A modern tectonic stress field for the north‐eastern margin of Tibetan Plateau was determined using linear inversion. Focal mechanism solutions and the depths of 54 earthquakes from 2009 to 2017 were obtained from broadband seismic waveforms. We derived the tectonic stress field using the SATSI (Spatial and Temporal Stress Inversion) software based on the damped linear inversion method. The stress tensor structures are primarily indicative of strike‐slip and thrust faulting; their distributions are controlled by the West Qinling and Haiyuan faults. The Longxi Block is surrounded by two faults dominated by thrust faulting; the regions in the periphery of the faults, (e.g., West Qingling Fault Zone and Liupanshan Basin) are primarily characterized by strike‐slip faulting. However, normal faulting has developed in the Haiyuan–Zhongwei Belt of Liupanshan Basin, indicating that the latest tectonic regime is an NNW–SSE extension instead of a strike‐slip fault with a thrust component, as has been previously suggested. This anomalous stress mechanism reflects the combined effects of block rotation and local extension resulting from movement along strike‐slip faults. The West Qinling Fault is dominated by thrust faulting instead of strike‐slip faulting. The Haiyuan–Liupanshan and Niushoushan–Luoshan faults are predominantly strike‐slip faulting. The directions of the maximum stress axes (σ1) in both Liupanshan Basin and the Longxi Block are ENE–WSW down to Liupanshan in the south and West Qinling Fault Zone, where the stress axes gradually rotate clockwise to E–W. The modern tectonic stress field implies that regional stress originates from far‐field effects of Indian and Eurasian plate collision.

中文翻译：

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青藏高原东北缘现代构造应力场的空间变异性

利用线性反演确定了青藏高原东北缘的现代构造应力场。从宽带地震波形中获得了震源机制解和2009年至2017年54次地震的深度。我们基于阻尼线性反演方法，使用SATSI（时空应力反演）软件导出了构造应力场。应力张量结构主要指示走滑和逆冲断层。它们的分布受西秦岭断裂和海原断裂的控制。龙溪区块周围有两个以逆冲断层为主的断层。断层外围的区域（如西庆陵断层带和六盘山盆地）的主要特征是走滑断层。然而，六盘山盆地海原-中卫一带已形成正断层，表明最新的构造机制是NNW-SSE扩展，而不是如前所述具有推力分量的走滑断层。这种异常应力机制反映了沿走滑断层运动引起的块体旋转和局部伸展的综合作用。西秦岭断层以逆冲断层而不是走滑断层为主。海原—六盘山断层和牛首山—罗山断层主要为走滑断层。六盘山盆地和Long西地块的最大应力轴（σ1）的方向都是ENE-WSW，一直到南，西秦岭断裂带的六盘山，应力轴逐渐沿顺时针方向旋转到E-W。