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Effects of lava-dome growth on the crater glacier of Mount St. Helens, Washington: Chapter 13 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

Professional Paper 1750-13

This report is Chapter 13 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006. For more information, see: Professional Paper 1750
By:
, , ,
Edited by:
David R. Sherrod, William E. Scott, Peter H. Stauffer

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Abstract

The process of lava-dome emplacement through a glacier was observed for the first time as the 2004-6 eruption of Mount St. Helens proceeded. The glacier that had grown in the crater since the cataclysmic 1980 eruption was split in two by the new lava dome. The two parts of the glacier were successively squeezed against the crater wall. Photography, photogrammetry, and geodetic measurements document glacier deformation of an extreme variety, with strain rates of extraordinary magnitude as compared to normal temperate alpine glaciers. Unlike such glaciers, the Mount St. Helens crater glacier shows no evidence of either speed-up at the beginning of the ablation season or diurnal speed fluctuations during the ablation season. Thus there is evidently no slip of the glacier over its bed. The most reasonable explanation for this anomaly is that meltwater penetrating the glacier is captured by a thick layer of coarse rubble at the bed and then enters the volcano’s groundwater system rather than flowing through a drainage network along the bed. Mechanical consideration of the glacier-squeeze process also leads to an estimate for the driving pressure applied by the growing lava dome.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Effects of lava-dome growth on the crater glacier of Mount St. Helens, Washington: Chapter 13 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006
Series title:
Professional Paper
Series number:
1750-13
Year Published:
2008
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Volcano Hazards Program
Description:
20 p.
Larger Work Type:
Report
Larger Work Subtype:
USGS Numbered Series
First page:
257
Last page:
276
Number of Pages:
20
Country:
United States
State:
Washington
Other Geospatial:
Mount St. Helens