基于地理信息系统与斜坡单元的峨边县地质灾害易发性评价

斜坡单元依据山脊线和山谷线划分的单元，能够体现研究区的真实地质环境条件，作为评价单元在地质灾害易发性评价中具有重要意义。采用地理信息系统(geographic information system, GIS),运用水文分析工具提取峨边县斜坡单元，选取归一化植被指数、坡度、高程、地形起伏度、地层岩性、距水系的距离、距断层距离、距道路的距离8个因子，使用逻辑回归模型(logistic regression, LR),制得地质灾害易发性概率图，将其划分为非易发区、低易发区、中易发区、高易发区和极高易发区。结果表明：ROC(receiver operating characteristic curve)曲线的线下面积(area under curve, AUC)精度检验值为0.917,极高易发区和高易发区内地质灾害点数占总灾害点数的81.3%,说明对峨边县进行基于斜坡单元使用逻辑回归进行地质灾害的易发性评价具有可行性和较高精度。

GIS and Slope Unit Based Geological Hazard Vulnerability Assessment in Ebian County

The slope unit is divided according to the ridge line and valley line, which can reflect the real geological environment conditions of the study area. As an evaluation unit, it is of great significance in the evaluation of geological hazard susceptibility. With the support of GIS (geographic information system), Taking hydrological analysis tools to obtain slope units in Ebian County, selecting eight factors, including normalized vegetation index, slope, elevation, topographic relief, formation lithology, distance from water system, distance from fault, distance from road, etc., and using logical regression model to obtain the probability map of geological hazard susceptibility, and divides it into non-prone area, low-prone area, medium-prone area High and extremely high risk areas. Conclusion: The accuracy test value of AUC(Area Under Curve) of the ROC (receiver operating characteristic curve) is 0.917, and the number of geological hazards in the extremely vulnerable area and the highly vulnerable area accounts for 81.3% of the total, indicating that it is feasible and highly accurate to evaluate the susceptibility of geological hazards in Ebian County based on the slope unit using logical regression.