汶川地震映秀镇地质条件与地表破裂特征调查

The Survey of Geological Condition and Surface Rupture Characters of Yingxiu Town in the Wenchuan Earthquake

2008年5月12日14时28分04秒,四川省汶川县发生了MS 8.0地震。根据地震部门测定,本次地震是从映秀开始破裂,震中位于四川汶川县映秀镇附近(北纬31.015°,东经103.365°)。在中国地震局组织的汶川地震科学考察成果基础上,本文分析了映秀地质条件:主要发育的地层为二叠系的石英闪长岩,震旦系的砂岩;通过研究区的主要构造为龙门山中央断裂—映秀-北川断裂;主要的地貌类型为河流地貌。调查了研究区的地表破裂特征,根据研究区的地貌类型将其划分为A、B、C三段,A段为河床沉积地貌,垂直断距最大;B段为丘陵地貌,断距中等,但诱发崩塌地质灾害;C段为河流边滩地貌,断距较小,但震害严重。

On May 12, 2008, an earthquake of magnitude 8.0 occurred in Wenchuan, Sichuan Province, China. The epicenter was located in Yingxiu Town （N 31.015° , E 103.365° ）.The paper analyses the condition of landform-geology and the characters of surface rupture, depending on the data of the Wenchuan earthquake survey. The stratum layers are black granite of Permian period and sandstone of Simian period; the fracture zone is Yingxiu-Beichuan fault, with river geomorphy. According to the types of geomorphy, we divide three-stage surface rupture. The stage A is river bed deposit and has the largest separation; the stage B is hilly geomorphy and has the middle separation; the stage C is marginal bank deposit and has the shortest separation, but there are serious damages, in this stage.