The ancient supervolcano under the national park was much more explosive in its early history and could be slowing down, a new study suggests
Roughly 8.7 million years ago, in areas that would become southern Idaho and northern Nevada, the grasslands began to break open, unleashing curtains of lava and clouds of gas and ash that rolled across the North American landscape. Within hours, if not minutes, the land would have been pummeled by black volcanic glass that rained from above, killing animals such as rhinoceroses, camels, and horses that roamed the region, and destroying plants. Soon the ground would cave in altogether. The event was the largest explosion ever from the supervolcano in Yellowstone National Park.
