Scientists say it is extremely challenging to try and predict when a supervolcano might erupt. There is not a single model which can describe how these catastrophic events happen.
Supervolcanoes are defined as a volcano that has at least one explosion of magnitude 8. This is the highest ranking of the Volcanic Explosivity Index, or VEI, meaning it has released more than 1000 cubic kilometers of material.
When these huge volcanic eruptions explode, the associated supereruption represents the most catastrophic of events caused by a natural hazard, resulting in widespread ash-fall blankets and pyroclastic flows, which can be hundreds of meters thick, covering thousands to tens of thousands of square kilometers.
These events also leave massive holes in the ground called Calderas due to the collapse of the Earth’s surface through removal of such large volumes of magma.
However, these events are extremely rare, occurring on average once every 100,000 years.
They studied events ranging from the most recent eruption at the Taupo volcano in New Zealand, over 24,000 years ago, to the oldest at Yellowstone in the U.S. roughly two million years ago.
Analysis of the data revealed no single, unified model that described how the events played out and showed that the supereruptions could start mildly over weeks to months or go into vigorous activity immediately. Individual supereruptions could last periods of days to weeks, or be prolonged over decades.