tag:theconversation.com,2011:/nz/topics/vesuvius-14408/articlesVesuvius – The Conversation2021-08-20T12:22:32Ztag:theconversation.com,2011:article/1660102021-08-20T12:22:32Z2021-08-20T12:22:32ZWhat a baker from ancient Pompeii can teach us about happiness<figure><img src="https://images.theconversation.com/files/416823/original/file-20210818-13-1humc70.jpg?ixlib=rb-1.1.0&rect=0%2C246%2C4854%2C3146&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">As they do today, threats of destruction loomed in ancient Pompeii.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/person-killed-by-the-pompeii-eruption-79-ad-vesuvius-news-photo/463921737?adppopup=true">Art Media/Print Collector via Getty Images</a></span></figcaption></figure><p>In a testament to its resiliency, happiness, according to this year’s <a href="https://brandgenetics.com/human-thinking/speed-summary-world-happiness-report-2021/">World Happiness Report</a>, remained remarkably stable around the world, despite a pandemic that upended the lives of billions of people.</p>
<p><a href="https://www.westga.edu/share/documents/vitae/vita_090977.pdf">As a classicist</a>, I find such discussions of happiness in the midst of personal or societal crisis to be nothing new.</p>
<p>“<a href="https://en.wikipedia.org/wiki/Felicitas#/media/File:Bible_Museum_-_Bordellzeichen.jpg">Hic habitat felicitas</a>” – “Here dwells happiness” – confidently proclaims an inscription found in a Pompeiian bakery nearly 2,000 years after its owner lived and possibly died in <a href="https://www.nationalgeographic.com/science/article/vesuvius-baked-people-turned-brain-to-glass">the eruption of Vesuvius</a> that destroyed the city in A.D. 79.</p>
<p>What did happiness mean to this Pompeiian baker? And how does considering the Roman view of felicitas help our search for happiness today? </p>
<h2>Happiness for me but not for thee</h2>
<p>The Romans saw both <a href="https://www.britannica.com/topic/Felicitas">Felicitas</a> and <a href="https://www.britannica.com/topic/Fortuna-Roman-goddess">Fortuna</a> – a related word that means “luck” – as goddesses. Each had temples in Rome, where those seeking the divinities’ favor could place offerings and make vows. Felicitas was also portrayed <a href="https://en.wikipedia.org/wiki/Felicitas#/media/File:Romeinse_munten_denarius_Macrinus_217-218.jpg">on Roman coins</a> from the first century B.C. to the fourth century, suggesting its connection to financial prosperity of the state. Coins minted by emperors, furthermore, connect her to themselves. “<a href="https://en.wikipedia.org/wiki/Felicitas#/media/File:Aureus_Valerian-RIC_0034-transparent.png">Felicitas Augusti</a>,” for example, was seen on the golden coin of the emperor Valerian, iconography that suggested he was the happiest man in the empire, favored by the gods. </p>
<p>By claiming felicitas for his own abode and business, therefore, the Pompeiian baker could have been exercising a name-it-claim-it philosophy, hoping for such blessings of happiness for his business and life. </p>
<figure class="align-center ">
<img alt="The front and back of a gold coin." src="https://images.theconversation.com/files/416626/original/file-20210817-24-rj6nle.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416626/original/file-20210817-24-rj6nle.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416626/original/file-20210817-24-rj6nle.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416626/original/file-20210817-24-rj6nle.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416626/original/file-20210817-24-rj6nle.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416626/original/file-20210817-24-rj6nle.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416626/original/file-20210817-24-rj6nle.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">‘Felicitas’ appears on the back of a Roman coin.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Romeinse_munten_denarius_Macrinus_217-218.jpg">NumisAntica</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>But just beyond this view of money and power as a source of happiness, there was a cruel irony. </p>
<p>Felicitas and Felix were commonly used names for female and male enslaved persons. For instance, <a href="https://www.livius.org/articles/person/antonius-felix/">Antonius Felix</a>, the governor of Judaea in the first century, was an ex-slave – clearly, his luck turned around – while Felicitas was the name of the enslaved woman <a href="https://sourcebooks.fordham.edu/source/perpetua.asp">famously martyred with Perpetua</a> in A.D. 203. </p>
<p>Romans perceived enslaved people to be proof of their masters’ higher status and the embodiment of their happiness. Viewed in this light, happiness appears as a zero-sum game, intertwined with power, prosperity and domination. Felicitas in the Roman world had a price, and enslaved people paid it to confer happiness on their owners. </p>
<p>Suffice it to say that for the enslaved, wherever happiness dwelled, it was not in the Roman Empire.</p>
<h2>Where does happiness really dwell?</h2>
<p>In today’s society, can happiness exist only at the expense of someone else? Where does happiness dwell, as <a href="https://mhanational.org/issues/state-mental-health-america">rates of depression and other mental illness</a> soar, and work days get longer? </p>
<p><a href="https://20somethingfinance.com/american-hours-worked-productivity-vacation/">Over the past two decades</a>, American workers have been working more and more hours. A <a href="https://www.bostonglobe.com/2021/08/19/magazine/busting-work-family-myth-turns-out-your-job-doesnt-have-be-your-life/">2020 Gallup poll</a> found that 44% of full-time employees were working over 45 hours a week, while 17% of people were working 60 or more hours weekly. </p>
<p>The result of this overworked culture is that happiness and success really do seem to be a zero-sum equation. There is a cost, often a human one, with work and family playing tug-of-war for time and attention, and with personal happiness the victim either way. This was true long before the COVID-19 pandemic.</p>
<p>Studies of happiness seem to become more popular during periods of high societal stress. It is perhaps no coincidence that the <a href="https://news.harvard.edu/gazette/story/2017/04/over-nearly-80-years-harvard-study-has-been-showing-how-to-live-a-healthy-and-happy-life/">longest-running study of happiness</a>, administered by Harvard University, originated during the Great Depression. In 1938, researchers measured physical and mental health of 268 then-sophomores and, for 80 years, tracked these men and some of their descendants. </p>
<p>Their main finding? “Close relationships, more than money or fame … keep people happy throughout their lives.” This includes both a happy marriage and family, and a close community of supportive friends. Importantly, the relationships highlighted in the study are those based on love, care and equality, rather than abuse and exploitation.</p>
<p>Just as the Great Depression motivated Harvard’s study, the current pandemic inspired social scientist Arthur Brooks to launch, in April 2020, a weekly column on happiness titled “<a href="https://www.theatlantic.com/family/archive/2020/04/how-increase-happiness-according-research/609619/">How to Build a Life</a>.” In his first article for the series, Brooks loops in research showing faith and meaningful work – in addition to close relationships – can enhance happiness.</p>
<h2>Finding happiness in chaos and disorder</h2>
<p>Brooks’ advice correlates with those findings in the <a href="https://worldhappiness.report/ed/2021/overview-life-under-covid-19/">World 2021 Happiness Report</a>, which noted “a roughly 10% increase in the number of people who said they were worried or sad the previous day.” </p>
<p>Faith, relationships and meaningful work all contribute to feelings of safety and stability. All of them were victims of the pandemic. The Pompeiian baker, who chose to place his plaque in his place of business, likely would have agreed about the significant connection among happiness, work and faith. And while he was not, as far as historians can tell, living through a pandemic, he was no stranger to societal stress.</p>
