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The 2015-2016 Earthquake Sequence in Cushing, Oklahoma driven by Coulomb Stress Changes and Fluid Diffusions
  • Qingjun Meng,
  • Sidao Ni,
  • Zhigang Peng
Qingjun Meng
Department of Geology and Geophysics, Texas A&M University
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Sidao Ni
State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences
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Zhigang Peng
School of Earth and Atmospheric Sciences, Georgia Institute of Technology

Corresponding Author:[email protected]

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Abstract

An M5 earthquake occurred on November 7th, 2016, near the city of Cushing in Oklahoma, the largest crude oil storage site in the USA, after nearby disposal wells had been shut-in responding to three M4+ earthquakes in 2015. In this study, we investigated the rupture process of these M4+ events with finite fault model (FFM) inversions and computed Coulomb stress changes during this Cushing sequence. We found that the rupture processes of the four M4+ earthquakes are very complex, and they appeared to trigger one another, as evidenced by the inverted finite fault slip distribution and the calculated Coulomb stress change after each event. The foreshocks of the first M4 earthquake are probably triggered by Coulomb stress changes from previous earthquakes during 2014 and 2015 on unmapped faults several kilometers to the south. Fluid diffusion likely drives the bilateral seismic migration of the Cushing earthquake sequence after the foreshocks were triggered. In addition, fluid injection from the northwest of Cushing fault might have gradually increased the pore pressure on the Cushing fault, making the shallow part of the fault critically stressed.
Jun 2021Published in Journal of Geophysical Research: Solid Earth volume 126 issue 6. 10.1029/2021JB022168