tag:theconversation.com,2011:/us/topics/volcanic-ash-47088/articlesVolcanic ash – The Conversation2023-07-13T12:38:33Ztag:theconversation.com,2011:article/2069772023-07-13T12:38:33Z2023-07-13T12:38:33ZLiving 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>
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<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>
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<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>
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<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>
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<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>
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<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>
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<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>
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<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>
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<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 RichmondLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1878582022-08-08T06:18:45Z2022-08-08T06:18:45ZA volcano is erupting again in Iceland. Is climate change causing more eruptions?<figure><img src="https://images.theconversation.com/files/477984/original/file-20220808-71528-enhyaa.jpeg?ixlib=rb-1.1.0&rect=232%2C161%2C5733%2C3819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Marco Di Marco/AP</span></span></figcaption></figure><p>The Fagradalsfjall volcano in Iceland began <a href="https://www.abc.net.au/news/2022-08-04/iceland-volcano-fagradalsfjall-erupts/101302732">erupting again</a> on Wednesday after eight months of slumber – so far without any adverse impacts on people or air traffic. </p>
<p>The eruption was expected. It’s in a seismically active (uninhabited) area, and came after several days of earthquake activity close to Earth’s surface. It’s hard to say how long it will continue, although an eruption in the same area last year lasted about six months. </p>
<p><a href="https://www.ipcc.ch/report/ar6/wg2/">Climate change</a> is causing the widespread warming of our land, oceans and atmosphere. Apart from this, it also has the potential to increase volcanic activity, affect the size of eruptions, and alter the “<a href="https://volcano.oregonstate.edu/climate-cooling">cooling effect</a>” that follows volcanic eruptions.</p>
<p>Any of these scenarios could have far-reaching consequences. Yet we don’t fully understand the impact a warming climate could have on volcanic activity.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/myt-oAkf8pE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Fagradalsfjall volcano is located some 30km from Iceland’s capital, Reykjavik.</span></figcaption>
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<h2>Cold volcanic regions</h2>
<p>First, let’s take a look at volcanic regions covered in ice. There’s a <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/96JB01308">long-established link</a> between the large-scale melting of ice in active volcanic regions and increased eruptions.</p>
<p>Research on Iceland’s volcanic systems has identified a heightened period of activity related to the large-scale ice melt at the end of the last ice age. The average eruption rates were found to be up to <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2001GC000282">100 times</a> higher after the end of the last glacial period, compared to the earlier colder glacial period. Eruptions were also smaller when ice cover was thicker. </p>
<p>But why is this the case? Well, as glaciers and ice sheets melt, pressure is taken off Earth’s surface and there are changes in the forces (stress) acting on rocks within the crust and upper mantle. This can lead to more molten rock, or “magma”, being produced in the mantle – which can feed more eruptions. </p>
<p>The changes can also affect where and how magma is stored in the crust, and can make it easier for magma to reach the surface. </p>
<p>Magma generation beneath Iceland is already <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/jgrb.50273">increasing</a> due to a warming climate and melting glaciers. </p>
<p>The intense ash-producing eruption of Iceland’s <a href="https://ncas.ac.uk/eyjafjallajokull-2010-how-an-icelandic-volcano-eruption-closed-european-skies">Eyjafjallajökull</a> volcano in 2010 was the result of an explosive interaction between hot magma and cold glacial melt water. Based on what we know from the past, an increase in Iceland’s melting ice could lead to larger and more frequent volcanic eruptions.</p>
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<a href="https://images.theconversation.com/files/477815/original/file-20220805-2912-a3hr2o.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A huge ash plume erupted from the top of a volcano" src="https://images.theconversation.com/files/477815/original/file-20220805-2912-a3hr2o.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477815/original/file-20220805-2912-a3hr2o.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477815/original/file-20220805-2912-a3hr2o.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477815/original/file-20220805-2912-a3hr2o.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477815/original/file-20220805-2912-a3hr2o.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477815/original/file-20220805-2912-a3hr2o.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477815/original/file-20220805-2912-a3hr2o.jpeg?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 Eyjafjallajokull is an active volcano covered by an ice cap. Back in 2010, an explosive eruption led to flights across Europe being halted.</span>
<span class="attribution"><span class="source">Arnar Thorisson/AP</span></span>
</figcaption>
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<h2>Weather-triggered eruptions</h2>
<p>But what about volcanic regions that aren’t covered in ice – could these also be affected by global warming? </p>
<p>Possibly. We know climate change is increasing the severity of storms and other weather events in many parts of the world. These weather events may trigger more volcanic eruptions.</p>
<p>On December 6 2021, an eruption at one of Indonesia’s most active volcanoes, Mount Semeru, caused ashfall, <a href="https://www.usgs.gov/programs/VHP/pyroclastic-flows-move-fast-and-destroy-everything-their-path">pyroclastic flows</a> and volcanic mudflows (called “lahars”) that claimed the lives of at least 50 people. </p>
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<a href="https://images.theconversation.com/files/477813/original/file-20220805-20-pc57rs.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A grainy aerial shot of a small village covered by volcanic ash" src="https://images.theconversation.com/files/477813/original/file-20220805-20-pc57rs.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477813/original/file-20220805-20-pc57rs.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477813/original/file-20220805-20-pc57rs.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477813/original/file-20220805-20-pc57rs.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477813/original/file-20220805-20-pc57rs.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477813/original/file-20220805-20-pc57rs.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477813/original/file-20220805-20-pc57rs.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The Semeru eruption left nearby villages covered in ash – forcing residents to flee.</span>
