0lyo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403892/original/file-20210602-27-rd0lyo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403892/original/file-20210602-27-rd0lyo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403892/original/file-20210602-27-rd0lyo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A mantle fragment from Mount Quincan in the Atherton Volcanic Province, Queensland.</span>
<span class="attribution"><span class="source">Heather Handley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Large volcanic events are far from recent human memory, but in the Asia-Pacific region, they occur with a frequency of around every <a href="https://www.asiainsurancereview.com/Magazine/ReadMagazineArticle?aid=35311">400 years</a>. </p>
<p>The federal government’s recent announcement of <a href="https://www.pm.gov.au/media/helping-communities-rebuild-and-recover-natural-disasters">A$600 million</a> towards establishing a new National Recovery and Resilience Agency will help Australia adapt to some climate change-associated hazards. But volcanic events appear to be excluded.</p>
<p>Preparing for the next potentially cataclysmic volcanic event in Australia’s neighbouring <a href="https://www.nationalgeographic.org/article/plate-tectonics-ring-fire/?utm_source=BibblioRCM_Row">Ring of Fire</a> should be part of Australia’s risk and resilience conversation.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-government-has-pledged-over-800m-to-fight-natural-disasters-it-could-be-revolutionary-if-done-right-160348">The government has pledged over $800m to fight natural disasters. It could be revolutionary — if done right</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/161176/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Heather Handley receives funding from the Australian Research Council. Heather is a General Governing Councillor of the Geological Society of Australia and Co-Founder and President of the Women in Earth and Environmental Science Australasia (WOMEESA) Network. She is a 2021-2022 Science and Technology Australia Superstar of STEM.</span></em></p>
I look at fragments of the Earth’s mantle under a microscope to learn how fast molten rock moves from deep in the Earth to the surface. This can help us prepare for future volcanic eruptions.
Heather Handley, Honorary Associate Professor in Volcanology and Geochemistry, Macquarie University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/159362
2021-04-21T08:39:21Z
2021-04-21T08:39:21Z
The St Vincent eruption is a reminder of how volcano research and monitoring can save lives
<p>Volcanic eruptions come with a variety of hazards, depending on the type of volcano and its magma. Some have effusive eruptions, where lava flows constantly, while others can expel large clouds of fragments of magma and gases – volcanic ash – into the atmosphere. </p>
<p>For some of the most powerful eruptions, these ash clouds can rise tens of kilometres into the air and travel thousands of kilometres. This is what has happened on the island of St Vincent and the Grenadines, after a new eruption was confirmed at La Soufrière volcano on April 9 2021.</p>
<p>The explosive eruption, the first since the volcano last erupted in 1979, produced an ash plume of about six kilometres, which was also seen <a href="https://landsat.gsfc.nasa.gov/landsat-8/operational-land-imager">in satellite images</a>. </p>
<p>The eruption prompted the evacuation of about 20,000 people, with no casualties. This was made possible thanks to our improved understanding of how volcanoes work and new advances in volcano monitoring. </p>
<p>What’s different about the eruption in St Vincent compared with the relatively quiet and tourist-friendly eruptions at the same time in <a href="https://www.bbc.co.uk/news/world-europe-56482798">Iceland</a>, is that the magma is much more viscous – or sticky – so the gases dissolved in it can’t easily escape. </p>
<p>As magma moves towards the surface, these gases form bubbles and try to expand, causing an increase in pressure, which can eventually produce an explosion. During explosive eruptions, magma is broken into pieces, which cool rapidly and are ejected from volcanic vents mixed with gases, forming an ash-rich volcanic plume.</p>
<figure class="align-center ">
<img alt="Satellite images of the La Soufriere volcano." src="https://images.theconversation.com/files/396034/original/file-20210420-21-1g2bo2w.jpg?ixlib=rb-1.1.0&rect=105%2C346%2C2155%2C1557&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/396034/original/file-20210420-21-1g2bo2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=547&fit=crop&dpr=1 600w, https://images.theconversation.com/files/396034/original/file-20210420-21-1g2bo2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=547&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/396034/original/file-20210420-21-1g2bo2w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=547&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/396034/original/file-20210420-21-1g2bo2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=687&fit=crop&dpr=1 754w, https://images.theconversation.com/files/396034/original/file-20210420-21-1g2bo2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=687&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/396034/original/file-20210420-21-1g2bo2w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=687&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Satellite image of the ash.</span>
