Formed during the largest volcanic eruption of the 20th century, Novarupta released 30 times the volume of magmaof the 1980 eruption of Mount St. Helens. The result was a removal of support from beneath Mount Katmai, which is six miles from Novarupta.
Novarupta, the least topographically prominent volcano in the Katmai area, was formed during a major eruption in 1912. Oct. 3 , 2006: In June 1912, Novarupta—one of a chain of volcanoes on the Alaska Peninsula—erupted in what turned out to be the largest blast of the twentieth century.
Gene Iwatsubo/U.S. It was so powerful that it drained magma from under another volcano, Mount Katmai, six miles east, causing the summit of Katmai to collapse to form a caldera half a mile deep. This eruption was the world's largest during the 20th century and produced a voluminous rhyolitic airfall tephra and the renowned Valley of Ten Thousand Smokes (VTTS) ash flow. The dome is a plug-like feature emplaced within a low ejecta ring. At the end of the eruption a small, 65-m-high, 400-m-wide lava dome grew to an elevation of 841 m … Map showing volcanoes of the Alaska Peninsula Novarupta is a Latin word meaning “new break.” Novarupta lava dome Novarupta, a lava dome in southern Alaska, was formed in June 1912, when tremendous amounts of ash, molten rock, and sulfur aerosols erupted from a vent near Mount Katmai. It is located on the Alaska Peninsulain Katmai National Park and Preserve, about 290 miles (470 km) southwest of Anchorage. Katmai Caldera & Novarupta Dome. Novarupta, the least topographically prominent volcano in the Katmai area, was formed during a major eruption in 1912. Geological Survey
From Miller and others (1998) : "The Novarupta dome is about 400 m in diameter and 65 m high at its center , and is surrounded by a 2-km-wide, funnel-shaped structure .The surface of the dome is completely fractured into chaotic blocks and crumble breccia. During the eruption a large amount of magma was drained from magma chambers below. This eruption was the world's largest during the 20th century and produced a voluminous rhyolitic airfall tephra and the renowned Valley of Ten Thousand Smokes (VTTS) ash flow.
The top several hundred feet of Katmai - about one cubic mile of material - collapsed into a magma chamber below.