Implications of Observed Fault Geometry and Stress Field on Rupture Dynamics Along the SGP Section of the San Andreas Fault

Zheqiang Shi, & Steven M. Day

Published 2015, SCEC Contribution #6057

We study the likelihood of through-going ruptures along the San Gorgonio Pass (SGP) section of the southern San Andreas Fault (SAF) from a mechanical point of view by preforming 3D dynamic rupture simulations. We investigate the effects of stress state and fault geometry on rupture propagation by adopting the SCEC Community Fault Model (CFM) and Community Stress Model (CSM) in our numerical study. Of the four currently available stress model candidates, SHELLS and FlatMaxwell provide absolute stresses while Hardeback_FM and YHSM-2013 contain only deviatoric stresses and therefore require additional assumptions for use in dynamic rupture simulations. Our simulation study showed that there exist apparent discrepancies among current stress model candidates regarding their implications on the likelihood of through-going ruptures along SGP, which points to the need for further improvement of these models. We also assumed small-scale roughness on top of the fault geometry given by the SCEC CFM and explored their static and dynamic effects on rupture propagation and ground motions.

Citation
Shi, Z., & Day, S. M. (2015). Implications of Observed Fault Geometry and Stress Field on Rupture Dynamics Along the SGP Section of the San Andreas Fault. Poster Presentation at 2015 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics