Poster #056, Seismology

Temporal Changes of Seismicity in Salton Sea Geothermal Field with Waveform-matched Catalog

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Poster Presentation

2020 SCEC Annual Meeting, Poster #056, SCEC Contribution #10642
The Salton Sea Geothermal Field (SSGF) is one of the most seismically active and geothermally productive fields in Southern California. It is bounded by the Southern San Andreas Fault to the NE, and the Imperial Fault, and Cerro Prieto Fault to the SW. Triggered seismicity in SSGF has been found after several M>7 earthquakes, including the 1999 M7.1 Hector Mine Earthquake and 2010 M7.2 El Mayor-Cucapah Earthquake. Here we systematically examine seismicity change in SSGF following regional and large teleseismic earthquakes utilizing a waveform-based matched-filter catalog. We apply a recently developed GPU-based matched-filter technique (WMFT) to the continuous data recorded by the Borehole Network (EN) in 2008-2014 to obtain a more complete catalog. We find triggered seismicity in SSGF following several regional M>6 earthquakes. However M>8.0 teleseismic earthquakes did not trigger significant seismicity rate change in SSGF. This suggests that short-period surface waves around 10 s is more efficient in triggering seismicity than long-period surface waves (> 20 s) in this region. We also characterize the correlation between seismicity and geothermal production rates, and the temporal and spatial variation of Guttenberg-Richter b-values inside and outside SSGF with the newly-detected catalog. The long-term seismicity shows that M>1.5 events are likely correlated with net production rates, while smaller events do not show any correlations with the geothermal production/injection rates. The b-values inside SSGF are higher than outside SSGF, and there is an increasing trend of b-value, which is consistent with the long-term poroelastic contraction due to geothermal productions.