Modeling the 2019 Ridgecrest Earthquake Sequence

Jordan Cortez, Christodoulos Kyriakopoulos, Baoning Wu, David D. Oglesby, Roby Douilly, Gareth Funning, & Abhijit Ghosh

Published August 15, 2019, SCEC Contribution #9818, 2019 SCEC Annual Meeting Poster #281

The July 2019 Ridgecrest earthquake sequence ruptured two nearly-perpendicular conjugate fault planes within 36 hours of each other. It produced a rich set of aftershocks outlining the ruptured fault surfaces, and triggered events in the Coso Geothermal Field and along the Garlock fault. Of particular scientific interest are the short-term (coseismic) and longer-term stress interactions between the foreshock, different parts of the mainshock, and aftershocks; these interactions may provide a physical mechanism and possible structural control over this remarkable series of events. Toward this goal, we model the dynamics of the M6.4 and M7.1 events using the 3D finite element method (Barall, 2009), incorporating up-to-date estimates of the fault geometry. We particularly investigate possible physical explanations for why the M6.4 event did not immediately trigger the M7.1 event, but instead led to numerous aftershocks on a conjugate fault, followed by a through-going event on that fault hours later. We also attempt to fit inferred slip patterns from geodetic models and other data. Our aim is to understand the dynamics of this unique series of earthquakes, with implications for seismic hazard in Southern California and beyond.

Key Words
Ridgecrest, Dynamic Modeling, Fault Interactions, Rupture Dynamics

Citation
Cortez, J., Kyriakopoulos, C., Wu, B., Oglesby, D. D., Douilly, R., Funning, G., & Ghosh, A. (2019, 08). Modeling the 2019 Ridgecrest Earthquake Sequence. Poster Presentation at 2019 SCEC Annual Meeting.

Related Projects & Working Groups
Ridgecrest Earthquakes