<span class="attribution"><span class="source">Antara TV/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Local authorities hadn’t expected the scale of the eruption. As for the cause, they said several days of heavy rain had destabilised the dome of lava in the volcano’s summit crater. This led to the dome collapsing, which reduced pressure on the magma below and triggered an eruption. </p>
<p>Signals of volcanic unrest are usually obtained from changes in volcanic systems (such as earthquake activity), changes in gas emissions from the volcano, or small changes in the shape of the volcano (which can be detected by ground-based or satellite monitoring).</p>
<p>Predicting eruptions is already an incredibly complex task. It will become even more difficult as we begin to factor in risk posed by severe weather which could destabilise parts of a volcano.</p>
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Read more:
<a href="https://theconversation.com/mount-semerus-deadly-eruption-was-triggered-by-rain-and-storms-making-it-much-harder-to-predict-173240">Mount Semeru's deadly eruption was triggered by rain and storms, making it much harder to predict</a>
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<p>Some scientists <a href="https://www.nature.com/articles/s41586-020-2172-5">suspect</a> increased rainfall led to the damaging 2018 Kīlauea eruption in Hawaii. This was preceded by months of heavy rainfall, which infiltrated the earth and increased underground water pressure within the <a href="https://earthresources.vic.gov.au/projects/victorian-gas-program/onshore-conventional-gas/porosity-permeability">porous</a> rock. They believe this could have weakened and fractured the rock, facilitating the movement of magma and triggering the eruption.</p>
<p>But other <a href="https://www.usgs.gov/publications/rainfall-unlikely-trigger-kilaueas-2018-rift-eruption">experts</a> disagree, and say there’s no substantial link between rainfall events and eruptions at Kīlauea volcano. </p>
<p>Rain-influenced volcanism has also been proposed at other volcanoes around the world, such as the Soufrière Hills <a href="https://www.sciencedirect.com/science/article/abs/pii/S0377027309002261">volcano</a> in the Caribbean, and <a href="https://onlinelibrary.wiley.com/doi/epdf/10.1046/j.1365-3121.2001.00297.x">Piton de la Fournaise</a> on Réunion Island in the Indian Ocean. </p>
<h2>Changes to the ‘cooling effect’</h2>
<p>There’s another layer we can’t ignore when it comes to assessing the potential link between climate change and volcanic activity. That is: volcanoes themselves can influence the climate. </p>
<p>An eruption can lead to <a href="https://www.usgs.gov/programs/VHP/volcanoes-can-affect-climate">cooling or warming</a>, depending on the volcano’s geographical location, the amount and composition of ash and gas erupted, and how high the plume reaches into the atmosphere. </p>
<p>Volcanic injections that were rich in sulphur dioxide gas have had the strongest climatic impact recorded in historic times. Sulphur dioxide eventually condenses to form sulfate aerosols in the stratosphere – and these aerosols reduce how much heat reaches Earth’s surface, causing cooling. </p>
<p>As the climate warms, <a href="https://www.nature.com/articles/s41467-021-24943-7">research</a> shows this will change how volcanic gases interact with the atmosphere. Importantly, the outcome won’t be the same for all eruptions. Some scenarios show that, in a warmer atmosphere, small to medium-sized eruptions could reduce the cooling effect of volcanic plumes by up to 75%. </p>
<p>These scenarios assume the “tropopause” (the boundary between the troposphere and stratosphere) will increase in height as the atmosphere warms. But since the volcano’s eruption column will stay the same, the plume carrying sulphur dioxide will be less likely to reach the upper atmosphere – where it would have the largest impact on the climate.</p>
<p>On the other hand, more powerful but less frequent volcanic eruptions could lead to a <em>greater</em> cooling effect. That’s because as the atmosphere gets warmer, plumes of ash and gas emitted from powerful eruptions are predicted to rise higher into the atmosphere, and spread <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2013RG000448">rapidly</a> from the tropics to higher latitudes. </p>
<p>One <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL099381">recent study</a> has suggested the major Hunga Tonga-Hunga Ha’apai volcanic eruption in January may contribute to global warming, by pumping massive amounts of water vapour (a greenhouse gas) into the stratosphere.</p>
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Read more:
<a href="https://theconversation.com/how-a-volcanic-bombardment-in-ancient-australia-led-to-the-worlds-greatest-climate-catastrophe-178037">How a volcanic bombardment in ancient Australia led to the world's greatest climate catastrophe</a>
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<img src="https://counter.theconversation.com/content/187858/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 a Science and Technology Australia Superstar of STEM, Co-Founder of Women in Earth and Environmental Sciences Australasia (WOMEESA) and Co-Founder and Director of the Earth Futures Festival.</span></em></p>Volcanoes themselves can also impact the climate, due to a “cooling effect” that comes after eruptions.Heather Handley, Associate Professor of Volcanology and Geoscience Communication, University of Twente and Adjunct Associate Professor, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1810902022-04-20T09:03:07Z2022-04-20T09:03:07ZNew research detects pre-eruption warning signals at Whakaari White Island and other active volcanoes<figure><img src="https://images.theconversation.com/files/458407/original/file-20220418-16-tlpral.jpg?ixlib=rb-1.1.0&rect=45%2C53%2C5013%2C3292&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Phil Walter/Getty Images</span></span></figcaption></figure><p>Scientifically and emotively, we think every volcano has its own “personality”. However, we’ve discovered that volcanoes share behaviour traits – and this could form the basis for an eruption warning system.</p>
<p>Whakaari White Island, a picturesque volcanic island in the Bay of Plenty, was a tourist magnet, with its alien landscape and spectacular hydrothermal features. This idyll was shattered on December 9 2019 when high-pressure steam and gas exploded, concentrating in a deadly surge of hot ash down its main access valley. Of the 47 guides and tourists present, 22 died while many others suffered horrific burns.</p>
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<img alt="Two rescuers seen walking across an ash field on Whakaari White Island in December 2019." src="https://images.theconversation.com/files/458408/original/file-20220418-87032-wjdgid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458408/original/file-20220418-87032-wjdgid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458408/original/file-20220418-87032-wjdgid.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458408/original/file-20220418-87032-wjdgid.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458408/original/file-20220418-87032-wjdgid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458408/original/file-20220418-87032-wjdgid.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458408/original/file-20220418-87032-wjdgid.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">
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<span class="caption">An explosion of steam and gas shot hot ash across the main access valley of Whakaari White Island.</span>
<span class="attribution"><span class="source">New Zealand Defence Force via Getty Images</span></span>
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<p>Since that tragedy, we have been <a href="https://www.nature.com/articles/s41467-020-17375-2">studying past eruptions at Whakaari</a>, and volcanoes like it, to identify the warning signs of an imminent eruption. </p>
