尼泊尔8.1级地震建筑物震害遥感提取与分析

Extraction and Analysis of Building Damage Caused by Nepal MS8.1 Earthquake from Remote Sensing Images

2015年4月25日尼泊尔发生的8.1级地震,造成重大人员伤亡与经济损失。在地震前、后灾区高分遥感影像分析处理基础上,结合现场实地调查,对灾区房屋建筑及其震害程度进行了遥感解译,编制了地震灾区房屋建筑震害分布图。结果分析表明:尼泊尔地震灾区影像上显示的建筑物震害分布与该区域房屋结构类型、主余震位置和区域活动构造分布密切相关。其中,房屋较为严重倒塌区域主要分布在8.1级主震和7.5级余震震中附近,但这两个区域并没有相连;居民点建筑物个别倒塌的居民地则连成一个区域。影像上显示的建筑物倒塌区域,与多数8级巨大地震比较,总体上极震区震害偏轻,但在南南西(垂直于破裂方向)上展布较宽。这一特征与引发该地震的印度与欧亚大陆板块边缘活动断裂在深部呈近似于平行地表的低角度断层面破裂引起的地震动能量在地表相对较宽而低的分布特征是一致的。

Nepal MS8.1 earthquake, occurred on April 25, 2015, has caused great catastrophic deaths, injuries and economic losses. By processing and analyzing pre- and post-earthquake high resolution remote sensing images,combined with the field survey, the building structure types and their damages were interpreted. Then the distribution map of building damage in the disaster area was compiled and analyzed. The results show that, the spatial distribution of building damage exists obvious influence of the combination of different structures such as stone, masonry and RC frame buildings, the locations of main event and strong aftershocks, as well as the distribution of active faults in the disaster area. The seriously collapsed areas are mainly located surrounding the epicenters of main event（MS8.1） and strong aftershock（MS7.5）. But these two regions are separated in space. Those residential areas with very few buildings collapsed are large enough into one region. The damage of building is generally slighter, but wider in the direction（SSW） perpendicular to the rupture fault, then the most historical large earthquakes with MS8 or greater. The characteristic is in agreement with the fact that the rupture along the low angle plan of the active fault as the boundary between the Eurasian and Asian plates, which is the basic tectonic background of the Nepal MS8.1 earthquake, is nearly parallel to the earth＇s surface and then it demonstrates a specific wider and lower distribution of the energy of seismic ground motion on earth surface.