USGS Open-File Report 1994-0313: Water Fact Sheet; Evolution of Sediment Yield from Mount St. Helens, Washington, 1980-1993

Water Fact Sheet; Evolution of Sediment Yield from Mount St. Helens, Washington, 1980-1993

By John E. Costa

Abstract

The most enduring geological consequence of the eruption of Mount St. Helens, Washington, on May 18, 1980, and the most costly single element in the recovery effort, has been the persistent downstream sedimentation caused by erosion of the approximately 3 cubic kilometers (km³) of sediment deposited on the landscape surrounding the volcano. Most of the sediment was associated with the emplacement of a 2.8 km³ debris avalanche in the upper part of the watershed of the North Fork Toutle River, and debris flows in the channels of the South Fork Toutle River, Pine Creek, Swift Creek, and Muddy River. An additional 0.2-0.3 km³ of volcanic material was emplaced by pyroclastic flows, blasts, and ash fall. Part of this vast quantity of volcaniclastic sediment has been subsequently eroded by runoff and streamflow. This brief report summarizes the changes in sediment yield at five locations around Mount St. Helens in the first 13 years following the May 18, 1980 eruption.

First posted March 29, 2002

Report PDF (2.5 MB)

This report is available only on the Web

For additional information, contact:
CVO, Volcano Science Center,
Cascades Volcano Observatory
U.S. Geological Survey
1300 SE Cardinal Court, Building 10, Suite 100
Vancouver, WA 98683-9589
http://vulcan.wr.usgs.gov/

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Suggested citation:

Costa, John E., 1994, Water fact sheet; evolution of sediment yield from Mount St. Helens, Washington, 1980-1993: U. S. Geological Survey Open-File Report 1994-0313, 2 pp., https://pubs.usgs.gov/of/1994/0313/.