地壳浅层应力场与深部运动耦合机制研究——以青藏高原东缘为例

Heterogeneity of the regional in situ stress state is a common phenomenon, especially in the areas with developmental geological structures and strong activities. However, researches at present have been limited to characterize the transverse distribution of in situ stress in the shallow crust. In situ stress research focus should be actively placed on the distributing characteristics in three dimensional space and its formation mechanism, in particular in the areas such as the eastern margin of the Tibetan Plateau, which characterized by special deep structure and motion difference between shallow and deep lithosphere. In the present study, influence of active faults to the forming and evolution of distributing characteristics of in situ stress will be analyzed in detail, combined with the stress measurement data and finite element numerical simulation method. The research contents will give insight into how shallow stress field responded to the deep process. Research on this topic has important theoretical and practical value for study of formation mechanism of stress spatial distribution and coupling mechanism between the shallow and deep crustal stress state.

地应力在空间分布上的不均匀性是普遍存在的现象，特别是在地质构造发育、活动强烈的区域，应力状态的不连续性分布特征更加显著。目前对于区域地壳应力状态的研究，多局限于地壳浅层及横向分布特征研究上。特别地，对于具有特殊深部结构及深浅运动差异的青藏高原东缘地区，应力状态空间展布特征及其成因机制的研究显著不足。本研究将基于前期青藏高原东缘地应力研究取得的初步成果展开，拟结合实测地应力数据及有限元数值模拟方法，建立较为精细的地质模型，详细讨论青藏高原东缘断裂分布对地应力空间分布特征形成及演化的影响；并探讨地壳浅层构造应力对深部运动的响应机制。本项目对应力状态空间分布结构成因机制以及深浅地壳构造应力场的耦合问题研究具有重要的理论意义和实际应用价值。

本项目以青藏高原东缘龙门山断裂带以及东北缘巴颜喀拉、祁连山-河西走廊和柴达木盆地等块体的交汇区为主要研究区域，基于浅表层原地应力测量和深部震源机制解等数据，结合数值模拟等技术手段，通过综合分析获得了研究区地壳浅表层和震源深度构造应力场的空间分布特征，分析了其成因机制和影响因素，讨论了活动断裂对应力应变分布特征的影响作用以及强震等构造活动对应力场的调整作用，探索了研究区深部动力学特征以及地壳浅表层和震源深度构造应力场对深部运动的响应机制。