High-Performance Computing Ground Motion Simulations of Large, Damaging Hayward Fault Earthquakes

Artie Rodgers

Lawrence Livermore National Laboratory

Date & Time
Location
Building 3, Rambo Auditorium
Host
Brad Aagaard
Summary

The Hayward Fault presents significant seismic hazard to the eastern San Francisco Bay Area (the “East Bay”). We report on a high-performance computing (HPC) simulation of strong ground motions for a magnitude (M) 7.0 scenario earthquake on the Hayward Fault resolved to 5 Hz and higher. We computed seismic motions obeying physics-based wave propagation in a regional-scale, three-dimensional (3D) Earth model with surface topography with the SW4 finite difference code. Both plane-layered (one-dimensional, 1D) and 3D earth models were considered, with 3D sub-surface material properties and topography sub-sampled from a 3D model by the USGS. The resulting ground motion intensities (peak ground acceleration and velocity, RotD50 spectral accelerations) are in good agreement with ground motion models (GMM) based on empirical data. Median intensities for sites across the domain are within the reported uncertainties of the Abrahamson et al. (2014) GMM across spectral periods 0.1-10 seconds (frequencies 0.1-10 Hz). The variance of ground motion intensity measurements (GMIM’s) residuals ranges 0.4-0.6 natural log units, representing the site-to-site, within event variability for this single rupture. These results demonstrate that earthquake simulations with fully 3D deterministic wave propagation on world-class HPC platforms provides ground motions consistent with empirical models for frequencies of relevance to engineering analysis.

Closed captions are typically available a few days after the seminar. To turn them on, press the ‘CC’ button on the video player. For older seminars that don’t have closed captions, please email us, and we will do our best to accommodate your request.

Video Podcast