The Community Code Verification Exercise for Simulating Sequences of Earthquakes and Aseismic Slip (SEAS)
Abstract
Numerical simulations of Sequences of Earthquakes and Aseismic Slip (SEAS) have made great progress over the past decades to address important questions in earthquake physics and fault mechanics. Significant challenges in SEAS modeling remain in resolving multiscale interactions between aseismic fault slip, earthquake nucleation, and dynamic rupture; and understanding physical factors controlling observables such as seismicity and ground deformation. In 2018 we initiated a community code-verification effort for SEAS simulations, supported by the Southern California Earthquake Center (SCEC). Our goals are to develop best practices, and code-verification and simulation tools for SEAS modeling that would benefit a larger community. Here we report our first four benchmarks (BP1-BP4), designed to test the capabilities of different computational methods in correctly solving mathematically well-defined problems in earthquake faulting. BP1 and BP2 are for a 2D antiplane problem, with a 1D planar vertical strike-slip fault obeying rate-and-state friction, embedded in a 2D homogeneous, linear elastic half-space. Sequences of quasi-dynamic earthquakes with periodic occurrences (BP1) or bimodal sizes (BP2) and their interactions with aseismic slip are simulated. The comparison of >70 simulations from 11 groups using different numerical methods, uploaded to our online platform, show excellent agreements in long-term and coseismic evolution of fault properties. In BP1, we found that the truncated domain boundaries influence interseismic fault stressing, earthquake recurrence, and coseismic rupture process, and that agreement between models is only achieved with sufficiently large domain sizes. In BP2, we found that complexity of earthquake patterns depends on how well important physical length scales are resolved in the simulations, which affects model observables, e.g., earthquake size distributions, moment release, and recurrence times. Building on the success of these first two benchmarks, BP3 and BP4 consider full dynamics and 3D effects, respectively, and we investigate their influence on earthquake behavior and patterns. Results from these benchmarks will inform the development of more advanced SEAS models, contributing to our further understanding of earthquake system dynamics.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T13D0309E
- Keywords:
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- 1209 Tectonic deformation;
- GEODESY AND GRAVITY;
- 1294 Instruments and techniques;
- GEODESY AND GRAVITY;
- 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICS;
- 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICS