Further evidence that the Yellowstone megavolcano could blow without warning
Yellowstone National Park sits on top of a giant volcanic caldera , or an earthen cap that covers a Brobdingnagian reservoir of superhot liquid rock and poison gasses . Large parts of the parking area were form in previous eruptions , the most recent of which fall out about 70,000 year ago . Now , the floor of the caldera is rising , and earthquake in the neighborhood hint magma movement beneath the park ....