<p>It’s possible his choice of décor reflected an undercurrent of anxiety – understandable, given some of the political turmoil in Pompeii and in the <a href="https://www.worldhistory.org/article/1724/the-year-of-the-four-emperors--the-demise-of-four/">empire at large</a> in the last 20 years of the city’s existence. At the time of the final volcanic eruption of A.D. 79, we know that some Pompeiians were still rebuilding and restoring from <a href="https://politicsofdisaster.wordpress.com/0790/06/09/62-a-d-pompeii-earthquake-and-79-a-d-eruption-of-mt-vesuvius/">the earthquake of A.D. 62</a>. The baker’s life must have been filled with reminders of instability and looming disaster. Perhaps the plaque was an attempt to combat these fears. </p>
<p>After all, would truly happy people feel the need to place a sign proclaiming the presence of happiness in their home?</p>
<p>[<em>Over 100,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p>
<p>Or maybe I’m overanalyzing this object, and it was simply a mass-made trinket – a first century version of a “Home Sweet Home” or “Live, Laugh, Love” placard – that the baker or his wife picked up on a whim.</p>
<p>And yet the plaque reminds of an important truth: people in antiquity had dreams of and aspirations for happiness, much like people do today. Vesuvius may have put an end to our baker’s dreams, but the pandemic need not have such a permanent impact on ours. And while the stress of the past year-and-a-half may feel overwhelming, there has been no better time to re-evaluate priorities, and remember to put people and relationships first.</p><img src="https://counter.theconversation.com/content/166010/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nadejda Williams 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>While they weren’t living through a pandemic, citizens of ancient Pompeii weren’t strangers to societal stress.Nadejda Williams, Professor of Ancient History, University of West GeorgiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1579792021-03-26T16:58:39Z2021-03-26T16:58:39ZPompeii: ancient remains are helping scientists learn what happens to a body caught in a volcanic eruption<p>The recent <a href="https://theconversation.com/south-west-iceland-is-shaking-and-may-be-about-to-erupt-156510">eruptions in Iceland</a>, <a href="https://www.youtube.com/watch?v=b9Hq6bTBF2A">vividly captured through dramatic drone footage</a>, have drawn public attention to the immense power of volcanoes. Beautiful though they are, and mesmerising to watch, they are also deadly. </p>
<p>History has recorded eruptions so spectacular they’ve never been forgotten. These include Krakatoa in 1883, whose explosion was heard around the world and Mount Tambora, which resulted in famines across the northern hemisphere. </p>
<p>But perhaps the most famous of all is the eruption of Vesuvius in Italy, in AD79, which sealed the Roman towns of Pompeii and Herculaneum beneath layers of ash.</p>
<p>Human activity has long been influenced by volcanic eruptions. Now, research into the variety of ways the skeleton reacts to heat is allowing us greater understanding of their impact on human death too.</p>
<p>The catastrophic impact of Vesuvius effectively froze the cities of Pompeii and Herculaneum in time, like insects trapped in amber. This has provided archaeologists with unique insights into the lives of those living in the shadow of the volcano thousands of years ago. The opportunity to <a href="https://www.pompeionline.net/en/">actually walk around an ancient city</a>, almost as it was, allows us to connect with our past in tangible ways. </p>
<p>The scientific study of the remains of victims of Vesuvius are, however, not without controversy. Until very recently, the prevailing theory was that the heat and force of the pyroclastic flow pouring out of Vesuvius caused the soft tissues <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0203210">to instantly vaporise</a>. </p>
<p>This doesn’t make sense. We know from studies in modern crematoria and from archaeological excavations of incompletely cremated remains that the soft tissues don’t vaporise, even at hundreds of degrees celsius. Instead they slowly dehydrate, contract and fall away from the body.</p>
<figure class="align-center ">
<img alt="An illustration of the volcano Vesuvius erupting with small buildings in the foreground." src="https://images.theconversation.com/files/391915/original/file-20210326-21-13a5t6t.jpg?ixlib=rb-1.1.0&rect=77%2C68%2C2932%2C2180&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391915/original/file-20210326-21-13a5t6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391915/original/file-20210326-21-13a5t6t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391915/original/file-20210326-21-13a5t6t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391915/original/file-20210326-21-13a5t6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391915/original/file-20210326-21-13a5t6t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391915/original/file-20210326-21-13a5t6t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Vesuvius.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/illustration-eruption-volcano-mount-vesuvius-pompeii-271331441">Shutterstock/Natalya Kalyatina</a></span>
</figcaption>
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<h2>Inconclusive evidence</h2>
<p>Work at Pompeii and Herculaneum has shown the temperatures experienced following the eruption were around 300°C-400°C, certainly not as hot as in a cremation. Other recent research has also suggested <a href="https://www.nejm.org/doi/full/10.1056/nejmc1909867">fragments of brain</a> and <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0240017">neurological tissues</a> were preserved at Herculaneum. As exciting as this sounds, the evidence is actually rather inconclusive due to a lack of data, unusual protein preservation and insufficient reference to previously published work.</p>
<p>Bodies do change significantly when burned. Skin dehydrates and then splits to reveal the deeper tissues. The body is pulled into the famed “pugilistic pose” – like the contorted plaster cast figures created from the cooled ash of the Pompeii victims. </p>
<p>This appearance had previously been interpreted as the victim fleeing or fighting, but we now know it’s simply the consequence of the muscles contracting. The internal organs will shrink and be destroyed and the skeleton will be made visible.</p>
<p>For me, this is where it gets interesting. I have spent the past 20 years studying what happens to the skeleton when it is subjected to extreme heat. Unlike the soft tissues, the bones are not fully destroyed, nor are they turned to ash. </p>
<figure class="align-center ">
<img alt="Two plaster casts of victims of the Vesuvius eruption in Pompeii." src="https://images.theconversation.com/files/391948/original/file-20210326-15-8x0dtd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391948/original/file-20210326-15-8x0dtd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391948/original/file-20210326-15-8x0dtd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391948/original/file-20210326-15-8x0dtd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391948/original/file-20210326-15-8x0dtd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391948/original/file-20210326-15-8x0dtd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391948/original/file-20210326-15-8x0dtd.jpg?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">
<figcaption>
<span class="caption">Victims at Pompeii.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/victim-pompeii-eruption-mt-vesuvius-778490941">Shutterstock/BlackMac</a></span>
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<h2>Extreme heat</h2>
<p>Bones crack and fragment in different ways depending on whether soft tissue is present or absent. They change colour as the carbon is lost and warp and shrink as the microscopic crystal structure of the bone becomes active. This shrinkage can be as much as 30%. </p>
<p>In fact, we can use these heat-induced changes to interpret the context of death. For example, by calculating the intensity of burning from the extent of the changes or, as we did in a <a href="https://www.sciencedirect.com/science/article/abs/pii/S2352409X21000675">recently published paper</a> from a Neolithic site in Sardinia, reconstructing the position of a body in relation to a fire.</p>
