金家梁^1,2,3,,
王盈^2,3,
袁仁茂^3,,,
杨晓燕^1,,
1. 中国科学院地理科学与资源研究所, 中国科学院陆地表层格局与模拟重点实验室, 北京 100101
2. 中国科学院大学, 北京 100049
3. 中国地震局地质研究所, 活动构造与火山重点实验室, 北京 100029

基金项目: 中国地震局地质研究所基本科研业务专项重点项目（批准号：IGCEA-1604）和地震行业科研专项项目（批准号：2015419024）共同资助


详细信息

作者简介: 金家梁, 男, 26岁, 硕士研究生, 自然地理学, E-mail:jinjl.15s@igsnrr.ac.cn

通讯作者: 袁仁茂, E-mail:yuanrenmao@ies.ac.cn; 杨晓燕, E-mail:yangxy@igsnrr.ac.cn

中图分类号: P694

收稿日期:2017-11-07
修回日期:2018-01-20
刊出日期:2018-03-30

Susceptibility analysis on factors of co-seismic landslides in the Longmenshan area based on the certainty factor method-Case study of the Wenchuan and Lushan earthquake-induced landslides

Jin Jialiang^1,2,3,,
Wang Ying^2,3,
Yuan Renmao^3,,,
Yang Xiaoyan^1,,
1. Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101
2. University of Chinese Academy of Sciences, Beijing 100049
3. Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029


More Information

Corresponding authors: Yuan Renmao,E-mail:yuanrenmao@ies.ac.cn ; Yang Xiaoyan,E-mail:yangxy@igsnrr.ac.cn

MSC: P694

--> Received Date: 07 November 2017
Revised Date: 20 January 2018
Publish Date: 30 March 2018


摘要
摘要:在我国西南地区，沿龙门山断裂带分别发生了2008年汶川M_S8.0级地震以及2013年芦山M_S7.0级地震，这两次地震均造成了严重的地表破裂，并诱发了大量的滑坡和崩塌等次生地质灾害。文章选择了位于青藏高原向四川盆地过渡的区域——以龙门山断裂带为中心的30°~34°N，102°~106°E区域作为研究区，借助GIS工具，基于确定性系数（CF）方法，选取了地震、地质构造、自然环境和人类活动4大类因子，包括烈度、震中距、岩性、断裂、高程、坡度、坡向、河流、降雨、公路共10个因子（子集），对汶川和芦山地震诱发的次生滑坡灾害进行影响因子敏感性分析，基于z值确定该区域内地震滑坡的关键因子类以及基于CF值确定各类集（子集）下各特定因子的具体地震滑坡敏感性。研究结果显示：地震因子具有最高的z值，是龙门山地区地震滑坡产生的关键影响因子，表明地震活动的强弱直接关系到斜坡的稳定性和次生滑坡灾害的面积分布。而对比烈度子集中的具体CF值表明：当烈度小于Ⅷ度时，烈度对次生滑坡发生的影响极低，区域内的主要影响因子则由地震因子转变为震中距、自然因子等其他类别的因子；其次以坡度、高程、与河流的距离为主的自然因子类别以及与断层的距离在地震滑坡过程中也有较高权重，而人类活动对研究区内坡体的稳定性也有着不可忽略的作用。本研究结果可作为该地区后续区域地震滑坡相关研究和发展规划的基础科学依据。
关键词: 确定性系数(CF)方法/
汶川与芦山地震/
地震滑坡/
影响因子/
敏感性分析

