The largest volcanoes on our planet may take as little as a few hundred years to form and erupt.

These "supervolcanoes" were thought to exist for as much as 200,000 years before releasing their vast underground pools of molten rock.

Researchers reporting in Plos One have sampled the rock at the supervolcano site of Long Valley in California.

Their findings suggest that the magma pool beneath it erupted within as little as hundreds of years of forming.