<p>Recent research by Italian scientists suggested the city of Pompeii was <a href="https://www.nature.com/articles/s41598-021-84456-7">engulfed in only 17 minutes</a>, causing the residents to suffocate to death. This supports our own work at the nearby town of Herculaneum. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/south-west-iceland-is-shaking-and-may-be-about-to-erupt-156510">South-west Iceland is shaking – and may be about to erupt</a>
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<p><a href="https://www.cambridge.org/core/journals/antiquity/article/reevaluation-of-manner-of-death-at-roman-herculaneum-following-the-ad-79-eruption-of-vesuvius/FD54E5B954D8E86B9B59001C0B0CC0BB">We combined new methods</a> of studying bone collagen and crystal structure to show the people sheltering in the stone boat houses by the beach, rather than being vaporised, were in fact suffocated and baked to death. </p>
<p>Herculaneum is different to Pompeii in that the victims had longer to respond to the eruption, due to the location of the town. Analysis of the skeletons of the deceased shows many people ran to the beach to await evacuation by sea to safety. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/scDy7gt4YEo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>Excavation and analysis of the skeletons suggest it was mainly men who died on the beach, while the women and children sheltered and ultimately died in the stone boat houses. </p>
<p>This gives us a poignant glimpse into not only who these people were, but how they lived their last moments – with the women and children sheltering and no doubt terrified as the temperature increased to fatal levels, while their husbands and fathers had been desperately trying to secure a means of escape.</p>
<p>Vesuvius didn’t just teach us about the living, it showed us what happens to bodies when they are hit by such a catastrophic geological force.</p><img src="https://counter.theconversation.com/content/157979/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Thompson 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>Research into the bodies of victims of the Vesuvius eruption show how pyroclastic flows affect the human body.Tim Thompson, Dean of Health & Life Sciences + Professor of Applied Biological Anthropology, Teesside UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1155712019-04-16T09:28:56Z2019-04-16T09:28:56ZNotre Dame: writers and the shock of destruction through history<p>Images of the skeletal frames of Notre Dame cathedral, enveloped in billowing smoke and flame, stopped us dead on April 15. What is so familiar from thousands of holiday photographs and postcards was suddenly made unfamiliar, strange. The stunned Parisians watching in horror as a staple of their city <a href="https://www.bbc.co.uk/news/world-europe-47941794">was destroyed before their eyes</a> brought to mind the faces of New Yorkers watching in disbelief as first one, then another tower came down in 2001, or the faces of Iraqi citizens watching the statue of Saddam Hussein topple in Iraq in 2003.</p>
<p>There are obviously very different political contexts to these events – some acts of terrorism, some natural acts of destruction – but what they share is the strange sense of watching one era of history end in real time: the end of a cultural icon that has stood, in Notre Dame’s case, through so many historical periods.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/notre-dame-how-a-rebuilt-cathedral-could-be-just-as-wonderful-115551">Notre Dame: how a rebuilt cathedral could be just as wonderful</a>
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<p>The many comment pieces we will see throughout the next few weeks will talk about the importance of this fire, not only in literal terms but its place in the cultural imagination – the loss of what the cathedral represents, its symbolic value as much as its literal one.</p>
<p>They won’t be the first. These expressions of cultural loss enter a long and storied tradition. Throughout history we have seen examples of writers and commentators expressing shock, disbelief, horror and awe over buildings disappearing before their eyes; wood and steel structures turning, rapidly and unstoppably to debris; of cities turning to dust. </p>
<p>One of the most famous examples we have is Pliny the Younger writing in a <a href="http://www.eyewitnesstohistory.com/pompeii.htm">letter</a> about the eruption of Vesuvius in 79 AD:</p>
<blockquote>
<p>Ashes were already falling, not as yet very thickly. I looked round: a dense black cloud was coming up behind us, spreading over the earth like a flood. […] We had scarcely sat down to rest when darkness fell, not the dark of a moonless or cloudy night, but as if the lamp had been put out in a closed room.</p>
</blockquote>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/269520/original/file-20190416-147499-1dqxrhr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/269520/original/file-20190416-147499-1dqxrhr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=422&fit=crop&dpr=1 600w, https://images.theconversation.com/files/269520/original/file-20190416-147499-1dqxrhr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=422&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/269520/original/file-20190416-147499-1dqxrhr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=422&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/269520/original/file-20190416-147499-1dqxrhr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=530&fit=crop&dpr=1 754w, https://images.theconversation.com/files/269520/original/file-20190416-147499-1dqxrhr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=530&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/269520/original/file-20190416-147499-1dqxrhr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=530&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Last Days of Pompeii by Karl Brullov (1830-1833).</span>
<span class="attribution"><span class="source">Russian Museum</span></span>
</figcaption>
</figure>
<p>It is not unlike the physical response that Samuel Pepys recorded in his <a href="https://www.pepysdiary.com/diary/1666/09/02/">diary</a> of the 1666 Great Fire of London:</p>
<blockquote>
<p>So near the fire as we could for smoke; and all over the Thames, with one’s face in the wind, you were almost burned with a shower of firedrops. … When we could endure no more upon the water; we to a little ale-house on the Bankside, over against the Three Cranes, and there staid till it was dark almost, and saw the fire grow; and, as it grew darker, appeared more and more, and in corners and upon steeples, and between churches and houses, as far as we could see up the hill of the City, in a most horrid malicious bloody flame, not like the fine flame of an ordinary fire … it made me weep to see it. The churches, houses, and all on fire and flaming at once; and a horrid noise the flames made, and the cracking of houses at their ruins. So home with a sad heart.</p>
</blockquote>
<h2>Reliving trauma</h2>
<p>These writers typically describe the scene they witness and the physical sensations they experience – an attempt to record the physical experience of the event for the historical record. Writing about an event can also be, in some cases, a form of reliving or reenacting it, especially if the event was personally traumatic. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/269516/original/file-20190416-147522-dwamgb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/269516/original/file-20190416-147522-dwamgb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/269516/original/file-20190416-147522-dwamgb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/269516/original/file-20190416-147522-dwamgb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/269516/original/file-20190416-147522-dwamgb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/269516/original/file-20190416-147522-dwamgb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/269516/original/file-20190416-147522-dwamgb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Great Fire of London by Philip James de Loutherbourg (1740–1812).</span>
<span class="attribution"><span class="source">Yale Center for British Art</span></span>
</figcaption>
</figure>
