Supervolcanoes and Long-Term Risk

A supervolcano, in the terminology introduced by volcanologists in the 1970s and popularized through the VEI scale, is a volcanic system capable of producing a VEI 8 "supereruption," ejecting more than 1,000 cubic kilometers of material, an amount roughly a thousand times greater than the 1980 eruption of Mount St. Helens. Rather than forming a single tall cone, supervolcanoes typically collapse into enormous calderas after eruption, since the sudden emptying of a shallow magma chamber leaves the overlying ground unsupported. No VEI 8 eruption has occurred within recorded human history, meaning scientific understanding of supereruptions rests on geological evidence from past events and on modeling rather than direct observation.