Supervolcano threat: Early warning system needed in face of ‘devastating’ risk says expert

Yellowstone: 'Swarm of earthquakes' spotted around volcano

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George Cooper, a Research Associate in the School of Earth and Environmental Sciences at Cardiff University, warned Yellowstone and other active volcanic systems had the potential to cause devastation on a global scale – but said the impact could be lessened by a better understanding of the processes at work. Mr Cooper set out his findings in a report which he co-authored last month and which was published in Nature Reviews Earth and Environment last month.

This concluded there is no single model which can describe how such catastrophic events play out, making it extremely difficult to determine how supervolcanoes may erupt in the future.

Mr Cooper told “Forecasting an imminent eruption would make a difference, although it would be a huge operation to evacuate people from the area, and a real challenge is knowing how much magma will be erupted and how long it will last for.

“For example some super-eruptions lasted for only a few days, whereas other lasted perhaps decades – which has very different implications for hazard management.”

He said: “The ignimbrite deposits (deposits from concentrated, ground-hugging pyroclastic flows, typically metres to hundreds of metres thick) from a super-eruption can cover areas of thousands to tens of thousands of square kilometres.

“It is within this area that devastating destruction would occur. Beyond that, ash fall from the eruption would extend further away, and may change global weather systems and climate in the short term.

“However, it is important to note that the super-eruptions are part of a suite of eruption styles from these volcanoes – and that smaller eruptions can occur which are really important to know about as we could effectively mitigate their impacts much better – so we should keep monitoring these systems.”

Supervolcanoes are defined as a volcano that has had at least one explosion of magnitude 8, the highest ranking on the Volcanic Explosivity Index, or VEI, meaning it has released more than 1000 cubic kilometres of material.

Such a super eruption would have a global impact in terms of weather and the climate, Mr Cooper emphasised.

He said: “We can look at the example from Eyjafjallajokull eruption in 2010 as the impact that a small volume ash-rich eruption could have on transport and supplies – we would expect larger impacts on aviation in a super-eruptive event, and the associated challenges that would bring.

“However, as we are not close to any large silicic systems in the UK, the volcanic hazards (ash fall, pyroclastic flows etc) do not pose a direct threat to life within the UK itself – it is the subsequent consequences that would be most challenging for UK-based people.”

Mr Cooper also stressed that in many ways, the very term “supervolcano” was an oversimplification.

He told “It is important to understand volcanic activity at all scales, not just the largest events.

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“What we highlight is that the largest systems in the Quaternary (last 2.6 million years) all operate differently.”

As a result, there was not one specific way to generate “super sized eruptions”, he stressed.

Mr Cooper added: “This is important information as it means that forecasting when the next eruption of this scale may occur will be difficult, as there isn’t one set of warning signs that can be monitored, and these volcanoes have the potential to produce small-size eruptions as well as large eruptions.

“The fact that these systems are so diverse highlights the importance of developing familiarity with individual systems, and having experts working with advanced monitoring systems in place at all of these locations.”

Such work was already underway in many places – for instance by Yellowstone Volcano Observatory in California, GNS in New Zealand, and SERNAGEOMIN in Chile, he pointed out.

He said: “One particularly important aspect that we can study is the timescales involved in the magmatic processes that lead up to these eruptions (eg the movement of large volumes of molten rock beneath the surface).

“We find that the formation of eruptible magma bodies beneath the surface may take anywhere from tens of thousands of years, to only centuries.

“If we are to monitor these systems in the future to have any kind of early warning system on place then this information is critical.”

One common misconception was that the Earth was “due” an eruptions, Mr Cooper said.

NASA: View of Sarychev volcano eruption from ISS in 2009

He explained: “These systems do not have a periodic interval over which eruptions happen.

“To imagine blowing up a balloon with magma until it bursts is very much an over simplification of the complex interactions between crustal stresses which eventually allow magma ascent.”

Geophysical evidence suggests several modern systems (Yellowstone, Toba in Indonesia and Laguna del Maule in Chile) have moderate amounts (between five and 15 percent) of magma, also known as melt, underneath them.

Such systems were active therefore, but additional processes would need to happen before the system could erupt, Mr Cooper said.

Detailed geological surveys could measure changes in the percentage of melt which in turn would offer vital clues about how the systems vary over decades and centuries.

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