<p>For many of these writers, there is a linking of the destruction of buildings with dead bodies. <a href="http://www.sfmuseum.net/hist5/jlondon.html">The article</a> the American writer Jack London wrote for Collier’s Magazine about the 1906 earthquake in San Francisco juxtaposes the destruction of buildings with the dead of the earthquake:</p>
<blockquote>
<p>Wednesday night saw the destruction of the very heart of the city. … An enumeration of the buildings destroyed would be a directory of San Francisco. An enumeration of the buildings undestroyed would be a line and several addresses. An enumeration of the deeds of heroism would stock a library and bankrupt the Carnegie medal fund. An enumeration of the dead will never be made. All vestiges of them were destroyed by the flames. The number of the victims of the earthquake will never be known. </p>
</blockquote>
<p>Edith Wharton wrote in similar terms about the devastation she witnessed on her trips to the war zones during World War I for articles written for Scribner’s Magazine in 1915, published later as <a href="https://edinburghuniversitypress.com/book-fighting-france.html">Fighting France</a>:</p>
<blockquote>
<p>Ypres has been bombarded to death, and the outer walls of its houses are still standing, so that it presents the distant semblance of a living city, while near by it is seen to be a disembowelled corpse. Every window-pane is smashed, nearly every building unroofed, and some house-fronts are sliced clean off, with the different stories exposed, as if for the stage-setting of a farce.</p>
</blockquote>
<h2>Fearful and tragic spectacle</h2>
<p>Wharton’s comparison with the theatrical is not untypical. We can see a similar sense of the unbelievable, the farcical, in John Updike’s <a href="https://www.newyorker.com/magazine/2001/09/24/tuesday-and-after-talk-of-the-town">response</a> to 9/11 in The New Yorker of September 24 2001:</p>
<blockquote>
<p>As we watched the second tower burst into ballooning flame … there persisted the notion that, as on television, this was not quite real; it could be fixed; the technocracy the towers symbolised would find a way to put out the fire and reverse the damage.</p>
</blockquote>
<p>There is also, of course, in all of these writers a fear for the self, even if we know the self is not in danger: “We knew we had just witnessed thousands of deaths; we clung to each other as if we ourselves were falling,” Updike writes.</p>
<p>The particularly strange sense of spectacle that accompanies the modern destruction of landmarks means the moment can be eternally replayed, as images become iconic. </p>
<p>This can link spectacle with mourning, as visual culture theorists such as <a href="https://steinhardt.nyu.edu/faculty/Marita_Sturken">Marita Sturken</a> have noted. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/269518/original/file-20190416-147505-195q91l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/269518/original/file-20190416-147505-195q91l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/269518/original/file-20190416-147505-195q91l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/269518/original/file-20190416-147505-195q91l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/269518/original/file-20190416-147505-195q91l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/269518/original/file-20190416-147505-195q91l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/269518/original/file-20190416-147505-195q91l.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">Notre Dame cathedral in Rheims after being destroyed by shellfire, 1914.</span>
<span class="attribution"><span class="source">Bibliothèque nationale de France</span></span>
</figcaption>
</figure>
<p>Wharton, writing about the <a href="https://www.peacepalacelibrary.nl/2014/07/the-destruction-of-the-cathedral-of-reims-1914/">destruction of the Cathedral of Rheims</a> in 1914 – another Notre Dame – found beauty in its strange ruins:</p>
<blockquote>
<p>When the German bombardment began, the west front of Rheims was covered with scaffolding: the shells set it on fire, and the whole church was wrapped in flames. Now the scaffolding is gone, and in the dull provincial square there stands a structure so strange and beautiful that one must search the Inferno, or some tale of Eastern magic, for words to picture the luminous unearthly vision. […] And the wonder of the impression is increased by the sense of its evanescence; the knowledge that this is the beauty of disease and death, that every one of the transfigured statues must crumble under the autumn rains, that every one of the pink or golden stones is already eaten away to the core, that the Cathedral of Rheims is glowing and dying before us like a sunset…</p>
</blockquote>
<p>There may be either sadness or comfort in knowing that our sensations today of something having been irreplaceably lost, of the destruction of culture and of part of ourselves, is not new.</p><img src="https://counter.theconversation.com/content/115571/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alice Kelly 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>Words are as important as pictures for helping us come to terms with such a huge cultural loss.Alice Kelly, Harmsworth Postdoctoral Fellow in History, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/962602018-05-08T18:43:04Z2018-05-08T18:43:04ZLava, ash flows, mudslides and nasty gases: Good reasons to respect volcanoes<figure><img src="https://images.theconversation.com/files/218151/original/file-20180508-34021-19wgpzp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lava flow moves in the Leilani Estates subdivision near Pahoa on the island of Hawaii, May 6, 2018.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Hawaii-Volcano/5f1db96d69c24dcea1d19c0d5e5401d2/12/0">USGS via AP</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Volcanoes are beautiful and awe-inspiring, but the ongoing eruption of Kilauea on Hawaii’s Big Island is showing how dangerous these events can be. So far this event has destroyed dozens of homes and displaced hundreds of people, but no deaths or serious injuries have been reported. Other volcanic eruptions have had deadlier impacts.</p>
<p>As a volcano scientist, I’m very aware of deadly volcanic eruptions can be, even the “nonexplosive” kind we’re seeing in Hawaii now. Since A.D. 1500, volcanic eruptions have killed <a href="https://doi.org/10.1186/s13617-017-0067-4">more than 278,000 people</a>.</p>
<p>Today there are 1,508 active volcanoes around the world. Each year, some 50 to 60 of them <a href="https://volcanoes.usgs.gov/vsc/file_mngr/file-153/FAQs.pdf">erupt</a>. <a href="https://blogs.worldbank.org/voices/inconvenient-apocalyptic-or-somewhere-between-why-we-shouldn-t-be-complacent-about-volcanic">Around 800 million people</a> live within volcanic risk zones. Volcanologists study and monitor volcanoes so that we can try to forecast future eruptions and predict how widely the damage could reach.</p>
<h2>When mountains explode</h2>
<p>Volcanic eruptions can be broadly divided into two types: explosive and nonexplosive. Explosive eruptions occur when magma, which is molten rock in the ground, contains gas. These eruptions are so energetic that the magma is pulverized into small rock particles, called volcanic ash. </p>
<p>Explosive eruptions are responsible for the <a href="http://volcano.oregonstate.edu/deadliest-eruption">highest number of volcanic-related deaths</a>. These events can distribute <a href="https://volcanoes.usgs.gov/vhp/tephra.html">volcanic ash</a> hundreds of miles from the volcano, causing billions of dollars in air travel disruption, water supply pollution and damage to power lines, structures and machinery. Krakatoa in the Pacific (1883) and Mount St. Helens in Washington state (1980) are examples of explosive eruptions. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/xP2dreOI8gI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">U.S. Geological Survey scientists recount their experiences before, during and after the May 18, 1980 eruption of Mount St. Helens, which killed 57 people, including a USGS researcher.</span></figcaption>
</figure>