<span class="attribution"><a class="source" href="https://appliedsciences.nasa.gov/our-impact/news/eruption-la-soufriere">NASA/Lauren Dauphin</a></span>
</figcaption>
</figure>
<p>The island of St Vincent is no stranger to the hazards posed by volcanoes, although it’s been over 40 years since the last explosive eruption of La Soufrière. The deadliest eruption from this volcano occurred from 1902 to 1903 when more than 1,600 people lost their lives. </p>
<p>The current eruption is being monitored by a team of scientists from the University of the West Indies, based at the Belmont Volcano Observatory, on St Vincent. Monitoring relies on various methods, including gas and seismic measurements, as well as observations from the ground and from satellites. Satellites help, for instance, track where the volcanic ash has travelled to.</p>
<h2>Volcanic plumbing</h2>
<p>All volcanic eruptions are fed by a “plumbing system”. This comprises magma-filled cracks, called dykes and sills, that are either created or used by the magma. Understanding the physics that control how volcanic plumbing systems are created and evolve is fundamental to accurately interpret the indirect signals of magma movement.</p>
<p>As the magma moves within the volcano, it deforms the surrounding rock. This can produce earthquakes, which can be located using seismometers and very small deformation of the Earth’s surface, which GPS devices or satellites are able to measure.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/magma-refills-could-predict-volcano-eruptions-16212">Magma refills could predict volcano eruptions</a>
</strong>
</em>
</p>
<hr>
<p>Research conducted in modelling laboratories uses a scaled-down model of the Earth’s crust and simulates magma moving through it. By using a transparent crust, we can see inside the volcano’s plumbing system and create a model volcano monitoring network using <a href="https://www.sciencedirect.com/science/article/pii/S0377027317304602">lasers</a>. </p>
<p>This set-up can be used to test how well data from real volcanoes might be interpreted, helping to understand important information such as where the magma is, how deep it is, how much magma might be erupted, and where and when an eruption might happen.</p>
<p>Based on recent observations, scientists have noticed that immediately before an eruption, the signals of magma movement <a href="https://www.frontiersin.org/articles/10.3389/feart.2018.00045/full">can go quiet</a>. This “quieting down” might be wrongly interpreted as the system going back to sleep, when in fact it might suggest an eruption is imminent. These uncertainties made volcano monitoring and hazard assessment especially difficult.</p>
<h2>Monitoring volcanoes</h2>
<p>Eruptions can happen suddenly, with little or no warning. Mitigating volcanic hazards depends on our ability to continuously measure the pulse of a volcano and assess its state of health – by measuring things like how much magma is being transferred into the crust and how its migration towards the surface. </p>
<p>In many respects, these efforts are similar to how doctors attempt to diagnose a condition in a patient based on their symptoms. Magma moving through the system is akin to blood moving through the body, feeding and nurturing the growing volcano.</p>
<p>There have been many advances over the past few decades meaning more data – collected as often as once every hundredth of a second – is being collected at active volcanoes. New methods are being developed that allow rapid and reliable assessment of the state of a volcano, in some cases revealing clear patterns in the <a href="https://www.frontiersin.org/articles/10.3389/feart.2020.00169/full">lead-up to eruptions</a>.</p>
<p>We know the style and intensity of eruptions are <a href="https://www.sciencedirect.com/book/9780123859389/the-encyclopedia-of-volcanoes">controlled by factors</a> that include magma composition and gas content, the tectonic environment, and the dynamics of magma migration. </p>
<p>Volcano monitoring and our ability to forecast eruptions remain incomplete. However, the eruption in St Vincent demonstrates the role of data interpretation. Getting better at forecasting eruptions is key to successfully inform risk mitigation efforts during volcanic crises, and so prevent loss of life. </p>
<p>A challenging task for the future will be to distil this ever-growing body of knowledge and translate it into new monitoring tools to inform volcano early warning and, possibly, to produce reliable forecasts.</p><img src="https://counter.theconversation.com/content/159362/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Silvio De Angelis receives funding from the Natural Environment Research Council. </span></em></p><p class="fine-print"><em><span>Janine Kavanagh receives funding from a UK Research and Innovation (UKRI) Future Leaders Fellowship. </span></em></p>
The eruption prompted the evacuation of about 20,000 people, with no casualties.
