Abstract On the basis of the GPS observations during 10 years, the variations of the baselines between adjacent GPS continuous sites in the QinghaiTibet block and the surrounding areas are calculated, and then the activities of largescale crustal blocks and tectonic zones are studied on the basis of obtained tendency and nonlinear variations. The NW ward baseline in the western part of the QinghaiTibet block shows a variation of extension and the crust displays a tensile change in the direction.The NE ward baseline in the eastern part shows a large convergent velocity, indicating that the crust contracts intensively in the direction. Before the West Kunlunshan mountain M8.1 earthquake and the Wenchuan M8.0 earthquake, the baselines showed obviously anomalous variations during a period of several months to more than a year, which reflects that the occurrence of large earthquake with shallow focus is associated with the intensification of largearea tectonic movement.
