High‐Angle Active Conjugate Faults in the Anza‐Borrego Shear Zone, Southern California
High‐Angle Active Conjugate Faults in the Anza‐Borrego Shear Zone, Southern California
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DOI：
10.1029/2023gl105783
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发表时间：
2023-11
影响因子：
5.2
通讯作者：
Xiaoyu Zou;Y. Fialko;Andrew Dennehy;Alexander Cloninger;Shabnam J. Semnani
中科院分区：
文献类型：
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作者：
Xiaoyu Zou;Y. Fialko;Andrew Dennehy;Alexander Cloninger;Shabnam J. Semnani
活动的对立断层的方向可以对发震地壳的原位强度提供有用的限制。我们使用 LINSCAN（一种用于识别准线性地震群的新型无监督学习算法）来绘制南加州 Anza-Borrego 剪切带的小规模走滑断层图。我们识别出 332 条长度在 0.1 至 3 公里之间的右旋和左旋断层。所有可能的共轭断层对之间的二面角几乎呈正态分布在 70° 左右，标准偏差约为 30°。观察到的二面角大于假定最佳断层方向和摩擦系数为 0.6-0.8 时的预期值，但与之前报道的东加州剪切带 Ridgecrest 地区的分布相似。我们表明，观察到的断层方向可以通过由于累积的构造应变而远离主缩短轴的断层旋转来解释。
Orientations of active antithetic faults can provide useful constraints on in situ strength of the seismogenic crust. We use LINSCAN, a new unsupervised learning algorithm for identifying quasi‐linear clusters of earthquakes, to map small‐scale strike‐slip faults in the Anza‐Borrego shear zone, Southern California. We identify 332 right‐ and left‐lateral faults having lengths between 0.1 and 3 km. The dihedral angles between all possible pairs of conjugate faults are nearly normally distributed around 70°, with a standard deviation of ∼30°. The observed dihedral angles are larger than those expected assuming optimal fault orientations and the coefficient of friction of 0.6–0.8, but similar to the distribution previously reported for the Ridgecrest area in the Eastern California Shear Zone. We show that the observed fault orientations can be explained by fault rotation away from the principal shortening axis due to a cumulated tectonic strain.