Hydrothermal monitoring in a quiescent volcanic arc: Cascade Range, northwestern United States (pages 326–346)
S. E. Ingebritsen, N. G. Randolph-Flagg, K. D. Gelwick, E. A. Lundstrom, I. M. Crankshaw, A. M. Murveit, M. E. Schmidt, D. Bergfeld, K. R. Spicer, D. S. Tucker, R. H. Mariner and W. C. Evans
Article first published online: 20 MAR 2014 | DOI: 10.1111/gfl.12079
In 2009, the USGS began a systematic hydrothermal-monitoring effort encompassing 25 sites and 10 of the highest-risk volcanoes in the Cascade Range. Targets included summit fumarole groups and springs/streams that show clear evidence of magmatic influence (high 3He/4He ratios and/or anomalous fluxes of magmatic CO2 or heat). The resulting hourly, multiyear records are suitable for retrospective comparison with continuous geophysical monitoring data, and inform ongoing efforts to capture unrest cycles at more active but less accessible volcanoes.