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Abstract The ShakeOut scenario of an M 7.8 northwestward rupture on the southern San Andreas fault (SSAF) (Jones et al., 2008) predicted significant long-period ground-motion amplification in the greater Los Angeles, California, area, caused by a waveguide from interconnected sedimentary basins. However, the early ShakeOut ground-motion simulations omitted important model features with immature versions of the velocity structure and fault geometry. Here, we present 0–1 Hz 3D numerical wave propagation simulations for the ShakeOut scenario including surface topography, as well as updated high-resolution velocity structures and SSAF geometry. Spectral accelerations at 3 s are increased by the local high-resolution basin models (25%–45%) but decreased from complexity in velocity and density updates outside the basins (65%–100%) and inclusion of surface topography (∼30%). The updated model reduces the simulated long-period ground motions in the waveguide by 60%–70%, bringing the predictions significantly closer to the values by a leading Next Generation Attenuation-West2 ground-motion model.
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Waveguide or not? Revised ground motion simulations for greater Los Angeles from the M7.8 ShakeOut earthquake scenario
The ShakeOut simulations of a M7.8 earthquake on the southern San Andreas fault (2008) studies predicted unexpectedly large ground motions throughout Southern California due to waveguide e#ects from interconnected sedimentary basins in 3D velocity model. Here, we re-examine the ground motion predictions from the ShakeOut scenario using the most recent updates on the velocity models and the realistic surface topography from the Digital Elevation Model. The exceptional scalability and performance of the AWP-ODC due to the most recent advancements allows for examination of plenty earth models including the irregular surface topography at low computational cost.
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- Award ID(s):
- 2311833
- PAR ID:
- 10538028
- Publisher / Repository:
- Annual MVAPICH USER Group (MUG) Meeting
- Date Published:
- Format(s):
- Medium: X
- Location:
- Columbus
- Sponsoring Org:
- National Science Foundation
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