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Broadband simulations for M_w 7.8 southern San Andreas earthquakes: Ground motion sensitivity to rupture speed

Graves, Robert W. and Aagaard, Brad T. and Hudnut, Kenneth W. and Star, Lisa M. and Stewart, Jonathan P. and Jordan, Thomas H. (2008) Broadband simulations for M_w 7.8 southern San Andreas earthquakes: Ground motion sensitivity to rupture speed. Geophysical Research Letters, 35 (22). L22302. ISSN 0094-8276. doi:10.1029/2008GL035750.

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Using the high-performance computing resources of the Southern California Earthquake Center, we simulate broadband (0–10 Hz) ground motions for three M_w 7.8 rupture scenarios of the southern San Andreas fault. The scenarios incorporate a kinematic rupture description with the average rupture speed along the large slip portions of the fault set at 0.96, 0.89, and 0.84 times the local shear wave velocity. Consistent with previous simulations, a southern hypocenter efficiently channels energy into the Los Angeles region along the string of basins south of the San Gabriel Mountains. However, we find the basin ground motion levels are quite sensitive to the prescribed rupture speed, with peak ground velocities at some sites varying by over a factor of two for variations in average rupture speed of about 15%. These results have important implications for estimating seismic hazards in Southern California and emphasize the need for improved understanding of earthquake rupture processes.

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Hudnut, Kenneth W.0000-0002-3168-4797
Additional Information:© 2008 by the American Geophysical Union. Received 20 August 2008; accepted 9 October 2008; published 20 November 2008. We thank members of the SCEC CME collaboration for their efforts on the ShakeOut simulation project. We appreciate the constructive comments by Art Frankel, Paul Spudich and two anonymous reviewers. Funding for this work was provided by SCEC under NSF grants EAR-0623704 and OCI-0749313 and by the USGS. The large-scale simulations were run at USC’s Center for High Performance Computing and Communications ( under an agreement with the SCEC CME project. This is SCEC contribution 1238.
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Southern California Earthquake Center (SCEC)UNSPECIFIED
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Southern California Earthquake Center Contribution1238
Issue or Number:22
Record Number:CaltechAUTHORS:20090701-151932462
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Official Citation:Graves, R. W., B. T. Aagaard, K. W. Hudnut, L. M. Star, J. P. Stewart, and T. H. Jordan (2008), Broadband simulations for Mw 7.8 southern San Andreas earthquakes: Ground motion sensitivity to rupture speed, Geophys. Res. Lett., 35, L22302, doi:10.1029/2008GL035750.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14480
Deposited By: Tony Diaz
Deposited On:13 Aug 2009 15:32
Last Modified:08 Nov 2021 23:12

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