[S04-3] Historical and macroseismic studies of earthquakes III

[S04-3-02] Dynamic Rupture Modeling of Historic, Pre-Instrumental Earthquakes on the San Andreas and San Jacinto Faults, Southern California

^○Julian Lozos (California State University, Northridge, Northridge, California, USA)

Southern California has an active record of instrumentally-recorded earthquakes, but its pre-instrumental historic record of damaging earthquakes is also extensive. Paleoseismic studies, and analysis of firsthand descriptions of ground motion and damage have attributed some of these events to specific fault sections. However, with the density of active faults in southern California, many of these interpretations are non-unique. Dynamic rupture modeling can be a helpful tool for further interpretation of these observational datasets. This type of modeling allows for physics-based assessment of plausible rupture paths and processes within complex fault systems. The models can take observation-based fault geometry, stresses, and surrounding geological setting as site-specific initial conditions; the calculated slip and ground motion patterns can then be compared to historic and paleoseismic records to determine the best match. Here, I discuss how I have used dynamic modeling to examine, and in some cases reevaluate, several historic earthquakes traditionally associated with the San Andreas and San Jacinto faults in inland southern California. A similar approach would likely also be helpful in examining source faults and processes in other regions with long historic pre-instrumental earthquake records.