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Presenter
Louis Quinones
Ph.D. Candidate
Southern Methodist University
Description
Since 2008, earthquake sequences within the Fort Worth Basin (FWB), north Texas, have been linked to wastewater disposal activities related to unconventional shale gas production. Here, I present my work analyzing and cataloging a complete record of the seismicity occurring within the basin over a time period of over a decade (2008-2020). Analysis of the catalog reveals that the earthquakes generally occur within the pre-Cambrian basement formation along steeply dipping normal faults, and while overall seismicity rates have decreased since 2016, new faults have become active. I observe strong spatial and temporal correlations between the earthquake locations and wastewater disposal well locations and injection volumes, implying that fluid injection activities may be the main driving force of seismicity in the basin. To test this hypothesis, I created a coupled geomechanical model of the Fort Worth Basin incorporating geology and fault data shared by our collaborators at TexNet and the Bureau of Economic Geology. These models show that while large injection associated stress changes are concentrated in those portions of the basin where injection activities are highest, that there are observable far-field stress changes capable of reaching faults at far distances (>15 km) away from injection wells such as the source fault of the Dallas-Irving sequence. Lastly, my talk shifts in focus to talk about some newer earthquake detection techniques which I’ve begun to utilize in north Texas and Oklahoma in order to understand their usefulness in monitoring and creating earthquake catalogs efficiently and rapidly.