Silvio De Angelis, Reader in Geophysics, University of Liverpool
Janine Kavanagh, Senior Lecturer in Volcanology and UKRI Future Leaders Fellow, University of Liverpool
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/156899
2021-03-12T19:00:29Z
2021-03-12T19:00:29Z
Earth’s early magma oceans detected in 3.7 billion year-old Greenland rocks
<figure><img src="https://images.theconversation.com/files/389271/original/file-20210312-13-1o4pbk9.jpg?ixlib=rb-1.1.0&rect=10%2C0%2C7252%2C4845&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">4 billion years ago, the Earth was composed of a series of magma oceans hundreds of kilometres deep.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/realistic-alien-planet-outer-space-3d-1429607681">Larich/Shutterstock</a></span></figcaption></figure><p>Earth hasn’t always been a blue and green oasis of life in an otherwise inhospitable solar system. During our planet’s first 50 million years, around 4.5 billion years ago, its surface was a hellscape of magma oceans, bubbling and belching with heat from Earth’s interior.</p>
<p>The subsequent cooling of the planet from this molten state, and the crystallisation of these magma oceans into solid rock, was <a href="https://www.nature.com/articles/nature06355">a defining stage</a> in the assembly of our planet’s structure, the chemistry of its surface, and the formation of its early atmosphere.</p>
<p>These primeval rocks, containing clues that might explain Earth’s habitability, were assumed to have been lost to the ravages of plate tectonics. But now, <a href="http://dx.doi.org/10.1126/sciadv.abc7394">my team has discovered</a> the chemical remnants of Earth’s magma oceans in 3.7 billion year-old rocks from southern Greenland, revealing a tantalising snapshot of a time when the Earth was almost entirely molten.</p>
<h2>Hell on Earth</h2>
<p>Earth is the product of a chaotic early solar system, which is believed to have featured a number of catastrophic impacts between the Earth and other planetary bodies. The formation of Earth culminated in <a href="https://www.nature.com/articles/35089010">its collision with a Mars-sized impactor planet</a>, which also resulted in the formation of Earth’s moon some 4.5 billion years ago.</p>
<p>These cosmic clashes are thought to have generated enough energy to melt the Earth’s crust and almost all of our planet’s interior (the mantle), creating planetary-scale volumes of molten rock that formed “magma oceans” hundreds of kilometres in depth. Today, in contrast, Earth’s crust is entirely solid, and the mantle is seen as a “plastic solid”: allowing slow, viscous geological movement a far cry from the liquid magma of Earth’s early mantle.</p>
<p>As the Earth recovered and cooled after its chaotic collisions, its deep magma oceans <a href="https://www.sciencedirect.com/science/article/pii/S0012821X19305771">crystallised and solidified</a>, beginning Earth’s journey to the planet we know today. The volcanic gases which bubbled out of Earth’s cooling magma oceans may have been decisive in the formation and composition of our planet’s early atmosphere – which would eventually support life. </p>
<figure class="align-center ">
<img alt="The Earth's layers in a cross-section, showing the core, mantle, and crust" src="https://images.theconversation.com/files/389270/original/file-20210312-20-8ptx8n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/389270/original/file-20210312-20-8ptx8n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/389270/original/file-20210312-20-8ptx8n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/389270/original/file-20210312-20-8ptx8n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/389270/original/file-20210312-20-8ptx8n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/389270/original/file-20210312-20-8ptx8n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/389270/original/file-20210312-20-8ptx8n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Earth is now composed of the inner core, the outer core, the lower mantle, the upper mantle, and the crust.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/structure-planet-earth-space-3d-rendering-1614442552">AlexLMX/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Geological search</h2>