<h2>Deciphering volcanic language</h2>
<p>Every volcano behaves differently: some have crater lakes while others are “dry”, they have diverse magmas and rise to different elevations. Despite these differences, we think volcanoes such as Whakaari, Ruapehu and Tongariro in New Zealand could be driven to eruption by common processes in the shallow sub-surface below their craters. </p>
<p>In our <a href="https://www.nature.com/articles/s41467-022-29681-y">new research</a>, we used machine learning to sift through 40 years of seismic data from the New Zealand volcanoes and three others around the world, listening for particular frequencies that track the depth where gas, magma or water are moving or building up. </p>
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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>
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<p>We saw one pattern repeatedly in the days before all the known Whakaari eruptions over the past decade, and most Ruapehu and Tongariro ones. This pattern is a slow strengthening of a quantity called Displacement Seismic Amplitude Ratio (DSAR), which peaks a few days before each event.</p>
<p>DSAR is a ratio that compares the “activity” of fluids (gas, hot water, steam) at the volcano’s surface to those several hundred metres deep. When DSAR increases, surface fluids are quiet, but deep ones are still actively moving and circulating vigorously below ground. </p>
<p>This indicates a blockage or seal has formed, preventing gas escape. Like a pressure-cooker, if the gas can’t escape a volcano, it explodes. </p>
<h2>What happened at Whakaari</h2>
<p>About a month before the December 2019 eruption, deep gas started to rise into Whakaari’s hydrothermal system. This put pressure onto the groundwater, keeping it in a liquid state, even as it became “superheated”. </p>
<p>As this fluid circulates below the vent, it is registered as noise or “tremor” on seismometers. GNS Science noted this increased tremor and, on November 18, <a href="https://web.archive.org/web/20191209093156/https://www.geonet.org.nz/vabs/1prVlz8jGXwWayA8D6Uu5y">raised Whakaari’s alert level</a> to Volcanic Alert Level (VAL) 2, which is the highest level outside an eruption. </p>
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<img alt="A graphic showing key changes at Whakaari White Island leading up to the December 9 2019 eruption." src="https://images.theconversation.com/files/457872/original/file-20220413-21-clmvot.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/457872/original/file-20220413-21-clmvot.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=203&fit=crop&dpr=1 600w, https://images.theconversation.com/files/457872/original/file-20220413-21-clmvot.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=203&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/457872/original/file-20220413-21-clmvot.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=203&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/457872/original/file-20220413-21-clmvot.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=256&fit=crop&dpr=1 754w, https://images.theconversation.com/files/457872/original/file-20220413-21-clmvot.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=256&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/457872/original/file-20220413-21-clmvot.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=256&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Key changes at Whakaari White Island leading up to the December 9 2019 eruption.</span>
<span class="attribution"><span class="source">Provided by author</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>About a week later, Whakaari began to pulse. Pressure and tremor would build over about 24 hours, before discharging explosively at the bottom of the crater lake. This resulted in <a href="https://web.archive.org/web/20191209093239/https://www.geonet.org.nz/vabs/5gMP3pBjFuQmNOQB89rZT4">geysers and fountains</a>, throwing mud and debris up to the height of a ten-storey building.</p>
<p>Crucially, these gas bursts were safety valves, easing the pressure in the system.</p>
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<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>
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<p>At the beginning of December, the gas bursts stopped and the surface became quiet. Rather than being cause for relief, we think this indicated a new and much more dangerous phase. A seal had formed, trapping the gas. The high DSAR shows that below the seal, the system was as noisy as ever, with pressure continuing to rise.</p>
<p>Between 9pm and midnight on December 8 2019, there was a <a href="https://www.nature.com/articles/s41467-020-17375-2">strong burst of seismic energy</a>. This was likely fresh magmatic fluid arriving to ramp up the pressure on gas and water already trapped in the rock. It also began the process of explosive release, because it caused small cracks to form in the seal. </p>
<p>The growth of cracks began to accelerate, setting Whakaari on the path to a cascading system failure, as has been seen <a href="https://www.sciencedirect.com/science/article/pii/S0377027315001742">before in eruptions in 2012 and 2013</a>. Once the weakness was widespread, the seal failed, disgorging the massive steam-explosion at 2:11pm on December 9.</p>
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<img alt="Balloons are seen as family and friends of victims gathered a few days after the White Island eruption." src="https://images.theconversation.com/files/458415/original/file-20220418-76539-5fztms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458415/original/file-20220418-76539-5fztms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458415/original/file-20220418-76539-5fztms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458415/original/file-20220418-76539-5fztms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458415/original/file-20220418-76539-5fztms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458415/original/file-20220418-76539-5fztms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458415/original/file-20220418-76539-5fztms.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">
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<span class="caption">Of the 47 people on Whakaari on the day of the eruption, 22 died and many others suffered horrific burns.</span>
<span class="attribution"><span class="source">John Borren/Getty Images</span></span>
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<h2>Understanding Ruapehu</h2>
<p>Mount Ruapehu is a 2800m stratovolcano in New Zealand’s central North Island. </p>
<p>It is also capped by a hydrothermal system and a warm crater lake (Te Wai a Moe). The temperature and level of its lake is known to vary in cycles, responding to changes in gas released into its base, local weather or the occasional formation of a gas seal. </p>
<p>Unfortunately, the lake is so large it hides the surface activity that is useful for diagnosing volcanoes like Whakaari. </p>
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<img alt="Mount Ruapehu" src="https://images.theconversation.com/files/458413/original/file-20220418-1583-z62k1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458413/original/file-20220418-1583-z62k1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=313&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458413/original/file-20220418-1583-z62k1q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=313&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458413/original/file-20220418-1583-z62k1q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=313&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458413/original/file-20220418-1583-z62k1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=393&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458413/original/file-20220418-1583-z62k1q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=393&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458413/original/file-20220418-1583-z62k1q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=393&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The same patterns of gas build-up observed at Whakaari have also been seen at Mount Ruapehu.</span>
