蓝田县滑坡灾害易发性区划与评价

Zoning andevaluation of landslide hazardsusceptibility in Lantian county

为了减少滑坡等地质灾害造成的人员伤亡和财产损失,对滑坡灾害易发性进行区划与评价。采用频率比法和加权信息量法,以地处秦岭北麓关中平原东南部的蓝田县为研究对象,选取高程、坡度、坡向、平面曲率、植被指数、地层岩性、距道路距离及距断层距离等作为滑坡的评价因子,并通过受试者工作特征(Receiver Operating Characteristic, ROC)曲线和密度法对上述两种方法的评价结果进行分析。结果表明,加权信息量法的评价结果优于频率比法,蓝田县的滑坡主要分布在高程500~1 000 m,坡度10°~20°,偏南坡向,曲率在-2~2范围内白鹿黄土塬沿边坡地和骊山黄土丘陵地区。随着归一化植被指数的增大和距断层距离减小,滑坡灾害的数量逐渐增多,滑坡中高易发区主要分布在西北部人为活动密集的地区。

In order to reduce casualties and property losses caused by geological disasters such as landslides,it is necessary to zone and evaluate the susceptibility of landslide disasters.Taking Lantian county,which is located in the southeast of Guanzhong Plain at the northern foot of Qinling Mountains,as the research object,the frequency ratio method and the weighted information method are adopted.The elevation,slope,aspect,plane curvature,vegetation index,stratum lithology,distances from the road and the fault are selected as the evaluation factors of landslide,and the evaluation results of the above two methods are analyzed by the receiver operating characteristic(ROC)curve and the density method.The results show that the evaluation result of the weighted information method is better than that of the frequency ratio method.Landslides in Lantian county are mainly distributed in the slope along the Bailu Loess plateau and the loess hilly area of Lishan mountain,with an elevation of 500~1000 m,a slope of 10°~20°,a southerly slope direction and a curvature of-2~2.With the increase of normalized vegetation index and the decrease of the distance from the fault,the number of landslide disasters gradually increases,and the middle and high landslide-prone areas are mainly distributed in areas with dense human activities in the northwest.