First-generation site-response maps for the Los Angeles region based on earthquake ground motions

Bulletin of the Seismological Society of America
By: , and 

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Abstract

Ground-motion records from aftershocks of the 1994 Northridge earthquake and mainshock records from the 1971 San Fernando, 1987 Whittier Narrows, 1991 Sierra Madre, and 1994 Northridge earthquakes are used to estimate site response relative to a rock site for the urban Los Angeles area. Site response is estimated at 232 mainshock and 201 aftershock sites relative to a low-amplitude site in the Santa Monica Mountains. Average amplification values are calculated for the frequency bands: 1 to 3, 3 to 5, and 5 to 7 Hz. These bands are chosen based on limitations in aftershock recording equipment at lower frequencies and reduced significance to the building inventory at higher frequencies. Site amplification factors determined at the instrumented locations are grouped by the surficial geology and contoured to produce a continuous spatial estimation of amplification. The maps in this article represent the first attempt to produce estimates of site amplification based on observations of ground motion for such a large areal extent of the Los Angeles region. These maps are expected to evolve as more data become available and more analysis is done.

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Publication type Article
Publication Subtype Journal Article
Title First-generation site-response maps for the Los Angeles region based on earthquake ground motions
Series title Bulletin of the Seismological Society of America
DOI 10.1785/BSSA0880020463
Volume 88
Issue 2
Year Published 1998
Language English
Publisher Seismological Society of America
Description 10 p.
First page 463
Last page 472
Country United States
State California
City Los Angeles
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