Supervolcano – super mystery

Every hour or so the "Old Faithful" geyser in Yellowstone National Park, Wyoming, shoots a column of boiling water up to 50m into the air. This incredible natural spectacle, along with multiple other geothermal features and the one to two thousand earthquakes that occur every year, are just some of the signs that this region is sitting atop a whopping great volcano. The last super-eruption was nearly 640,000 years ago, but gentle swelling of the ground indicates that the underlying magma chamber is refilling, and Yellowstone will erupt again one day.

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