<span class="attribution"><span class="source">Shutterstock/bondjb</span></span>
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<p>This is where DSAR is so powerful. We have spotted the same pattern that reveals gas sealing at Whakaari numerous times at Ruapehu. We monitor DSAR at Ruapehu closely: over the past month it has increased dramatically. </p>
<p>We think this shows a new seal has formed, building pressure. This could end in an eruption similar to the <a href="https://en.wikipedia.org/wiki/Mount_Ruapehu#2006_and_2007_activity">2006/07 cycle</a> that generated destructive lahars (volcanic mud flows). </p>
<p>GNS Science has <a href="https://www.geonet.org.nz/vabs/7dyfMjTIP8ITRFrv1kmlL0">reported similar concerns</a> in their decision to <a href="https://www.geonet.org.nz/vabs/2Cy40dBlXKJ0KXP4eAfMM2">raise Ruapehu’s alert level to VAL 2</a>.</p>
<p>This type of analysis is so new we have not had many chances to test how reliable the DSAR and other automated measures are for forecasting. However, the current high DSAR and lake heating have put all scientist on alert. History shows this state does not always lead to an eruption, but we must remain vigilant.</p><img src="https://counter.theconversation.com/content/181090/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Dempsey receives funding from the New Zealand Ministry for Business, Innovation and Employment (Transitioning Taranaki to a Volcanic Future). </span></em></p><p class="fine-print"><em><span>David Dempsey receives funding from the New Zealand Ministry for Business, Innovation and Employment (Transitioning Taranaki to a Volcanic Future).</span></em></p><p class="fine-print"><em><span>Shane Cronin receives funding from the New Zealand Ministry for Business, Innovation and Employment (Transitioning Taranaki to a Volcanic Future UOAX1913). He works for the University of Auckland. </span></em></p>Before the deadly eruption of Whakaari White Island in December 2019, pressure and a tremor built up in a pattern seen in other volcanoes. It could help scientists develop an early-warning system.David Dempsey, Senior lecturer, University of CanterburyAlberto Ardid, Post Doctoral Researcher, University of CanterburyShane Cronin, Professor of Earth Sciences, University of Auckland, Waipapa Taumata RauLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/982512018-07-22T20:09:28Z2018-07-22T20:09:28ZCurious Kids: Why do volcanoes erupt?<figure><img src="https://images.theconversation.com/files/223750/original/file-20180619-126537-gka5w8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some explosive volcanoes can send ash high up into the sky and it can travel around the world over different countries.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com">Shutterstock</a></span></figcaption></figure><p><em>This is an article from <a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a>, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky! You might also like the podcast <a href="http://www.abc.net.au/kidslisten/imagine-this/">Imagine This</a>, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.</em></p>
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<p><strong>Why do volcanoes erupt? - Nicholas, age 3 years and 11 months, Northmead, NSW.</strong> </p>
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<p>The rock inside the planet we live on can melt to form molten rock called magma. This magma is lighter than the rocks around it and so it rises upwards. Where the magma eventually reaches the surface we get an eruption and volcanoes form. </p>
<p>The top part of the Earth is made up of a number of hard pieces called tectonic plates. Magma and volcanoes often form where the plates are pulled apart or pushed together but we also find some volcanoes in the middle of tectonic plates.</p>
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Read more:
<a href="https://theconversation.com/curious-kids-why-doesnt-lava-melt-the-side-of-the-volcano-90683">Curious Kids: why doesn't lava melt the side of the volcano?</a>
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<p>Volcanoes have many different shapes and sizes, some look like steep mountains (stratovolcanoes), others look like bumps (shield volcanoes) and some are flat with a hole (a crater or caldera) in the centre that is often filled with water.</p>
<p>The shape of the volcano and how explosively it erupts depend largely on how “sticky” and how “fizzy” (how much gas) the magma is that is erupted. </p>
<p>For example, if you try to blow bubbles in cooking oil though a straw, the bubbles can escape quite easily because the cooking oil is runny.</p>
<p>If you try to blow bubbles in jam or peanut butter you would find it very difficult because the jam and peanut butter are very sticky, they wouldn’t move much at all if you tried to pour them out of the jar.</p>
<p>It is the same with volcanoes. When magma rises towards the surface gas bubbles start to form. Whether or not they can escape as the magma is rising affects how explosive the eruption will be.</p>
<p>Where the magma is runny like cooking oil and doesn’t have much bubbly gas mixed in it, such as places like Hawaii, then we see lots of slow-moving lava flows and shield volcanoes. Lava is what we call magma when it reaches the surface.</p>
<p>Here are some pictures of a recent Hawaiian eruption:</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1001626626273103872"}"></div></p>
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<p>However, where the magma is very sticky, like jam or peanut butter, and if it contains a lot of bubbly gas then the gas can get stuck and eruptions can be very powerful and explosive, like the recent eruptions at Fuego volcano in Guatemala.</p>
<h2>Damage caused by eruptions</h2>
<p>In explosive eruptions the frothy, bubbly magma can be ripped apart into tiny bits called volcanic ash. This is not ash like you get after a barbecue or fire, it does not crumble away in your fingers. It is very sharp and is dangerous to breathe in.</p>
<p>Some explosive volcanoes can send ash high up into the sky and it can travel around the world over different countries. If aeroplanes travel through an ash cloud from a volcano it can cause a lot of damage to the engine.</p>
<p>Other explosive eruptions create fast-moving, hot clouds of volcanic ash, gas and rocks that travel down the sides of the volcanoes and destroy pretty much everything in their path.</p>
<h2>The benefits of volcanoes</h2>
<p>Despite the great damage they can cause, volcanoes also help us to live. Volcanic ash provides food for the soil around volcanoes which helps us grow plants to eat. The heat from some volcanoes is used to make energy to power lights, fridges, televisions and computers in people’s houses. </p>
<p>You can find some more information about different types of volcanoes <a href="https://www.gns.cri.nz/Home/Learning/Science-Topics/Volcanoes/Types-of-Volcanoes-Eruptions">here</a> and <a href="http://www.bgs.ac.uk/discoveringGeology/hazards/volcanoes/types.html">here</a>. </p>
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Read more:
<a href="https://theconversation.com/curious-kids-do-most-volcanologists-die-from-getting-too-close-to-volcanoes-82496">Curious Kids: Do most volcanologists die from getting too close to volcanoes?</a>
