Seismic Tomography of China and Surrounding Regions

New Mexico State University, Las Cruces NM

Investigators

Abstract

Hearn, Thomas M. EAR-0001227 This 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.