Seismic Tomography of China and Surrounding Regions

本项目主要研究中国及亚洲大陆周边地区的上地幔结构。现今的亚洲构造以印度-亚洲大陆碰撞和南部青藏高原的隆升以及东部边缘的俯冲为主导。重新激活的褶皱带容纳了大部分的变形。这些褶皱带形成于显生宙克拉通地块与欧亚大陆东部地块的合并。然而，这些地块和褶皱带与深部地幔结构的关系尚不清楚。岩石圈厚度、碰撞下沉和地幔各向异性仍未得到充分解决。断层扫描将使用0到50度以上距离的P相位来成像中国及其周边地区的上地幔。层析成像的一个关键发展是引入各向异性。以往的层析成像研究表明，各向异性是问题的关键，不能忽视。各向异性层析成像已经发展并应用于二维Pn问题。本研究将各向异性层析成像扩展到三维空间，并将其应用于亚洲数据集。

Hearn, Thomas M.EAR-0001227This project focuses on upper mantle structure beneath China and surrounding regions of the Asian continent. Asian tectonics is now dominated by the Indian-Asian continental collision and uplift of the Tibetan Plateau in the south and subduction along the eastern margin. Reactivated fold belts accommodate much of the deformation. These fold belts formed during the Phanerozoic amalgamation of cratonic blocks and blocks along eastern Eurasia. It is not clear, however, what the relationship of these blocks and fold belts are to their deeper mantle structure. Lithospheric thickness, collisional downwellings, and mantle anisotropy remain inadequately resolved. The tomography will use P phases from 0 to past 50 degrees distance to image the upper mantle beneath China and its surrounding regions. A key development in the tomography is the introduction of anisotropy. Previous tomographic studies show that anisotropy is essential to the problem and cannot be ignored. Anisotropic tomography has been developed and applied to the two-dimensional Pn problem. This proposal will extend anisotropic tomography to three-dimensions and apply it to the Asian data sets.