Yellowstone Caldera

Yellowstone Caldera is the immense volcanic depression and plateau at the center of Yellowstone National Park, part of a broader Quaternary volcanic field spanning Wyoming, Idaho, and Montana. A complex of four overlapping calderas rather than a single crater, it formed through three major eruptive cycles beginning about 2.15 million years ago, including the 2.08-million-year-old Huckleberry Ridge eruption and the eruption about 640,000 years ago that created the present caldera. Volcanic activity continued afterward through lava flows, domes, and smaller explosions until about 70,000 years ago. Today it is one of the world’s most closely monitored volcanic systems, with no eruption considered imminent.

Mammoth, Wyoming · United States