<P> The loosely defined term `` supervolcano '' has been used to describe volcanic fields that produce exceptionally large volcanic eruptions . Thus defined , the Yellowstone Supervolcano is the volcanic field which produced the latest three supereruptions from the Yellowstone hotspot ; it also produced one additional smaller eruption , thereby creating the West Thumb of Yellowstone Lake 174,000 years ago . The three supereruptions occurred 2.1 million , 1.3 million , and approximately 630,000 years ago , forming the Island Park Caldera , the Henry 's Fork Caldera , and Yellowstone calderas , respectively . The Island Park Caldera supereruption ( 2.1 million years ago ) , which produced the Huckleberry Ridge Tuff , was the largest , and produced 2,500 times as much ash as the 1980 Mount St. Helens eruption . The next biggest supereruption formed the Yellowstone Caldera ( ~ 630,000 years ago ) and produced the Lava Creek Tuff . The Henry 's Fork Caldera ( 1.2 million years ago ) produced the smaller Mesa Falls Tuff , but is the only caldera from the Snake River Plain - Yellowstone hotspot that is plainly visible today . </P>
<P> The loosely defined term `` supervolcano '' has been used to describe volcanic fields that produce exceptionally large volcanic eruptions . Thus defined , the Yellowstone Supervolcano is the volcanic field which produced the latest three supereruptions from the Yellowstone hotspot ; it also produced one additional smaller eruption , thereby creating the West Thumb of Yellowstone Lake 174,000 years ago . The three supereruptions occurred 2.1 million , 1.3 million , and approximately 630,000 years ago , forming the Island Park Caldera , the Henry 's Fork Caldera , and Yellowstone calderas , respectively . The Island Park Caldera supereruption ( 2.1 million years ago ) , which produced the Huckleberry Ridge Tuff , was the largest , and produced 2,500 times as much ash as the 1980 Mount St. Helens eruption . The next biggest supereruption formed the Yellowstone Caldera ( ~ 630,000 years ago ) and produced the Lava Creek Tuff . The Henry 's Fork Caldera ( 1.2 million years ago ) produced the smaller Mesa Falls Tuff , but is the only caldera from the Snake River Plain - Yellowstone hotspot that is plainly visible today . </P>
when was the last time yellowstone supervolcano erupted
when was the last time yellowstone supervolcano erupted
174,000 years ago
174,000 years ago