The 2017 Mw 6.3 Jinghe earthquake represents one of the few large earthquakes that are well recorded by seismic instruments and Interferometric Synthetic Aperture Radar (InSAR) observations in the seismically active Tian Shan region. In this study, we use the rupture fault solution (dip, dip direction, and slip sense) from seismologic and InSAR results, along with analysis of our collected surface mapping data, to determine the subsurface fault‐plane geometry of the seismogenic Jinghenan fault. This geometric model, integrated with the coseismic slip distribution from seismologic and InSAR data, reveals that: (1) the Jinghenan fault extends downward from the land surface at a dip of ∼46° S (upper ramp), then bends to ∼42° S (lower ramp) at the depth of 9–13 km; (2) the coseismic rupture is confined within the Jinghenan lower ramp, and its upper limitation is approximately coincident with the fault‐bend location. This coseismic rupture pattern and seismic behavior can be broadened to other active thrust faults within the Tian Shan, suggesting that, during moderate‐strong earthquakes, such faults may only rupture partially in the down‐dip extension, and the unruptured fault portion remains to pose high‐seismic risk in the future.

中文翻译：

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2017年6.3级泾河地震期间逆冲断层下部断裂：对天山地区地震灾害的影响

2017 年 6.3 级泾河地震是地震活跃的天山地区地震仪器和干涉合成孔径雷达 (InSAR) 观测记录良好的少数大地震之一。在这项研究中，我们使用来自地震学和 InSAR 结果的破裂断层解（倾角、倾角方向和滑动感），以及对我们收集的地表测绘数据的分析，以确定发震的京河南断层的地下断层平面几何形状。该几何模型结合地震学和 InSAR 数据的同震滑移分布表明：（1）泾河南断层从地表向下延伸约 46° S（上斜坡），然后弯曲到约 42° S（下坡道）在 9-13 公里的深度；(2) 同震破裂局限在泾河南下匝道内，其上限与断层弯曲位置近似重合。这种同震破裂模式和地震行为可以扩展到天山内的其他活动逆冲断层，表明在中强地震期间，此类断层可能仅在下倾延伸部分破裂，而未破裂的断层部分仍然存在未来的高地震风险。