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Using a Dynamic Earthquake Simulator to Explore Three-Dimensional Multicycle Dynamics of Stepover Faults

Description: 

Classical earthquake simulators such as RSQsim do not capture spontaneously dynamic rupture propagation, which calls into questions about robustness of rupture extent and path from these simulators on geometrically complex faults from these simulators. We have been developing a finite element method (FEM) dynamic earthquake simulator to capture both spontaneously dynamic rupture propagation and other quasi-static processes of earthquake cycles. The dynamic earthquake simulator is based on EQdyna, an explicit FEM dynamic solver originally developed for spontaneous rupture propagation along geometrically complex faults and seismic wave propagation in heterogeneous media. We adopt a dynamic relaxation technique to solve quasi-static problems of earthquake cycles using the dynamic solver. Therefore, the EQdyna-based dynamic earthquake simulator solves both dynamic and quasi-static processes of earthquake cycles in the same FEM framework.

Previous studies on dynamics of stepover faults are primarily in two dimensions. In this research, we apply the dynamic earthquake simulator to explore three-dimensional dynamics of stepover faults over multiple earthquake cycles. To our knowledge, this is the first of fully dynamic earthquake cycle simulations on geometrically complex faults in the scientific community. In this study, we specifically examine effects of different depth profiles of the effective normal stress and different loadings on earthquake patterns and rupture behaviors of stepover faults over many earthquake cycles. Our preliminary results show that the depth-dependent effective normal stress results in more complex event patterns and rupture behaviors than the depth-independent case. For the depth-independent case, different loading rates do not affect the event pattern much, though faster loading rates result in shorter recurrence intervals. Our results also suggest that jumping ruptures are more difficult to occur in three dimensional models than in their two-dimensional counterparts over many earthquake cycles.

Session: Numerical Modeling in Seismology: Developments and Applications - III

Type: Oral

Date: 5/1/2024

Presentation Time: 02:15 PM (local time)

Presenting Author: Benchun

Student Presenter: No

Invited Presentation: 

Authors