A new crustal model based on isostatic residual gravity, geologic mapping, well information, and density measurements shows that the high-gradient parts of the residual gravity anomaly can be explained in terms of lithologic variations within the upper 7 km of the crust, consistent with the upper-crustal framework of the area. This conclusion does not rule out the presence of a magma chamber at lower crustal depths; the broad aspects of the gravity anomaly support the presence of low-density partial melting at 15 to 20 km depth, consistent with magnetotelluric soundings and other geophysical measurements.
Additional publication details
Geyser's magma chamber, California: constraints from gravity data, density measurements, and well information
Publ by Geothermal Resources Council
Davis, CA, United States
Larger Work Title:
Transactions - Geothermal Resources Council
Proceedings of the 1993 Annual Meeting on Utilities and Geothermal: An Emerging Partnership