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<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p class="fine-print"><em><span>Heather Handley receives funding from the Australian Research Council. She is affiliated with WOMEESA.</span></em></p>When magma rises towards the surface gas bubbles start to form. Whether or not they can escape as the magma is rising affects how explosive the eruption will be.Heather Handley, Associate Professor in Volcanology and Geochemistry, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/964692018-05-16T20:14:41Z2018-05-16T20:14:41ZTrouble in paradise: eruptions from Kīlauea volcano place the Hawaiian island on red alert<p>A code red alert level for aviation has been issued this week on Hawai'i’s big island, as Kīlauea volcano continues its explosive activity at the summit.</p>
<p>The Hawaiian Volcano Observatory’s <a href="https://volcanoes.usgs.gov/volcanoes/kilauea/status.html">warning for Kīlauea</a> said:</p>
<blockquote>
<p>At any time, activity may become more explosive, increasing the intensity of ash production and producing ballistic projectiles near the vent. </p>
</blockquote>
<p>But Kīlauea has erupted before, and just as today its violent activity attracted the crowds. The challenge for authorities is to balance that curiosity with the safety of people on the island.</p>
<p>The observatory warning said there were reports of an ash cloud reaching heights of up to 3.5km above sea level. Ashfall and vog (volcanic air pollution) have been reported almost 29km downwind of the summit.</p>
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Read more:
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<p>There were also <a href="http://www.hawaiinewsnow.com/story/38186017/new-eruptions-spur-more-evacuations-in-lava-ravaged-lower-puna">reports</a> of new fissures erupting lava into new areas furthering the extent of the damage.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/219146/original/file-20180516-155584-y25epn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/219146/original/file-20180516-155584-y25epn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/219146/original/file-20180516-155584-y25epn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/219146/original/file-20180516-155584-y25epn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/219146/original/file-20180516-155584-y25epn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/219146/original/file-20180516-155584-y25epn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/219146/original/file-20180516-155584-y25epn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/219146/original/file-20180516-155584-y25epn.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 lava flow from one of the fissures moves on Makamae Street in Leilani Estates on May 6.</span>
<span class="attribution"><a class="source" href="https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_chronology.html">USGS</a></span>
</figcaption>
</figure>
<h2>Respect for Kīlauea</h2>
<p>Kīlauea is a majestic and beautiful volcano. Native Hawaiians and Hawai'i residents who live on her flanks speak of her beauty with a healthy dose of respect and awareness of the constant threat of eruptive activity and destruction.</p>
<p>Kīlauea’s eruptive activity this year began in early May in residential areas on its east flank, about 35km from the summit.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/219149/original/file-20180516-155579-8y3v0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/219149/original/file-20180516-155579-8y3v0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/219149/original/file-20180516-155579-8y3v0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/219149/original/file-20180516-155579-8y3v0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/219149/original/file-20180516-155579-8y3v0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/219149/original/file-20180516-155579-8y3v0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/219149/original/file-20180516-155579-8y3v0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/219149/original/file-20180516-155579-8y3v0b.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 new fissure erupting from Luana Street, Leilani Estates subdivision on Kilauea Volcano’s lower East Rift Zone near Pahoa, Hawai'i, May 5, 2018.</span>
<span class="attribution"><span class="source">USGS</span></span>
</figcaption>
</figure>
<p>The eruptive activity has captivated us for days. Spectacular fountains and rivers of lava have been emanating from volcanic vents, together with the tragic destruction of property and livelihoods.</p>
<p>This devastation led to President Donald Trump’s <a href="https://edition.cnn.com/2018/05/12/us/hawaii-kilauea-volcano/index.html">declaration</a> of a “major disaster” on the island. </p>
<p>Crucially, residents are safe, but those who have visited Hawai’i or with similar experiences of destructive natural hazard events will be sad to see pictures of this devastation. </p>
<p>At the same time, and away from the current eruption on the flank of Kīlauea, another crisis is unfolding at the volcano’s summit. Kīlauea Volcano hosts the Hawaii Volcanoes National Park at its summit, which is now closed to all visitors because of the hazard.</p>
<p>It may seem odd that at a distance of more than 35km from the active spattering and lava effusion on the eastern flank of the volcano, volcanic hazards pose such a significant risk to warrant the closure.</p>
<p>But Kīlauea is up to its old tricks again, possibly replicating <a href="https://volcanoes.usgs.gov/volcanoes/kilauea/geo_hist_1924_halemaumau.html">activity seen last in 1924</a> which led to a variety of violent and sporadic explosions, dispersing volcanic ejecta around the summit and killing one visitor. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/219141/original/file-20180516-104301-14041lr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/219141/original/file-20180516-104301-14041lr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/219141/original/file-20180516-104301-14041lr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=411&fit=crop&dpr=1 600w, https://images.theconversation.com/files/219141/original/file-20180516-104301-14041lr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=411&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/219141/original/file-20180516-104301-14041lr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=411&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/219141/original/file-20180516-104301-14041lr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=516&fit=crop&dpr=1 754w, https://images.theconversation.com/files/219141/original/file-20180516-104301-14041lr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=516&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/219141/original/file-20180516-104301-14041lr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=516&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 crowd of visitors view the eruption plume from the front of the Volcano House hotel. They were subsequently warned by Ruy H Finch, acting director of the Hawaiian Volcano Observatory, that it was unwise to remain there.</span>
<span class="attribution"><a class="source" href="https://volcanoes.usgs.gov/volcanoes/kilauea/geo_hist_1924_halemaumau.html">USGS</a></span>
</figcaption>
</figure>
<p>The decision to close access to the summit is driven by current monitoring data, and crucial past experience and knowledge of Kīlauea’s violent behaviour. </p>
