When volcanoes fall down—Catastrophic collapse and debris avalanches

Abstract

The steep-sided Augustine lava-dome complex in Cook Inlet of Alaska is ringed by deposits of multiple debris avalanches. Augustine volcano has collapsed a dozen times or more in the past 2,500 years and has the highest known rate of edifice collapse of any volcano. The debris-avalanche deposits (colored) in this image extend out to sea on all sides and are partly covered by deposits of younger eruptions (gray) closer to the volcano. The impact of the debris sweeping into the ocean may have produced tsunamis, such as the 1883 Cook Inlet tsunami caused by the Burr Point collapse. Selected deposits are named, with the Burr Point deposit (in red) being the youngest. Base map from July 3, 2018, Landsat 8 image is overlain by debris-avalanche deposits mapped by Waitt and Begét (2009).