Osceola Mudflow
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The Osceola Mudflow, also known as the Osceola Lahar, was a debris flow and lahar in the U.S. state of Washington that descended from the summit and northeast slope of Mount Rainier, a volcano in the
Mount Rainier with its main summit, Columbia Crest (14410 feet) at the center. Emmons Glacier covers most of the visible flank of the mountain with Disappointment Cleaver visible below Gibraltar Rock, right of the sharp pointed Little Tahoma (11138 feet). Liberty Cap (14112 feet) is visible on the right center skyline behind Russell Cliff.
Sector collapse
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A sector collapse or lateral collapse is the structural failure and subsequent collapse of a minimum volume of 1 km3 of a volcano. Unlike smaller flank collapses, a sector collapse can involve the cen
Osceola Mudflow
…lahar within 2 km (1.2 mi) of where it was initiated as it incorporated significant amounts of water from within the volcano's hydrothermal system. The sector collapse formed a 1.8 km (1.1 mi) wide horseshoe-shaped crater, open to the northeast, almost the same size as the crater produced by the 1980 eruption of Mount…
Sector collapse during the 1980 eruption of Mount St. Helens
Example of sector collapse: cross-section diagram of Tata Sabaya volcano (in Bolivia) (a) pre-collapse volcano, (b) after collapse, (c) new edifice built on top of collapsed old edifice
Mudflow-induced property damage caused by the 1980 Mount St. Helens sector collapse
Debris avalanche deposit of Tata Sabaya volcano's sector collapse