tag:theconversation.com,2011:/au/topics/volcanic-vents-6912/articlesvolcanic vents – The Conversation2018-05-22T14:43:37Ztag:theconversation.com,2011:article/969472018-05-22T14:43:37Z2018-05-22T14:43:37ZLava in Hawai'i is reaching the ocean, creating new land but also corrosive acid mist<p>There is something special and awe-inspiring about watching new land form. This is what is now happening in Hawai’i as its <a href="https://volcanoes.usgs.gov/volcanoes/kilauea/status.html">Kīlauea volcano erupts</a>. Lava is reaching the ocean and building land while producing spectacular plumes of steam. These eruptions are hugely important for the creation of new land. But they are also dangerous. Where the lava meets the ocean, corrosive acid mist is produced and glass particles are shattered and flung into the air. Volcanic explosions can also hurl lava blocks hundreds of metres and produce waves of scalding hot water. </p>
<p>At Kīlauea, lava is erupting from a line of vents on the volcano’s flanks, and is moving downslope to the edge of the island, where it enters the ocean. This is a process that has been witnessed many times at Hawai’i and other volcanic islands. And it is through many thousands of such eruptions that volcanic islands like Hawai’i form.</p>
<p>The new lava being added to Hawai’i by this latest Kīlauea eruption replaces older land that is being lost by erosion, and so prolongs the island’s lifespan. In contrast, older islands to the north-west have no active volcanoes, so they are being eroded by the ocean and will eventually disappear beneath the waves. The opposite is happening to the south-east of Hawai’i, where an underwater volcano (Lōʻihi Seamount) is building the foundations of what will eventually become the next volcanic island in this area.</p>
<h2>How lava gets to the ocean at Hawai’i</h2>
<p>The lava erupting from the current Kīlauea vents has a temperature of roughly 1150 degrees °C, and has a journey of between 4.5km and 5.5km to reach the ocean. As this lava moves swiftly in channels, it loses little heat and so it can enter the ocean at a temperature of over 1000 degrees°C.</p>
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<img alt="" src="https://images.theconversation.com/files/219812/original/file-20180521-14953-hps3d7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/219812/original/file-20180521-14953-hps3d7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/219812/original/file-20180521-14953-hps3d7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/219812/original/file-20180521-14953-hps3d7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/219812/original/file-20180521-14953-hps3d7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/219812/original/file-20180521-14953-hps3d7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/219812/original/file-20180521-14953-hps3d7.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">When lava meets the sea, new land is formed.</span>
<span class="attribution"><a class="source" href="http://www.epa.eu/disasters-photos/volcanic-eruption-photos/fissure-20-flow-reaches-the-ocean-photos-54352112">EPA</a></span>
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<h2>What happens when lava meets the ocean?</h2>
<p>We are witnessing one of the most spectacular sights in nature - billowing white plumes of steam (technically water droplets) as hot lava boils seawater. Although these billowing steam clouds appear harmless, they are dangerous because they contain small glass shards (fragmented lava) and acid mist (from seawater). This acid mist known as “laze” (lava haze) can be hot and corrosive. If anyone goes to near it, they can experience breathing difficulties and irritation of their eyes and skin.</p>
<p>Apart from the laze, the entry of lava into the ocean is usually a gentle process, and when steam is free to expand and move away, there are no violent steam-driven explosions.</p>
<p>But a hidden danger lurks beneath the ocean. The lava entering the sea breaks up into blobs (known as pillows), angular blocks, and smaller fragments of glass that form a steep slope beneath the water. This is called a lava delta. </p>
<p>A newly formed lava delta is an unstable beast, and it can collapse without warning. This can trap water within the hot rock, leading to violent steam-driven explosions that can hurl metre-sized blocks up to 250 metres. Explosions occur because when the water turns to steam it suddenly expands to around 1,700 times its original volume. <a href="https://volcanoes.usgs.gov/observatories/hvo/hawaii_ocean_entry.html">Waves of scalding water</a> can also injure people who are too close. People have died and been seriously injured during lava delta collapses </p>
<p>So, the ocean entry points where lava and seawater meet are doubly dangerous, and anyone in the area should pay careful attention to official advice on staying away from them.</p>
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<img alt="" src="https://images.theconversation.com/files/219813/original/file-20180521-14965-kfzbff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/219813/original/file-20180521-14965-kfzbff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/219813/original/file-20180521-14965-kfzbff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/219813/original/file-20180521-14965-kfzbff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/219813/original/file-20180521-14965-kfzbff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/219813/original/file-20180521-14965-kfzbff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/219813/original/file-20180521-14965-kfzbff.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">
