On the Rupture Propagation of the 2019 M6.4 Searles Valley, California, Earthquake, and the Lack of Immediate Triggering of the M7.1 Ridgecrest Earthquake

Jordan T. Cortez, David D. Oglesby, Christodoulos Kyriakopoulos, Baoning Wu, Kuntal Chaudhuri, Abhijit Ghosh, & Roby Douilly

Published February 17, 2021, SCEC Contribution #10884

The 2019 M6.4 Searles Valley earthquake had a remarkable rupture path. The rupture nucleated on a buried right-lateral fault segment and soon propagated around a perpendicular fault intersection to a surface-outcropping left-lateral segment, but it did not propagate coseismically to the intersecting fault of the subsequent M7.1 Ridgecrest mainshock. We use the 3D finite element method to explore the physical reasons for this curious rupture path. Rather than model the details of the measured and inferred slip distribution, we use simple constant-traction assumptions to explore how initial stress, hypocenter location, and the depth of burial of the initial right-lateral segment may have influenced rupture propagation in this earthquake. The results suggest that only a narrow range of fault stresses, fault burial depths, and hypocenter locations would result in the observed rupture path in this earthquake. The results may have implications for interactions between faults in Southern California and beyond.

Citation
Cortez, J. T., Oglesby, D. D., Kyriakopoulos, C., Wu, B., Chaudhuri, K., Ghosh, A., & Douilly, R. (2021). On the Rupture Propagation of the 2019 M6.4 Searles Valley, California, Earthquake, and the Lack of Immediate Triggering of the M7.1 Ridgecrest Earthquake. Geophysical Research Letters, 48(4). doi: 10.1029/2020GL090659.