<p>The most dangerous features of these events are <a href="https://volcanoes.usgs.gov/vhp/pyroclastic_flows.html">volcanic ash flows</a> – swift, ground-hugging avalanches of searing hot gas, ash and rock that destroy everything in their path. Ash flows produced during the A.D. 79 eruption of Mount Vesuvius in Italy entombed the towns of <a href="http://www.bbc.co.uk/history/ancient/romans/pompeii_portents_01.shtml">Herculaneum and Pompeii</a>. In 1902, ash flows from the eruption of Mount Pelee on the Caribbean island of <a href="https://www.theguardian.com/world/2002/apr/28/physicalsciences.highereducation">Martinique</a> killed more than 29,000 people.</p>
<h2>Lava flows and fountains</h2>
<p>Nonexplosive eruptions occur when little to no gas is contained within the magma. These events produce small fire fountains and lava flows, such as those <a href="https://volcanoes.usgs.gov/volcanoes/kilauea/status.html">currently erupting from Kilauea</a>.</p>
<p>Nonexplosive eruptions tend to be less deadly than explosive eruptions, but can still cause great disruption and destruction. Eruptions at Hawaiian-style volcanoes can occur at the summit or along the flanks. New eruptions typically begin with the opening of a fissure, or long crack, that spews molten lava into the air and sometimes forms <a href="https://volcanoes.usgs.gov/vhp/lava_flows.html">lava flows</a>. </p>
<p>As reports from Hawaii are showing, lava tends to flow rather slowly. Typically it is easy to outrun a lava flow but impossible to stop or divert it. People can escape, but homes and property are vulnerable.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/DNbbNZ5sHIM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Lava flows and fountains consuming homes and property in Leilani Estates on the island of Hawaii.</span></figcaption>
</figure>
<p>Both explosive and nonexplosive eruptions release <a href="https://volcanoes.usgs.gov/vhp/gas.html">volcanic gases</a>, producing a hazardous blend called volcanic fog, or <a href="https://volcanoes.usgs.gov/observatories/hvo/hvo_gas.html">VOG</a>. VOG contains aerosols – fine particles created when sulfur dioxide reacts with moisture in the air. It can cause health problems, damage crops and pollute water supplies. </p>
<p>These particles have global consequences when eruptions eject them into the stratosphere, where they block sunlight, cooling Earth’s climate. This effect can cause widespread crop failure and famine and is responsible for many historic volcanic-related deaths. For example, the 1815 explosive eruption of Tambora in Indonesia caused <a href="http://volcano.oregonstate.edu/vwdocs/volc_images/southeast_asia/indonesia/tambora.html">92,000 starvation-related deaths</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/218154/original/file-20180508-34038-lqdfa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/218154/original/file-20180508-34038-lqdfa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/218154/original/file-20180508-34038-lqdfa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/218154/original/file-20180508-34038-lqdfa6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/218154/original/file-20180508-34038-lqdfa6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/218154/original/file-20180508-34038-lqdfa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/218154/original/file-20180508-34038-lqdfa6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/218154/original/file-20180508-34038-lqdfa6.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">VOG (volcanic fog), produced by gases from Kilauea, hangs low over the Hawaiian Islands on December 3, 2008, producing unhealthy sulfur dioxide concentrations.</span>
<span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/NaturalHazards/view.php?id=36089">NASA Earth Observatory</a></span>
</figcaption>
</figure>
<p>Snow-capped volcanoes, such as those in the <a href="https://volcanoes.usgs.gov/observatories/cvo">Cascades</a> and <a href="https://www.avo.alaska.edu/">Alaska</a>, can produce mudflows, or <a href="https://volcanoes.usgs.gov/vhp/lahars.html">lahars</a>. These hazards form when ice and snow melt during an eruption, or ash is washed loose from the surface by heavy rain. </p>
<p>Mudflows have tremendous energy and can travel up to 60 miles per hour down river valleys. They are capable of destroying bridges, structures, and anything else in their path. A mudflow from the 1985 eruption of <a href="https://www.ngdc.noaa.gov/hazard/stratoguide/nevadofeat.html">Nevado del Ruiz</a> in Colombia killed 25,000 people.</p>
<h2>Getting ready for the next eruption</h2>
<p>By studying past and current eruptions, volcanologists constantly refine our ability to predict and mitigate the hazards and risk associated with volcanic activity. But people who live within range of volcanic hazards also can <a href="http://www.redcross.org/get-help/how-to-prepare-for-emergencies#About">minimize their risk</a>. </p>
<p>All residents of these zones should develop household plans for evacuating or sheltering in place and prepare emergency kits with first aid supplies, essential medicines, food and water. Events like the Kilauea eruption are reminders that preparing before natural disasters can make communities more resilient when these events strike.</p><img src="https://counter.theconversation.com/content/96260/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brittany Brand 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>Fountains of lava from Hawaii’s Kilauea volcano are dramatic, but the most deadly impacts of volcanic eruptions are toxic gases and ash and mud flows.Brittany Brand, Assistant Professor of Geosciences, Boise State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/749012017-04-10T10:18:17Z2017-04-10T10:18:17ZThe world’s five deadliest volcanoes … and why they’re so dangerous<figure><img src="https://images.theconversation.com/files/161632/original/image-20170320-9121-1xus7sp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mount Etna: boiling over ... again.</span> <span class="attribution"><a class="source" href="https://www.youtube.com/watch?v=cHA3Kl1yTPI">Shutterstock</a></span></figcaption></figure><p><a href="http://www.bbc.co.uk/news/world-europe-39295860">An eruption of Mount Etna</a> recently caught out some BBC journalists who were filming there. The footage was extraordinary and highlighted the hazards volcanoes pose to humans and society. </p>
<p>Since 1600, <a href="https://appliedvolc.springeropen.com/articles/10.1186/2191-5040-2-2">278,880 people have been killed</a> by volcanic activity, with many of these deaths attributed to secondary hazards associated with the main eruption. Starvation killed 92,000 following the 1815 <a href="http://www.smithsonianmag.com/history/blast-from-the-past-65102374/">Tambora eruption</a> in Indonesia, for example, and a volcanic tsunami killed 36,000 following the <a href="http://www.livescience.com/28186-krakatoa.html">1883 Krakatoa eruption</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/C-wyo7lmjEI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Since the 1980s, deaths related to volcanic eruptions have been rather limited, but this is not entirely a result of increased preparedness or investment in hazard management – it is significantly a matter of chance. </p>
<p><a href="http://jamanetwork.com/journals/jama/fullarticle/1791497">Research shows</a> that volcanic activity has shown no let up since the turn of the 21st century – it just hasn’t been around population centres. Indeed, there remain a number of volcanoes poised to blow which pose a major threat to life and livelihood.</p>
<iframe src="https://www.facebook.com/plugins/video.php?href=https%3A%2F%2Fwww.facebook.com%2FConversationUK%2Fvideos%2F742942229207453%2F&show_text=0&width=560" width="100%" style="border:none;overflow:hidden" scrolling="no" frameborder="0" allowtransparency="true" allowfullscreen="true" height="400"></iframe>
<h2>Vesuvius, Italy</h2>
<p>Known for its <a href="http://www.bbc.co.uk/history/ancient/romans/pompeii_portents_01.shtml">79AD eruption</a>, which destroyed the towns of Pompeii and Herculaneum, Vesuvius is still a significant hazard given that it overshadows the city of Naples and its surrounds, which are home to over 3m people.</p>
