S068-05
Enhancing CyberShake Simulations for Engineering Applications
Wednesday, 16 December 2020: 17:48
Virtual
Scott Callaghan1, Philip J Maechling2, Christine A. Goulet2, Kevin R Milner1, Robert W Graves3, Kim Bak Olsen4, Fabio Silva2 and Yehuda Ben-Zion5, (1)University of Southern California, Los Angeles, CA, United States, (2)Southern California Earthquake Center, Los Angeles, CA, United States, (3)US Geological Survey, Pasadena, CA, United States, (4)San Diego State Univ, San Diego, CA, United States, (5)University of Southern California, Department of Earth Sciences and Southern California Earthquake Center, Los Angeles, CA, United States
Abstract:
The Southern California Earthquake Center (SCEC) has developed the CyberShake platform to implement a physics-based probabilistic seismic hazard analysis (PSHA) method which uses 3D wave propagation simulations to calculate seismograms and ground motions from sources defined in regional earthquake rupture forecasts. CyberShake has been used to calculate PSHA models for Southern California, Central California, and the San Francisco Bay Area, and is able to quantify effects such as basin amplification and rupture directivity that are difficult to capture in a typical GMPE parameterization.
To improve the accuracy of CyberShake results and their usefulness for engineering applications, we have recently integrated the latest version of the Graves-Pitarka rupture generator, which includes increased variability in rupture parameters and decreased coherency. We examine the influence of reduced rupture coherence and rupture velocity on hazard estimates.
We have also enabled end-to-end hybrid broadband CyberShake, in which deterministic low-frequency (1Hz) physics-based simulation results are combined with stochastic high-frequency results to produce broadband seismograms up to 50 Hz. To support this capability, we have integrated the Graves and Pitarka high-frequency stochastic approach released in the SCEC Broadband Platform (version 19.4) into the CyberShake workflows.
We will present CyberShake PSHA simulation results using the new rupture generator, assessing its impact on ground motion and overall hazard. We will also present our updated hybrid broadband results for a variety of sites around Southern California.
