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Hydrothermal monitoring data from the Cascade Range, northwestern United States

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DOI: 10.5066/F72N5088

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Abstract

This database serves as a repository for hydrothermal-monitoring data collected at 25 sites in the U.S. portion of the Cascade Range volcanic arc. These data are intended to quantify baseline hydrothermal variability at most (10 of 12) of the highest-risk volcanoes in the Cascades, as defined by the U.S. Geological Survey’s (USGS’) National Volcanic Early Warning System (NVEWS) report (Ewert and others, 2005).

 

Traditionally, most measurement and sampling of hydrothermal fluids has been on a highly intermittent basis. Such intermittent data, with sampling frequencies typically >1 year, are not well-suited for comparison with continuous seismic and geodetic monitoring data. Further, when volcanic unrest becomes evident from other geophysical observations, baseline hydrothermal observations are sometimes non-existent, and are often limited to the season when weather conditions are most amenable to field work. The preponderance of field-season, daytime data means that there is limited information on seasonal or diurnal variability.

 

Beginning in the summer of 2009, motivated by the dramatic hydrothermal anomalies associated with volcanic unrest at South Sister volcano (Wicks and others, 2002; Evans and others, 2004), the USGS made a concerted effort to develop hourly hydrothermal records in the Cascade Range. The 25 selected monitoring sites show evidence of magmatic influence in the form of high 3He/4He ratios and (or) large fluxes of magmatic CO2 or heat. The monitoring sites can be grouped into three broad categories (Fig. 1): (1) sites with continuous pressure-temperature-conductivity monitoring and intermittent liquid sampling and discharge measurements; (2) sites with continuous temperature monitoring and intermittent gas sampling; and (3) sites that lack hourly data, but where the USGS has carried out intermittent flux measurements over a period of several decades.

 

For most sites, correlations have been developed to convert pressure-temperature-conductivity data into a flux of heat or (more often) to the flux of a solute species of interest. We relate (1) specific electrical conductance to lab-measured concentrations of dissolved constituents and (2) pressure (depth of water) to field-measured discharge. The metadata includes descriptions of the sites and methods and plots of the calculated fluxes. The workbook files contain all of the data and correlations upon which those fluxes are based.

 

Part of the database compilation is a list of relevant references for each area. These lists include all references cited in the metadata.

Geospatial Extents

Additional Publication Details

Publication type:
Dataset
Publication Subtype:
USGS Data Release
Title:
Hydrothermal monitoring data from the Cascade Range, northwestern United States
DOI:
10.5066/F72N5088
Year Published:
2013
Language:
English
Publisher:
U.S. Geological Survey
Contributing office(s):
National Research Program - Western Branch
Description:
USGS Data Web Page
Online Only (Y/N):
Y
Additional Online Files(Y/N):
Y