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Yellowstone supervolcano larger than previously known, study shows

It is one of the most iconic spots in the United States: the gushing geyser of Yellowstone National Park. Travelers flock to see Old Faithful, to take in the blue and green steaming hot springs and other natural wonders. But there is more than meets the eye: beneath the famous caldera and the steaming pools, there is a supervolcano that could erupt with 2,000 times the force of the 1980 Mount St. Helens blast.

According to a study presented last week at the American Geophysical Union, the supervolcano contains more hot, molten rock than previously estimated.

The magma chamber beneath the park's famous caldera is 55 miles long and 18 miles wide, running from 3 to 9 miles deep, the study's lead author, Jamie Farrell, told the Associated Press. His University of Utah research team used a series of seismometers located around the park to map out the size of the magma chamber. 

“We’ve been working there for a long time, and we’ve always thought it would be bigger, but this finding is astounding,” University of Utah professor Bob Smith told the BBC.

The massive chamber contains enough volcanic material to match the supervolcano's last three eruptions. But there's no telling when that eruption will occur, says Farrell.  With the volume of activity monitoring underway, scientists will know with plenty of warning, he added. 

It has only erupted three times in the last 2.1 million years.

“You can only use the time between eruptions (to work out the frequency), so in a sense you only have two numbers to get to that 700,000 year figure,” Smith told the BBC. “How many people would buy something on the stock market on two days of stock data?”

If the next eruption is anything like its last, which happened 640,000 years ago, it will spew large amounts of volcanic ash and material into the atmosphere, Farrell said. The volcanic material will circle around the Earth.

"It would be a global event," he said. "There would be a lot of destruction and a lot of impacts around the globe."
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