Ground‐Motion Attenuation in the Sacramento–San Joaquin Delta, California, from 14 Bay Area Earthquakes, including the 2014 M 6.0 South Napa Earthquake

2019 ◽  
Vol 109 (3) ◽  
pp. 1025-1033
Author(s):  
Jemile E. Erdem ◽  
John Boatwright ◽  
Jon B. Fletcher
Keyword(s):  
Ground Motion ◽  
Bay Area ◽  
Ground Motion Attenuation

A Monte Carlo approach to seismic hazard analysis

1999 ◽  
Vol 89 (4) ◽  
pp. 854-866 ◽  
Author(s):  
John E. Ebel ◽  
Alan L. Kafka
Keyword(s):  
Monte Carlo ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Epicentral Distance ◽  
Ground Motions ◽  
Source Parameters ◽  
Parametric Models ◽  
Earthquake Catalog ◽  
Attenuation Relations ◽  
Ground Motion Attenuation

Abstract We have developed a Monte Carlo methodology for the estimation of seismic hazard at a site or across an area. This method uses a multitudinous resampling of an earthquake catalog, perhaps supplemented by parametric models, to construct synthetic earthquake catalogs and then to find earthquake ground motions from which the hazard values are found. Large earthquakes extrapolated from a Gutenberg-Richter recurrence relation and characteristic earthquakes can be included in the analysis. For the ground motion attenuation with distance, the method can use either a set of observed ground motion observations from which estimates are randomly selected, a table of ground motion values as a function of epicentral distance and magnitude, or a parametric ground motion attenuation relation. The method has been tested for sites in New England using an earthquake catalog for the northeastern United States and southeastern Canada, and it yields reasonable ground motions at standard seismic hazard values. This is true both when published ground motion attenuation relations and when a dataset of observed peak acceleration observations are used to compute the ground motion attenuation with distance. The hazard values depend to some extent on the duration of the synthetic catalog and the specific ground motion attenuation used, and the uncertainty in the ground motions increases with decreasing hazard probability. The program gives peak accelerations that are comparable to those of the 1996 U.S. national seismic hazard maps. The method can be adapted to compute seismic hazard for cases where there are temporal or spatial variations in earthquake occurrence rates or source parameters.

scholarly journals The Effect of Fault Geometry and Minimum Shear Wavespeed on 3D Ground-Motion Simulations for an Mw 6.5 Hayward Fault Scenario Earthquake, San Francisco Bay Area, Northern California

2019 ◽  
Vol 109 (4) ◽  
pp. 1265-1281 ◽  
Author(s):  
Arthur J. Rodgers ◽  
Arben Pitarka ◽  
David B. McCallen
Keyword(s):  
Ground Motion ◽  
San Francisco ◽  
Hanging Wall ◽  
3D Models ◽  
Peak Ground Velocity ◽  
Earth Model ◽  
Fault Geometry ◽  
Bay Area ◽  
Ground Motion Simulations ◽  
Vertical Fault

Abstract We investigated the effects of fault geometry and assumed minimum shear wavespeed (VSmin) on 3D ground-motion simulations (0–2.5 Hz) in general, using a moment magnitude (Mw) 6.5 earthquake on the Hayward fault (HF). Simulations of large earthquakes on the northeast-dipping HF using the U.S. Geological Survey (USGS) 3D seismic model have shown intensity asymmetry with stronger shaking for the Great Valley Sequence east of the HF (hanging wall) relative to the Franciscan Complex to the west (footwall). We performed simulations with three fault geometries in both plane-layered (1D) and 3D models. Results show that the nonvertical fault geometries result in larger motions on the hanging wall relative to the vertical fault for the same Earth model with up to 50% amplifications in single-component peak ground velocity (PGV) within 10 km of the rupture. Near-fault motions on the footwall are reduced for the nonvertical faults, but less than they are increased on the hanging wall. Simulations assuming VSmin values of 500 and 250  m/s reveal that PGVs are on average 25% higher west of the HF when using the lower VSmin, with some locations amplified by a factor of 3. Increasing frequency content from 2.5 to 5 Hz increases PGV values. Spectral ratios of these two VSmin cases show average amplifications of 2–4 (0.5–1.5 Hz) for the lower VSmin west of the fault. Large differences (up to 2×) in PGV across the HF from previous studies persist even for the case with a vertical fault or VSmin of 250  m/s. We conclude that assuming a VSmin of 500  m/s underestimates intensities west of the HF for frequencies above 0.5 Hz, and that low upper crustal (depth <10  km) shear wavespeeds defined in the 3D model contribute most to higher intensities east of the HF.

A study of ground motion attenuation in the Southern Great Basin, Nevada-California, using several techniques for estimates ofQs, logA0, and codaQ

1987 ◽  
Vol 92 (B5) ◽  
pp. 3527 ◽  
Author(s):  
A. M. Rogers ◽  
S. C. Harmsen ◽  
R. B. Herrmann ◽  
M. E. Meremonte
Keyword(s):  
Ground Motion ◽  
Great Basin ◽  
Ground Motion Attenuation
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