汶川地震房屋倒塌的遥感监测与分析

地震灾害中房屋倒塌受害程度表征了地震作用下地面运动的强度大小以及地震灾害造成的人员经济损失状况。2008-05-12汶川大地震震级高达八级,最大烈度接近极限达11(Ⅺ)度,波及区域范围广,造成大面积房屋倒塌。利用航空高分辨率光学遥感图像,基于房屋倒塌的图像目视判读及插值方法获取了大面积受灾区房屋倒塌灾情信息,结合灾区地震烈度和地震地表破裂带相关数据对房屋倒塌受害程度的空间变化特征进行了分析与评价。判明在汶川地震灾区房屋普遍受害,其中以汶川县房屋倒塌受害最重,其次是绵竹市、什邡市、彭州市。房倒率与地震烈度成线性对应关系,房屋倒塌严重区沿龙门山断裂呈西南-东北向分布。

Assessment and analysis of collapsing houses by aerial images in the Wenchuan earthquake

Information of houses collapsed by the earthquake is one of the important indicators to assess the earthquake damage intensity, and support the emergency decision-making process in rescue and recovery operations. We monitored the house collapse ratio and its spatial variation in the 5.12 Wenchuan earthquake by airborne images, and analyzed its spatial variation relationship with the earthquake intensity, geological structure, stratum lithology and surface rupture caused by the earthquake. The house collapse ratio was derived by visually interpreting ADS40 airborne images acquired from May 15 to May 28, 2008. The results show that the houses were widely damaged in the earthquake-damaged region, especially in Wenchuan County, Mianzhu City, Shifang City, and Pengzhou City and Wenchuan County which experienced the severest damage. We analyzed the spatial variation of the house collapse ratio and its relationship with earthquake intensity, geological structure, stratum lithology and surface rupture caused by earthquake. The results demonstrate that the house collapse ratio and the earthquake intensity have positive relationship, and the ratio of house collapse is controlled by the geological structure, stratum lithology, and building structure too. The house collapse ratios, which are above 50%, mainly distributed along the surface rupture in a SW to NE direction.