Catastrophic Supervolcano Eruptions Happen Way More Often Than Scientists Thought

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The eruption of Bali's Mount Agung is feared to be imminent. The volcano is pictured here from Ampenan beach in Mataram, Bali, Indonesia on 28 November. Antara Foto Agency/Reuters

One-thousand gigaton volcanic supereruptions are much more frequent than previously thought, with scientists discovering they could happen as often as every 5,000 years—and the next big one is due at any time.

One eruption could cover an entire continent in ash

Super-eruptions are the very biggest volcanic eruptions, spewing more than 1,000 gigatons of ash, gas and molten lava. One supereruption could cover an entire continent in volcanic ash. To put that in perspective, a cloud of ash from the tallest peak of Bali's Mount Agung—which is in danger of "imminent eruption"reached only 6,000 feet on Saturday.

The damage of a supereruption—which could be produced by the likes of Yellowstone in the U.S. or Lake Toba in Indonesia—could cause global catastrophe.

In a study published in the journal Earth and Planetary Science Letters, a team of researchers from the University of Bristol in the U.K., combed through 100,000 years of geological records to estimate the average time between supereruptions.

The team's analysis revealed that supereruptions may occur almost ten times as often as scientists previously believed.

Jonathan Rougier, professor of Statistical Science at the University of Bristol, explained in a press release: "The previous estimate, made in 2004, was that supereruptions occurred on average every 45,000 to 714,000 years…But in our paper just published, we re-estimate this range as 5.2–48,000 years, with a best guess value of 17,000 years."

Yellowstone supervolcano last erupted 640,000 years ago. Jim Urquhart/Reuters

Our civilization stretches back approximately 12,000 years, with the last super-eruption occurring 20,000 to 30,000 years ago—so is an eruption imminent? Rougier cautions against building underground shelters just yet. He said that while we have been "slightly lucky" not to experience any super-eruptions in civilized history, "it is important to appreciate that the absence of super-eruptions in the last 20,000 years does not imply that one is overdue," he said, adding, "nature is not that regular."

"What we can say is that volcanoes are more threatening to our civilization than previously thought."

Rather than preparing for the next super-eruption, however, Rougier argues that there are far more pressing matters to focus on—a catastrophic blow to mankind might well come before the next supereruption.