基于加权信息量模型的藏东南地区滑坡易发性评价  

Landslide Susceptibility Assessment Based on Weighted Information Value Model in Southeast Tibet

作　　者：杜国梁[1] 张永双[1,2] 吕文明 张广泽 周成灿 郭长宝[1,2] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]国土资源部新构造与地质灾害重点实验室,北京100081 [3]西藏地质环境监测总站,西藏拉萨830000 [4]中铁二院成都地勘岩土工程有限公司,四川成都610031

出　　处：《灾害学》2016年第2期226-234,共9页Journal of Catastrophology

基　　金：国家科技基础性工作专项课题(2011FY110100-2);"十二五"国家科技支撑课题(2011BAK12B09);中国地质调查局项目(12120113038000);中铁二院科研计划(二院科字201303);国家自然科学基金项目(41402321)

摘　　要：藏东南地区位于青藏高原中东部,地形和地质构造都极为复杂,是我国地质灾害发育最为严重的地区之一。在区域地质灾害调查和相关因素分析的基础上,对藏东南地区滑坡发育特征进行了分析。滑坡影响因素相关性分析结果表明：研究区内滑坡多发育于较坚硬—较软弱层状砂板岩、粉砂岩、泥岩、页岩岩组,较硬层状砂岩、灰岩岩组,松散堆积物岩组内,以及地形坡度大于45°,高程2 500~4 000 m区域内;滑坡发育密度受断裂影响大,随着断裂密度的增大,其与河流、道路距离的减小而增大。根据上述分析结果,综合选取地层岩性、坡度、坡向、地面高程、断裂密度、河流和公路7个因素作为评价因子,采用基于GIS的加权信息量评价模型对研究区滑坡易发性进行评价,并将研究区划分为极高易发、高易发、中易发、低易发和不易发等五个等级,通过成功率曲线（AUC）方法检验,评价结果具有较高的准确性。其中,极高易发区主要沿嘉黎断裂、怒江断裂和澜沧江断裂等区域大型活动断裂带和主干河流两侧分布;高易发区主要分布在主干河流两侧极高易发区边界向两侧扩展的区域;中易发区主要位于大江、大河及深切峡谷的支流两岸,及断裂密度相对较大的区域;低易发区主要在水系发育程度较低、断裂密度较小的区域分布;不易发区主要分布在断裂不发育、人类工程活动微弱的高山地带以及地形相对平缓的区域。此评价结果对藏东南地区滑坡发育特征和重大滑坡灾害防治规划具有重要的指导作用。Southeast Tibet located in the east-central Tibetan plateau where the topography and geological structures is complex. The region is one of the areas seriously suffered from landslide disasters in China. Based on the geological disaster investigation and the correlative factors analysis,it is concluded that landslides generally occur at soft-hard layer of sandy slate,phyllite,mudstone,slate; hard layer of sandstone,limestone and loose sediments. The areas which slope gradient slope are greater than 45° and the elevation range from 2500 m to 4000 m also occur landslides frequently. And the landslides density is greatly influenced by fault. With the increase of fault density and decrease of distance to drainages and roads,the landslide occurrence is increasing. According to above analysis,seven typical factors are selected as evaluation factors including the formation lithology,slope,slope direction,elevation,fracture densities,drainages and roads. The evaluation model based on weighted information value is established to analyze landslide susceptibility in Southeast Tibet. The resulting susceptibility map showed five classes of landslide susceptibility,i. e. extremely high,high,moderate,low,stability. The extremely high grade areas are mainly distributed along the both side of active faults and major rivers. The high grade areas expand along the both side of extremely high grade areas border. The moderate grade areas are mostly along the tributaries of the great rivers and deep-cutting valleys,as well as the areas with relatively high fracture densities. The low grade areas have relatively low fracture densities,and there are no great rivers pass through. The stability areas areprimarilydistribute in the areas where islack of faults and high mountain areas where human engineering activity is weak,as well as areas where is relatively flat. By examination,the evaluation result has high accuracy. It provides a reference forlearning the development characters of the landslideand disaster prevention plan in southeast

关 键 词：藏东南 GIS 加权信息量法 滑坡 易发性 

分 类 号：P649[天文地球—地质矿产勘探] X43[天文地球—地质学]