CyberShake Advancements: Broadband Seismograms and Central California Sites

Scott Callaghan, Philip J. Maechling, Christine A. Goulet, Karan Vahi, Robert W. Graves, Kim B. Olsen, Kevin R. Milner, David Gill, Yifeng Cui, & Thomas H. Jordan

Submitted August 15, 2016, SCEC Contribution #6874, 2016 SCEC Annual Meeting Poster #337

The CyberShake computational platform, developed by SCEC, is an integrated collection of scientific software and middleware that performs 3D physics-based probabilistic seismic hazard analysis (PSHA). CyberShake integrates large-scale parallel and high-throughput research codes to produce probabilistic seismic hazard curves for individual locations of interest and hazard maps for an entire region.
The most recent CyberShake deterministic hazard models have been calculated at seismic frequencies up to 1 Hz. To expand this with PSHA results at frequencies of wider interest to civil engineers (1-10 Hz), we performed CyberShake Study 15.12, which augmented the 1 Hz deterministic results using high-frequency stochastic seismograms produced using the Graves and Pitarka (2015) module from the SCEC Broadband Platform. For each of about 500,000 events and at each of 336 locations of interest, stochastic seismograms were simulated, filtered, combined with deterministic seismograms, and post-processed to obtain intensity measures and hazard curves at frequencies from 0-10 Hz. Additionally, Study 15.12 included the calculation of 9 new duration measures for each simulated earthquake of interest to building engineers.
In developing and verifying CyberShake, we have focused our modeling in the greater Los Angeles region. We are now expanding the hazard calculations into Central California. Using workflow tools running jobs across two large-scale open-science supercomputers, NCSA Blue Waters and OLCF Titan, we are calculating 1 Hz deterministic PSHA results for over 400 locations in Central California. For each location, we are producing hazard curves using two different velocity models: a 3D central California velocity model created via tomographic inversion (CCA), and a regionally averaged 1D model. These new results will provide low-frequency ground motion exceedance probabilities for the rapidly expanding metropolitan areas of Santa Barbara, Bakersfield, and San Luis Obispo. The results will also lend new insights into the effects of directivity-basin coupling associated with basins juxtaposed with major faults such as the San Andreas, and produce physics-based PSHA results for structures of interest such as water pumping stations.
We will present our approach for incorporating stochastic seismograms into CyberShake, show results from Study 15.12 as well as preliminary results for new Central California locations, and describe our future CyberShake plans.

The most recent CyberShake deterministic hazard models have been calculated at seismic frequencies up to 1 Hz. To expand this with PSHA results at frequencies of wider interest to civil engineers (1-10 Hz), we performed CyberShake Study 15.12, which augmented the 1 Hz deterministic results using high-frequency stochastic seismograms produced using the Graves and Pitarka (2015) module from the SCEC Broadband Platform. For each of about 500,000 events and at each of 336 locations of interest, stochastic seismograms were simulated, filtered, combined with deterministic seismograms, and post-processed to obtain intensity measures and hazard curves at frequencies from 0-10 Hz. Additionally, Study 15.12 included the calculation of 9 new duration measures for each simulated earthquake of interest to building engineers.

In developing and verifying CyberShake, we have focused our modeling in the greater Los Angeles region. We are now expanding the hazard calculations into Central California. Using workflow tools running jobs across two large-scale open-science supercomputers, NCSA Blue Waters and OLCF Titan, we are calculating 1 Hz deterministic PSHA results for over 400 locations in Central California. For each location, we are producing hazard curves using both a 3D central California velocity model created via tomographic inversion (CCA), and a regionally averaged 1D model. These new results will provide low-frequency ground motion exceedance probabilities for the rapidly expanding metropolitan areas of Santa Barbara, Bakersfield, and San Luis Obispo. The results will also lend new insights into the effects of directivity-basin coupling associated with basins juxtaposed with major faults such as the San Andreas, and produce physics-based PSHA results for structures of interest such as water pumping stations.
We will present our approach for incorporating stochastic seismograms into CyberShake, show results from Study 15.12 as well as preliminary results for new Central California locations, and describe our future CyberShake plans.

Key Words
seismic hazard analysis, computational seismology, high performance computing

Citation
Callaghan, S., Maechling, P. J., Goulet, C. A., Vahi, K., Graves, R. W., Olsen, K. B., Milner, K. R., Gill, D., Cui, Y., & Jordan, T. H. (2016, 08). CyberShake Advancements: Broadband Seismograms and Central California Sites. Poster Presentation at 2016 SCEC Annual Meeting.


Related Projects & Working Groups
Community Modeling Environment (CME)