Detection of postseismic fault-zone collapse following the Landers earthquake

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Stress changes caused by fault movement in an earthquake induce transient aseismic crustal movements in the earthquake source region that continue for months to decades following large events. These motions reflect aseismic adjustments of the fault zone and/or bulk deformation of the surroundings in response to applied stresses, and supply information regarding the inelastic behaviour of the Earth's crust. These processes are imperfectly understood because it is difficult to infer what occurs at depth using only surface measurements, which are in general poorly sampled. Here we push satellite radar interferometry to near its typical artefact level, to obtain a map of the postseismic deformation field in the three years following the 28 June 1992 Landers, California earthquake. From the map, we deduce two distinct types of deformation: afterslip at depth on the fault that ruptured in the earthquake, and shortening normal to the fault zone. The latter movement may reflect the closure of dilatant cracks and fluid expulsion from a transiently over-pressured fault zone.
Publication type Article
Publication Subtype Journal Article
Title Detection of postseismic fault-zone collapse following the Landers earthquake
Series title Nature
DOI 10.1038/382612a0
Volume 382
Issue 6592
Year Published 1996
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Nature
First page 612
Last page 616
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