The Community Code Verification Exercise for Simulating Sequences of Earthquakes and Aseismic Slip (SEAS)

Brittany A. Erickson, Junle Jiang, Michael Barall, Nadia Lapusta, Eric M. Dunham, Ruth A. Harris, Lauren S. Abrahams, Kali L. Allison, Jean-Paul Ampuero, Sylvain D. Barbot, Camilla Cattania, Ahmed E. Elbanna, Yuri Fialko, Benjamin Idini, Jeremy E. Kozdon, Valere R. Lambert, Yajing Liu, Yingdi Luo, Xiao Ma, Maricela Best Mckay, Paul Segall, Pengcheng Shi, Martijn van den Ende, & Meng Wei

Published August 14, 2019, SCEC Contribution #9618, 2019 SCEC Annual Meeting Poster #174

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. However, 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. The increasing capability and complexity of SEAS modeling calls for extensive efforts to verify codes and advance these simulations with rigor, reproducibility, and broadened impact. Here we report the first community code-verification exercises for SEAS modeling, based on our first two benchmarks (BP1 and BP2), designed to test the capabilities of different computational methods in correctly solving a mathematically well-defined, basic problem in crustal faulting. These benchmarks 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 simulation results 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 models, which affects model observables, e.g., earthquake size distributions, moment release, and recurrence times, to different extents. These results inform the development of more advanced SEAS models, contributing to our further understanding of earthquake system dynamics.

Citation
Erickson, B. A., Jiang, J., Barall, M., Lapusta, N., Dunham, E. M., Harris, R. A., Abrahams, L. S., Allison, K. L., Ampuero, J., Barbot, S. D., Cattania, C., Elbanna, A. E., Fialko, Y., Idini, B., Kozdon, J. E., Lambert, V. R., Liu, Y., Luo, Y., Ma, X., Best Mckay, M., Segall, P., Shi, P., van den Ende, M., & Wei, M. (2019, 08). The Community Code Verification Exercise for Simulating Sequences of Earthquakes and Aseismic Slip (SEAS). Poster Presentation at 2019 SCEC Annual Meeting.

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