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Hydrothermal circulation at Mount St. Helens determined by self-potential measurements

Journal of Volcanology and Geothermal Research

By:
, ,
DOI: 10.1016/j.jvolgeores.2006.09.003

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Abstract

The distribution of hydrothermal circulation within active volcanoes is of importance in identifying regions of hydrothermal alteration which may in turn control explosivity, slope stability and sector collapse. Self-potential measurements, indicative of fluid circulation, were made within the crater of Mount St. Helens in 2000 and 2001. A strong dipolar anomaly in the self-potential field was detected on the north face of the 1980-86 lava dome. This anomaly reaches a value of negative one volt on the lower flanks of the dome and reverses sign toward the dome summit. The anomaly pattern is believed to result from a combination of thermoelectric, electrokinetic, and fluid disruption effects within and surrounding the dome. Heat supplied from a cooling dacite magma very likely drives a shallow hydrothermal convection cell within the dome. The temporal stability of the SP field, low surface recharge rate, and magmatic component to fumarole condensates and thermal waters suggest the hydrothermal system is maintained by water vapor exsolved from the magma and modulated on short time scales by surface recharge. ?? 2006 Elsevier B.V. All rights reserved.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Hydrothermal circulation at Mount St. Helens determined by self-potential measurements
Series title:
Journal of Volcanology and Geothermal Research
DOI:
10.1016/j.jvolgeores.2006.09.003
Volume
160
Issue:
1-2
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
137
Last page:
146
Number of Pages:
10