青藏高原东北缘及邻区地壳方位各向异性研究

由于强烈的地壳变形、垂直隆升构造以及地震活动，青藏高原东北缘及邻区一直是地学研究的热点地区。然而，目前对该区域的地壳变形特征认识不清，关于地壳变形机制、以及不同块体间的相互作用和动力学过程仍存在争议。地壳方位各向异性是研究地壳变形的有效手段之一，目前研究区地壳各向异性探测结果的空间覆盖率不足(比如鄂尔多斯块体、银川-河套地堑以及阿拉善块体北部)，在很大程度上是由于低速沉积层产生的多次波混响对接收函数造成干扰所致。本项目拟收集研究区内843个流动和固定地震台记录的资料，提取接收函数，应用去除沉积层混响技术，利用转换震相(Pms波、Pis波)到时偏移的方法得到单层和分层地壳各向异性结果图像，分析地壳不同深度的变形特征和耦合关系，为探讨青藏高原构造演化和动力学过程提供可靠的深部结构信息。

It is commonly believed that the northeastern margin of the Tibetan Plateau is an ideal natural laboratory for understanding continental deformation due to the crustal deformation, orogeny and seismicity. However, mechanisms responsible for the crustal deformation and interaction and dynamical process among different blocks remain enigmatic. Crustal azimuthal anisotropy is an effective method for understanding the crust deformation. At most parts of the limited spatial coverage of crustal azimuthal anisotropy (such as in the Ordos Block, Yinchuan-Hetao Graben, and northern Alxa Block) lie in the fact that the strong reverberations generated from the low velocity sedimentary layer can mask the P-to-S conversions associated with the Moho discontinuity, making it difficult to reliably apply most receiver function methods to study the crust. We plan to collect the seismic data that recorded by 843 stations in this study area, and then apply a recently-developed deconvolution approach to effectively remove near-surface reverberations in the receiver functions, and subsequently determine the crustal anisotropy by analyzing the moveout of the Pms and Pis phases. The results are expected to offer reliable deep structure information for understanding the geodynamic process of the crustal thickening and deformation mechanism of the Tibetan plateau.