基于GIS的华宁县滑坡灾害影响因子分析及易发性评价

GIS-Based Analysis on Impact Factors and Susceptibility Evaluation of Landslide Hazard in Huaning County

为了明析区域滑坡灾害影响因子及其易发性,为滑坡地质灾害的防治提供借鉴。以云南省华宁县为研究对象,利用GIS空间分析技术,对华宁县滑坡空间分布及诱发因子进行了分析研究,依据区域地质灾害详细调查资料,建立GIS灾害数据库的同时选取海拔、坡度、坡向、距水系、道路、断层距离、岩性7个诱发因子,利用统计指数对滑坡在每个因子各类别中的占比进行了权重分析,最终确定滑坡灾害易发性分区并阐述其空间分布特征。结果表明:(1)在滑坡灾害分布特征上,具有空间集中分布特征,灾害点密度以中部地区最大,受灾影响人数最大的主要分布在海拔较低的宁州街道和通红甸乡。(2)从诱发因子上看,滑坡灾害大多分布在海拔1 600~2 300 m(占76.06%),坡度10°~30°(占71.83%),坡向为E,NE,NW,N等方向上(占71.82%),距离河流、断层和道路越近,发生滑坡的可能性越大。(3)在滑坡灾害易发性上,高易发区主要分布在宁州街道、青龙镇、华溪镇;中易发区主要分布在青龙镇东北部、宁州街道西南部、通红甸彝族苗族乡中部和盘溪东部;低易发区主要分布在通红甸彝族苗族乡、盘溪镇。华宁县滑坡灾害呈现出东少西多,南少北多的特征,未来华宁县应重点关注中部和西部区域的滑坡灾害预防。

The aim of this study is to analyze the impact factors and susceptibility of regional landslide hazards,provide the reference for the prevention and control of landslide hazards.Taking Huaning County of Yunnan Province as the research object,we used a spatial analysis technology of geographic information system(GIS)to analyze and study the spatial distribution and inducing factors of landslides.According to the detailed investigation data of geological hazards,the GIS disaster database was established,and seven inducing factors,such as elevation,slope,slope direction,distance from water system,road,fault and lithology,were selected at the same time.The statistical index was used to analyze the proportion of landslides in each category of each factor,and the landslide susceptibility zone and elaborates its spatial distribution characteristics were finally determined.The results show that:(1)in terms of the distribution characteristics of landslide hazards,in space,the landslide hazards have the centralized distribution characteristics,the density of disaster points is the largest in the central region,and the largest number of people affected by landslide hazards mainly distribute in Ningzhou streets and Tonghongdian Township at lower altitudes;(2)from the point of view of inducing factors,most of the landslide disasters are located at the elevations of 1 600~2 300 m(accounting for 76.06%),slope of 10°~30°(accounting for 71.83%),slope direction of east,northeast,northwest,north(accounting for 71.82%);the closer to rivers faults and roads is,the greater the possibility of landslide occurrence is;(3)for the susceptibility of landslide disasters,the high susceptibility areas mainly distribute in Ningzhou Street,Qinglong Town and Huaxi Town;the middle susceptibility areas mainly distribute in the northeast of Qinglong Town,the southwest of Ningzhou Street,the central part of Tonghongdian Yi Miao Township and the eastern part of Panxi;the low susceptibility areas mainly distribute in Tonghongdian Yi Miao Township and Panxi Town.The results indicate that the landslide disasters are characterized as fewer occurrences in the east,more occurrences in the west,fewer occurrences in the South and more occurrences in the north.In the future,prevention of landslide disasters should be focused on the central and western regions of Huaning County.