Abstract:

The Mw7.8 Kunlun earthquake of 14 November, 2001, in the northern Tibetan Plateau of China, is the largest event in the Chinese continent in the latest 50 years. In this paper, layered viscoelastic models are calculated by PSGRN/PSCMP code; and the results are used to fit post-seismic deformation obtained from four GPS stations of CEA across the earthquake fault. The results show that model of a single anelastic layer of 10 km thick upper crust overlying an elastic lower crust cannot explain the amplitude of deformation; the relaxation model of 30 km elastic upper crust overriding 40 km ductile lower crust can explain the main features of exponential attenuation of post-seismic deformation. Combination of the two models, however, can fit the character better with deformation rate being higher in the first few weeks and slower rate thereafter. The viscous layer of lower crust provide the main control of the post-seismic deformation of long term decay of deformation in months, while the upper anelastic layer may contribute to the high rate of initial few weeks after the main earthquake. The result also suggests that rheological differences exist at two sides of the Kunlun Mountains fault.

Key words: post-seismic deformation, viscosity rheological model, anelasticity standard line solid, maxwell body