Three Gorges Deep Geophysics

YANGTSE GORGES CHONGQING Reservoir Area is situated in the east edge of the middle of our nation' s north and south earthquake belt. The area lays in the brim and transition zone of the continental lithosphere that is obvious diversity from east to west. The area transverses our nation' s gravity grads belt, and the lithosphere shows that the east is thinner than the west and tends towards to NWW. The gravity grads belt corres -ponding to big rupture is very obvious.It takes many years that China Geology Academy of Sciences, China Earthquake Bureau, the former Ministry of Geology and Mineral, the former Ministry of Petroleum and so on have carried through many kinds of method to survey and prospect in the area. Especially the wide-angle reflection and refraction wave prospecting supply the gist. The current data indie -ates that Sichuan lithosphere takes on the characteristic of multi-layer and inhomogeneous. The tendency of the Moho depth changing is that the depth gradually becomes deep from east to west.The study in this paper depends on the current geophysical data. The new way and method are applied in studying. We start from synthesis geophysics, apply new method to process the practical seismic data that includes west-east and north-south section seismic data. The new method mainly is Ray tracing and Pg imaging. We also select separating field and displacing digital imaging to dispose the gravity and magnetism data. We build the 2-D(Two Dimensions) structure section through united inversion. Then, We carefully and finely analyze and study the earth' s crust structure and main ruptures and MOHO fluctuating. Taking the section as foundation, linking to geophysical plane field characteristic, we fully study the feature of the reversion area' s fundus and lithosphere. Finally, we extend study to 3-D(Three Dimensions) lithosphere structure model. The study result provides the basic information and datum to deeplyanalyze the lithosphere dynamics characteristic and whose influence on controlling rupture. It also supplies the fundamental data of watching and preventing geology and earthquake disaster.The study indicates that the new way is definite and proper. The 2-D section that is based on the new processing technique is reliable and in focus. The method is appropriate and suitable. Moreover the result is credible and trustable which is good consistent with other correlating data.