What happens if the volcano erupted?

Volcanoes are spectacular — sometimes deadly — forces of nature and Planet Earth is covered in hundreds of them. But how do these iconic wonders form, and what risks do they really pose? read more

Caldera volcanoes are volcanoes where the diameter of the crater exceeds one mile. These form when so much lava is blown out so rapidly it partially empties the underlying magma chamber. When this happens the summit of the volcano collapses into the emptied magma chamber, creating a dip in the ground. read more

We asked USGS geologist Jake Lowenstern, scientist-in-charge of the Yellowstone Volcano Observatory. Lurking beneath Yellowstone National Park is a massive underground reservoir of magma, capped by the park's famous caldera. 640,000 years ago, a super eruption rocked the region. read more