<p>Over the past week the mesmerising convecting lava lake that has resided at the summit for a decade is no longer. Magma has evacuated to depths greater than 285m into the deeper magma plumbing system. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/218795/original/file-20180514-178740-1lb8iy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/218795/original/file-20180514-178740-1lb8iy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/218795/original/file-20180514-178740-1lb8iy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/218795/original/file-20180514-178740-1lb8iy0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/218795/original/file-20180514-178740-1lb8iy0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/218795/original/file-20180514-178740-1lb8iy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/218795/original/file-20180514-178740-1lb8iy0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/218795/original/file-20180514-178740-1lb8iy0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&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 summit lava lake has dropped significantly over the past few days, and on May 6 was roughly 220m below the crater rim.</span>
<span class="attribution"><a class="source" href="https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_chronology.html">USGS</a></span>
</figcaption>
</figure>
<p>The last time that happened – <a href="https://volcanoes.usgs.gov/volcanoes/kilauea/geo_hist_1924_halemaumau.html">in 1924</a> – it explosively interacted with groundwater at depth, producing violent, sporadic eruptions and a visitor fatality.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/219143/original/file-20180516-155573-bzlvb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/219143/original/file-20180516-155573-bzlvb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/219143/original/file-20180516-155573-bzlvb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=435&fit=crop&dpr=1 600w, https://images.theconversation.com/files/219143/original/file-20180516-155573-bzlvb2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=435&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/219143/original/file-20180516-155573-bzlvb2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=435&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/219143/original/file-20180516-155573-bzlvb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=546&fit=crop&dpr=1 754w, https://images.theconversation.com/files/219143/original/file-20180516-155573-bzlvb2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=546&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/219143/original/file-20180516-155573-bzlvb2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=546&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 block was thrown out during an explosion at Halema‘uma‘u crater on Kīlauea on May 18, 1924, and landed about 600 meters from today’s rim.</span>
<span class="attribution"><a class="source" href="https://volcanoes.usgs.gov/volcanoes/kilauea/kilauea_gallery_52.html">USGS/HVO photo courtesy of Bishop Museum</a></span>
</figcaption>
</figure>
<h2>Volcanic hazards at Kīlauea and the ‘ash problem’</h2>
<p>Hazards from violent explosive activity at Kīlauea’s summit are substantial. Magma and water interactions are highly intense and violent – think hot oil in a frying pan mixing with cold water.</p>
<p>Eruptions are likely to have very little or no warning, and the “how big” and “how long” are impossible to predict. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/219152/original/file-20180516-155579-titnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/219152/original/file-20180516-155579-titnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/219152/original/file-20180516-155579-titnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/219152/original/file-20180516-155579-titnic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/219152/original/file-20180516-155579-titnic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/219152/original/file-20180516-155579-titnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/219152/original/file-20180516-155579-titnic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/219152/original/file-20180516-155579-titnic.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">Civil Air Patrol flight CAP20 reported plume tops at about 2.9km with the dispersed plume rising as high as 3.5km.</span>
<span class="attribution"><a class="source" href="https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_chronology.html">USGS</a></span>
</figcaption>
</figure>
<p>Residents on the fringe of the national park are not in life-threatening hazardous conditions. But they are susceptible to the annoying “ash problem” where ash accumulation on electricity infrastructure interrupts supply, contaminates water, causes health hazards such as throat and lung irritation, and damages crops.</p>
<p>This will have complex social, health and economic impacts, further devastating communities if the summit activity does begin and is long-lived. </p>
<p>Society’s fascination of volcanic phenomena and the curiosity-driven need of people to know more, see more and experience more will make the safe management of the millions of tourists each year in the Hawaii Volcanoes National Park a significant challenge.</p>
<p>Nearly 50km of <a href="https://www.youtube.com/watch?v=H4_zkgZAJ1E&t=830s">bumper-to-bumper traffic</a> to view the <a href="https://volcanoes.usgs.gov/volcanoes/kilauea/geo_hist_kilauea_iki.html">1959 eruption of Kilauea</a> testifies to the impending management issues. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/219159/original/file-20180516-155619-2o2m4f.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/219159/original/file-20180516-155619-2o2m4f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/219159/original/file-20180516-155619-2o2m4f.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/219159/original/file-20180516-155619-2o2m4f.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/219159/original/file-20180516-155619-2o2m4f.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/219159/original/file-20180516-155619-2o2m4f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/219159/original/file-20180516-155619-2o2m4f.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/219159/original/file-20180516-155619-2o2m4f.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bumper to bumper traffic on the way to see the eruption in 1959.</span>
<span class="attribution"><a class="source" href="https://www.youtube.com/watch?v=H4_zkgZAJ1E">YouTube/Centre for Study of Active Volcanoes/Screengrab</a></span>
</figcaption>
</figure>
<p>Exclusion and access will be an important and potentially long-lived management issue as the geological rock record at the summit tells a story of violent, centuries-long explosive activity.</p>
<h2>Reading the rock record</h2>
<p>Kīlauea is not a gentle giant of a volcano. It has a long-lived and violent explosive history as determined from detailed geological investigations of volcanic rocks and ash layers in the rock record.</p>
<p>The last period of violent explosive activity was between the years 1500 and 1800, when magma frequently interacted with the groundwater table deep within the volcano. </p>
<p>During those three centuries of activity, Kīlauea’s summit produced around 10km high columns and umbrella clouds of volcanic ash, short-lived violent explosions and ballistic ejecta, and ground-hugging high-velocity currents called pyroclastic density currents, which destroyed everything in their path. </p>
<p>This period is not without observation. Native Hawaiians were within the summit area and in 1790 at least 80 Hawaiian warriors were killed in a devastating hot, high velocity explosion that seared their lungs. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lava-ash-flows-mudslides-and-nasty-gases-good-reasons-to-respect-volcanoes-96260">Lava, ash flows, mudslides and nasty gases: Good reasons to respect volcanoes</a>
