Abstract:The paper considers the Wenchuan and Lushan earthquakes, which occurred in the Longmenshan fault zone. Based on the cross fault leveling data of Longmenshan, Xianshuihe and Anninghe-Zemuhe fault zones, the annual deformation rate of different sites and the accumulation rate of fault vertical deformation are calculated. The analyses of the annual deformation rate and the spatial distribution of Dc contour map changes reveal the fault activity law. We ascertain the regional strain and the stress field before and after the Wenchuan earthquake, then discuss the correlation of the two earthquakes. The results show: (1) The occurrence of the Wenchuan earthquake obviously increases the fault activity in the southern tip of the Longmenshan fault zone. The average annual rate of change before the earthquake is increased by <1 mm/a, increasing to a maximum of 10.01 mm/a after the earthquake. The occurrence of Wenchuan earthquake has great impact on Tangjiaping and Xichang sites on Anninghe-Zemuhe fault zone, where the annual rate of change increases, and the activity of the fault is strengthened. (2) Before the occurrence of the Wenchuan earthquake, the northeast section of Longmenshan fault shows a high Dc value area; afterward, it gradually reduces. The occurrence of Wenchuan earthquake presents a background of stress accumulation. The spatial distribution of Dc in the Longmeshan fault zone obviously changes after the Wenchuan earthquake, accelerating the formation of a high Dc value around the site of Shuanghe site. The Lushan earthquake epicenter is located in the high value and the low value region, with a significant spatial difference.