Numerical simulations of stress variations with depth in a model for the San Jacinto fault zone

Niloufar Abolfathian, Christopher W. Johnson, & Yehuda Ben-Zion

Published August 14, 2018, SCEC Contribution #8505, 2018 SCEC Annual Meeting Poster #155

Depth dependent crustal stress orientations produced in strike-slip faulting environments are explored using quasi-static numerical simulations with variations to the geometry and rheology of the layered substrate to test model conditions that support or reject focal mechanism stress inversion from the San Jacinto fault zone. We attempt to understand observed rotations up to ~30 ̊ of the principal stress axes below 10 km depth in this region. The simulations employ the finite element software package PyLith for solving the partial differential equations describing the tectonic deformation. The basic model consists of a vertical right-lateral frictional fault in horizontal crustal layers with constant tectonic loading and gravitational forces. The model design incorporates three different scenarios with a fault in an elastic upper layer atop a viscoelastic transition zone which can be adapted to simulate a widening viscoelastic region at the base of the fault. Preliminary results indicate that the stress evolution shows similar pattern in cases with different rheological parameters. The continuing work will focus on effects of spatial variations of background stress related to topography and variations of geometrical features of faults and the crust on changes of the stress tensor with depth.

Citation
Abolfathian, N., Johnson, C. W., & Ben-Zion, Y. (2018, 08). Numerical simulations of stress variations with depth in a model for the San Jacinto fault zone. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Stress and Deformation Over Time (SDOT)