<p>It is also known for a particularly intense form of eruption. <a href="http://www.geology.sdsu.edu/how_volcanoes_work/Plinian.html">Plinian</a> (after Pliny the Younger who was the first to describe the 79AD event) eruptions are characterised by the ejection of a vast column of gas and ash which extends into the stratosphere, far higher than commercial airliners fly. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164532/original/image-20170408-2918-1briqqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164532/original/image-20170408-2918-1briqqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164532/original/image-20170408-2918-1briqqo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164532/original/image-20170408-2918-1briqqo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164532/original/image-20170408-2918-1briqqo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=452&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164532/original/image-20170408-2918-1briqqo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=452&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164532/original/image-20170408-2918-1briqqo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=452&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mount Vesuvius looms over Naples.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/night-view-volcano-vesuvius-gulf-naples-415975417?src=z0HmOHseURqmR9bO20rabw-1-25">Shutterstock</a></span>
</figcaption>
</figure>
<p>Were such an eruption to occur at Vesuvius today, it is likely that much of the population would already have been evacuated as a precursory swarm of earthquakes would likely herald its imminent approach. But those who remained would initially be showered with huge pumice rocks too large to be kept aloft by the column of gas. </p>
<p>Then, as the volcano began to run out of energy, the column itself would collapse, causing smaller particles of rock (from fine ash to small boulders) to fall from the sky and back to Earth at high velocity. Asphyxiating clouds of gas and pulverised rock – pyroclastic density currents – would then flood down the slopes of the volcano, annihilating anything in their path. Such gas-ash features have been known to travel tens of kilometres and at terrifying speeds, potentially turning modern Naples into a new Pompeii. </p>
<h2>Nyiragongo, Democratic Republic of Congo</h2>
<p>This <a href="https://volcano.si.edu/volcano.cfm?vn=223030">central African volcano</a> has erupted several times over the last few decades and while its eruptions aren’t particularly explosive, it produces a particularly runny – and dangerous – form of lava. Once effused, this lava can rapidly move down the flanks of the volcano and inundate areas with little or no warning. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164533/original/image-20170408-22688-gpwii5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164533/original/image-20170408-22688-gpwii5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164533/original/image-20170408-22688-gpwii5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164533/original/image-20170408-22688-gpwii5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164533/original/image-20170408-22688-gpwii5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164533/original/image-20170408-22688-gpwii5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164533/original/image-20170408-22688-gpwii5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The fiery heart of Nyiragongo.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/lava-lake-nyiragongo-dr-congo-erupting-571534195?src=h_pwqbduYWCXTVgaovlHRA-1-0">Shutterstock</a></span>
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<p><a href="https://www.researchgate.net/profile/Franco_Tassi/publication/27774149_January_2002_volcano-tectonic_eruption_of_Nyiragongo_volcano_Democratic_Republic_of_Congo/links/09e4150ae462b78133000000.pdf">In 2002</a>, the lava lake at the volcano’s summit was breached, resulting in streams of lava hurtling towards the nearby city of Goma at 60km/h, engulfing parts of it to a depth of two metres. </p>
<p>Fortunately, warnings had been issued as the volcano’s unrest has made it the focus of intense research – and over 300,000 people were evacuated in time. Should such an event occur again, we have to hope that the authorities are equally prepared, but this is a politically unstable area and it remains seriously vulnerable.</p>
<h2>Popocatepetl, Mexico</h2>
<p><a href="https://volcano.si.edu/volcano.cfm?vn=341090">“Popo”, as the locals call it</a>, is just 70km south-west of the one of the largest cities in the world: Mexico City, home to 20m people. Popo is regularly active and its most recent bout of activity in 2016 sent a plume of ash to an altitude of five kilometres. </p>
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<p>In recent times, and indeed throughout much of its history, eruptive events at Popo have consisted of similarly isolated ash plumes. But these plumes coat the mountain in a thick blanket of ash which, when mixed with water, can form a dense muddy mixture which has the potential to flow for many kilometres and at relatively high speeds. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164534/original/image-20170408-31640-1g36t19.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164534/original/image-20170408-31640-1g36t19.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164534/original/image-20170408-31640-1g36t19.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164534/original/image-20170408-31640-1g36t19.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164534/original/image-20170408-31640-1g36t19.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=492&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164534/original/image-20170408-31640-1g36t19.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=492&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164534/original/image-20170408-31640-1g36t19.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=492&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Letting off steam: Popocatepetl.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/success?src=5hjoFLeBcDBA6Spo_A-2SQ-1-0">Shutterstock</a></span>
</figcaption>
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<p>Such phenomena, known as <a href="https://volcanoes.usgs.gov/vhp/lahars.html">“lahars”</a>, can be extremely deadly, as exemplified by the <a href="http://news.bbc.co.uk/onthisday/hi/dates/stories/november/13/newsid_2539000/2539731.stm">Nevado del Ruiz disaster of 1985</a> when around 26,000 people were killed in the town of Armero, Colombia, by a lahar with a volcanic source that was 60km away. </p>
<p>The Nevado del Ruiz tragedy was the direct result of volcanic activity melting ice at the volcano’s summit, but a large volume of rainfall or snowmelt could feasibly generate a similar lahar on Popo. This could flow down-slope towards nearby settlements with little or no warning. </p>
<h2>Krakatoa, Indonesia</h2>
<p>Otherwise named Krakatau, Krakatoa’s name is infamous; 36,000 people were killed by the tsunami triggered by its 1886 eruption, which released more energy than 13,000 Hiroshima atomic bombs. The eruption destroyed the volcanic island completely, but within 50 years, a new island had appeared in its place. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164535/original/image-20170408-29399-mwt632.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164535/original/image-20170408-29399-mwt632.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164535/original/image-20170408-29399-mwt632.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164535/original/image-20170408-29399-mwt632.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164535/original/image-20170408-29399-mwt632.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164535/original/image-20170408-29399-mwt632.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164535/original/image-20170408-29399-mwt632.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Anak Krakatau erupts in 2011.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/indonesia-january-20-boat-near-volcano-231954214?src=ebePlNMkmjO7qscgPJ3Z3w-1-16">Shutterstock</a></span>
</figcaption>
