SCEC Award Number 24087 View PDF
Proposal Category Collaborative Research Project (Multiple Investigators / Institutions)
Proposal Title Advancing Simulations of Sequences of Earthquakes and Aseismic Slip (SEAS)
Investigator(s)
Name Organization
Valere Lambert University of California, Santa Cruz Brittany Erickson University of Oregon
SCEC Milestones C1,2,3-1, C2-1, C3-1 SCEC Groups FARM, SDOT, RC
Report Due Date 03/15/2025 Date Report Submitted 04/05/2025
Project Abstract
 Developing robust predictive models of earthquake source processes is one of the main SCEC goals. Research groups within the earthquake science community are contributing to this goal through the development of computational methods for simulating Sequences of Earthquakes and Aseismic Slip (SEAS). In SEAS models, the goal is to capture the interplay of interseismic periods and the associated aseismic fault slip—that ultimately lead to earthquake nucleation—and earthquakes (dynamic rupture events) themselves, and understand which physical factors control the full range of observables such as aseismic deformation, earthquake nucleation, ground shaking during dynamic rupture, recurrence times and magnitudes of major earthquakes. One of the significant challenges in SEAS modeling efforts arises from the varying temporal and spatial scales that characterize earthquake source behavior. Computations are further complicated when material heterogeneities, bulk inelastic responses, fault non-planarity, and their evolution with time and slip, are included. However, accounting for such complexity is widely recognized as crucial for understanding the real Earth and predicting seismic hazards.
Intellectual Merit SCEC has supported community code exercises on verifying and validating spontaneous dynamic earthquake rupture simulations and comparing Earthquake Simulators. A new generation of numerical SEAS models are needed to simulate longer periods of earthquake activity beyond single-event simulations but with the same level of computational rigor, while incorporating physical factors important over longer time scales. These verified SEAS models would better inform initial conditions and nucleation procedures for dynamic rupture simulations and provide physics-based approximations for larger-scale, longer-term earthquake simulators. We plan to incrementally incorporate additional physical factors in such efforts to advance the state-of-the-art computational capabilities in our field.
Broader Impacts The SEAS initiative has grown in its seventh year at SCEC, with strides in community building, developing new code verification benchmarks, organizing workshops, and promoting visibility of SEAS modeling in the SCEC community and beyond. For all our code verification efforts, the workshops have proven to be particularly valuable in providing an ideal platform for all modelers to share and follow recent scientific progress in the field, discuss details in benchmark design/results, and collectively decide the directions of our future efforts, with considerable inputs from students and early career scientists.
Project Participants SEAS leadership: Valere Lambert and Brittany A. Erickson, with new additions of Pierre Romanet and Prithvi Thakur
Additional contributors to our manuscripts for BP6 and BP7:
Junle Jiang, Eric M. Dunham, Taeho Kim, Jean-Paul Ampuero, Ryosuke Ando, Frederic Cappa, Pierre Dublanchet, Ahmed Elbanna, Yuri Fialko, Alice-Agnes Gabriel, Nadia Lapusta, Meng Li, Jasper Marcum, David May, Md Shumon Mia, So Ozawa, Casper Pranger, Marco M. Scuderi, Ylona van Dinther, Yuyun Yang, Jeena Yun, Mary Agajanian, Camilla Cattania, Alexandre Chen, Jinhui Cheng, Duo Li, Yohai Magen, Piyush Karki, Amy Lu, Rosalie Verwijs, Matteo Cusini, Vidar Stiernstroem
Exemplary Figure Figure 3. A) BP7 is a 3D problem with a planar fault including a circular velocity-weakening asperity (green) surrounded by velocity-strengthening regions (blue). The problem considers an infinite whole-space, however we have included a version specifying boundary conditions on a finite model domain to facilitate comparison of volume-based numerical methods (light blue). Model parameters are chosen that produce sequences of either repeating earthquakes or alternating aseismic and seismic slip events. Our results show that sequences of slip events, including partitioning of aseismic and seismic moment, are sensitive to (B) treatment of inertial effects and C) model domain size.
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