Petascale Earthquake Simulations

Dr, Geoffrey P. Ely
Seminar

The scarcity of near-source recordings for large earthquakes motivates the use of numerical simulations for the prediction of possible ground motion from future events. The relevant phenomena (frictional breakdown, shear heating, effective normal-stress fluctuations, material damage, etc.) controlling rupture are strongly interacting and span many orders of magnitude in spatial scale, requiring high-resolution simulations that couple disparate physical processes (e.g., elastodynamics, thermal weakening, pore-fluid transport, and heat conduction). The capacity to perform 3D rupture simulations that couple these processes will provide guidance for constructing appropriate source models for high-frequency ground motion simulations. Compounding the computational challenge, for the case physics-based probabilistic seismic hazard analysis (PSHA), is the need to perform simulations for multiple variations of all statistically significant possible events. A goal of the Southern California Earthquake Center (SCEC) during the ALCF Early Science Program is to calculate a 1Hz PSHA hazard map for California using improved rupture models from our multi-scale dynamic rupture simulations. This calculation will provide numerous important seismic hazard results, including a state-wide extended earthquake rupture forecast with rupture variations for all significant events, a synthetic seismogram catalog for thousands of scenario events and more than 5000 physics-based seismic hazard curves for California. I will highlight recent milestones toward reaching this goal, as well as discuss the current state of SCEC simulations codes as we begin preparation for upcoming ALCF systems.