On the variability of aftershock ground motions in the San Fernando Valley

Hough, Susan E.; Dietel, C.; Glassmoyer, G.; Sembera, E.

doi:10.1029/95gl00204

Cited by 17 publications

(17 citation statements)

References 3 publications

(2 reference statements)

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“…Both ground-motion modeling studies, such as the work by Olsen (2000), and previous observational studies (e.g., Hough et al, 1995;Hartzell et al, 2003) reveal that earthquakes in different locations--and/or with different rupture parameters--will cause markedly different responses in three-dimensional basins and valleys. One could similarly investigate topographic effects by looking at the azimuthal distribution of residuals at sites where such effects might be expected.…”

Section: Discussionmentioning

confidence: 99%

Geotechnical Characterization of TriNet Sites: A Status Report

Tinsley

Hough

Yong

et al. 2004

Seismological Research Letters

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Section: Discussionmentioning

confidence: 99%

Geotechnical Characterization of TriNet Sites: A Status Report

Tinsley

Hough

Yong

et al. 2004

Seismological Research Letters

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“…Discounting the possibility that DYFI responses are plagued by exaggerations, there are three obvious explanations for this variability: (1) ground motions vary over a few to 10 km due to varying local site response or other wave-propagation effects (e.g., Borcherdt, 1970;Hartzell et al, 1996;Hough and Field, 1996); (2) throughout any metropolitan region there will be structures of varying construction quality, and therefore seismic vulnerability, such that a similar level of shaking will cause more dramatic effects in some areas (the same effect that I earlier argued will give rise to biases in traditional MMI values); and (3) certain types of structures, notably relatively large buildings with masonry chimneys, might be more vulnerable than more prevalent smaller structures to damage from relatively long-period ground motions generated by moderate-to-large earthquakes (e.g., Ambraseys, 2002). It is likely that all of these effects contribute to some extent to the observed small-scale variability of intensities.…”

Section: Spatial Variability Of Intensity Within Citiesmentioning

confidence: 99%

Spatial Variability of "Did You Feel It?" Intensity Data: Insights into Sampling Biases in Historical Earthquake Intensity Distributions

Hough

2013

Bulletin of the Seismological Society of America

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“…The primary use in site response analyses has been to evaluate the spatial coherence of a wavefield ͑Menke et Field 1996͒. Hough andField ͑1996͒ found that waveform coherence estimates from earthquakes in the San Fernando Valley support the general conclusion that a site response estimate is an adequate representation of expected site response over a region several kilometers in diameter if the local geology is consistent. As compared to work in rock regions ͑Menke et al 1990͒, Hough and Field ͑1996͒ concluded that sedimentary basins may possess more coherent wavefields as a result of the resonant behavior of the sediments.…”

Section: Discussionmentioning

confidence: 99%

Site Response at Treasure and Yerba Buena Islands, California

Baise

2003

J. Geotech. and Geoenvir. Engrg.

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A variety of methods are utilized to reinvestigate the physical relationship between the seismic response of Treasure Island ͑TI͒ and Yerba Buena Island ͑YBI͒ in California. These islands are a soil ͑TI͒ and rock ͑YBI͒ site pair separated by 2 km. The site pair has been used previously by researchers to identify soil response to earthquake shaking. Linear regime ground motions (M W 4.0-M W 4.6 and PGA: 0.014 -0.017 g͒ recorded in the TI vertical array indicate a coherent wavefield in the sediments and an incoherence between the rock and sediments. Our analyses show that the greatest change in the wavefield occurred between the rock and soil layers, corresponding to a significant impedance contrast. The waveforms change very little as they propagate through the sediments, indicating that the site response is a cumulative effect of the entire soil structure and not a result of wave propagation within individual soil layers. In order to highlight the complexity of the site response, correlation analysis was used to demonstrate that the rock and soil ground motions were not highly coherent between the two sites. YBI was, therefore, shown to be an inappropriate reference site for TI. One-dimensional ͑1D͒ vertical wave propagation and inverse techniques were used to differentiate between 1D site response and more complex site behavior. Both 1D methods ͑vertical wave propagation and inverse transfer functions͒ proved incapable of capturing the site response at TI beyond the initial four seconds of motion. Finite difference waveform modeling, based on a two-dimensional velocity structure of the northern San Francisco Bay was needed to explain the linear site response at TI as horizontally propagating surface waves trapped in the bay sediments. A simplified velocity structure for the San Francisco Bay including a single 100 m basin layer ͑constant shear-wave velocity of 400 m/s͒ over a 1.5 km/s layer of Franciscan bedrock was able to trap energy in the basin and produce surface waveform ringing similar to that observed in the TI data. Due to surface waves propagating in the San Francisco Bay sediments, any 1D model will not fully characterize site response at TI. All 1D models will fail to produce the late arriving energy observed in the ground motions.

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On the variability of aftershock ground motions in the San Fernando Valley

Cited by 17 publications

References 3 publications

Geotechnical Characterization of TriNet Sites: A Status Report

Geotechnical Characterization of TriNet Sites: A Status Report

Spatial Variability of "Did You Feel It?" Intensity Data: Insights into Sampling Biases in Historical Earthquake Intensity Distributions

Site Response at Treasure and Yerba Buena Islands, California

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