芦山7.0级地震和康定6.3级地震是近两年来在龙门山断裂带和鲜水河断裂带上发生的最为显著的两次地震事件,都发生在巴颜喀拉地块与四川盆地的挤压构造带边缘。利用芦山科学考察项目和中国地球物理场观测——青藏高原东缘地区项目中获得的水准资料,研究芦山地震震前、震中和震后垂直形变演化和康定地震震前垂直形变特征。结果 表明:芦山地震前龙门山断裂带南段的小金相对于芦山地区上升速率约为1.7 mm/a,同震垂直变形可以达到197.7 mm,变形最大区域分布在芦山灌县—安县断裂附近; 芦山地震后鲜水河断裂带色拉哈段两侧垂直形变迅速增加至13 mm/a,之后发生康定地震。1982年以来,鲜水河断裂带和龙门山断裂带Y字型交汇区域保持着4.5 mm/a的快速隆升,同时在都江堰和大邑一带存在一条垂直形变高梯度带。
The Lushan M7.0 and Kangding M6.3 earthquakes which occurred on the edge of compressed structural zone of Bayanharshan block and Sichuan Basin carat were two most significant seismic events in the Longmenshan Fault Zone and the Xianshuihe Fault Zone for the past two years. Using leveling data obtained by Lushan Scientific Investigation Project and China Geophysical Field Observation-the eastern Qinghai Tibet Plateau Project, we researched the vertical deformation evolution characteristics before, in and after Lushan earthquake and before Kangding earthquake. The results showed that before Lushan earthquake, the rising velocity of vertical deformation was about 1.7 mm/a in Xiaojin which located at the south segment of the Longmenshan Fault relative to the Lushan region. The coseismic vertical deformation could reach 197.7 mm, and the maximum deformation region located around Guanxian-Anxian Fault in Lushan. The vertical deformation on both sides of Salad segment in Xianshuihe Fault Zone rapidly increased to 13 mm/a after the Lushan earthquake, then the Kangding earthquake occurred. The intersection region of Y-shaped between the Xianshuihe Fault Zone and the Longmenshan Fault Zone uplifted rapidly for 4.5 mm/a since 1982. There also exited the vertical deformation gradient zone in the area of Dujiangyan and Dayi.
