Asked by: Eric Lee, London
These are volcanoes with a Volcanic Explosivity Index of 8 that throw out more than 1000km cubed of material. By comparison, the 1980 eruption of Mount St Helens released 2.8km cubed. The last known supervolcano eruption was in New Zealand, 26,500 years ago; the last but one, 75,000 years ago, wiped out 60 per cent of the global human population.
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