关键词: 活断层, 地壳变形, 速度场, 双三次样条函数

Abstract: Active tectonics is the important manifestation of the present crustal deformation. The data of the major active faults in China and its adjacent regions were collected and sorted according to their scale and significance. Furthermore, the faults were classified roughly on the basis of available quantitative data of active faults. Based on these data, the strain rate field of the crustal deformation and the distribution of horizontal velocity field in China’s continent were modeled by using Haines’ method. The results of modeling were obtained on the assumption that the crustal deformation in China’s continent is continuous deformation. The results of the modeling accord very well with those obtained from GPS observation. In addition, the variation of motion vectors in every block of China’s continent was analyzed on the basis of the modeling result. The effects of the secondary faults on the crustal deformation in this region were estimated quantitatively by comparing with the results of GPS observation. From the afore-mentioned results, some important conclusions can be drawn as follows: (1) crustal deformations are mostly absorbed by the major faults, and only about 10% of the deformation is absorbed by the secondary faults; (2) crustal deformation in west China is much stronger than that in east China. The geodynamics of crustal deformation in east and west China is quite different. The collision between the Indian and Eurasian plates is the dominating cause of crustal deformation in west China; (3) crustal deformation in China is characterized as block movement. The active block boundaries and the major faults are the place where the velocity vector changes significantly; (4) a small-angle clockwise rotation of the deformation vector occurs in South China, which is the result of the combined action of the Philippines and Pacific plates.

Key words: active fault, crustal deformation, velocity field, bi-cubic spline method