Abstract:Using observation data of GPS, gravity and across fault in divergence area, we analyze crustal deformation anomaly distribution and dynamic image characteristics in Sichuan province before and after the Lushan 7.0, Ludian 6.5 and Kangding 6.3 earthquakes. The results show: 1) before the earthquakes during 2013 and 2014 in divergence area, the crustal deformation data in Sichuan province presents group mid-term and short-term precursory anomalies in different degrees, including cross fault deformation that appears as a short-term anomaly in the form of direct precursors, and that earthquakes occurred within one month from the end of the anomaly, which has instructive significance in strong earthquake occurrence time forecasting; 2) a prominent short-term anomaly point located about 200 kilometers from the epicenter, earthquake location and anomaly belong to the same tectonic system; 3) strong earthquakes occurred in the relative gravity anomaly zone and in faults which are parallel to or intersect the fault,which has cross fault secondary anomaly amplitude, which has instructive significance in strong earthquake location forecasting. These several moderate-strong earthquakes show that, during 2013 and 2014 the south-eastern drive function of the Bayan Har Block acceleratedsensitive fault activity in the divergence area; in the process of accelerating, the stress accumulation area ruptured because of the instability, which further resulted in brittle rock burst, thus releasing long-term accumulated energy in strong earthquakes.