Effects of deep basins on structural collapse during large subduction earthquakes

Earthquake Spectra
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Abstract

Deep sedimentary basins are known to increase the intensity of ground motions, but this effect is implicitly considered in seismic hazard maps used in U.S. building codes. The basin amplification of ground motions from subduction earthquakes is particularly important in the Pacific Northwest, where the hazard at long periods is dominated by such earthquakes. This paper evaluates the effects of basins on spectral accelerations, ground-motion duration, spectral shape, and structural collapse using subduction earthquake recordings from basins in Japan that have similar depths as the Puget Lowland basin. For three of the Japanese basins and the Puget Lowland basin, the spectral accelerations were amplified by a factor of 2 to 4 for periods above 2.0 s. The long-duration subduction earthquakes and the effects of basins on spectral shape combined, lower the spectral accelerations at collapse for a set of building archetypes relative to other ground motions. For the hypothetical case in which these motions represent the entire hazard, the archetypes would need to increase up to 3.3 times its strength to compensate for these effects.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Effects of deep basins on structural collapse during large subduction earthquakes
Series title Earthquake Spectra
DOI 10.1193/071916EQS114M
Volume 33
Issue 3
Year Published 2017
Language English
Publisher Earthquake Engineering Research Institute
Contributing office(s) Earthquake Science Center
Description 15 p.
First page 963
Last page 997