According to the findings
published in Science
in April, cross sections of the newly discovered magma body reveal it’s more than four times larger than the one on top of it, making Yellowstone one of the largest volcanic sites on the planet.
The new find doesn’t make the supervolcano any more dangerous, however. The reservoir has been there for millennia and is not getting bigger — the only thing that has changed is our awareness of it. And although there have been major eruptions at Yellowstone, most recently 640,000 years ago, Utah geophysicist Robert Smith puts the odds for a major eruption at 1 in 700,000 during any given year.
[This article originally appeared in print as "Supervolcano Supersized."]