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<span class="caption">Pillow Lavas form underneath the ocean.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Nur05028_-_pile_of_pillow_lava.jpg">National Oceanic & Atmospheric Adminstration (NOAA)</a></span>
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<h2>What more can we learn from these eruptions?</h2>
<p>Once lava deltas have cooled and become stable they represent new land. <a href="http://sp.lyellcollection.org/content/202/1/91">Studies</a> have revealed that lava deltas have distinctive features, and this has enabled volcanologists to recognise lava deltas in older rocks.</p>
<p>Remarkable examples of lava deltas have been discovered near the top of extinct volcanoes (called tuyas) in Iceland and Antarctica. These deltas can only form in water and the only plausible source of this water in this case is melted ice. This means that these volcanoes had melted water-filled holes up to 1.5km deep in ice sheets, which is an astonishing feat. In fact, these lava deltas are the only remaining evidence of long-vanished ice sheets. </p>
<p>It is a privilege to see these incredible scenes of lava meeting the ocean. The ongoing eruptions form part of the natural process that enables beautiful volcano islands like Hawai'i to exist. But the creation of new land here can also bring danger to those who get too close, whether it be collapsing lava deltas or acid mist.</p><img src="https://counter.theconversation.com/content/96947/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span><a href="mailto:ian.skilling@southwales.ac.uk">ian.skilling@southwales.ac.uk</a> received funding from National Science Foundation in US. </span></em></p><p class="fine-print"><em><span>Dave McGarvie 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>At Kīlauea in Hawai'i, a recent volcanic eruption has created some of the most spectacular sights in nature. But also danger for those around it.Dave McGarvie, School of Physical Sciences, The Open UniversityIan Skilling, Senior Lecturer (Volcanology), University of South WalesLicensed 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>
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<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>
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<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>
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<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>
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<p>Here’s a video of a scientist collecting some lava:</p>
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<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>
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<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>
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</em>
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<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>
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<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>
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<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>
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<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
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* 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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<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="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<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/587662016-05-24T20:09:23Z2016-05-24T20:09:23ZAustralia’s volcanic history is a lot more recent than you think<figure><img src="https://images.theconversation.com/files/122942/original/image-20160518-9501-192uytw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The incredible Blue Lake at Mount Gambier fills one of the craters from the last volcanic eruption just 5,000 years ago.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-75754672/stock-photo-the-incredible-blue-lake-at-mt-gambier-south-australia.html?utm_source=77643&utm_campaign=Idee%20Inc.&irgwc=1&utm_medium=Affiliate&tpl=77643-108110">ian woolcock from www.shutterstock.com</a></span></figcaption></figure><p>Australia is an old and stable continent with not many geological risks such as major earthquakes and volcanic eruptions. At least that is what most people think.</p>
<p>But throughout its geological history Australia has known volcanic activity right up to the time that humans lived here. The most recent eruptions on the Australian mainland occurred at Mt Gambier and Mt Schank in South Australia about 5,000 years ago.</p>
