Multi-year high-frequency hydrothermal monitoring of selected high-threat Cascade Range volcanoes

Journal of Volcanology and Geothermal Research
By: , and 

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Abstract

From 2009 to 2015 the U.S. Geological Survey (USGS) systematically monitored hydrothermal behavior at selected Cascade Range volcanoes in order to define baseline hydrothermal and geochemical conditions. Gas and water data were collected regularly at 25 sites on 10 of the highest-risk volcanoes in the Cascade Range. These sites include near-summit fumarole groups and springs/streams that show clear evidence of magmatic influence (high 3He/4He ratios and/or large fluxes of magmatic CO2 or heat). Site records consist mainly of hourly temperature and hydrothermal-flux data. Having established baseline conditions during a multiyear quiescent period, the USGS reduced monitoring frequency from 2015 to present. The archived monitoring data are housed at (doi:10.5066/F72N5088). These data (1) are suitable for retrospective comparison with other continuous geophysical monitoring data and (2) will provide context during future episodes of volcanic unrest, such that unrest-related variations at these thoroughly characterized sites will be more clearly recognizable. Relatively high-frequency year-round data are essential to achieve these objectives, because many of the time series reveal significant diurnal, seasonal, and inter-annual variability that would tend to mask unrest signals in the absence of baseline data. Here we characterize normal variability for each site, suggest strategies to detect future volcanic unrest, and explore deviations from background associated with recent unrest.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Multi-year high-frequency hydrothermal monitoring of selected high-threat Cascade Range volcanoes
Series title Journal of Volcanology and Geothermal Research
DOI 10.1016/j.jvolgeores.2018.02.014
Volume 356
Year Published 2018
Language English
Publisher Elsevier
Contributing office(s) Volcano Science Center
Description 12 p.
First page 24
Last page 35
Country United States
State California, Oregon, Washington
Other Geospatial Cascades Range