Yellowstone Caldera

The Yellowstone Caldera, sometimes referred to as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States. The caldera and most of the park are located in the northwest corner of Wyoming. The caldera measures , and postcaldera lavas spill out a significant distance beyond the caldera proper. The caldera formed during the last of three supereruptions over the past 2.1 million years: the Huckleberry Ridge eruption 2.1 million years ago (which created the Island Park Caldera and the Huckleberry Ridge Tuff), the Mesa Falls eruption 1.3 million years ago (which created the Henry's Fork Caldera and the Mesa Falls Tuff), and the Lava Creek eruption approximately 640,000 years ago (which created the Yellowstone Caldera and the Lava Creek Tuff). The caldera was the largest caldera ever recorded until the record was beaten by Apolaki Caldera having twice the size of the caldera. Volcanism at Yellowstone is relatively recent, with calderas created by large eruptions that took place 2.1 million, 1.3 million, and 640,000 years ago. The calderas lie over the Yellowstone hotspot under the Yellowstone Plateau where light and hot magma (molten rock) from the mantle rises toward the surface. The hotspot appears to move across terrain in the east-northeast direction, and is responsible for the eastern half of Idaho's Snake River Plain, but in fact the hotspot is much deeper than the surrounding terrain and remains stationary while the North American Plate moves west-southwest over it. Over the past 16.5 million years or so, this hotspot has generated a succession of explosive eruptions and less violent floods of basaltic lava. Together these eruptions have helped create the eastern part of the Snake River Plain (to the west of Yellowstone) from a once-mountainous region. At least a dozen of these eruptions were so massive that they are classified as supereruptions. Volcanic eruptions sometimes empty their stores of magma so swiftly that the overlying land collapses into the emptied magma chamber, forming a geographic depression called a caldera.