Abstract

FE modeling under plane stress condition was used to analyze the state of stress and failure in and around the San Andreas Fault (SAF) System. This study mainly focused on the state of stress at the general seismogenic depth of 12 km, imposing elastic rheology. The purpose of the present study was to simulate the regional stress field, displacement vectors and failures. Series of calculations were performed with the parametrical variations of rock domain properties and were applied for the strong/weak SAF. The imposed boundary condition (fixed North American plate, Pacific plate motion along N 34° W vector up to northern terminus of the San Andreas faults and N 50° E vector motion for the subducting Gorda and Juan de Fuca plates) has simulated the present day regional σ_Hmaxorientation and displacement vector comparable with the observed data. Failure analysis performed based on Byerlee’s law directly tests the strong SAF, and variation of physical parameters in the Mohr-Coulomb failure criterion was utilized to test relatively strong/weak SAF. Simulated results (stress, displacement vector, and failures) in the weak fault in relatively strong crust conditions had more or less reproduced comparable and theoretically correct results, allowed to favor weak fault in relatively strong crust.

Key words: SAF, FE modeling, σ_Hmax orientation, failure analysis.