Aftershocks driven by afterslip and fluid pressure sweeping through a fault-fracture mesh

Geophysical Research Letters
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Abstract

A variety of physical mechanisms are thought to be responsible for the triggering and spatiotemporal evolution of aftershocks. Here we analyze a vigorous aftershock sequence and postseismic geodetic strain that occurred in the Yuha Desert following the 2010 Mw 7.2 El Mayor-Cucapah earthquake. About 155,000 detected aftershocks occurred in a network of orthogonal faults and exhibit features of two distinct mechanisms for aftershock triggering. The earliest aftershocks were likely driven by afterslip that spread away from the main shock with the logarithm of time. A later pulse of aftershocks swept again across the Yuha Desert with square root time dependence and swarm-like behavior; together with local geological evidence for hydrothermalism, these features suggest that the events were driven by fluid diffusion. The observations illustrate how multiple driving mechanisms and the underlying fault structure jointly control the evolution of an aftershock sequence.

Publication type Article
Publication Subtype Journal Article
Title Aftershocks driven by afterslip and fluid pressure sweeping through a fault-fracture mesh
Series title Geophysical Research Letters
DOI 10.1002/2017GL074634
Volume 44
Issue 16
Year Published 2017
Language English
Publisher American Geophysical Union
Contributing office(s) Earthquake Science Center
Description 8 p.
First page 8260
Last page 8267
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