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| Simulation of a “wall-to-wall” rupture of the southern San Andreas Fault. The peak ground velocities during this magnitude-8 earthquake are shown in color. White lines are seismograms at selected points. Graphic by Geoff Ely, Southern California Earthquake Center (click on image to enlarge). |
The highly nonlinear, multiscale dynamics of large earthquakes is a wicked physics problem that challenges HPC systems at extreme computational scales. This presentation will summarize how earthquake simulations at increasing levels of scale and sophistication have contributed to our understanding of seismic phenomena, focusing on the practical use of simulations to reduce seismic risk and enhance community resilience.
Milestones include the terascale simulations of large San Andreas earthquakes that culminated in the landmark 2008 ShakeOut planning exercise and the recent petascale simulations that have created the first physics-based seismic hazard models.
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| CyberShake seismic hazard map for the Los Angeles region, showing the 2-s spectral acceleration response (in units of surface gravity) at an exceedance probability of 2% in 50 years. To create this map, over 300 million seismograms were computed at 336 sites for multiple realizations of all fault ruptures in Version 2 of the Uniform California Earthquake Rupture Forecast using the tomographic velocity model CVM-S4.26. This is the information engineers need to design seismically safe structures. |
From the latter it is shown that accurate simulations can potentially reduce the total hazard uncertainty by about one-third relative to empirical models, which would lower the exceedance probabilities at high hazard levels by orders of magnitude.
Realizing this gain in forecasting probability will require enhanced computational capabilities, but it could have a broad impact on risk-reduction strategies, especially for critical facilities such as large dams, nuclear power plants, and energy transportation networks.
Click here for an animation of ground motions in the Los Angeles region excited by a magnitude-7.8 earthquake on the southern San Andreas Fault. Areas of high plastic strain and inelastic dissipation are shown in green. Credit: Dan Roten, San Diego Supercomputer Center.
Speaker Background:
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| Dr. Thomas H. Jordan |
Dr. Thomas H. Jordan is a University Professor and the W. M. Keck Foundation Professor of Earth Sciences at the University of Southern California. His current research is focused on system-level models of earthquake processes, earthquake forecasting, continental structure and dynamics, and full-3D waveform tomography.
As the director of the Southern California Earthquake Center (SCEC), he coordinates an international research program in earthquake system science that involves over 1000 scientists at more than 70 universities and research organizations. He is an author of more than 230 scientific publications, including two popular textbooks.
Jordan received his Ph.D. from the California Institute of Technology in 1972 and taught at Princeton University and the Scripps Institution of Oceanography before joining the Massachusetts Institute of Technology in 1984. He was head of MIT’s Department of Earth, Atmospheric and Planetary Sciences from 1988 to 1998.
He has received the Macelwane and Lehmann Medals of the American Geophysical Union and the Woollard Award and President’s Medal of the Geological Society of America. He is a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and the American Philosophical Society.
