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Seismicity rate change at the Coso Geothermal Field following the July 2019 Ridgecrest M7.1 earthquake

June 2, 2020

Many geothermal and volcanic regions experience remote and regional triggering following large earthquakes. The transient or permanent changes in stresses acting on faults and fractures can lead to changes in seismicity rates following either the passage of teleseismic waves or the permanent change in stresses following regional events. One such region of prevalent triggering is the Coso Geothermal Field (CGF) in eastern California, which is located roughly 30km to the north of the 2019 M7.1 Ridgecrest epicenter. Previous regional earthquakes have seemingly caused increases in seismicity rate surrounding the CGF, but also showed an absence of such rate increases in the CGF itself. To test whether seismicity rates in the CGF were dissimilar to the surrounding area following the M7.1 Ridgecrest earthquake, I carry out seismicity rate change calculations using a catalog of seismicity complied using a local seismic network and find that the CGF behaves identical to the surrounding area. Comparisons of seismicity rate changes calculated using a regional network derived catalog and the local network derived catalog show that for a moderate, regional earthquake, the local network catalog reveals a change in seismicity rate while the regionally network catalog shows no significant changes. The differences are likely related to incomplete sampling of seismicity using the regional network due to the existence of a very shallow brittle ductile transition centered on the CGF. The CGF thus is prone to triggering from both teleseismic and regional earthquakes.

Publication Year 2020
Title Seismicity rate change at the Coso Geothermal Field following the July 2019 Ridgecrest M7.1 earthquake
DOI 10.1785/0120200017
Authors Joern Kaven
Publication Type Article
Publication Subtype Journal Article
Series Title Bulletin of the Seismological Society of America
Index ID 70211936
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center