Rate of magma supply beneath Mammoth Mountain, California based on helium isotopes and CO2 emissions
Mammoth Mountain, California, has exhibited unrest over the past ~30 years, characterized by seismicity over a broad range of depths, elevated 3He/4He ratios in fumarolic gas, and large-scale diffuse CO2 emissions. This activity has been attributed to magmatic intrusion, but minimal ground deformation and the presence of a shallow crustal gas reservoir beneath Mammoth Mountain pose a challenge for estimating magma supply rate. Here, we use the record of fumarolic 3He/4He ratios and CO2 emissions to estimate that of the ~5.2 Mt of CO2 released from Mammoth Mountain between 1989 and 2016, 1.6 Mt was associated with active intrusion and degassing of ~0.05–0.07 km3 of basaltic magma. Intrusion at an average rate of ~0.002–0.003 km3/year into a postulated zone of partial melt at ~15-km depth could occur without detection by local Global Navigation Satellite System stations.
Citation Information
| Publication Year | 2019 |
|---|---|
| Title | Rate of magma supply beneath Mammoth Mountain, California based on helium isotopes and CO2 emissions |
| DOI | 10.1029/2019GL082487 |
| Authors | Jennifer L. Lewicki, William C. Evans, Emily Montgomery-Brown, Margaret T. Mangan, John King, Andrew Hunt |
| Publication Type | Article |
| Publication Subtype | Journal Article |
| Series Title | Geophysical Research Letters |
| Index ID | 70222370 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Geology and Geophysics Science Center; Volcano Hazards Program; Volcano Science Center |
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