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Spatial and temporal evolution of seismicity, seismic velocity, and pore pressure in the Guy-Greenbrier, Arkansas, earthquake sequence

Zhuo Yang, & Marine A. Denolle

Published August 14, 2019, SCEC Contribution #9575, 2019 SCEC Annual Meeting Poster #076

Hydraulic fracturing is a widely-used technique to enhance natural gas production in northern Arkansas. The process also produces a large amount of wastewater. In the Guy-Greenbrier area in Arkansas, wastewater has been injected into the subsurface through several disposal wells since April 2009. Seismicity in the surrounding area has increased sharply and 98% of the earthquakes, following the injection, are located within 6 km of three wastewater disposal wells by Horton (2012) who related the increase in seismicity to wastewater injection. This project gives a comprehensive study on the Guy-Greenbrier earthquake sequence. We have modeled the evolution of pore pressure in response to fluid injection in a poroelastic 3D medium with deformation-dependent evolution of the permeability structure typical of damage fault zones (Yehya et al, 2018). We then attempt to validate our model against some seismic observables. First, we measure time-dependent changes in seismic velocities using auto correlations of ambient seismic noise in different frequencies. Second, we compare our time series with the peak ground acceleration to correlate with potential seismic damage. The change in seismic velocity does not seems to temporarily correlate with onset and arrest of injection or to peak ground motions. However, a shallow change in seismic velocity occurs as a 1-month long precursory phase to the swarm of March 2011. Finally, we compared the observed evolution of elastic properties in different depth with our previous simulation results. Combining these theoretical and observational approaches, we aim to gain more insights in the interaction between fluid injection, structural evolution, and seismicity production for induced earthquake hazard mitigation. (Research supported at Harvard by the NSF-EAR Geophysics Program (Grant EAR-1315447) and by the NSF Materials Research Science and Engineering Center (Contract DMR-14-20570))

Yang, Z., & Denolle, M. A. (2019, 08). Spatial and temporal evolution of seismicity, seismic velocity, and pore pressure in the Guy-Greenbrier, Arkansas, earthquake sequence. Poster Presentation at 2019 SCEC Annual Meeting.

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