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Comparison of ground motions from hybrid simulations to NGA prediction equations

Lisa M. Star, Jonathan P. Stewart and Robert W. Graves
Comparison of ground motions from hybrid simulations to NGA prediction equations
Earthquake Spectra (May 2011) 27 (2): 331-350


We compare simulated motions for a Mw 7.8 rupture scenario on the San Andreas Fault known as the ShakeOut event, two permutations with different hypocenter locations, and a Mw 7.15 Puente Hills blind thrust scenario, to median and dispersion predictions from empirical NGA ground motion prediction equations. We find the simulated motions attenuate faster with distance than is predicted by the NGA models for periods less than about 5.0 s After removing this distance attenuation bias, the average residuals of the simulated events (i.e., event terms) are generally within the scatter of empirical event terms, although the ShakeOut simulation appears to be a high static stress drop event. The intra-event dispersion in the simulations is lower than NGA values at short periods and abruptly increases at 1.0 s due to different simulation procedures at short and long periods. The simulated motions have a depth-dependent basin response similar to the NGA models, and also show complex effects in which stronger basin response occurs when the fault rupture transmits energy into a basin at low angle, which is not predicted by the NGA models. Rupture directivity effects are found to scale with the isochrone parameter.

ISSN: 8755-2930
EISSN: 1944-8201
Serial Title: Earthquake Spectra
Serial Volume: 27
Serial Issue: 2
Title: Comparison of ground motions from hybrid simulations to NGA prediction equations
Affiliation: University of California, Civil and Environmental Engineering Department, Los Angeles, CA, United States
Pages: 331-350
Published: 201105
Text Language: English
Publisher: Earthquake Engineering Research Institute, Berkeley, CA, United States
References: 33
Accession Number: 2021-008699
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps
N32°00'00" - N36°00'00", W120°00'00" - W115°00'00"
Secondary Affiliation: U. S. Geological Survey, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2021, American Geosciences Institute.
Update Code: 202107
Program Name: USGSOPNon-USGS publications with USGS authors
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