To better understand relationships among crustal anisotropy, fracture orientations, and the stress field in Oklahoma and southern Kansas, we conduct shear‐wave splitting analysis on the last 9 yr of data (2010–2019) of local earthquake observations. Rather than a predominant fast direction (⁠ϕ⁠), we find that most stations have a primary fast direction of polarization (⁠ϕpri⁠) and a secondary fast direction of polarization (⁠ϕsec⁠). At most stations, either the primary fast direction of polarization (⁠ϕpri⁠) or the secondary fast direction of polarization (⁠ϕsec⁠) is consistent with the closest estimated maximum horizontal stress (⁠σHmax⁠) orientation in the vicinity of the observation. The general agreement between fast directions of polarization (⁠ϕ⁠) and the maximum horizontal stress orientations (⁠σHmax⁠) at the regional level implies that the fast polarization directions (⁠ϕ⁠) are extremely sensitive to the regional stress field. However, in some regions, such as the Fairview area in western Oklahoma, we observe discrepancies between fast polarization directions (⁠ϕ⁠) and maximum horizontal stress orientations (⁠σHmax⁠), in which the fast directions are more consistent with local fault structures. Overall, the primary fast direction of polarization (⁠ϕpri⁠) is mostly controlled and influenced by the stress field, and the secondary fast direction of polarization (⁠ϕsec⁠) likely has some geologic structural control because the secondary direction is qualitatively parallel to some mapped north‐striking fault zones. No significant changes in fast directions over time were detected with this technique over the 5 yr (2013–2018) of measurements, suggesting that pore pressure may not cause a significant enough or detectable change above the magnitude of the background stress field.

中文翻译：

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从剪切波分裂推断出横跨俄克拉荷马州的空间不同构造带

为了更好地理解俄克拉荷马州和堪萨斯州南部地壳各向异性、裂缝方向和应力场之间的关系，我们对过去 9 年（2010-2019 年）当地地震观测数据进行了剪切波分裂分析。我们发现大多数站不是一个主要的快速方向（⁠ϕ⁠），而是有一个主要的快速极化方向（⁠ϕpri⁠）和一个次要的快速极化方向（⁠ϕsec⁠）。在大多数台站，主要快速极化方向 (⁠ϕpri⁠) 或次要快速极化方向 (⁠ϕsec⁠) 与观测附近最接近的估计最大水平应力 (⁠σHmax⁠) 方向一致。快速极化方向 (⁠ϕ⁠) 与区域水平的最大水平应力方向 (⁠σHmax⁠) 之间的普遍一致性意味着快速极化方向 (⁠ϕ⁠) 对区域应力场极为敏感。然而，在一些地区，例如俄克拉荷马州西部的 Fairview 地区，我们观察到快速极化方向 (⁠ϕ⁠) 和最大水平应力方向 (⁠σHmax⁠) 之间的差异，其中快速方向与局部断层结构更一致. 总体而言，主要快速极化方向 (⁠ϕpri⁠) 主要受应力场控制和影响，而次要快速极化方向 (⁠ϕsec⁠) 可能具有一些地质结构控制，因为次要方向在性质上平行于某些绘制了北走向的断层带。