Earthquake Cycles With Complex Fault Geometries

Brittany A. Erickson, & Jeremy E. Kozdon

Published August 15, 2017, SCEC Contribution #7791, 2017 SCEC Annual Meeting Poster #167

The overall goal of this project is to develop an understanding of the earthquake cycle that takes into account the interaction of remote tectonic loading and near-fault structure. To do this we are developing a model that uses a quasi-static formulation in the interseismic period and a fully dynamic formulation in the coseismic phase. By coupling these two approaches we hope to both generate self-consistent initial stress states for dynamic rupture simulations as well as properly account for dynamic effects which may influence the overall earthquake cycle (such as the ability for ruptures to penetrate regions which are not favorable to coseismic slip).

We are particularly interested in studying earthquake nucleation and propagation in geometrically complex fault networks. We have recently developed a discontinuous Galerkin finite element method for quasi-dynamic/quasi-static cycle simulation. The purpose of this work is to verify our new finite element framework against our existing finite difference method as well as perform an initial, quasi-dynamic study of the effect of large-scale fault non-planarity on the earthquake cycle.

In this initial study, we consider two-dimensional, antiplane simulations of quasi-dynamic ruptures on faults with large scale bends and branches. The fault is embedded in a finite dimensional elastic medium, and extends from the lower boundary at depth up to Earth’s free surface. Rate-and-state friction parameters are chosen so that the fault is seismogenic down to a specified locking depth. The model is loaded by displacing the remote side boundaries at the plate rate. As one would expected, we find that the location and angle of the fault bend influences both the recurrence interval and periodicity of the events. In this initial quasi-dynamic study, we have also found that extreme bends can result in some events remaining buried.

Key Words
earthquake cycle, complex fault geometry, computational method

Citation
Erickson, B. A., & Kozdon, J. E. (2017, 08). Earthquake Cycles With Complex Fault Geometries. Poster Presentation at 2017 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)