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<p>The new island is named <a href="https://www.volcanodiscovery.com/krakatau.html">Anak Krakatau</a> (Child of Krakatoa) and since the 1920s, it has been growing in episodic phases, reaching about 300 metres in height today. New and significant activity commenced in 2007 and since this time, further episodes of activity were noted at the volcano, most recently in March 2017. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/SauQYUJ2Ckw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>No one knows for sure whether or not the spectacular growth of Anak Krakatau means it may one day repeat the catastrophe its “father” unleashed, but its location between Indonesia’s two most populated islands, Java and Sumatra, means it poses a grave threat to life.</p>
<h2>Changbaishan, China</h2>
<p>Few have heard of this volcano in a remote part of Asia – <a href="https://volcano.si.edu/volcano.cfm?vn=305060">and its last eruption was in 1903</a>. However, its history tells a rather scarier story. In around 969AD, the volcano produced one of the largest eruptions of the last 10,000 years, releasing three times more material than Krakatoa did in 1886. </p>
<p>One of the chief hazards is posed by the massive crater lake at its peak (with a volume of about nine cubic kilometres). If breached, this lake could generate lahars that would pose a significant threat to the 100,000 people that live in the vicinity. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/164536/original/image-20170408-29386-1t4aewq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164536/original/image-20170408-29386-1t4aewq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=380&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164536/original/image-20170408-29386-1t4aewq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=380&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164536/original/image-20170408-29386-1t4aewq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=380&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164536/original/image-20170408-29386-1t4aewq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=477&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164536/original/image-20170408-29386-1t4aewq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=477&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164536/original/image-20170408-29386-1t4aewq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=477&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Changbaishan: looks peaceful, but …</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/volcanic-rocky-mountains-lake-tianchi-wild-143645611?src=PqeTF59iUxaNCbmHZjvrHQ-1-3">Shutterstock</a></span>
</figcaption>
</figure>
<p>In the early 2000s, scientists began monitoring the hitherto under-monitored volcano, and determined that its <a href="https://phys.org/news/2012-09-china-changbaishan-volcano.html">activity was increasing</a>, that its magma chamber dormancy was coming to an end, and that it could pose a hazard in the following decades. </p>
<p>Further complicating things is the fact that Changbaishan straddles the border of China and North Korea. Given such a geo-politically sensitive location, the effects of any volcanic activity here would likely be very hard to manage.</p><img src="https://counter.theconversation.com/content/74901/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Blackett does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The clock is ticking.Matthew Blackett, Senior Lecturer in Physical Geography and Natural Hazards, Coventry UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/362772015-01-15T06:03:10Z2015-01-15T06:03:10ZThe very useful art of assessing a supervolcano without making it erupt<figure><img src="https://images.theconversation.com/files/69058/original/image-20150114-3891-fqh8a2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">If Campi Flegrei ever goes off, you won't want to be in Naples - or Europe!</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/emainthecoffee/476237979/in/photolist-J5QXD-drW76x-9fCX6g-8KZKw4-7iK4vz-f7KXLt-9NM1by-pMc4Ky-81Y6a2-qwfeyi-o3hwrZ-gvR4QZ-gME3KC-hycMvd-arFHsZ-pRzJ1H-7J285W-fEn3Lj-6hVsmj-6hVsmh-5ZJLMc-pNzJrG-fDL3Cw-pdQkJK-q3iRV5-a884et-kjcowK-ocz19m-otij4z-q6zDa3-cEZRW1-jvqaXU-cv6e5o-cv6ez9-fDu8na-cYbs7o-obqhor-cKTAUN-gGY9Li-iDkd3Y-b5SiDp-hdTkQe-gRiWPC-c2QDd1-cKUMNS-yrzJf-drWfkS-5XFc6w-jcK847-hJMPg7">Emanuele Nicastro</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Ever heard of <a href="http://www.volcanodiscovery.com/campi-flegrei.html">Campi Flegrei</a>? It is a supervolcano in southern Italy. Literally translating as “fields of fire,” only the <a href="http://io9.com/what-will-really-happen-when-yellowstone-volcano-has-a-508274690">Yellowstone caldera</a> in the United States has more potential to devastate. </p>
<p>The Naples urban area, with its four million inhabitants, extends within this amazing volcanic complex, though it lies mostly beneath the sea. The last time that Campi Flegrei <a href="http://www.geo.mtu.edu/volcanoes/boris/mirror/mirrored_html/Montenuovo.html">erupted was</a> less than 500 years ago, in 1538. It was one of the volcano’s smallest eruptions down the millennia, but it lasted a week and killed 24 people. </p>
<h2>The risks</h2>
<p>You may think that the chance of living in a city where the weather is nice and warm and you smell history at every corner is well worth the volcanic risk. But before buying the tickets, note that Campi Flegrei and <a href="http://www.bbc.co.uk/science/earth/collections/mount_vesuvius">Mt Vesuvius</a>, his more famous and much smaller brother (remember Pompei?) are just the visible scars of a supervolcano whose <a href="http://www.vuelco.net/campi2.php">previous eruptions</a> 35,000 and 15,000 years ago spread volcanic materials over an area of 10,000 sq km. The effects of an eruption of Campi Flegrei could dwarf those of any eruption recorded in human history, and, in the worst-case scenario, challenge human life on the old continent.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/69050/original/image-20150114-3859-13vqcls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/69050/original/image-20150114-3859-13vqcls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/69050/original/image-20150114-3859-13vqcls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/69050/original/image-20150114-3859-13vqcls.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/69050/original/image-20150114-3859-13vqcls.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/69050/original/image-20150114-3859-13vqcls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/69050/original/image-20150114-3859-13vqcls.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/69050/original/image-20150114-3859-13vqcls.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Vesuvius: big brother’s little brother.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/glosters/3704149196/in/photolist-5BMQME-cCZXis-8ZASJi-dNfef1-7z1jBX-bp5avf-9LDioy-a3Rswx-a3Ui8Y-ezHgdK-6DjJvj-dXEHk9-2fuJfs-KZ9cg-gMD3zD-8ZE1qf-dYYK36-5Vje4X-9VDe23-5zkK6f-4NUrvD-4y5eLQ-cCZUfG-npkHNg-8bjVu6-7b3Wd4-nBj2ec-98LF9y-823jhT-bXgFip-8NHQEg-buGCFj-f28U3R-5uiYBD-4eZMQz-pNPkBN-bgVpdR-oS68A-4phaG8-pHCTi-49Q4MY-98EBqE-546erG-6TY9j9-98EBV1-pjfVT9-2ra2Sv-5jLZMy-bLgdR6-7t2Jqd">shipscompass</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>This is possibly the moment where you start thinking about what scientists are doing to understand if and when such an eruption will take place. The good news is that the <a href="http://www.ov.ingv.it/ov/en.html">Vesuvius Observatory</a> (OV), monitoring both Mt Vesuvius and Campi Flegrei, is the oldest volcanology observatory in the world. Here geologists, geophysicists, and physicists join forces in a unique environment to understand what’s beneath these volcanoes.</p>
<h2>Drilling and drawbacks</h2>
<p>A good example is the <a href="http://www.icdp-online.org/projects/world/europe/campi-flegrei/">EU deep drilling project</a>, which the OV sponsors. The idea is simple: you drill to a depth of 2.5 miles inside Campi Flegrei caldera to get sensitive scientific data and rock samples, and obtain geothermal energy from the heated volcanic complex. </p>
