Teleseismic-Seismic Monitoring At Coso Geothermal Area (1988)
Exploration Activity: Teleseismic-Seismic Monitoring At Coso Geothermal Area (1988)
|Exploration Activity Details|
|Location||Coso Geothermal Area|
|Exploration Technique||Teleseismic-Seismic Monitoring|
To analyze three-dimensional Vp/Vs variation
A tomographic inversion for the 3D variations of the Vp/V s, the ratio of compressional to shear velocity, was performed. Iterative back projection of 2966 shear and compressional wave travel time residuals from local earthquakes recorded on vertical instruments reveals that Vp/Vs is generally high at the surface and decreases systematically to 10 km depth. Near Devil's Kitchen in the Coso Geothermal Area, Vp/Vs values are very low near the surface, consistent with measured values for steam-dominated geothermal systems. Abnormally high values of Vp/Vs are observed in portions of Indian Wells Valley and also below the Cactus Peak rhyolite dome from 2 to 5 km in depth. In Indian Wells Valley the co-occurrence of low P velocities, low S velocities, high Vp/Vs, and anomalous SV attenuation are indicative of subsurface partial melt.
- Walck, M.C. (1 March 1988) Three-dimensional V p /V s variations for the Coso region, California