</strong>
</em>
</p>
<hr>
<h2>Back to basics: the geological rock record as a prediction tool</h2>
<p>Kīlauea is one of Earth’s most well studied volcanoes. It has been the site of an active volcano observatory since 1912, and current monitoring technologies are state-of-the-art. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/218802/original/file-20180514-178749-19mvuak.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/218802/original/file-20180514-178749-19mvuak.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/218802/original/file-20180514-178749-19mvuak.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=259&fit=crop&dpr=1 600w, https://images.theconversation.com/files/218802/original/file-20180514-178749-19mvuak.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=259&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/218802/original/file-20180514-178749-19mvuak.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=259&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/218802/original/file-20180514-178749-19mvuak.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=325&fit=crop&dpr=1 754w, https://images.theconversation.com/files/218802/original/file-20180514-178749-19mvuak.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=325&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/218802/original/file-20180514-178749-19mvuak.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=325&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Always a crowd pleaser: Visitors observing the Halemaʻumaʻu eruption in Hawaii Volcanoes National Park in 2017.</span>
<span class="attribution"><span class="source">Bruce Houghton, University of Hawaii at Manoa, US</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Volcanic behaviour is by its nature complex. Prediction of the exact when, duration and how big is riddled with uncertainty despite sophisticated monitoring technologies. </p>
<p>As such, disaster management challenges are numerous, but observational records in 1924 and the geological rock record have certainly provided early warning of the timing, type and duration of possible violent activity at the summit, and therefore the protection of people within the national park.</p><img src="https://counter.theconversation.com/content/96469/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Carey receives funding from the Australian Research Council and the United States National Science Foundation</span></em></p>The Kīlauea volcano on Hawai'i’s big island is threatening to produce violent and energetic eruptions not seen since 1924.Rebecca Carey, Senior Lecturer in Earth Sciences, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/906832018-02-11T19:09:47Z2018-02-11T19:09:47ZCurious Kids: why doesn’t lava melt the side of the volcano?<figure><img src="https://images.theconversation.com/files/203948/original/file-20180130-170429-1nm8qia.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Although it is very hot, when lava flows over the ground, it generally does not melt the soil or rock.</span> <span class="attribution"><span class="source">Marcella Cheng/The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p><em>This is an article from <a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a>, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!</em> </p>
<hr>
<blockquote>
<p><strong>Does lava from an erupting volcano melt everything in its path? And why does lava not melt the sides of the volcano itself? - Liam, age 5, Ashwood.</strong></p>
</blockquote>
<p>Thank you, Liam, for asking these very interesting questions. I can see you are starting to think like a scientist.</p>
<p>The short answer is that while lava is hot, it’s not hot enough to melt the rocks on the side of or surrounding the volcano. </p>
<p>Most rocks have melting points higher than 700°C. Lava is between 700°C and 1200°C when it erupts but starts to cool as it slides down the side of the volcano. The air and the ground help cool it down. You only need 100°C to boil water, so this is very, very hot.</p>
<p>So by the time it’s out of the volcano, lava is generally not quite hot enough to melt the rocks it flows over.</p>
<p>But lava flows can set fire to grass, bushes, and trees. And sometimes if houses are in the way, the lava flow will set fire to the wood that is in the houses. All that is left of the house is ash.</p>
<p>Most people in Australia don’t get to see lava - but if you do, it’ll be the hottest stuff you ever see in your life.</p>
<p>There is only one volcano in Australia where you can see lava. It’s called Big Ben. It is on Heard Island, a very long way west of Australia in the Indian Ocean.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-dont-the-planets-closest-to-the-sun-melt-or-burn-up-80001">Curious Kids: Why don't the planets closest to the Sun melt or burn up?</a>
</strong>
</em>
</p>
<hr>
<p>Here’s a video of a scientist collecting some lava:</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/DF_J3vCcbBA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Scientists collect lava from a volcano.</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-do-most-volcanologists-die-from-getting-too-close-to-volcanoes-82496">Curious Kids: Do most volcanologists die from getting too close to volcanoes?</a>
</strong>
</em>
</p>
<hr>
<p>The lava from the Big Ben volcano flows down the sides of a mountain covered in snow and ice. And the lava melts the ice, which makes water. When the lava touches the water, it makes steam and explodes.</p>
<p>Here’s a photo I took of Big Ben erupting, during an expedition in early 2016:</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/203365/original/file-20180125-107963-1axu5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/203365/original/file-20180125-107963-1axu5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/203365/original/file-20180125-107963-1axu5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/203365/original/file-20180125-107963-1axu5e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/203365/original/file-20180125-107963-1axu5e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/203365/original/file-20180125-107963-1axu5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=320&fit=crop&dpr=1 754w, https://images.theconversation.com/files/203365/original/file-20180125-107963-1axu5e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=320&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/203365/original/file-20180125-107963-1axu5e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=320&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Big Ben is on Heard Island.</span>
<span class="attribution"><span class="source">Richard Arculus</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>There are lots of places in Australia where old lava flows can be seen. These are now quite cool and it is safe to touch them.</p>
<p>They were flowing a very long time ago. You can visit old lava flows in Western Australia near the southwest coast at Bunbury, around Mount Gambier in South Australia, near Mount Leura in Victoria, along the northwest coast at Stanley in Tasmania, around Cooma in NSW, and at Undara in Queensland.</p>
<p>The First Australians would have seen some of these lava flows coming out of volcanoes and flowing over the ground. That must have been an amazing sight.</p>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:</em></p>
<p><em>* Email your question to curiouskids@theconversation.edu.au
<br>
* Tell us on <a href="https://twitter.com/ConversationEDU">Twitter</a> by tagging <a href="https://twitter.com/ConversationEDU">@ConversationEDU</a> with the hashtag #curiouskids, or
