青藏高原东北缘是青藏高原东北向扩展前缘，自新生代以来发生了强烈广泛的构造形变，其下方地幔物质在印度-欧亚板块持续汇聚过程中可能发生东向挤出。现有研究表明鄂尔多斯块体南北可能存在由青藏高原东北缘东向挤出的地幔流，且其所在位置和深度范围仍未有定论。明确是否存在地幔物质东向挤出及其通道位置和深度范围对解释青藏高原隆升和扩展非常关键。本项目拟利用布设在青藏高原东北缘及其周边密集流动台阵所记录的地震数据，使用背景噪音成像和地震双平面波成像获得不同周期相速度图像及方位角各向异性，并利用邻域算法反演获得该区域地壳上地幔剪切波速度结构及不同深度方位角各向异性；进而判明是否存在自青藏高原东北缘东向流经鄂尔多斯北缘的地幔物质流，并探讨潜在地幔流的通道位置和深度范围，从而加深对高原地幔物质东北向逃逸及其与周边块体相互作用的认识，为解释青藏高原如何向周缘块体过渡和扩展提供观测证据。

The Northeast Tibet is the frontal zone of the Tibet Plateau northeast expansion to the Inner land of China and has been experienced strong tectonic deformation since Cenozoic. The mantle material beneath the Northeast Tibet may escape eastwards influenced by the continuous convergence of the Indian-Eurasian continents. Previous studies show the existence of the mantle flow beneath the southern and northern margin of the Ordos block, which is originated from the Northeast Tibet. However, the location and the depth of this mantle flow are still under debate. It is of great meaning for explaining the way Tibet Plateau expands to its surrounding blocks to obtain S-wave velocity and azimuthal anisotropy of the crust and uppermost mantle in the Northeast Tibet and its surrounding areas. By using the dense temporary and permanent seismic arrays deployed in the study area, this project is supposed to construct phase velocity map and azimuthal anisotropy of different periods via ambient noise tomography and two-plane-wave tomography. Furthermore, a non-linear Neighborhood Algorithm is presented to estimate the Vsv velocity model and azimuthal anisotropy in different depths beneath the Northeast Tibet and its surrounding areas. The resulting model is used to determine whether the eastwards mantle flow originated from the Northeast Tibet exists or not and the location and the depth of the mantle flow beneath the northern Ordos block if it really exists. This project will provide insight into the interactions between the hot mantle material escaped from the Northeast Tibet and the overlying lithosphere beneath the surrounding areas, which is helpful to understanding the lithospheric deformation mechanism and geodynamic pattern of the plateau growth.