Method for Establishing the Speed Field Model of Crustal Movement in China

In this paper,two different methods are used to establish the speed field model of crustal movement in China on the basis of 468 high precision GPS speeds by different subdivisions of plate.The method of computing Euler vector is a classical method for deformation analysis,but it is just suitable for the rigid plate.For China continent block,it is difficult to determine a plate is rigid or stretch,so the method of computing Euler vector is not the best method to establish the speed field model of crustal movement in China.Compared to the method of computing Euler vec-tor,Interpolation is irrelative to the characteristic of the plate,and it can impend over the continu-ous deformation and discontinuous deformation with freewill precision.For wide use,many interpolation methods have limitations.So the multi-quadric equations interpolation is first used to establish a large-covered and valuable speed field model of crustal movement in China.The practical results show that it is a good method for this work.By the crustal movement model established in this paper,the large-covered and valuable crustal movement images(1°×1°) are achieved.These images are more complete and detailed than previous ones.Under the background of NNR-NUVEL1A model,China continent land mass movement shows the difference between in the west and east by the borderline of 105°E,besides different movement velocity vectors in each area.In the east the trend is towards the east and southeast,while in the west the trend is moving towards the north and northeast.Generally speaking,the mainly deformation occurrs in the western part of China.The western part of Qing-Zang block moves northwestward by about 15-25 mm/a,but the eastern part of Qing-Zang block moved northeastward by about 25-35 mm/a.The western part of Xinjiang block moves northward by about 5-10 mm/a,but the eastern part of Xinjiang block moves mainly eastward by about 5 mm/a.The area in Yunnan and east Tibet shows a significant clockwise tectonic rotation.The average speed of the rotation is about 15 mm/a and the rotation center is at 28°N and 97°E.The whole movement of the western part of China is fanlike and the deformation speeds weaken from south to north.Unlike the western part of China,the deformation in the eastern part of China is relatively small and quite stable.The average deformation speed there is about 5 mm/a.The crustal movement image shows that the northward pushing by the Indian plate is still playing the dominant role in the crustal movement in the Chinese continent.Both the speed field model and the crustal movement imags presented in this paper can cause to study the dynamic movement and dynamics mechanism of China continent blocks better.