论文部分内容阅读
通过汶川地震震区大量的实地考察已证实沿着早先活动断裂主要发育了两条地表破裂带:一条是沿着映秀-北川断裂产生的逆冲伴随右旋走滑破裂带,长275km,最大垂直位移达11m,水平位移达12m;另一条纯逆冲性质的破裂带,沿着灌县-安县断裂发育,最大垂直位移达4m。活动断裂之上的地表破裂带是野外工作中确定地震断裂性质的重要现象。另外,在活动断裂相邻区域和远离区域的路面以及建筑体还大量存在变形现象。通常沿活动断裂产生的地表破裂是典型的同震破裂,相邻区域的地表路面及建筑体发育的变形属于次生变形,远离区域发育的变形则属于震后变形。对次生变形和震后变形测量数据的应用容易影响活动断裂特征的确定和性质的判断,因为路面等建筑体上的挤压拱起、叠置以及水平错断等现象多是受到地震过程中通过断裂活动突然释放的巨大能量作用在局部地表建筑体产生的变形。但是,分布广泛的挤压现象暗示了区域上挤压应力场环境,有利于地表同震破裂位置的推测及地震断裂性质的判断。
A large number of field trips through the Wenchuan earthquake have confirmed that two major surface rupture zones have been developed along the previous active faults: one is a thrust strike along the Yingxiu-Beichuan fault accompanied by a dextral strike-slip rupture zone of 275 km long and vertical maximum Displacement up to 11m, the horizontal displacement of 12m; another purely thrust nature of the rupture zone, along the Guanxian - An County fault development, the maximum vertical displacement of 4m. Surface rupture zones above active faults are an important phenomenon in determining the nature of seismic fractures in field work. In addition, there are also a large number of deformations in pavements and buildings that are adjacent to and away from active faults. The surface rupture usually occurs along the active faults is a typical coseismic rupture. The deformation of the surface pavement and the building body in the adjacent area belongs to the secondary deformation, and the deformation away from the area belongs to the post-earthquake deformation. The application of secondary deformation and post-earthquake deformation measurement data will easily affect the determination of the characteristics of active faults and the judgment of their nature. The phenomena such as extrusion arching, stacking and horizontal fault on pavement and other buildings are mostly affected by the earthquakes Through the sudden release of the breaking activity of the huge energy effect in the local surface deformation of the building body. However, the widespread extrusion phenomenon implies that the compressive stress field in the area is favorable for the prediction of the location of the surface coseismic rupture and the judgment of the nature of the earthquake fracture.