江汉盆地与周缘造山带地壳上地幔横波速度结构与径向各向异性研究

江汉盆地与周缘造山带位于中国二、三级阶梯转变的关键部位，是研究盆地与造山带形成和演化等动力学过程的天然实验室。深入研究江汉盆地与周缘造山带地壳上地幔横波速度与径向各向异性结构，有助于进一步理解中国三大地势阶梯的建立过程。本项目基于密集流动台阵观测数据和中国地震台网及区域台网数据，利用背景噪声面波成像结合地震面波双平面波成像技术，对噪声数据进行同步和异步互相关，采用高分辨率拉东变换进行面波模式分离、对重构的基阶信号进行面波频散与瑞雷面波H/V测量等数据处理技术，发挥面波不同参数对横波速度拥有互补敏感性的优势，联合反演群速度、相速度与H/V，研究江汉盆地与周缘造山带地壳上地幔三维横波速度与径向各向异性结构。重点研究沉积层厚度、莫霍界面和下地壳上地幔顶部横波速度与径向各向异性的空间分布特征，以期为盆山构造体系的形成和演化研究提供地球物理依据。预期研究成果对盆山耦合的动力学机制具有重要科学意义。

The Jianghan Basin and its surrounding orogenic belts are located in the key part of the second- and third-level step transitions in China. They are natural laboratories for the study of the formation and evolution of basins and orogenic belts. Research on the crust and upper mantle shear wave velocity and radial anisotropy structure beneath the Jianghan Basin and its surrounding orogenic belts will help to further understand the establishment of Chinese three topographic steps. The objective of this project is to construct crust and upper mantle velocity and radial anisotropy structure beneath the Jianghan Basin and its surrounding orogenic belts by applying seismic ambient noise and teleseismic surface wave two-plane wave tomography to seismic stations deployed by the dense transportable array and the Chinese National Seismic Network in this region. Data processing techniques, such as synchronize and asynchronously ambient noise cross-correlation, and surface wave mode separation by the high-resolution Radon transform, are used to perform dispersion and H/V measurements on the surface wave data only containing fundamental mode. Joint inversion of group velocity, phase velocity and H/V is applied to construct shear wave velocity and anisotropy due to different surface wave parameters with complementary sensitivities to the shear wave velocity. The research focuses on the spatial distributions of the thickness of the sediment, the Moho interface and the shear wave velocity and radial anisotropy at the top of the lower crust and upper mantle, which will provide geophysical evidences for the formation and evolution of basin-mountain tectonic systems. The project will provide important constraints on the understanding of the dynamic mechanism of basin-mountain coupling.