Abstract

The current stress state of the Earth’s crust in the territory of Uzbekistan was studied by cataclastic analysis of displacements along fault sets for the collected catalog of earthquake focal mechanisms (EFM), compiled from the data of different authors. Two stages of stress field reconstruction are implemented at different levels of area detail of averaging parameters and for different magnitude hierarchies of the analyzed earthquakes. Azimuths and dip angles of principal stresses axes, Lode–Nadai coefficient values, geodynamic type of stress state, relative (normalized to the cohesion strength of the rock massif) normalized values of the maximum shear stress and effective pressure are determined for different areas of the studied territory. As a result of natural stress reconstructions based on the focal mechanisms of earthquakes with magnitudes M ≤ 4.5 and M ≥ 5, differences in the parameters of the stressed state were revealed. It has been suggested that the hierarchy of magnitude levels of the considered earthquakes reflects the stressed state of various deep layers of the crust. It is shown that strong earthquakes gravitate to zones of reduced effective pressure. On this basis, segments of active faults have been identified in the territory of eastern Uzbekistan, which are considered zones of potentially increased seismic hazard.

中文翻译：

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乌兹别克斯坦地震活动区的应力状态

摘要

乌兹别克斯坦领土上地壳的当前应力状态，是通过对沿断裂集的位移进行分解弹塑性分析研究的，以收集地震震源机制（EFM）目录，并根据不同作者的数据进行了汇编。在平均参数的不同区域细节级别和所分析地震的不同震级层次上，实施了两个阶段的应力场重建。确定主应力轴的方位角和倾角，Lode–Nadai系数值，应力状态的地球动力学类型，相对于最大剪切应力和有效压力的归一化值（相对于岩体的内聚强度进行归一化）。研究领域。中号≤4.5和中号≥5，在应力状态的参数的差异，揭示。已经提出，所考虑的地震的震级水平反映了地壳各个深层的应力状态。结果表明，强地震会引向有效压力降低的区域。在此基础上，已在乌兹别克斯坦东部地区确定了活动断层的片段，这些片段被认为可能增加地震危险。