Abstract:In Southwest China, the 2008 Wenchuan M_S8.0 earthquake and the 2013 Lushan M_S7.0 earthquake occurred respectively along the Longmenshan Fault zone system, both of which produced serious surface ruptures and caused a large number of secondary geological hazards, such as landslides and collapses in a broad region with the area of over 1100 km². In this paper, the transition area from the Tibetan Plateau to Sichuan Basin is selected as the research area, which is in the region of 30°~34°N, 102°~106°E, with the Longmenshan fault system being central developed. Ten cities, such as Chengdu, Ya'an and Mianyang, and so on, are involved in the research region, covering the distribution area of all landslides induced by these two earthquakes. The study area is located at the upper stream region of the Minjiang River, Tuojiang River, Fujiang River and the Jialingjiang River, which is affected not only by the East Asian monsoon and the Indian Ocean monsoon, but also by the circulation system of the Tibetan Plateau because of the special geographical location and climatic conditions. The stratigraphic lithology of the study area is complex, mainly composed of the deposits of the Quaternary lakes and modern rivers, mudstones, shale and soft rock mass. Among them, the soft rock mass is represented by relatively broken magmatic rock mass damaged by weathering, rain water erosion and fault activity. At the same time, the active faults are developed well in the study area, such as the Yingxiu-Beichuan Fault, Huya Fault, Minjiang Fault, Pingwu-Qingchuan Fault and the Maowen Fault, and so on. According to the data supplied by the Science data Center of Resources and Environment of the Chinese Academy of Sciences(www.resdc.cn), and from the DEM data of ASTER GDEM with the resolution of 30 m, the authors classified the influence factors into four sets:seismic factor set including intensity sub-set and epicentral distance sub-set; tectonic factor set including lithology sub-set and fault sub-set; natural environmental factor set including the sub sets of elevation, slope, direction, river and rainfall; human-being activity factor set with the sub-set of distance to highway. The susceptibility of the factors for the landslides induced by the Wenchuan and Lushan earthquakes is then analyzed by using these selected factors based on the GIS tool and the certainty factor(CF)method. The principle influence factors for earthquake-induced landslide are thus determined based on the z values and CF values. Research results show that:
(1) For the Longmen Mountain area, seismic factor set is the most important for earthquake-induced landslides, indicating that seismic activity is directly related to the stability of slope and the distribution area of secondary landslide disasters. However, the influence of the seismic factor set is mainly concentrated in the region where the intensity of earthquake is over Ⅷ degree and the distance to the epicenter is less than 50 km.
(2) The distance to rivers, the slope, the elevation and the distance to faults are also the important influencing factors of the earthquake landslide. Especially when the distance to river is less than 2 km, the slope is 30°~50°, the height is from 1000 m to 3000 m and the distance to the fault is less than 10 km, these factor should be assigned the higher weight values during assessing seismic landslides.
(3) In the study area, the sensitivity of lithology to seismic landslide in the study area is very low, but it should be taken into appropriate consideration in the evaluation of earthquake-induced landslides when the main materials of slope are composed of hard rock masses such as gabbros, Triassic granites and granodiorite, and so on.
(4) Results of this paper show that human-being activities have a significant effect on earthquake-induced landslide in a certain region, especially in the zone of < 0.5 km to the road. Human-being activities are one of the important factors to change the stability of slope, the human-being activities and their environmental impact should not be ignored in the analysis and evaluation of earthquake-induced landslides.
(5) The sensitivity on seismic landslide of different factor sub-sets is different, even these factor sub-sets are in the same influence factor set. It shows that seismic landsliding is a very complicated nonlinear dynamic process. There are obvious differences between the influence factors on earthquake-induced landslides and that on rainfall-induced landslides, suggesting that it is necessary to consider the specific classification of the factors on earthquake-induced landslides according to the actual regional geological environment characteristics.
The analysis results presented in this paper also suggest that the damage and loss of earthquake-induced landslides can be effectively reduced when construction land is planned in the area being composed mainly of the soft and extremely soft rock masses with the height < 1000 m, the slope is less than 20°, the distance to river is over 2 km and the distance to fault is over 10 km. The research results are useful for selecting influence factors and assigning weight values in the model of earthquake-induced landslide evaluation.
Key words:Certainty Factor Method(CF)/
Wenchuan and Lushan earthquakes/
earthquake-induced landslide/
influence factor/
susceptibility analysis



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