Investigation of complex rupture processes in the 2008 M8 Wenchuan earthquake using dynamic source models

Texas A&M Research Foundation, College Station TX

Investigators

Abstract

This project is to use dynamic source models to investigate complex rupture processes in the 2008 Ms 8.0 Wenchuan (China) earthquake and to advance our understanding of what controls spontaneous rupture propagation on complex fault systems embedded in complex geologic structure in large earthquakes. The primary goals of the proposed research are (1) to understand how and why the rupture in the Wenchuan earthquake spontaneously propagated (and terminated) on the geometrically complex Longmenshan fault system, and (2) to advance our general understanding of how large earthquakes work, by investigating complex rupture processes in the event using spontaneous rupture models constrained by surface rupture, geological and geophysical observations of fault geometry and velocity structure, laboratory-derived friction laws, and near-field strong ground motion recordings. Simultaneous rupturing of a branched fault system formed by the Beichuan fault and the Pengguan fault and incomplete coseismic slip partitioning between the two faults observed in this earthquake are two major scientific questions to be explored.This project is part of a longer-term research program that will develop complete earthquake cycle models and use these models to assimilate a variety of observations of earthquake processes, to test existing theories and formulate new theories. The PI will also use a hybrid MPI/OpenMP approach to parallelize an existing 3D finite element dynamic rupture code (EQdyna) in this project so that the above questions can be explored at high resolutions using high-performance supercomputing systems, which is necessary to accurately capture rupture propagation on geometrically complex faults and inelastic off-fault deformation in the models.