Part of what makes Yellowstone National Park so special is the supervolcano upon which it sits. Also known as the Yellowstone Caldera, the supervolcano's major features measure about 25 by 37 miles. And so when something of that magnitude stops and takes a breath, the entire park feels it.

A substantial area of the park's grounds has now dramatically risen due to the volcano's activity over the last few years. Starting in 2004, scientists began to notice the ground over the caldera rising--at around 2.8 inches per year. Although this rate slowed in the last 3 years, the total increase since the beginning of the swelling is now at around 10 inches in some places.

The caldera is an ancient crater. Each time it has erupted, the eruptions have been a thousand times more powerful than the 1980 eruption of Mount St. Helens. Its last major blow-up was about 640,000 years ago, but about 30 smaller blasts have filled the caldera with lava and ash since then. The most recent of those smaller blasts was around 70,000 years ago.

But there's no need to worry. Even though scientists were initially concerned that this commotion was pointing toward a soon-to-come eruption, that's no longer a concern. Read more about the situation with the Yellowstone Caldera on National Geographic.

[photo by Elizabeth Seward]

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