The 2019 Ridgecrest earthquake sequence initiated on July 4th with a series of foreshocks, including an M_w 6.4 event, that culminated a day later with the M_w 7.1 mainshock and resulted in rupture of a set of cross‐faults. In this study, we use subpixel correlation of optical satellite imagery to measure the displacement, finite strain, and rotation of the near‐field coseismic deformation to understand the kinematics of strain release along the surface ruptures. We find the average off‐fault deformation along the mainshock rupture is 34% and is significantly higher along the foreshock rupture (56%), suggesting it is a less structurally developed fault system. Measurements of the 2D dilatational strain along the mainshock rupture show a dependency of the width of inelastic strain with the degree of fault extension and contraction, indicating wider fault zones under extension than under shear. Measurements of the vorticity along the main, dextral rupture show that conjugate sinistral faults are embedded within zones of large clockwise rotations caused by the transition of strain beyond the tips of dextral faults leading to bookshelf kinematics. These rotations and bookshelf slip can explain why faults of different shear senses do not intersect one another and the occurrence of pervasive and mechanically unfavorable cross‐faulting in this region. Understanding the causes for the variation of fault zone widths along surface ruptures has importance for reducing the epistemic uncertainty of probabilistic models of distributed rupture that will, in turn, provide more precise estimates of the hazard distributed rupture poses to nearby infrastructure.

中文翻译：

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书架运动学和扩张对断层带非弹性形变的影响：来自2019年Ridgecrest地震序列光学图像相关性测量的示例

7月4日发起的一系列前震，其中包括2019年里奇克莱斯特地震序列中号_W¯¯ 6.4事件中，达到高潮，一天后用中号_{w ^}7.1主震并导致一系列交叉故障的破裂。在这项研究中，我们使用光学卫星图像的亚像素相关性来测量位移，有限应变和近场同震变形的旋转，以了解沿表面破裂的应变释放的运动学。我们发现沿主震破裂的平均断层变形为34％，而沿前震破裂的平均断层变形明显更高（56％），表明这是一个结构欠发达的断层系统。沿着主震破裂的二维膨胀应变的测量结果表明，非弹性应变的宽度与断层伸展和收缩程度的相关性，表明伸展作用下的断层区域比剪切作用下的要宽。沿主旋涡的测量，右旋断裂表明，共轭正弦断裂嵌在大的顺时针旋转区域内，这是由应变引起的，超出了右旋断裂的尖端导致书架运动的过渡。这些旋转和书架滑移可以解释为什么不同剪切方向的断层不会彼此相交，并且在该区域发生了普遍存在且在机械上不利的交叉断层。理解断层宽度随地表破裂而变化的原因，对于降低分布式破裂概率模型的认识论不确定性具有重要意义，而后者又可以为分布在附近基础设施上的危险性提供更精确的估计。