The Coso geothermal area: A laboratory for advanced MEQ studies for geothermal monitoring

B.R. Julian; G.R. Foulger; K. Richards-Dinger

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USGS · 70026310

The Coso geothermal area: A laboratory for advanced MEQ studies for geothermal monitoring

B.R. Julian·G.R. Foulger·K. Richards-Dinger

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Abstract

The permanent 16-station network of three-component digital seismometers at the Coso geothermal area, California, supplemented by 14 temporary instruments deployed in connection with the DOE Enhanced Geothermal Systems (EGS) Project, provides high-quality microearthquake (MEQ) recordings that are well suited to monitoring a producing geothermal area. We are currently using these data to investigate structure and active processes within the geothermal reservoir by applying three advanced methods: a) high-precision MEQ hypocenter location; b) time-dependent tomography; c) complete (moment tensor) MEQ source mechanism determination. Preliminary results to date resolve seismogenic structures in the producing field more clearly than is possible with conventional earthquake-location techniques. A shallow part of the producing field shows clear changes in the ratio of the seismic wave speeds, V p / V s , between 1996 and 2002, which are probably related to physical changes in the reservoir caused by fluid extraction.

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Source-reported bounding extent: 35.87242213045528° to 36.09689067835505° latitude; -117.9428256323103° to -117.7485049535994° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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B.R. Julian, G.R. Foulger, K. Richards-Dinger. 2004. The Coso geothermal area: A laboratory for advanced MEQ studies for geothermal monitoring. https://pubs.usgs.gov/publication/70026310

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