广西东南部容县崩塌滑坡的易发性评价

Evaluation on the Susceptibility of Collapse and Landslide in Rongxian County,Southeastern Guangxi

广西东南部容县的崩塌滑坡多发频发,对该县造成了严重的威胁.目前,由于缺乏崩塌滑坡易发性分区图,区域的防灾减灾工作正面临前所未有的挑战.因此,本文的目的是在基于对崩塌滑坡综合认识的基础上,采用信息量模型和逻辑回归模型来构建崩塌滑坡的易发性分区图.结果表明:(1)容县划分为极低、低、中、高易发区,信息量模型中四个区域的面积分别为0.86%、26.82%、44.11%和28.21%,逻辑回归模型中四个区域的面积分别为9.88%、17.73%、46.36%和26.03%;(2)崩塌滑坡在具备以下特征的区域发生:人类活动强度高、坡度为25°~35°、风化土层厚度大于15 m、岩性为花岗岩、页岩和泥岩;(3)两个模型的ROC曲线下的面积分别为0.768 8和0.736 2,相应的成功率分别为76.88%、73.62%.本文所采用的两种模型均具有有效的易发性评估能力并且能够达到预期的准确性,但信息量模型计算结果的精度较逻辑回归模型的略高.

The frequent occurrence of landslide has posed a serious threat to Rongxian county,southeastern Guangxi.The regional disaster prevention work is facing unprecedented challenges due to the lack of the susceptibility map.Therefore,the purpose of this paper is to construct the susceptibility map of landslide using the information value model(IVM)and the logical regression model(LRM)based on the comprehensive understanding of landslide.The results show that:(1)Rongxian county can be divided into extremely low,low,medium and high susceptive regions,which respectively cover areas of 0.86%,26.82%,44.11%,and 28.21%in IVM,or areas of 9.88%,17.73%,46.36%and 26.03%in LRM;(2)the landslide occurs in areas with following characteristics,high intensity of human activity,slope angle of 25°~35°,weathered soil thickness of greater than 15 m,lithologic conditions of granite,shale and mudstone;(3)the areas of the receiver operating characteristics curves obtained from two models are 0.7688 and 0.7362,respectively,which represents the success rate are 76.88%and 73.62%,respectively.The models adopted in this paper can evaluate the susceptibility effectively and can reach the expected accuracy.In addition,the result accuracy of IVM is slightly higher than that of LRM.