<p>These volcanoes are part of a larger volcanic area or province in south-eastern Australia, where we can still expect another eruption. What will such an eruption look like and where will it happen?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/122632/original/image-20160516-10682-1fuqfal.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/122632/original/image-20160516-10682-1fuqfal.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122632/original/image-20160516-10682-1fuqfal.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122632/original/image-20160516-10682-1fuqfal.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122632/original/image-20160516-10682-1fuqfal.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122632/original/image-20160516-10682-1fuqfal.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122632/original/image-20160516-10682-1fuqfal.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122632/original/image-20160516-10682-1fuqfal.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>
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<span class="caption">Mt Elephant, at 190m, is the tallest scoria cone in western Victoria.</span>
<span class="attribution"><span class="source">Jozua van Otterloo</span></span>
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<h2>Looking into Australia’s recent volcanoes</h2>
<p>Researchers from Monash University have looked at a few of the more recent volcanoes in the <a href="http://www.tandfonline.com/doi/abs/10.1080/08120099.2013.806954">Newer Volcanics Province</a> to work out what happened and what we can expect in the future.</p>
<p>This volcanic province stretches more than 400km from the Melbourne CBD in the east to Mount Gambier in the west. More than 400 volcanoes have been identified in this area.</p>
<p>The majority of these produced extensive lava flows, especially in the Western Plains district of Victoria. But many volcanoes were also explosive, ranging from beautiful fire fountains like those seen in Hawaii to very explosive ash-cloud-forming eruptions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/122626/original/image-20160516-10691-1xbxy11.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/122626/original/image-20160516-10691-1xbxy11.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122626/original/image-20160516-10691-1xbxy11.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=354&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122626/original/image-20160516-10691-1xbxy11.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=354&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122626/original/image-20160516-10691-1xbxy11.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=354&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122626/original/image-20160516-10691-1xbxy11.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=444&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122626/original/image-20160516-10691-1xbxy11.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=444&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122626/original/image-20160516-10691-1xbxy11.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=444&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">Map of the Newer Volcanics Province of southeast Australia, Australia’s most recent volcanic area.</span>
<span class="attribution"><span class="source">Jozua van Otterloo</span></span>
</figcaption>
</figure>
<p>Many of the younger volcanoes in Victoria and South Australia are maar volcanoes. Maar volcanoes are craters with low rims around them and are formed by intensely explosive interaction between magma (mixture of molten rock, crystals and gases) and groundwater.</p>
<p>Victoria hosts two of the world’s largest maar volcanoes: Tower Hill near Warrnambool and <a href="http://www.sciencedirect.com/science/article/pii/S0377027312003848">Lake Purrumbete</a> near Camperdown. </p>
<p>These large maars are more than 3km wide, whereas normally maars are only up to 500m in diameter. The size of these maars is actually the result of eruption from <a href="http://www.sciencedirect.com/science/article/pii/S0377027315002760">multiple vents</a> that merged into a larger maar crater.</p>
<h2>Know your volcanic eruption style</h2>
<p>Volcanic eruptions can be in various forms or <a href="http://geology.com/volcanoes/types-of-volcanic-eruptions/">styles</a>. Mildly explosive styles are the Hawaiian-style fire fountains and the Strombolian-style spraying, as it happens on the Mediterranean island of Stromboli. </p>
<p>When eruptions become more explosive they turn to Plinian, named after <a href="http://www.britannica.com/biography/Pliny-the-Younger">Pliny the Younger</a> who described the 79AD eruption of Vesuvius that destroyed Pompeii.</p>
<p>Plinian eruptions develop tall eruption columns with umbrella clouds that last for many days to weeks. </p>
<p>But if the intense explosions occur more like bursts, then they are Vulcanian, with a smaller eruption column that can disappear with the wind within a few hours.</p>
<p>When the cloud of a Plinian or Vulcanian eruption is no longer upheld by upwards forces from the explosions, this cloud can collapse. A collapsing eruption column results in fast-travelling clouds of hot gases and volcanic material down the slopes of the volcano called <a href="https://volcanoes.usgs.gov/vhp/pyroclastic_flows.html">pyroclastic flows</a>.</p>
