GPS DATA INVERSION OF KINEMATIC MODEL OF MAIN FAULTS IN YUNNAN

On the basis of GPS observations in Yunnan from 1999 to 2001, we adopt the robust Bayesian least square estimation and multi fault dislocation model to analyze the quantitative kinematics models of the main faults in Yunnan. The geodetic inversion suggests that: (1) The horizontal movement of crust in Yunnan is affected distinctly by fault activity whose characters are consistent with geological results; (2) The activity of the north segment of the Red River fault zone is maximum, in the middle segment is moderate, and in the south segment is minimum; (3)Among others, the Xiaojiang fault zone has the strongest activity, the secondary are the Lancang fault zone and the north segment of Nujiang fault zone, the Qujiang fault zone shows the characteristic of hinge fault; (4)Each fault could produce an earthquake of M s=6 more or less per year; (5) The larger value of maximum shear strain are mostly located along the main active fault zones and their intersections; earthquakes did not occur at the place of maximum shear strain, and mostly take place at the higher gradient zones, especially at its corner.