Connecting crustal seismicity and earthquake-driven stress evolution in Southern California

Journal of Geophysical Research B: Solid Earth
By:  and 

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Abstract

Tectonic stress in the crust evolves during a seismic cycle, with slow stress accumulation over interseismic periods, episodic stress steps at the time of earthquakes, and transient stress readjustment during a postseismic period that may last months to years. Static stress transfer to surrounding faults has been well documented to alter regional seismicity rates over both short and long time scales. While static stress transfer is instantaneous and long lived, postseismic stress transfer driven by viscoelastic relaxation of the ductile lower crust and mantle leads to additional, slowly varying stress perturbations. Both processes may be tested by comparing a decade-long record of regional seismicity to predicted time-dependent seismicity rates based on a stress evolution model that includes viscoelastic stress transfer. Here we explore crustal stress evolution arising from the seismic cycle in Southern California from 1981 to 2014 using five M≥6.5 source quakes: the M7.3 1992 Landers, M6.5 1992 Big Bear, M6.7 1994 Big Bear, M7.1 1999 Hector Mine, and M7.2 2010 El Mayor-Cucapah earthquakes. We relate the stress readjustment in the surrounding crust generated by each quake to regional seismicity using rate-and-state friction theory. Using a log likelihood approach, we quantify the potential to trigger seismicity of both static and viscoelastic stress transfer, finding that both processes have systematically shaped the spatial pattern of Southern California seismicity since 1992.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Connecting crustal seismicity and earthquake-driven stress evolution in Southern California
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1002/2017JB014200
Volume 122
Issue 8
Year Published 2017
Language English
Publisher AGU
Contributing office(s) Earthquake Science Center
Description 18 p.
First page 6473
Last page 6490
Country United States
State California