Super size: About 2.1 m years ago the Yellowstone supervolcano erupted 2,500 times more ash than Mount St Helens (pictured).
Read about the 1980 Mount St Helens eruption on 主播大秀 On This Day. (photo: Austin Post/USGS)
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Super size: About 2.1 m years ago the Yellowstone supervolcano erupted 2,500 times more ash than Mount St Helens (pictured). Read about the 1980 Mount St Helens eruption on 主播大秀 On This Day. (photo: Austin Post/USGS)
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