2015年尼泊尔M_s8.1地震震害分布与地质构造关系研究

Study on the relationship between the earthquake damage distribution and geological structure of the 2015 M_s8.1 Nepal earthquake

2015年4月25日尼泊尔廓尔喀县发生了Ms8.1地震,震源机制解表明为低角度逆冲型地震,造成了大量建筑物倒塌与滑坡等次生灾害发生。现场震害调查结果显示震区建筑物主要分为自建框架结构、砖混结构、砖木结构和片石结构等4种类型。地震烈度圈形状呈芒果形,长轴走向NWW向,出现两个宏观震中,最高烈度达Ⅸ度。基于高分影像解译出的589组地震滑坡点密集成带,与地形地貌、地震烈度以及余震特征较为一致,主要分布在高喜马拉雅与低喜马拉雅交界区域,基本沿主中央逆冲断裂(MCT)展布,地势落差大。地震滑坡统计结果显示震区坡度30-50°、坡向150-180°范围内山区是滑坡灾害最敏感的区域。

An earthquake of M s8.1 occurred on 25 April,2015 in Nepal Himalaya,with a focal mechanism of low-angle thrust.This earthquake caused the collapse of a large number of buildings and landslides.According to the investigation,types of buildings investigated include reinforced concrete frame structures,brick concrete structure,brick-wood structures and rubble structures.Long axis direction of intensity circle is in the direction of NWW and the max intensity isⅨand there appeared 2 macroscopic epicenters.About 589 landslides from the High-resolution Remote Sensing Image interpretation are distributed intensively in a strip,which is similar to topography,intensity and aftershock distribution and mainly distributed in the boundary area between Greater Himalaya and Lesser Himalaya nearly along the Main Central Thrust(MCT).Statistical data of slope gradient and aspect reveal that the areas where the gradient is from 30 to 50°and aspect from 150 to 180°are most sensitive to landslide.