GPS Measurements and Tectonics Activity Simulation of Present-day Crustal Deformation in China's Capital Region

An accurate crustal deformation field is derived from repeat surveys of 280 GPS stations during 1992-2004 in China's capital region.It shows that the horizontal rate relative to stable Euro-Asia plate ranges from 4 mm/a in the north to 9 mm/a in the south.Boundary element method(BEM) and displacement discontinuity method(DDM) are used to establish a 3D faults construction of the capital region.The faults slip is calculated and the displacement of GPS sites is simulated in a linear-elastic,homogeneous and isotropic half-space.Consequently,the quasi-static displacement,strain and stress fields of main active fault surfaces and profiles in earth's surface,15 km and 25 km underground in capital region are computed.The results indicate that the difference of GPS measurements and simulations is 0.68 mm and 0.77 mm along NS and EW,respectively.The tectonics activities of main faults are weaker during 1992-2004.The profile strain is proportional to the depth underground.