汶川地震北川县城地质灾害调查与初步分析

Investigation and preliminary analysis of geologic disasters in Beichuan county induced by Wenchuan Earthquake

汶川8.0级地震造成了北川县巨大的破坏,导致上万人死亡,整个北川县城变为废墟。现场地震科考分析显示,造成北川县城区建筑物和道路严重损毁,以及人员重大伤亡的三个主要原因为:①强地震产生的振动破坏效应;②活断层错动产生的地表破裂效应;③地震引发的次生地质灾害(崩塌、滑坡和泥石流)。地震次生地质灾害造成了北川县城区上千人死亡、大量房屋被埋、多处路段被毁。在分析地震地质构造背景基础上,对地震引发的北川县城崩塌、滑坡和泥石流次生地质进行了现场调查,查明了地质灾害分布和发育特征,初步分析了王家岩滑坡和景家山崩塌的地震地质灾害破坏机理。

MS 8.0 Wenchuan earthquake caused Beichuan County massive destruction, and resulted in casualties more than ten thousand. The whole Beichuan County has become in ruins. Field seismic investigation showed that the three principal causes of such huge destruction are as follows ： （ 1 ） the vibration failure effect caused by macroseism vibration ; （2） the earth＇s surface rupture effect caused by seismo-active fault slippage; and （3） the secondary geological hazards（collapse, landslide and debris flow） caused by the earthquake. According to statistic data, the earthquake-induced geological disasters have caused not only about one thousand casualties but also many buildings and reads＇ ruined in the urban area of Beichuan County. Based on analyzing seismogeology tectonic background, all geological hazards caused by the earthquake were investigated in details. Not only the distribution and growth feature of geological hazards were found out, but also the mechanism of earthquake damages（Wangjiayan landslide and Jingjiashan collapse） was studied preliminarily.