<p>Finding geological evidence for the Earth’s former molten state is extremely difficult. This is because magma ocean events are likely to have taken place over 4 billion years ago, and many of the rocks from that period of Earth’s history have since been recycled by plate tectonics. </p>
<p>But while rocks from this period no longer exist, their chemical traces may still be stored in Earth’s depths. Solidified crystals from Earth’s cooling period would have been so dense that they’d have sunk to the base of Earth’s mantle. Scientists even believe that these mineral residues may be stored in isolated zones deep within <a href="https://www.sciencedirect.com/science/article/pii/S0012821X19301797">Earth’s mantle-core boundary</a>.</p>
<p>If they do exist, these ancient crystal graveyards are inaccessible to us – hiding far too deep for us to take direct samples. And if they were to ever rise to the Earth’s surface, the magma ocean crystals would naturally undergo a process of melting and solidifying, leaving only traces of their origins in the volcanic rocks that make it to Earth’s crust.</p>
<h2>Crystal clues</h2>
<p>We knew Greenland would be a good place to search for these traces of Earth’s molten past. Our samples originate from the Isua supracrustal belt in southwestern Greenland, which is a <a href="https://royalsocietypublishing.org/doi/10.1098/rsnr.2009.0004">famous area for geologists</a>. At first glance, Isua’s rocks look just like any modern basalt you’d find on the sea floor. But these rocks some of the oldest in the world, believed to be between 3.7 and 3.8 billion years old. </p>
<p>On analysing Isua’s rocks, we discovered unique iron isotope signatures. These signatures showed that the region of the mantle from which the rocks had formed had been subjected to very high pressure, over 700 kilometres below Earth’s surface. That’s exactly where minerals formed during magma ocean crystallisation would have been located. </p>
<p>But if these rocks did indeed bear traces of crystallised magma ocean, how did they find their way to the Earth’s surface? The answer lies in how the Earth’s interior melts, producing volcanic rocks on the planet’s surface.</p>
<h2>Melting rocks</h2>
<p>When regions of the Earth’s semi-solid mantle heat up and melt, they rise buoyantly towards the Earth’s crust, ultimately producing volcanic rocks when the magma reaches the surface and cools. By studying the chemistry of these rocks on the surface, we can probe the composition of the material that melted to form them.</p>
<p>The isotopic makeup of Isua rocks revealed that their journey to Earth’s surface involved several stages of crystallisation and remelting in the interior of the planet – a kind of distillation process on their way to the surface. But the rocks that emerged, located in present-day Greenland, still retain chemical signatures that connect them to Earth’s magma-covered past. </p>
<p>The results of our work provide some of the first direct geological evidence for the signature of magma ocean crystals in volcanic rocks found on Earth’s surface. Now, we’d like to understand whether other ancient volcanic rocks across the world can tell us more about Earth’s former magma oceans, or whether we’ve instead stumbled upon a geological oddity: more of a one-off clue. </p>
<p>If other volcanoes may have spewed similar geological artefacts, we might also look to modern eruption hotspots such as Hawaii and Iceland for further <a href="https://www.pnas.org/content/117/49/30993.short">isotopic novelties</a> that speak of Earth’s ancient past. It’s possible that more primordial rocks may be found in the future which could help us understand more about the Earth’s violent, magma-covered past.</p><img src="https://counter.theconversation.com/content/156899/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Helen M Williams has received funding from NERC and the ERC. </span></em></p>
The rocks provide rare evidence of a time when Earth’s surface was a deep sea of incandescent magma.
