Emplacement of a silicic lava dome through a crater glacier: Mount St Helens, 2004-06

Annals of Glaciology
By: , and 

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Abstract

The process of lava-dome emplacement through a glacier was observed for the first time after Mount St Helens reawakened in September 2004. 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 alpine glaciers. Unlike normal temperate glaciers, the 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.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Emplacement of a silicic lava dome through a crater glacier: Mount St Helens, 2004-06
Series title Annals of Glaciology
DOI 10.3189/172756407782282426
Volume 45
Year Published 2007
Language English
Contributing office(s) Volcano Hazards Program
Description 7 p.
First page 14
Last page 20
Country United States
State Washington
Other Geospatial Mount St. Helens