The Contemporary Tectonic Strain Rate Field of Continental China Predicted from GPS Measurements and its Geodynamic Implications

Abstract

In Appling studies, the strain rate in China has been computed from using different methods, resulting in quite different estimates of the strain rate the geo-statistics from GPS velocity field of Chinese continent, we obtain the velocity value at each little regularly spaced grid point, by kriging interpolation and the component of strain rate for each volume element, using a method similar to the derivation of shape functions in the finite element algorithm. Therefore the distribution of the strain rate field in whole for the Chinese continent is presented. The result shows that the orientations of principal strain rates are consistent with those of the P and T axes of focal mechanisms. The distribution of maximum shear strain rate clearly delineates some major active fault zones surrounding the Tibetan Plateau. The maximum shear strain rate is comparable with that obtained from analysis of seismic moment release. In part of the Tibetan Plateau containing normal faults and pull-apart grabens, we obtain an extensional state of strain. The absolute value of the strain rate in West China is approximately 5 times larger than that of East China, and the pattern of the strain rate field in most of the Chinese continent is controlled by the India/Eurasia collision.