Study The Geodynamic Driving Mechanism Of Continental Lithosphere In China By The India-Eurasia Collision

In the past fifty years, for the purpose of understanding the form and evolvement of Tibetan Plateau and their geodynamic process, many geoscientists in China and overseas have making a lot of field investigations and observations, doing many geognosy, geophysics, seismology researches, and developing some numerical computations and laboratorial researches. All of the results, especially the GPS observation data, make it possible for us to probe the geodynamic driving mechanism of continental lithosphere in China by the India-Eurasia collision.Under the restricts of the observation results of the horizon principal stress direction and the GPS data, and on the base of former researches about the lithosphere structures of Tibetan Plateau and other part of the mainland of China, we mainly study the geodynamic process and the geodynamic driving mechanism of continental lithosphere in China by plates collision.The main contents are: 1) establishing the physical model of continent lithosphere for numerical computation, 2) under the restricts of the observation result of the horizon principal stress direction and the GPS data, probing into the long term geodynamic driving mechanism of continental lithosphere in China, 3) establishing new model for computing the disturbing stress field in China, which is caused by the uneven activity of crust movement in Tibetan Plateau, 4)by using the spatial distribution of disturbing stress field to explain the strong earthquake activity relation between in Tibetan Plateau and in North China area,5) taking Xingtai strong earthquake in 1966 as example to understand the relation between the speedup activity of deep-seated fault in upper mantle and the vertical deformation on the earth's surface .In the computation model, the medium of lithosphere is treated as Maxwell medium. The physical parameters of the model accorded with the lithosphere structures, and the viscosity coefficient has an alterable range. Two different models are adopted in the paper. Model I is that the material of the upper mantle in lithosphere has lower viscosity coefficient, Model II is that the material of the upper mantle in lithosphere has higher viscosity coefficient. By comparing the different results calculated from different model and different boundary condition, we explore the connection between the intensity of plate driving force and the viscosity coefficient of model, and the characteristic of long term geodynamic driving mechanism of continental lithosphere in different layers, and the different behavior of the India-Eurasia collision and the additional forces in vertical direction which included geopotential of Tibetan Plateau landform, buoyancy of heat convection in upper mantle.The strong earthquake activity in China not only relates with the background stress field but also with the disturbing stress field. A new model for calculating this disturb is present, and the disturbing stress, caused by the speedup or quietude of crustal movement in Tibetan Plateau are given. On the base of these results calculated from the model, the geodynamics process of the strong earthquake brewing correlation between in Tibetan Plateau and in North China is discussed.The main purpose of this paper is to probe into the driving mechanism to China continent by continental collision and by geopotential of Tibetan Plateau landform from the viewpoint of geodynamics process, to present a new model to calculate the disturbing stress, and to explain the possible mechanism of crustal deformation before Large Earthquake in Xingtai in 1966. The main conclusions are as follows.1) When the horizon principal stress direction, and the velocity of crust movement calculated from the two three-dimensional Maxwell viscoelastic models are generally good agreement withresults from seismology study and geodetic in china continent and its vicinity, the intensity ratio of driving force to China continental lithosphere from India plate, pacific plate and Philippine plate is 4:1.25:1. The behaviors of the India-Eurasia coll...