InSAR observations of aseismic slip associated with an earthquake swarm in the Columbia River flood basalts

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

In 2009 a swarm of small shallow earthquakes occurred within the basalt flows of the Columbia River Basalt Group (CRBG). The swarm occurred within a dense seismic network in the U.S. Department of Energys Hanford Site. Data from the seismic network along with interferometric synthetic aperture radar (InSAR) data from the European Space Agencys (ESA) ENVISAT satellite provide insight into the nature of the swarm. By modeling the InSAR deformation data we constructed a model that consists of a shallow thrust fault and a near horizontal fault. We suggest that the near horizontal lying fault is a bedding-plane fault located between basalt flows. The geodetic moment of the modeled fault system is about eight times the cumulative seismic moment of the swarm. Precise location estimates of the swarm earthquakes indicate that the area of highest slip on the thrust fault, ???70mm of slip less than ???0.5km depth, was not located within the swarm cluster. Most of the slip on the faults appears to have progressed aseismically and we suggest that interbed sediments play a central role in the slip process. Copyright 2011 by the American Geophysical Union.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title InSAR observations of aseismic slip associated with an earthquake swarm in the Columbia River flood basalts
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/2011JB008433
Volume 116
Issue 12
Year Published 2011
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Geophysical Research B: Solid Earth