Cascades Volcano Observatory

U.S. Geological Survey
Open-File Report 02-468
version 1.0

Geologic Map of Mount St. Helens, Washington Prior to the 1980 Eruption

By Clifford A. Hopson


Photo of the volcano taken before the 1980 eruption.  This photo shows the full pre-1980 height of the mountain
Oblique aerial view of Mount St. Helens before the May 18, 1980, eruption, as seen from Bear Cove, Spirit Lake. Lake visible in foreground. Photo courtesy of U.S. Forest Service. Skamania County, Washington. August 1973 (USGS Photographic Library collection).

Note by Michael A. Clynne

It is rare that a geologic map exists for a volcano prior to such a catastrophic modification as that produced by the eruption of Mount St. Helens in 1980. As such, this map provides an important historical record of the volcano prior to that eruption. The map has not been reviewed or checked for conformity to USGS editorial standards or stratigraphic nomenclature, and it has not been digitized. This version of the map is unchanged from that submitted to the USGS for publication shortly after the 1980 eruption of Mount St. Helens and includes unresolved inconsistencies with the subsequently published work of Crandell (1987) and Mullineaux (1996). Nevertheless, it is the most accurate available depiction of the pre-1980 edifice and is published here for comparison with more recent geologic mapping and historical perspectives.

Crandell, D. R., 1987, Deposits of the pre-1980 pyroclastic flows and lahars from Mount St. Helens Volcano, Washington: U.S. Geological Survey Professional Paper 1444, 91 p.

Mullineaux, D. R., 1996, Pre-1980 tephra-fall deposits erupted from Mount St. Helens, Washington: U.S. Geological Survey Professional Paper 1563, 99 p.

Digital restoration by David W. Ramsey

Download sheet 1 as a 34" x 44" PDF file. This sheet consists of the geologic map with a topo base (of02-468_sheet1.pdf; 1.9 MB)

Download sheet 2 as a 34" x 44" PDF file. This sheet consists of text, correlation of map units, description of map units, references, and historical note (of02-468_sheet2.pdf; 1.4 MB)

For questions about this report, contact Cliff Hopson, Mike Clynne, or Dave Ramsey.

Suggested citation and version history

Note, as this map is a raster scan rather than a vector digital product, there are no GIS data nor metadata for it.

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