Source-dependent amplification of earthquake ground motions in deep sedimentary basins

Geophysical Research Letters
By: , and 

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Abstract

Deep sedimentary basins amplify long-period shaking from seismic waves, increasing the seismic hazard for cities within such basins. We perform 3-D simulations of point source earthquakes distributed around the Seattle and Tacoma basins in Washington State, to examine the dependence of basin amplification on source azimuth, depth, and earthquake type. For periods between 1-10 s, the pattern of amplification is spatially heterogeneous and differs considerably with the source-to-site azimuth. For close-in earthquakes, the greatest basin amplification occurs towards the far side of the basin and ground motions from crustal earthquakes experience greater amplification than those from more vertically-incident, deeper intraplate earthquakes. Love and Rayleigh waves form similar spatial patterns for a given source location, although the magnitude of amplification varies. The source dependence of basin amplification is an important factor for seismic hazard assessment, both in the Seattle and Tacoma basins, and by extension for deep sedimentary basins worldwide.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Source-dependent amplification of earthquake ground motions in deep sedimentary basins
Series title Geophysical Research Letters
DOI 10.1029/2019GL082474
Volume 46
Issue 12
Year Published 2019
Language English
Publisher American Geophysical Union
Contributing office(s) Earthquake Science Center, Geologic Hazards Science Center
Description 8 p.
First page 6443
Last page 6450
Country United States
State Washington