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<a href="https://images.theconversation.com/files/69061/original/image-20150114-3874-1y2622y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/69061/original/image-20150114-3874-1y2622y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/69061/original/image-20150114-3874-1y2622y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/69061/original/image-20150114-3874-1y2622y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/69061/original/image-20150114-3874-1y2622y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/69061/original/image-20150114-3874-1y2622y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/69061/original/image-20150114-3874-1y2622y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/69061/original/image-20150114-3874-1y2622y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Ah southern Italy: sun, sea… and lots of boiling lava.</span>
<span class="attribution"><span class="source">Luca de Siena</span></span>
</figcaption>
</figure>
<p>But what happens when you drill an active caldera like this one? As with many simple ideas, this project has been accused of being simplistic and <a href="http://www.popsci.com/science/article/2011-01/what-could-possibly-go-wrong-deep-drilling-supervolcano">somewhat dangerous</a>, due to the fact that the drilling itself may cause changes in the state of the volcanic complex, triggering earthquakes and, possibly, a volcanic eruption.</p>
<p>This is a perfect example of striking the balance between not doing enough to prevent a catastrophe, and doing too much. In the case of Campi Flegrei, the drilling was stopped by the local authority after only a preliminary hole had been drilled. <a href="http://www.icdp-online.org/projects/world/europe/iceland/">In other volcanoes</a>, the drilling caused no problems, but the debate about the safety of the technique rages on – and it has the added disadvantage of being very expensive. </p>
<p>A possible solution may come from another, completely different question: is there another way to “see” inside a volcano without drilling? Using modern technology, we can look at distant stars and inside our own bodies. Can we do the same with a volcano? The answer is that although it is not the same, we can. </p>
<h2>How attenuation tomography works</h2>
<p>You can’t use light to look into the Earth, at least not the “light” we employ to look at the cosmos. And there is no instrument that can scan a volcano like we can do with a human body. But the Earth and, to an even greater extent, volcanoes, talk to us continuously – although our ears are not particularly good at listening. Notice that I say “listening” rather than “looking,” since the sound waves from our voices are in fact the most similar to the Earth’s way of expression: earthquakes, producing elastic waves.</p>
<p>When a strong earthquake happens it is similar to a shout that we record by measuring vibrations on the Earth’s surface. We can use this shout to <a href="http://www.iris.edu/hq/files/programs/education_and_outreach/aotm/7/SeismicTomography_Background.pdf">scan the</a> deep Earth interior, looking at how and where the velocity of the waves is changed by the medium. </p>
<p>Having said that, the voice of a large tectonic earthquake is actually quite plain. A supervolcano like Campi Flegrei speaks in much more interesting and various ways, with magma and hot fluids creating a song of continuous drumbeats and blasts.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/69053/original/image-20150114-3888-m7vizx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/69053/original/image-20150114-3888-m7vizx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/69053/original/image-20150114-3888-m7vizx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/69053/original/image-20150114-3888-m7vizx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/69053/original/image-20150114-3888-m7vizx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/69053/original/image-20150114-3888-m7vizx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/69053/original/image-20150114-3888-m7vizx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/69053/original/image-20150114-3888-m7vizx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Campi Flegrei’s sulphurous nostrils.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/ekieram/1843803321/in/photolist-3NVYur-dqEhg1-oM7MZH-8Jpqj6-8JnRD4-8Jpk9t-8Jr1XQ-8Jr1wj-8JpkVD-8Jr6RN-8Jss8U-8JpNbX-8JsP2U-8JnQJi-8JnUue-8JsGXJ-8JsxqC-8JqTtS-8JqT1y-8JsPmu-8JnNuB-8Jo4ut-8JssZd-8JpLTH-8JnQg8-8JsL3N-8JsJ95-8JpHKK-8JsJyY-8JpCqM-8Jr2mA-8JsxPY-8Jrft7-8JpDEn-8JnYxz-8JqUR9-8JnN5F-8JnSBe-8Jr181-8Jptqt-8JsCR9-8JpqKP-8JpJXx-8JsBzm-8JqYBY-8JrcMu-8JpBG4-8JsALm-8JsQbm-8Jobn6">EkieraM</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Volcano seismologists use this energy to produce images of what’s inside them. Here’s how this works, in simple terms. Think of loud music coming out of a stereo (the earthquake). If the stereo is in your room, you hear it strong and clear (the louder the nearer you are to it). </p>
<p>Now put a wall between you and the stereo. The volume is lowered as the sound energy is either reflected by the wall or lost inside it. If you are able to measure which notes are lost the most and where “the wall” is you are performing an “attenuation tomography”: only that, instead of the wall, we are talking about a magmatic chamber. </p>
<p>This technique is still relatively new. The Japanese developed it for their volcanoes in the 1990s, but it is only in the past decade that it has reached the West. It has also been applied to Mt St Helen in the north-western US and some South American volcanoes, but not yet to Yellowstone. </p>
<p>In combination with other geophysical and geological observations, we have used this technique to establish that there is <a href="http://onlinelibrary.wiley.com/doi/10.1029/2009JB006938/abstract">no large magmatic chamber</a> under Campi Flegrei between 0km and 4km depth – at least there wasn’t during the last seismic crisis, which <a href="http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CDYQFjAD&url=http%3A%2F%2Felea.unisa.it%3A8080%2Fjspui%2Fbitstream%2F10556%2F1486%2F1%2Ftesi_I_Sabbetta.pdf&ei=Os-2VOz0JYXxaozsgYAE&usg=AFQjCNHbJ398rAyVP8xGLCk7WOLnJarf3Q&sig2=NWa4TTGL3dB39srGwk0Uuw&bvm=bv.83640239,d.ZWU">was between</a> 1980 and 1984. </p>
<p>So if you were thinking about relocating to southern Italy, perhaps this suggests that you would be safe and sound. It probably does mean that there is no immediate risk of an eruption of lava or magma, though you could still see eruptions of gas and fluids (a so-called phreatic eruption). </p>
<p>The volcano is alive and “breathes,” even inside the Naples urban area. You can see it in the way its surface goes <a href="http://whc.unesco.org/en/tentativelists/2030/">up and down</a> each year and you can smell it from the steam produced by the holes that the volcano <a href="http://www.tripadvisor.co.uk/LocationPhotoDirectLink-g187785-i67186179-Naples_Province_of_Naples_Campania.html">has opened</a> on the Earth’s surface. </p>
<p>This “breathing” is a constant reminder to those living in the area, though it is possibly good news. You can think of it like a bottle of champagne continually losing pressure. Having said that, we do not know what’s happening deeper underground – except that there is probably <a href="http://onlinelibrary.wiley.com/doi/10.1029/2008GL034242/full">magma at a depth of 8 km</a>, which is quite a long way down, feeding both Campi Flegrei and Mt. Vesuvius. If magma is recharged and heated continuously, the pressure could grow and the lava could arrive to the surface very quickly – though with clear signs days/weeks before the eruption.</p>
<p>A volcano scientist monitoring Campi Flegrei uses all these senses to understand what he would see if we could actually drill a large hole in the ground. Although we are still not perfect at it, we have at least started listening to Campi Flegrei’s voice.</p><img src="https://counter.theconversation.com/content/36277/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luca spent four years working for the Vesuvius Observatory, including three at PhD level and one as a post-doc </span></em></p>Ever heard of Campi Flegrei? It is a supervolcano in southern Italy. Literally translating as “fields of fire,” only the Yellowstone caldera in the United States has more potential to devastate. The Naples…Luca De Siena, Lecturer, University of AberdeenLicensed as Creative Commons – attribution, no derivatives.