汶川地震中的地表破裂与灾害

发生在龙门山断裂带上的汶川Ms8.0级地震引起的地表破裂主要分布在北川—映秀断裂带和江油—灌县断裂带上,尤其是沿前者发育了长达240 km的地表破裂带,造成了重大的人员与财产损失。灾害发生的原因是多方面的:地震的震级大;震中所处地区构造发育,地质环境极为脆弱;人口较为密集,城镇的场地普遍狭窄,空间有限等。但是,断层的作用是决定性的,且在不同地段表现出了明显的差异性,导致了不同类型的地震灾害。对于断层的避让与设防问题考虑不足,放大了本次地震的灾害效应。

THE SURFACE RUPTURE AND DISASTER IN WENCHUAN EARTHQUAKE

The Ms8.0 Wenchuan earthquake that occurred on the Longmenshan area had produced two surface rupture faults： Beiehuan-Yingxiu fault and Jiangyou-Guanxian fault. Especially along the first fault, the earth- quake produced a 240 kin-long rupture zone, causing huge casualties and property losses. There were many rea- sons for this disaster ： the earthquake magnitude was very high, reaching Ms8.0 ; the epicenter region was in tec- tonic development, so its geological environment was very fragile; the town had a relatively dense population but a generally narrow venue and limited space. However, the role of faults was decisive, which in different loca- tions showed significant differences, leading to the emergence of different types of earthquake damages. Lack of consideration for fault avoidance and fortification amplified the disastrous effects of the earthquake.