Advanced Earthquake Cycle Simulations: Bimaterial Interfaces, LVFZ, and nonlinear bulk rheology

Mohamed Abdelmeguid, & Ahmed E. Elbanna

Published August 16, 2021, SCEC Contribution #11514, 2021 SCEC Annual Meeting Poster #155

Modeling earthquake ruptures is a complex challenge due to the eclectic sources of nonlinearities and heterogeneities, in addition to the multi-scale nature of the problem, both spatially and temporally. In this study, we utilize FEBE and efficient numerical scheme that couples finite element (FE) and spectral boundary integral (SBIE) method to study the long-term behavior of a 2D in-plane rate and state fault subjected to slow tectonic loading over a long duration intermittent by episodes of dynamic fracture in the presence of a near fault low velocity zone. FEBE combines the numerical superiority of SBIM with the flexibility of FEM to handle nonlinear problems with varying length scales at a substantially reduced computational cost. We handle the different time scales during the periods of loading and dynamic rupture by alternating between a quasi-dynamic and a dynamic solver. Utilizing the proposed scheme, we study multitude of problems with varying consequences on the earthquake cycle. We investigate the impact of bi-material interface and its role in altering the earthquake sequence, as well as the influence of normal stress variation on the rupture propagation and subsequent nucleation. The impact of the LVZ in altering the overall pattern and behavior of the earthquake cycle is highlighted. Specifically, the material mismatch result wave reflections that contributes toward the generation of persistent pulse like ruptures that are absent from the homogeneous case. Finally, we comment on the overall changes to the earthquake patterns in terms of interevent time, magnitudes, and event pattern, in the presence of off-fault plasticity.

Citation
Abdelmeguid, M., & Elbanna, A. E. (2021, 08). Advanced Earthquake Cycle Simulations: Bimaterial Interfaces, LVFZ, and nonlinear bulk rheology. Poster Presentation at 2021 SCEC Annual Meeting.

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