基于贡献率模型的南宁地质灾害危险性分析

Hazard Assessment of Geological Disaster in Nanning City Based on Factor Contribution Rate Mode

摘要: 以南宁市主要地质灾害为研究对象，选取地层岩性、坡度、高程、坡向、植被覆盖指数NDVI和土地利用6大因子，构建地质灾害危险性评价指标体系，利用贡献率模型确定各因子的自权重和互权重，并建立地质灾害危险性综合评价模型。基于GIS平台，精细获取各指标分析数据，计算得到各网格地质灾害危险性综合指数值，并根据该值对地质灾害进行危险性分析。结果表明：南宁市地质灾害危险性综合指数值分布在1.18368~19.8259之间；根据该值将南宁市地质灾害危险性划分为5个分区：安全区、低危险区、中危险区、较高危险区和高危险区。高度危险区主要分布在南宁市中部，人类活动较强烈，面积约为5274.189 km²，占全市总面积6.84%；较高危险区主要在南宁市南部、东南部地区，面积约为9859.604 km²，占总面积的12.79%；中危险区主要分布在南宁市西南部、北部地区，面积约为12358.724 km²，占总面积的16.04%；低危险区主要分布在南宁市东部，面积约为16198.205 km²，占总面积的21.02%；安全区面积较大，约为33379.713 km²，占全市总面积的43.31%。研究成果可以为南宁市地质灾害防灾减灾提供依据，对于减轻和预防地质灾害具有重要意义。

Abstract: Taking geological disasters in Nanning as a case study, 6 factors including geological lithology, slope, elevation, aspect, NDVI and land use are selected to construct the index system of geological hazard zoning. The factor contribution rate model is used to calculate the self-weight and inter- weigh of each factors, and the geological disaster risk evaluation model is established finally. Based on GIS platform, after obtaining each indicator analysis data, the comprehensive indexes for geological disaster risk zonings in each grid are calculated, and then the risk zonings of geological disaster in Nanning are divided into different zones according to calculated indexes. The results show that the comprehensive indexes of geological disaster risk zonings range from 1.18368 to 19.8259, and the risk zonings of geological disaster in Nanning can be divided into five: safety area, low dangerous area, moderate dangerous area, high dangerous area and extremely high dangerous area. The extremely high dangerous area is mainly distributed in the central of Nanning, human activity is relatively strong, and the area is 5274.189 km² accounting for 6.84% of the total. The high dangerous area is mainly distributed in the south and south-east of Nanning and the area is 9859.604 km² accounting for 12.79% of the total area. The moderate dangerous area is mainly distributed in the southwest and north of Nanning and the area is 12358.724 km², accounting for 16.04% of the total area. The low dangerous area is mainly distributed in the east of Nanning and the area is 16198.205 km², accounting for 21.02% of the total. The safety area is large and the area is about 33379.713 km², accounting for 43.31% of the total area. Research results can provide the basis for geological disaster prevention and mitigation of Nanning, which is of great significance for reducing and preventing geological disasters.