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Supervolcanoes evolve superquickly

Huge underground magma chambers appear and erupt within just several hundred years

California’s Long Valley is the remains of a supervolcano that exploded 760,000 years ago. Quartz grains in rocks from the eruption  suggest the magma chamber beneath it was there only briefly.

The biggest eruptions on Earth may happen faster than volcanologists had thought. Giant blobs of magma appear underground and then pour onto the surface within centuries, suggests a new study of a California supereruption.

If the work holds true for other volcanoes, it means the most powerful eruptions don’t have magma chambers beneath them for very long. So if big changes start happening, like the ground rising or new geysers spouting, volcanologists might expect an eruption sooner rather than later. Yellowstone, for one, experienced a supereruption about 2.1 million years ago.

“The fact that at Yellowstone there’s no giant magma body right now doesn’t mean that in hundreds to thousands of years we couldn’t have one,” says Guilherme Gualda, a geologist at Vanderbilt University in Nashville. “By understanding these time scales better, we know better what to expect.”

Gualda and his colleagues report the discovery May 30 in PLoS ONE.

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