Elevated Seismic Hazard in Kansas Due to High-Volume Injections in Oklahoma

Abstract

Induced seismicity has expanded into south-central Kansas, an area with rare damaging natural earthquakes, leading to the second-highest seismicity rate in the central United States after Oklahoma. Here we assess the mechanical effects of large-scale injection in the combined area of western Oklahoma and southern Kansas during 2010–2018 and its link to the observed seismicity using physics-based hydromechanical and seismicity rate models. Such models link injection operations to seismic hazards and allow solving for the spatially variable distribution of background seismic productivity that yields an acceptable match between the observed and modeled seismicity. We show that injection in Oklahoma amplifies the total Coulomb stress change and seismicity rate by 1.5-fold and threefold, respectively, in south-central Kansas. This cross-border interaction modulates the annual earthquake probability in Kansas. We conclude that the issue of induced seismicity is not a local problem due to the far-reaching effects of fluid diffusion.