Triggered Seismicity and Temporal Change of Seismic Velocity in Salton
Sea Geothermal Field
Abstract
The Salton Sea Geothermal Field (SSGF) is one of the most seismically
active and geothermally productive fields in Southern California.
Previous studies showed that local seismicity and seismic velocity in
SSGF was disturbed by the 2010 M7.2 El Mayor-Cucapah earthquake. Here we
present a systematic investigation of triggered seismicity and the
spatial-temporal change of seismic velocity in SSGF following some
regional and remote earthquakes. The continuous waveform from 2007 to
2014 in the Calenergy Borehole Network (EN) is used for this study. We
apply a GPU-based waveform matched-filter technique (WMFT) to 60 days
before and after the selected earthquakes, and find possible triggered
seismicity following several regional earthquakes, such as the 2009
Mw6.9 Baja California and 2010 Mw5.7 Ocotillo Earthquakes. We also
utilize an ambient noise cross-correlation method to quantify the
temporal and spatial velocity changes in SSGF. Our result shows clear
velocity reduction following the 2010 M7.2 El-Mayor earthquake, and the
co-seismic reductions are larger for ray paths outside the geothermal
regions. We also find some possible triggered events in SSGF following
the 2019 M7.1 Ridgecrest earthquake. Our next step is to conduct a
detailed investigation on the possible correlation between triggered
seismicity and seismic velocity changes associated with the occurrence
of the 2010 M7.2 earthquake, and other regional earthquakes.