<p>If water from the sea, a lake or under the ground starts interacting with the magma, very explosive reactions can occur. These magma-water explosions, or phreatomagmatic explosions, produce large craters and release lots of fine material less than 2mm in diameter called ash. </p>
<p>A large part of this ash is transported along the ground surface by fast-travelling clouds of water vapour called base surges.</p>
<h2>Volcanic eruptions in south-eastern Australia</h2>
<p>Many of the younger Australian volcanoes erupted with a mixture of different styles. </p>
<p>Tower Hill not only erupted very explosively because of the interaction between magma and water, but it also produced fire fountains, resulting in the cones in the centre of the crater.</p>
<p>Mt Gambier and Mt Schank contain piles from Hawaiian-style fire fountains, explosive cones from milder Plinian eruptions (Micro-Plinian) with eruption columns between 5km and 10km high, and maar craters from explosive magma-water interaction. </p>
<p>The eruption of <a href="http://link.springer.com/article/10.1007/s00445-013-0737-y">Mt Gambier</a> 5,000 years ago is probably the best studied of all of these volcanoes. This volcano has at least 14 different vents from which the eruption occurred. </p>
<p>The most prominent are the Valley Lake and the Blue Lake craters, which were formed as maar craters, but not in the normal style. These craters were capped under a lava flow from earlier phases in the eruption, so with increased magma-water interaction later on, pressure built up.</p>
<p>This pressure built up until it broke through the capping lava flow, producing a big Vulcanian-style blast with actual <a href="http://jgs.lyellcollection.org/content/early/2016/02/23/jgs2015-122.abstract">pyroclastic flows</a>!</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/122627/original/image-20160516-10694-1sqpsnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122627/original/image-20160516-10694-1sqpsnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122627/original/image-20160516-10694-1sqpsnj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122627/original/image-20160516-10694-1sqpsnj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122627/original/image-20160516-10694-1sqpsnj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122627/original/image-20160516-10694-1sqpsnj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122627/original/image-20160516-10694-1sqpsnj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pyroclastic flows at Mt Gambier formed by Vulcanian-style blasts after Hawaiian fire-fountaining. Firstly, the Blue Lake crater erupted with such a large blast, which was followed by a westward-directed blast in the Valley Lake crater.</span>
<span class="attribution"><span class="source">Jozua Van Otterloo and Cas, RAF. in the Journal of the Geological Society</span></span>
</figcaption>
</figure>
<h2>Size matters</h2>
<p>Volcanic eruptions are ranked on the Volcanic Explosivity Index (<a href="http://onlinelibrary.wiley.com/doi/10.1029/JC087iC02p01231/full">VEI</a>). The smallest explosive eruptions such as fire fountains have a ranking of 1 and supervolcanoes rank 8.</p>
<p>The <a href="http://www.theguardian.com/uk/interactive/2010/apr/15/volcano-airport-disruption-iceland">2010 Eyafjallajökull eruption</a> (or just the 2010 Iceland eruption) that caused a lot of disruption in Europe ranked 4.</p>
<p>The studied volcanic cones and maars formed by more intense explosive activity in the Newer Volcanics Province ranged in VEI from 2 to 4. Eruptions at <a href="http://www.sciencedirect.com/science/article/pii/S0377027314000717">Mt Leura in Camperdown, Ecklin Maar</a> and <a href="http://www.sciencedirect.com/science/article/pii/S037702731200128X">Red Rock</a> near Colac were of <a href="http://www.sciencedirect.com/science/article/pii/S0377027315001304">VEI category 2</a>, forming small plumes of 1-5km.</p>
<p>Most volcanoes in the area would have erupted with similar magnitudes. But Australia’s youngest volcano, Mt Gambier, has also been the most explosive (that we know of) with a <a href="http://link.springer.com/article/10.1007/s00445-013-0769-3">VEI of 4</a>. </p>
<p>It produced eruption plumes of about 10km in height and a large volume of magma erupted over a very short time. This eruption would have been very similar to the 2010 Iceland eruption.</p>
<h2>The next eruption?</h2>
<p>So what can we expect the next volcanic eruption to be like? It depends where it happens. </p>
<p>If the next eruption occurs in the northern areas of the Newer Volcanics Provinces (around Bendigo, Ballarat or Hamilton), we can expect lots of lava flows and fire fountains. </p>
<p>But if it occurs in the southern part (Colac, Camperdown, Warrnambool or Mt Gambier), the presence of groundwater could make it much more explosive. </p>
<p>We could be up for an eruption just like the 2010 Iceland eruption where a big plume of ash was sent high in the atmosphere. In this case disruption will occur in Eastern Australia and New Zealand.</p>
<p>Will it happen any time soon? Well, the Newer Volcanics Province has been active for more than 4.5 million years, with eruptions occurring at least once every 10,000 years. </p>
<p>It could happen in our lifetime, but more likely it will happen after that. </p>
