外文翻譯--中國(guó)的地裂縫災(zāi)害-文庫(kù)吧資料
2025-05-22 08:13本頁(yè)面
【正文】 y attention to them until the tragedyTang Shan earthquake (July 28, 1976, M=) happened, when ground fissures became to severe that they were thought might be the precursor of a potential earthquake in Xi’an region (LI,et al,1986).In many other provinces of North China region, such as Hebei, Shanxi, Shandong and Jiangsu, ground fissures also occurred in this period. Since the beginning of 1980s, ground fissures have bee a very severe geological hazard in many places (XIE, 1988). The characteristics of ground fissures in China The ground fissures so called as earth fissure in USA are called tensile fissure in China. As their opposing sides move perpendicular to the plane of failure, they are also called horizontal tensile fissures. This kind of ground fissures occur since the beginning of 2 subsidence process. Usually after Harvey rein they are visual clearly. They can occur either independently or acpany with shear displacements, in the district where groundwater has been over tapped, and also in some area of extraction of oil or gas. The fissures usually are not very deep, only 5～ 30m,with the crack open at the width of 2～ 50cm on the surface of land, and the deeper the narrower. By erosion of water, the open cracks bee as 2m, monly wide enough to trap a vehicle. This kind of hazard happened for many times in Xi’an. The ground fissures so called as surface faults in USA are called shear fissures in China. There opposing sides move parallel to the plane of fracture, usually one side sinks while another rises relatively, in the same way of normal fault. Usually, preexisting faults are the foundation of this kind of ground fissures. As the fissures look like normal faults, they are also called tectonic ground fissures. However, the creeping rate(12 mm/a average in Xi’an region) is ten times larger than the normal active faults in the same area. This characteristic of ground fissures is very typical in China. The scarps are ～ and the lengths are several kilometers. The longest one () is in Xi’an, with the average scarp of the ground fissures, the heights of scarps are changing, the nearer the subside centers, the higher the scarps are. Distribution of ground fissures in China There are mainly four ground fissure zones: FenWei basin ground fissure zone, and
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