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