中文摘要：

2008年5月12日汶川8.0级地震在北川县城造成了巨大的破坏,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：活断层错动产生的地表破裂效应,地震引发的次生地质灾害（崩塌、滑坡）和强地震动产生的振动破坏效应。北川县城主断裂和次级断裂沿线分布的建筑物震害较重,而邻近断裂的建筑物震害相对较轻;地震触发的王家岩滑坡和景家山崩塌对北川县城造成了极大的破坏,导致2000余人死亡;而振动破坏效应在北川县城普遍存在,它产生的水平剪切运动对建筑物的危害很严重。

英文摘要：

MS 8.0 Wenchuan earthquake on May 12,2008 caused Beichuan county massive damage,and resulted in more than ten thousands deaths.The whole Beichuan county town has become ruin.Based on the field seismic investigation,three principal causes of building and road＇s serious damage as well as personnel heavy casualties are given：the ground surface rupture effect caused by seismo-active fault movement,the secondary geological hazards （collapse and landslide） and the vibration failure effect caused by strong ground motion.Damage of buildings along the main fault and secondary faults were more serious,but destruction in adjacent buildings is relatively not severe.The Wangjiayan landslide and Jingjiashan collapse brought about huge damage to the Beichuan county town and led to more than 2000 people death.The effects of vibration failure were ubiquitous for all buildings,especially horizontal shear movement generated serious constructional damage.