<p>Oh, another outcome of the research was that the first warning signs with Mt Gambier would have been noticed only by the most sensitive equipment up to <a href="http://petrology.oxfordjournals.org/content/55/7/1317.short">two days in advance</a>.</p>
<p>Such equipment is not present in the area at the moment.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/122633/original/image-20160516-10691-jga3pl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/122633/original/image-20160516-10691-jga3pl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122633/original/image-20160516-10691-jga3pl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122633/original/image-20160516-10691-jga3pl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122633/original/image-20160516-10691-jga3pl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122633/original/image-20160516-10691-jga3pl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122633/original/image-20160516-10691-jga3pl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122633/original/image-20160516-10691-jga3pl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">What if another volcano would erupt with an impact similar to that of the 2010 Eyjafjallajökull eruption? This image was created by overlaying the 2010 ash cloud over the Pacific region, taking into account the southern hemisphere atmospheric situation.</span>
<span class="attribution"><span class="source">Jozua van Otterloo</span></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/58766/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jozua van Otterloo 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>What can we expect Australia’s next volcanic eruption to be like? That depends where and when it happens, and it could be sooner than you think.Jozua van Otterloo, Assistant Lecturer in Volcanology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/505762015-12-03T02:10:33Z2015-12-03T02:10:33ZAttack of the jellies: the winners of ocean acidification<figure><img src="https://images.theconversation.com/files/102464/original/image-20151119-19382-15i4a4w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Jelly invasion: is this a vision of the future for our oceans?</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>For most marine biologists, myself included, it wasn’t until 2005 that it dawned on us that a third of all human-caused carbon dioxide emissions are dissolving into and <a href="https://royalsociety.org/topics-policy/publications/2005/ocean-acidification/">acidifying the sea</a>.</p>
<p>By driving down <a href="https://en.wikipedia.org/wiki/PH">seawater pH</a> (and increasing acidity), these emissions are <a href="https://www.iaea.org/ocean-acidification/act3/new%20RUG%20docs/aooa.web.pdf">increasingly bad news</a> for marine organisms that build their protective shells and skeletons out of <a href="https://en.wikipedia.org/wiki/Calcium_carbonate">calcium carbonate</a>. When seawater becomes too acidic, calcium carbonate structures begin to corrode, dissolving baby oysters, coral skeletons, and many other creatures.</p>
<p>And while much has been written about the <a href="https://theconversation.com/global-warmings-evil-twin-ocean-acidification-19017">species that will lose out</a>, a lot less has been said about the potential “winners” of ocean warming and acidification.</p>
<p>In a <a href="https://www.dovepress.com/the-impact-of-co2-emissions-on-39nuisance39-marine-species-peer-reviewed-article-RRBS">recently published paper</a>, we present evidence that the slimy, jelly-like creatures of the oceans are far more tolerant of rising marine carbon dioxide levels. It is these creatures that are likely to proliferate in a warmer and increasingly acidic ocean. </p>
<p>Unfortunately for life in the sea, many of these lucky species are already considered a nuisance in marine ecosystems.</p>
<h2>What volcanic vents can tell us about ocean acidification</h2>
<p>There are places already on Earth that show us what the future might look like. The waters surrounding some coastal volcanoes are high in CO₂ and low in aragonite (a form of calcium carbonate).</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ADJ9kg-IAxE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Testing the waters around volcanic seeps helps us understand the effects of ocean acidification on marine species.</span></figcaption>
</figure>
<p>Volcanic activity causes CO₂ to bubble up (or “seep”) from the sea floor, acidifying large areas for hundreds of years. The tricky bit is finding carbon dioxide seeps without other minerals which confuse the story. But it can be done, and researchers have begun to study a number of these naturally acidified areas to understand which organisms thrive, and which are most vulnerable to ocean acidification.</p>
<p>We have found that chronic exposure to increases in CO₂ alters food webs and causes marine biodiversity loss around underwater volcanic seeps in the Mediterranean, the Sea of Cortez, and off Papua New Guinea. Key groups, like corals and hard, skeleton-building algae, are consistently compromised and fish reproduction is disrupted.</p>
<p>Meanwhile, higher CO₂ levels stimulate the growth of certain single-celled algae, seaweeds, and seagrasses. If temperatures remain low enough then the symbiotic algae of corals and anemones do well, as do numerous invasive species of animals and algae.</p>
