Cybershake models of seismic hazards in southern and central california

CyberShake is a high-performance computational platform developed by the Southern California Earthquake Center (SCEC) to produce seismic hazard models from large suites of earthquake simulations. Code optimization and the development of workflow tools on the NCSA Blue Waters and OLCF Titan supercomputers have substantially reduced the computational costs. A recent workflow efficiently utilized both machines to generate 285 million two-component seismograms for the central California region from which 46 billion intensity measurements were extracted. We summarize the current suite of CyberShake models and apply averagingbased factorization (ABF) to decompose each model into a hierarchy of site, path, directivity, stress-drop, and source complexity effects. We summarize how the strength of the directivity effect decreases with increasing source complexity, and how the site and path effects vary with differences in crustal structure. Comparisons quantified by the ABF variances indicate that simulation-based hazard models can potentially reduce σ", the total unexplained variability in current ground-motion prediction equations, by as much as one-third. Dept. of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740 (email: tjordan@usc.edu) Southern California Earthquake Center, University of Southern California, Los Angeles, CA 90089-0742 U.S. Geological Survey, Pasadena, CA 91106 AIR Worldwide Inc., Boston, MA 02116 San Diego State University, San Diego, CA 92182 San Diego Supercomputer Center, San Diego, CA 92093 USC Information Sciences Institute, Los Angeles, CA 90292 Jordan TH, Callaghan S, Graves RW, Wang F, Milner KR, Goulet CA, Maechling PJ, Olsen KB, Cui Y, Juve G, Vahi K, Yu J, Deelman E, Gill D. CyberShake Models of Seismic Hazards in Southern and Central California. Proceedings of the 11 National Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Los Angeles, CA. 2018. CyberShake Models of Seismic Hazards in Southern and Central California Thomas H. Jordan , Scott Callaghan, Robert W. Graves, Feng Wang, Kevin R. Milner, Christine A. Goulet, Philip J. Maechling, Kim Bak Olsen, Yifeng Cui, Gideon Juve, Karan Vahi, John Yu, Ewa Deelman, and David Gill