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* Tell us on <a href="http://www.facebook.com/conversationEDU">Facebook</a></em></p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><em>Please tell us your name, age and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.</em></p><img src="https://counter.theconversation.com/content/90683/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard John Arculus receives funding from the Australian Research Council</span></em></p>The short answer is that while lava is hot, it’s not hot enough to melt the rocks that make up the side of the volcano.Richard John Arculus, Emeritus professor in geology, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/883532017-12-01T15:16:20Z2017-12-01T15:16:20ZWhy Mount Agung’s volcanic ash is a particular problem for aircraft<p>The eruption of Mount Agung on the island of Bali in Indonesia has emitted a huge plume of volcanic ash over the region, reaching more than 9km up into the atmosphere. This has disrupted flights over Bali and nearby islands. With the <a href="http://www.bom.gov.au/products/IDD65300.shtml">Aviation Colour Code</a> listed as red (the most dangerous), air passengers are once again being stranded, just as many were following the 2010 <a href="http://news.bbc.co.uk/1/hi/8621407.stm">Eyjafjallajökull eruption</a> in Iceland, or during the <a href="https://www.reuters.com/article/us-chile-volcano-flights/ash-cloud-from-chile-volcano-wreaks-airline-havoc-idUSTRE75C4L620110613">Puyehue-Cordón eruption</a> in Chile the following year.</p>
<p>The volcano is <a href="https://magma.vsi.esdm.go.id">still erupting</a>. This means it could become even more explosive – and as such flying nearby remains a risk. In addition, volcanic ash disruption is strongly influenced by wind direction and speed – so the evolving situation still needs to be carefully monitored by the local meteorological offices, and also the <a href="http://www.bom.gov.au/info/vaac/advisories.shtml">Darwin Volcanic Ash Advisory Centre</a> that issues various ash warnings to the aviation sector.</p>
<p>The threat posed by a particular volcano’s ash <a href="https://volcanoes.usgs.gov/volcanicash/resources.html">depends on what it is made of</a>, as no two eruptions are exactly alike. Volcanic ash consists of fragments of pulverised rocks, minerals and volcanic glass (silica) that varies dependent on the chemical composition of the magma. </p>
<p>Once this glass is sucked into jet engines, it is heated up and can accumulate as resolidified ash on the turbines, resulting in engine failure. The higher the concentration and density of glass, the more problematic the ash will be, although even fine ash has electrostatic charge that can lead to electrical failure. </p>
<p>Therefore even at low concentrations, where the ash is barely visible to the naked eye (if at all), it can still pose <a href="https://volcanoes.usgs.gov/volcanic_ash/ash_clouds_air_routes_effects_on_aircraft.html">significant threats and damage to aircraft</a>. Ash also causes significant abrasion to the plane and its windows, while disrupting communications and damaging sensitive equipment.</p>
<p>Mt Agung has previously emitted <a href="https://link.springer.com/article/10.1007/s00445-015-0943-x">sulphur-rich gases</a>. Following its most recent major eruption in 1963, its emissions may have led to <a href="https://link.springer.com/article/10.1007/s004450050139">significant atmospheric cooling</a> of 0.3°C in average northern hemisphere temperatures. High levels of sulphur dioxide and carbon dioxide can also generate discomfort for aircraft passengers, leading to irritations to the eyes, nose, throat and increased airway resistance – as well as corroding the aircraft. Therefore these gas emissions pose a real risk to passenger comfort, as well as cooling of the tropical troposphere. </p>
<h2>If ash, no fly</h2>
<p>It is no surprise then that a policy of “if ash, no fly” was adopted internationally following two key disasters in Indonesia in 1982 and Alaska in 1989. However, this policy was eventually disregarded during the Eyjafjallajökull ash crisis, after a five-day air-space closure over much of Europe created chaos. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/197310/original/file-20171201-318-p79v3y.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/197310/original/file-20171201-318-p79v3y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/197310/original/file-20171201-318-p79v3y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/197310/original/file-20171201-318-p79v3y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/197310/original/file-20171201-318-p79v3y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/197310/original/file-20171201-318-p79v3y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/197310/original/file-20171201-318-p79v3y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/197310/original/file-20171201-318-p79v3y.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"></a>
<figcaption>
<span class="caption">Ash from Eyjafjallajökull spread across much of the Northern Hemisphere.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Eyjafjallaj%C3%B6kull_volcanic_ash_composite.png">MetOffice / wiki / Cogiati</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>“No fly” was replaced by a safe ash limit of 200-300 micrograms per cubic metre of air, the removal of the flying buffer zone of 60 nautical miles, and then a “<a href="https://www.flightglobal.com/news/articles/new-uk-rules-double-ash-concentration-safety-thresho-342070/">time-limited zone</a>” whereby aircraft can fly through higher concentrations of ash for a limited time. </p>
<p>This raised fundamental questions about standardised protocols in volcanic ash hazard management. If they can be ignored or revised based on social and economic circumstances, rather than scientific evidence, what’s the point of them?</p>
<p>Yet the science remains uncertain. It’s hard (and expensive) to work out with any precision where atmospheric ash is located in real time and at what concentration. Equally, the risk it poses to aircraft is not fully understood. Figuring out an official safe threshold of ash concentration would require significant testing on the varying aircraft jet engines, which can cost tens of millions of dollars each. </p>
<h2>Years of disruption?</h2>
<p>The key question now, is whether Mt Agung will continue to erupt and cause similar types of disruption. The volcano’s previous major eruption lasted between February 1963 and January 1964, with a number of explosive eruptions throughout. If this is anything to go by, the current aviation disruption from volcanic ash may continue for some time. </p>
<p>Indeed, rather than a short, sharp and large emission of ash, some volcanic eruptions can occur on and off for years. Such on-going unpredictability can be far more disruptive, particularly for an island as dependent on tourism as Bali. This of course does not address the ground-based hazards including flows of lava or volcanic debris that put local people in significant danger. </p>
<p>Should Agung continue to erupt, it will be interesting to see whether the ash concentration limits established in 2010 will be implemented. Those affected by the volcanic eruption should have faith in the sophisticated early warning systems set up to monitor the volcanic ash, but if there is one thing we can learn from volcanoes, it is to expect the unexpected.</p><img src="https://counter.theconversation.com/content/88353/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Carina Fearnley receives funding from the Arts and Humanities Research Council through the project "Orkney: Beside the Ocean of Time".</span></em></p>And will the aviation sector implement vital lessons learned from Icelandic disruption in 2010?Carina Fearnley, Lecturer in Science and Technology Studies, UCLLicensed as Creative Commons – attribution, no derivatives.