Spatial distribution analysis of landslides triggered by 2008.5.12 Wenchuan Earthquake, China
Spatial distribution analysis of landslides triggered by 2008.5.12 Wenchuan Earthquake, China
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2008年5月12日汶川地震引发滑坡空间分布分析
DOI：
10.1016/j.enggeo.2010.07.011
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发表时间：
2010-10-27
影响因子：
7.4
通讯作者：
Liu, Jianyou
中科院分区：
文献类型：
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作者：
Qi, Shengwen;Xu, Qiang;Liu, Jianyou
2008年5月12日汶川大地震（美国地质调查局的地震震级为M-w7. 9）引发了大量的滑坡。利用遥感数据建立了地震重灾区11个县（市）面积约31686.12km2的滑坡灾害空间数据库。详细绘制了研究区的地质背景图，包括地质构造和岩性。提出了研究区域的数字高程模型（OEM），分辨率为30 m x 30 m，以解决地形特征。利用GIS空间建模技术，结合野外调查资料，分析了滑坡的发生与地质背景（活动断层（同震地表破裂）、地质单元、坡度、坡高、坡向）的关系。结果表明，距发震断层的距离和坡度是影响地震活动的重要因素。滑坡沿F2、F3断层呈沿着分布，且随距断层距离的增加，滑坡发生率显著降低。在F1活动断裂附近，滑坡发生率明显增加。滑坡密度（LC，losses/km（2））随坡度呈明显的指数增长。但LC与地质单元和斜坡高程没有明显关系：各地质单元（各斜坡高程类别）LC值的差异可能是受各地质单元（各斜坡高程类别）坡度和各地质单元（各斜坡高程类别）距成因断裂带距离影响的结果。等震线图在一定程度上反映了滑坡的发生率，随着烈度的增加，滑坡的LC值急剧增加，几乎所有的滑坡都发生在VI度以上的区域，统计结果还表明，在发震断层附近，滑坡的初始滑动方向往往与发震断层的运动方向相似。初步研究表明，不同结构类型边坡的滑坡发生率不同，顺层边坡和逆层边坡的滑坡发生率较高。(C)2010爱思唯尔有限公司版权所有。
The 2008.5.12 Wenchuan Earthquake (seismic magnitude M-w 7.9 according to the USGS) triggered a great number of landslides. A spatial database of landslides is built by interpreting the remote sensing (RS) data which covers 11 counties severely damaged by the earthquake with area of about 31,686.12 km(2). The geological settings of the study area are detailed mapped including geologic structure and lithology. The digital elevation model (OEM) of the study area with resolution of 30 m x 30 m is presented to address the topographic characteristics. Correlations between the occurrence of landslides with geological settings i.e. active faults (the coseismic surface ruptures), geological unit, slope gradient, slope elevation as well as slope aspect are analyzed using spatial modeling in GIS with the aids of field investigations. It can be concluded that the distance to the causative faults and slope gradient are much more important than other factors. Landslides are clustered distributed along the causative faults of F2 and F3, and landslides incidence are dramatically decreasing with the increasing of the distance to the causative faults. The landslides incidence has an obvious increase near the active faults i.e. F1. Landslide concentration (LC, landslides/km(2)) has an obvious exponent increase with slope gradient. However, LC has no obvious relationship with geological unit and slope elevation: the difference of LC value in each geological unit (each slope elevation category) maybe have been the result affected by slope gradient for each geological unit (each slope elevation category) and distance of each geological unit (each slope elevation category) to causative fault zone. Isoseismal map reflects the incidence of landslides in some degree, and LC increases dramatically with Intensity increasing, almost all landslides occurred in the region above VI degree.Statistics result also indicates that in the near field of causative faults, landslides tend to have the initial sliding direction similar to the movement of the causative faults. And preliminary study shows that landslides incidence varies in different slopes with different structure, and consequent slopes and obsequent slopes have a higher landslides incidence than other layered slopes. (C) 2010 Elsevier B.V. All rights reserved.