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2008年汶川MS8.0地震在北川-映秀断裂产生了长达240km的同震地表破裂。通过详细的测量、基于测量标志与断裂变形的几何关系对数据的分析,给出了观测点的断裂同震地表变形的垂直位移、倾向水平缩短、走向滑动、断层上盘水平运动方向等参数。结果显示,断裂同震变形分布的空间变化很大,目前获得的最大水平位移位于虹口乡深溪沟,为4.98m,同时也是最大右旋走滑位移点,走滑量4.5m,而目前获得的最大垂直位移在其东北的支沟,为5.7~6.7m。NE向断裂水平位移多为1~2m,垂直位移多为3m左右,而小鱼洞-草坝分支断裂水平位移和垂直位移都更小,只有0.5~1.5m。擂鼓镇附近的数据则反映与断裂相关的巨型滑坡可能将重力变形叠加到构造变形中。由断层水平缩短和垂直位移计算的断层倾角表明,北川-映秀断裂是浅部陡倾的具有走滑分量的逆断层。
The Wenchuan MS8.0 earthquake in 2008 produced a 240 km coseismic surface rupture at the Beichuan - Yingxiu fault. Based on the detailed measurements, the parameters such as the vertical displacements, the dip of dip, the strike slip and the horizontal motion of the upper plate of the fault are given based on the data analysis of the geometrical relationship between the measured flag and the fracture. The results show that the spatial variation of the distribution of the coseismic deformation is very large. The maximum horizontal displacement currently obtained is located at Shaxitou of Hongkou Township, which is 4.98m and is also the site of maximum right-lateral strike-slip strike and the amount of strike-slip of 4.5m. However, The maximum vertical displacement in its northeast branch trench, 5.7 ~ 6.7m. The horizontal displacement of NE fracture is mostly 1 ~ 2m and the vertical displacement is about 3m, while the horizontal displacement and vertical displacement of the small fish cave-grass dam branch are both smaller, only 0.5 ~ 1.5m. The data near Leigu town reflect that the giant landslide associated with the fault may superimpose the deformation of gravity into the tectonic deformation. The fault dip calculated from the horizontal fault shortening and vertical displacement shows that the Beichuan-Yingxiu fault is a steep shallow fault with a strike-slip component.