<p>Some organisms have tissues that protect their shells and skeletons – including some corals in the tropics, and mussels in temperate seas – meaning they can <a href="http://www.nature.com/nclimate/journal/v1/n6/full/nclimate1200.html?WT.ec_id=NCLIMATE-201109">tolerate acidified seawater</a>. Yet these animals, despite being tough, can still experience adverse effects on reproduction, behaviour, respiration, and growth when carbon dioxide levels ramp up.</p>
<p>The fossil record serves as a warning. Shells found after high-CO₂ mass extinction events are much smaller than their ancestors — a phenomenon known as the <a href="http://www.theguardian.com/environment/2015/may/16/global-warming-shellfish-warning">Lilliput effect</a>. Work at volcanic seeps has shown that smaller animals are better able to cope with the stress of ocean acidification.</p>
<p>And while the carbon boost provided by ocean acidification can drive up phytoplankton productivity, it can also harm tropical coral reefs. A fall in carbonate levels causes coral skeletons to dissolve, and increased CO₂ levels stimulates the growth of seaweeds that smother the reefs.</p>
<h2>Nuisance species will thrive</h2>
<p>It is now clear that tropical coral reefs face a host of interconnected problems (bleaching, corrosion, disease, spreading seaweed, invasive species) that are all exacerbated by rising CO₂ levels.</p>
<p>Invasive species of algae and jellyfish thrive at the levels of carbon dioxide that are predicted to occur this decade. Our review of laboratory experiments reveals stand-out cases such as so called “<a href="http://cisr.ucr.edu/caulerpa_taxifolia.html">Killer algae</a>” (<em>Caulerpa taxifolia</em>). This species, which benefits from higher CO₂, is spreading world-wide and is so toxic that native herbivores die of starvation rather than eat it.</p>
<p>It turns out that loads of notorious <a href="https://www.youtube.com/watch?v=xvlHH0y2hwE&feature=youtu.be">nuisance species</a> – such as Japanese kelp (<em>Undaria pinnatifida</em>) and stinging jellyfish (<em>Pelagia noctiluca</em>) — are resilient to rising CO₂ levels.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/103805/original/image-20151130-26559-iyzr0l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/103805/original/image-20151130-26559-iyzr0l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/103805/original/image-20151130-26559-iyzr0l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/103805/original/image-20151130-26559-iyzr0l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/103805/original/image-20151130-26559-iyzr0l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/103805/original/image-20151130-26559-iyzr0l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/103805/original/image-20151130-26559-iyzr0l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Stinging jellyfish, like this one found near a CO₂ seep, might become an even bigger nuisance as the oceans continue to acidify.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Global warming and changes in seawater chemistry may help the spread of hundreds of these damaging marine organisms.</p>
<h2>Tackling the issue</h2>
<p>Ocean acidification research is the new kid on the block amongst planetary environmental issues. But as evidence rolls in from across the globe it is clear that many organisms are likely to be affected, resulting in both winners and losers.</p>
<p>Both the decline of vulnerable species and the spread of harmful marine organisms should be factored into calculations of the risks of climate change and ocean acidification.</p>
<p>If we want to curb the spread of harmful marine life, like toxic algae and stinging jellyfish, then reducing CO₂ emissions is definitely part of the solution. This is why there is a <a href="http://voices.nationalgeographic.com/2015/09/16/uniting-ocean-and-earth-for-climate-action/">growing awareness</a> of the central role of ocean issues in climate negotiations at COP21 in Paris and beyond.</p>
<p>But local solutions to this global issue can also have a range of benefits. The International Union for the Conservation of Nature <a href="http://www.conservation.org/projects/Pages/mitigating-climate-change-on-coasts-blue-carbon.aspx">Blue Carbon</a> initiative, for example, recognises the ability of coastal vegetation (e.g. saltmarshes and seagrasses) to prevent acid water run-off, and capture and store carbon - raising the pH of coastal waters. Other solutions include seaweed farming and the gradual restoration of mangroves in areas that have been converted to shrimp farms.</p>
<p>To properly address the crisis of our warming and acidifying oceans, we must attack this issue from every angle. It’s time we began thinking about the ways we can more sustainably work with, and for, our oceans in order to preserve life on Earth.</p><img src="https://counter.theconversation.com/content/50576/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Hall-Spencer 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>We know a lot about the potential negative effects of ocean acidification on marine creatures. But might some species actually benefit? The answer is yes, but this isn’t necessarily a good thing.Jason Hall-Spencer, Professor of Marine Biology, University of PlymouthLicensed as Creative Commons – attribution, no derivatives.