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Seasonal and multi-year changes in CO2 degassing at Mammoth Mountain explained by solid-earth-driven fault valving

March 9, 2022

Changes in CO2 emissions from volcanoes may evidence volcanic unrest. We use a multiyear time series of CO2 flux collected at the Horseshoe Lake Tree Kill area on Mammoth Mountain, CA, to understand processes that cause variations in flux from this system. Seasonal variations are systematically lowest during the winter months and reach maximum values during the summer season. A persistent ∼20% reduction in CO2 flux occurred during the Spring of 2017, coincident with the emergence of the area from drought and earthquake swarms in Long Valley Caldera. We used continuous GNSS measurements to calculate seasonal strains and stresses across the Mammoth Mountain area, and resolved resultant stresses onto the Mammoth Mountain Fault, which appears to facilitate gas transport to the surface. The normal stress changes are consistent with seasonal and multiyear changes in CO2 flux, suggesting that fault valving by solid earth processes can alter surface gas fluxes.

Citation Information

Publication Year 2022
Title Seasonal and multi-year changes in CO2 degassing at Mammoth Mountain explained by solid-earth-driven fault valving
DOI 10.1029/2021GL096595
Authors George E. Hilley, Jennifer L. Lewicki, Curtis W Baden
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Series Number
Index ID 70230303
Record Source USGS Publications Warehouse
USGS Organization Volcano Science Center