thumbnail

Three-dimensional crustal structure of Long Valley caldera, California, and evidence for the migration of CO2 under Mammoth Mountain

Journal of Geophysical Research B: Solid Earth

By:
, , , , ,

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time

Abstract

A temporary network of 69 three-component seismic stations captured a major seismic sequence in Long Valley caldera in 1997. We performed a tomographic inversion for crustal structure beneath a 28 km ?? 16 km area encompassing part of the resurgent dome, the south moat, and Mammoth Mountain. Resolution of crustal structure beneath the center of the study volume was good down to ???3 km below sea level (???5 km below the surface). Relatively high wave speeds are associated with the Bishop Tuff and lower wave speeds characterize debris in the surrounding moat. A low-Vp/Vs anomaly extending from near the surface to ???1 km below sea level beneath Mammoth Mountain may represent a CO2 reservoir that is supplying CO2-rich springs, venting at the surface, and killing trees. We investigated temporal variations in structure beneath Mammoth Mountain by differencing our results with tomographic images obtained using data from 1989/1990. Significant changes in both Vp and Vs were consistent with the migration of CO2 into the upper 2 km or so beneath Mammoth Mountain and its depletion in peripheral volumes that correlate with surface venting areas. Repeat tomography is capable of detecting the migration of gas beneath active silicic volcanoes and may thus provide a useful volcano monitoring tool.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Three-dimensional crustal structure of Long Valley caldera, California, and evidence for the migration of CO2 under Mammoth Mountain
Series title:
Journal of Geophysical Research B: Solid Earth
Volume
108
Issue:
3
Year Published:
2003
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article