Summary

The ShakeOut Scenario 2.0 is a collaborative effort to generate updated earthquake scenarios that build upon the influential 2008 ShakeOut Scenario using current scientific understanding and engineering capabilities to evaluate earthquake impacts under today’s built environment, infrastructure systems, and societal conditions. The simulated ShakeOut Scenario 2.0 mainshock is a dynamically propagating large earthquake rupturing the southern San Andreas fault in California. Working within SCEC’s ShakeOut Scenario Technical Activity Group (TAG), the Statewide California Earthquake Center – U.S. Geological Survey (SCEC-USGS) dynamic rupture group is modeling a scenario large aftershock occurring in the weeks following the mainshock in a region of calculated increased static stress generated by the mainshock. The scenario large aftershock will be an M6.7-6.9 on the Raymond-Hollywood faults in the densely populated Los Angeles Basin. The scenario will be used by members of the engineering and earthquake effects teams to investigate its impact on the built and human environment in the Los Angeles Basin and beyond. 

Dynamic rupture codes simulate how earthquake ruptures evolve from specified fault geometry, rock, stress, and friction conditions. Benchmark exercises test whether independently developed codes produce consistent results under the same assumptions—an essential step in confirming that the codes are working as intended before the models can be validated against observations. The SCEC-USGS dynamic rupture group is using this scenario aftershock as a benchmark exercise to test if multiple codes can produce the same earthquake source and near-field ground motion results when incorporating the 3D fault geometry adapted from the SCEC Community Fault Model (CFM), 3D velocity and density structure from the SCEC Community Velocity Model (CVM) truncated at the lowest velocities, along with slip-weakening friction, and initial stress conditions informed by the SCEC Community Stress Model (CSM).

At this workshop we will introduce the aftershock-scenario benchmark exercise, and discuss the latest findings from dynamic rupture simulations and related projects. Presentations and discussions will explain the benchmark’s scientific basis, prescribed model inputs, and participation process; invite additional modeling groups to contribute results from their own codes; and provide a forum for sharing new scientific ideas and related community projects. The workshop will conclude by reviewing what was learned and identifying next steps for the community verification effort.

Participation

The workshop is open to researchers, model developers, students, and others interested in dynamic rupture simulation, earthquake-source physics, code verification, and near-field ground motions. Modelers interested in participating in the new ShakeOut Scenario 2.0 aftershock benchmark exercise are especially encouraged to attend.

To participate, complete the online registration form by October 7. Registrants may also propose a one-slide, 100-second lightning talk through the form. There is no registration fee, and the Zoom link will be provided with the registration confirmation.