Helen M Williams, Reader in Geochemistry, University of Cambridge
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/151174
2020-11-30T23:12:17Z
2020-11-30T23:12:17Z
Scientists should welcome charges against agency over Whakaari/White Island — if it helps improve early warning systems
<figure><img src="https://images.theconversation.com/files/372086/original/file-20201130-21-1a2hurf.jpg?ixlib=rb-1.1.0&rect=17%2C80%2C2977%2C1904&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">New Zealand Defence Force</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>The decision by <a href="https://worksafe.govt.nz/">WorkSafe</a>, a government agency focused on workplace safety, to <a href="https://worksafe.govt.nz/about-us/news-and-media/13-parties-charged-by-worksafe-new-zealand-over-whakaariwhite-island-tragedy/">bring criminal charges against 13 parties</a> in relation to last December’s eruption of Whakaari/White Island heralds a new chapter for volcano scientists in New Zealand. </p>
<p>On December 9 2019, 22 people died and 25 suffered injuries when Whakaari erupted. They were not locals caught by a bigger than expected eruption. They were tourists and their guides on an adventure tourism visit to the island and the volcanic vent. </p>
<p>It is now clear that even though the <a href="https://www.geonet.org.nz/about/volcano/val">volcanic alert level</a> had been raised to “unrest” several days before the eruption, the visitors and their guides were unaware of the likelihood and especially the consequences of an eruption. </p>
<p>Had they known, as we do now, there was a <a href="https://www.nature.com/articles/s41467-020-17375-2">10% chance of an eruption</a> over a 48-hour period and their risk of death and injury was so high, no one would have gone onto the island.</p>
<p>Why didn’t we know that at the time? We live in an uneasy truce with volcanoes, and we do not make the rules, nor do we even know many of them. As deeply as we delve into the physical and chemical processes behind volcanic activity, each eruption brings surprises. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-zealands-white-island-is-likely-to-erupt-violently-again-but-a-new-alert-system-could-give-hours-of-warning-and-save-lives-142656">New Zealand's White Island is likely to erupt violently again, but a new alert system could give hours of warning and save lives</a>
</strong>
</em>
</p>
<hr>
<h2>Volcano warnings</h2>
<p>The main science agency responsible for volcanic warnings, <a href="https://www.gns.cri.nz/">GNS Science</a>, is one of the parties charged. To what extent should volcanologists, or the agency they work for, be culpable for the loss of lives during an eruption?</p>
<p>Volcanology has always been an observational activity. Throughout the world, descriptions of eruptions are recorded in cave art, legend and myriad images and cultural references. Formal descriptions of volcanoes are just an extension of this.</p>
<p>In this age of big data, micro-sensors and instant communication technologies, we have made rapid advances in our understanding of volcano behaviour. We now apply computational and numerical models to <a href="https://theconversation.com/new-zealands-white-island-is-likely-to-erupt-violently-again-but-a-new-alert-system-could-give-hours-of-warning-and-save-lives-142656">recognise signal patterns</a> that may precede an eruption, but our knowledge of the actual processes behind these lags behind. </p>
<p>This knowledge gap often leads to hesitation in applying our most advanced tools.</p>
<figure class="align-center ">
<img alt="Satellite image of Whakaari/White Island" src="https://images.theconversation.com/files/372092/original/file-20201130-15-89epji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/372092/original/file-20201130-15-89epji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=478&fit=crop&dpr=1 600w, https://images.theconversation.com/files/372092/original/file-20201130-15-89epji.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=478&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/372092/original/file-20201130-15-89epji.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=478&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/372092/original/file-20201130-15-89epji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=601&fit=crop&dpr=1 754w, https://images.theconversation.com/files/372092/original/file-20201130-15-89epji.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=601&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/372092/original/file-20201130-15-89epji.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=601&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Whakaari/White Island is an active volcano.</span>
<span class="attribution"><span class="source">NASA</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Bolder implementation of new technologies</h2>
