Observations of static Coulomb stress triggering of the November 2011 M5.7 Oklahoma earthquake sequence

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

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Abstract

In November 2011, a M5.0 earthquake occurred less than a day before a M5.7 earthquake near Prague, Oklahoma, which may have promoted failure of the mainshock and thousands of aftershocks along the Wilzetta fault, including a M5.0 aftershock. The M5.0 foreshock occurred in close proximity to active fluid injection wells; fluid injection can cause a buildup of pore fluid pressure, decrease the fault strength, and may induce earthquakes. Keranen et al. [2013] links the M5.0 foreshock with fluid injection, but the relationship between the foreshock and successive events has not been investigated. Here we examine the role of coseismic Coulomb stress transfer on earthquakes that follow the M5.0 foreshock, including the M5.7 mainshock. We resolve the static Coulomb stress change onto the focal mechanism nodal plane that is most consistent with the rupture geometry of the three M ≥ 5.0 earthquakes, as well as specified receiver fault planes that reflect the regional stress orientation. We find that Coulomb stress is increased, e.g., fault failure is promoted, on the nodal planes of ~60% of the events that have focal mechanism solutions, and more specifically, that the M5.0 foreshock promoted failure on the rupture plane of the M5.7 mainshock. We test our results over a range of effective coefficient of friction values. Hence, we argue that the M5.0 foreshock, induced by fluid injection, potentially triggered a cascading failure of earthquakes along the complex Wilzetta fault system.

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Publication type Article
Publication Subtype Journal Article
Title Observations of static Coulomb stress triggering of the November 2011 M5.7 Oklahoma earthquake sequence
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1002/2013JB010612
Volume 119
Issue 3
Year Published 2014
Language English
Publisher American Geophysical Union
Contributing office(s) Earthquake Science Center
Description 20 p.
First page 1904
Last page 1923
Country United States
State Oklahoma
City Prague
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