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

The 2019 M6.4 Searles Valley, Southern California, earthquake nucleated on a buried right-lateral fault segment and 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 three dimensional 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. 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.

Automated summary

The study used a 3D finite element method to explore the unusual rupture path of the 2019 Searles Valley earthquake in Southern California, indicating that the rupture path is influenced by fault stresses, burial depths, and hypocenter locations, with implications for fault interactions in Southern California and beyond.