<p>The WorkSafe charges are a symptom of society demanding greater precision in warnings of volcanic eruptions. These are not unreasonable demands, considering the tragic consequences of missing the warning signals.</p>
<p>How do we face up to this expectation as volcanologists?</p>
<p>Primarily, we must be brave enough to try new things. Technology untested by actual events is risky, but volcanoes are not an ideal production line. They do not erupt often enough, or on a convenient schedule to effectively develop and test new systems well. </p>
<p>Also, each volcano is subtly different. This means we must be prepared as scientists and science agencies to be wrong, and we must prepare our communities for our failures. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/call-for-clearer-risk-information-for-tourists-following-whakaari-white-island-tragedy-128772">Call for clearer risk information for tourists following Whakaari/White Island tragedy</a>
</strong>
</em>
</p>
<hr>
<p>We must harness the criticism of society to be bolder in our work. Clearly, we have not done enough to avoid the Whakaari tragedy, nor many other catastrophes over the past decades around the world. None of these calamities can be laid solely at the feet of volcano scientists, but our science advances can help other agencies do their work better.</p>
<h2>Call for open flow of information</h2>
<p>We must also push against political and corporate systems that attempt to control or sanitise science advice. Fear of being held legally or socially culpable for well-intentioned, but ultimately incorrect advice means new technology takes too long to be implemented.</p>
<p>The prime minister’s chief science advisor, <a href="https://www.pmcsa.ac.nz/who-we-are/our-office/">Juliet Gerrard</a>, has issued a <a href="https://www.pmcsa.ac.nz/2020/11/26/reflection-on-science-in-emergencies-2/">statement</a> highlighting the importance of science advice in emergencies.</p>
<blockquote>
<p>Attempts to limit access to science through institutional or other barriers and preventing scientists from giving their free and frank advice in emergency situations […] places a handicap on good decision making by our officials and politicians. Only by being able to access all the available knowledge, including its level of uncertainty and whether it is disputed, can decision makers effectively weigh up the possible consequences of the paths forward, guided by the best evidence.</p>
</blockquote>
<p>We must be much clearer about how volcanic hazard and risk is communicated to tourists, especially on volcanoes with a history of frequent eruptions. It is telling that the last five eruptions at Whakaari were not predicted, despite constant seismic monitoring over this time. </p>
<p>We also need a more proactive system that operates in real time and is more intuitive than the current volcanic alert level approach used widely around the world.</p>
<h2>Questions and blame</h2>
<p>Where does this leave volcano scientists in considering the court proceedings against GNS Science? Perhaps, the best approach is to welcome it. </p>
<p>A healthy society should review the role of science agencies in the prevention of disasters. Hard questions need to be asked so victims and their families can be sure we have done our best, with the best of our knowledge at the time. </p>
<p>But this should not be about blame. It should be about closing the gap between societal expectations of hazard information and how it is used or enforced at dangerous volcanoes — which is another topic addressed by charges also laid against those responsible for administering access to Whakaari.</p>
<p>From a scientist’s point of view, these charges against a science agency should be a call for innovation. Recognising the mass fatalities at Whakaari and other monitored volcanoes in recent times (including <a href="https://earth-planets-space.springeropen.com/articles/10.1186/s40623-016-0452-y">Ontake</a>, Japan in 2014 and <a href="https://earthobservatory.nasa.gov/images/46881/eruption-at-mount-merapi-indonesia">Merapi</a>, Indonesia in 2010), we must do better to avoid a possible “next time”.</p><img src="https://counter.theconversation.com/content/151174/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shane Cronin is a member of the NZ Volcano Science Advisory Group which is convened by NEMA (formerly MCDEM).</span></em></p>
Charges regarding last year’s fatal Whakaari/White Island eruption should not be about blame, but about improving hazard warnings and enforcement, particularly for sites with a history of eruptions.
Shane Cronin, Professor of Earth Sciences, University of Auckland, Waipapa Taumata Rau
Licensed as Creative Commons – attribution, no derivatives.