Induced seismicity predominantly occurs along faults that are optimally oriented to the local principal compressive stress direction, and the characterization of these stress orientations is an important component of understanding seismic hazards. The seismicity rate in southern Kansas rapidly increased in 2013 primarily due to the disposal of large volumes of wastewater into the Arbuckle Group. Previously, local stress orientations in this area were poorly constrained, which limited our understanding of the complex faulting and diverse earthquake mechanisms in this region. We use shear‐wave splitting and focal mechanism inversion techniques to create multiple, independent estimates of maximum horizontal stress directions (⁠SHmax⁠) and their spatial variation across the study area. We then create an integrated model of stress orientations for southern Kansas and northern Oklahoma using our local results in conjunction with previous, regional stress orientation estimates. We find that SHmax in both southern Kansas and central Oklahoma exhibits an east‐northeast (⁠∼N78° E⁠) orientation, and these regions bound a northeast (⁠∼N59° E⁠) rotation within a ∼20 km area in northern Oklahoma near the Nemaha ridge.

中文翻译：

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表征堪萨斯州南部的应力方向

诱发地震活动主要发生在沿局部主压应力方向最佳定向的断层上，这些应力方向的表征是了解地震灾害的重要组成部分。堪萨斯州南部的地震活动率在 2013 年迅速增加，这主要是由于向 Arbuckle Group 排放了大量废水。以前，该地区的局部应力方向约束很差，这限制了我们对该地区复杂断层和多种地震机制的理解。我们使用横波分裂和震源机制反演技术来创建对最大水平应力方向 (⁠SHmax⁠) 及其跨研究区域的空间变化的多个独立估计。然后，我们使用我们的本地结果以及先前的区域应力方向估计，为堪萨斯州南部和俄克拉荷马州北部创建了一个综合的应力方向模型。我们发现堪萨斯州南部和俄克拉荷马州中部的 SHmax 都呈现出东-东北 (?∼N78° E?) 方向，并且这些区域在俄克拉荷马州北部约 20 公里的区域内限制了东北 (?∼N59° E?) 旋转尼马哈山脊附近。