山西断陷带地壳各向异性及壳幔变形研究

Shanxi rift is located in the central part of the North China Craton. With strong tectonic deformation and intense seismic activity, its crust-mantle deformation and deep structure have always been highly concerned by scholars. At present, the understanding of the crust-mantle deformation in the Shanxi rift is mainly based on the results of the SKS splitting. For the lack of the results on the crustal deformation, there are still many debates about the interpretation of the deformation in the crust and mantle in this area. If the crustal anisotropy and velocity structure with high-resolution can be combined, the deformation and coupling mechanism of the crust and mantle can be well constrained. In recent years, China Earthquake Administration has deployed a dense temporary seismic array in North China. Combining with permanent stations and other temporary stations previously deployed, it forms a very dense network consisting of about 550 stations in the area. This study will make full use of these observations and obtain the crustal anisotropic parameters and crust-mantle S-wave velocity structure in the Shanxi rift. After comprehensively analyzing these results with stress field distribution and SKS splitting results, we could establish the crust-mantle deformation model in the study area and further discuss the deformation mechanism and deep dynamic process, which will provide an important reference for the study on the formation and evolution of the Shanxi rift.

山西断陷带位于华北克拉通中部，构造变形强烈、地震活动频繁，其壳幔变形和深部结构一直受到学者们的高度关注。目前关于山西断陷带壳幔变形的认识主要基于SKS分裂的结果，地壳内部变形的研究结果仍然很少，致使该地区壳幔变形解释存在诸多争议。开展地壳各向异性及高分辨率壳幔速度结构研究，可更好地约束该地区壳幔变形模式和耦合机制。近年来，中国地震局在华北地区开展了大规模流动地震台阵观测，与固定台站和以前架设的流动观测台站相结合，形成了该地区约550个台站组成的密集观测台网。本研究将充分利用这些观测资料，采用接收函数方法获得山西断陷带地壳各向异性参数，并利用接收函数与面波联合反演方法获得高分辨率的壳幔S波速度结构。综合分析这些结果与应力场分布及SKS分裂结果，建立研究区的壳幔变形模型，探讨山西断陷带地区的壳幔变形机制及深部动力学过程，为研究断陷带的形成演化提供重要的参考依据。

山西断陷带位于华北克拉通的中部，由于其强烈的构造变形和频繁的地震活动，其壳幔变形和深部结构一直受到广泛关注。本研究充分利用山西断陷带及邻区密集的宽频带流动地震台站及固定台站观测资料，采用接收函数与面波联合反演方法获得研究区的壳幔S波速度结构；利用H-k叠加方法计算山西断陷带地区的地壳厚度和波速比；采用噪声层析成像方法获得相速度分布图像；利用最小能量法获得台站下方的SKS分裂结果，给出研究区的各向异性分布图像。综合分析壳幔S波速度结构与各向异性特征，探讨了山西断陷带地区的壳幔变形机制及深部动力学过程，建立了壳幔变形模型，为了解山西断陷带的演化过程提供了新的参考。