基于RS和GIS技术的清江隔河岩库区滑坡易发性评价与制图

ETM+ imagery and GIS-based landslide susceptibility mapping for the regional area of Geheyan reservoir on the Qingjiang River,Hubei Province,China

为了探索滑坡空间定量评价与制图技术和方法,文中利用RS与GIS技术相结合,以鄂西清江流域隔河岩水库库区为例,在滑坡调查编录和数据库建设的基础上,利用DEM数据提取地形地貌和水文因素,利用ETM+多光谱影像获取植被指数(NDVI)和地表湿度指数(NDWI),利用DEM、矢量数据、工程地质图及典型滑坡调查分析相结合,确定斜坡结构类型、工程地质岩组、库岸再造范围等滑坡因素的定量化指标。通过这些因素与滑坡的相关性统计分析,采用基于GIS空间分析的信息量计算因素的权重,利用GIS的空间分析功能实现清江隔河岩库区滑坡易发性分区制图。结果显示:高易发区占15.65%,主要分布在清江干流及其一级支流两侧,包含已知滑坡的73.17%;中易发区占41.54%,包含已知滑坡的17.81%,低易发区占42.81%,包含已知滑坡的9.02%。

For developing quantitative approaches and methodologies for landslide susceptibility assessment and mapping, RS and GIS were applied as the main tools, and the regional area of Geheyan reservoir on the Qingjiang River in the eastern Hubei Province was selected as the ease study area. Based on the landslide inventory database, we use DEM data to extract topographic, geomorphologic and hydrological factors; use the Landsat7 ETM＋ satellite image to extract land-cover indices like NDVI, NDSI, etc. ; and use DEM, feature dataset, lithological map and typical landside investigation and analysis to generate landslide diagnostic factors like the slope topographic/bedding relation-ship indices, the engineering geological indices, the range of bank ruin of reservoir, etc. Further, we carry out the statistical analysis of the relationship between the landslide spatial distribution and the diagnostic factors, in which we employ the integrated information model, use entropy calculation to determine the weight of each factor and use the spatial analysis function of GIS. Based on the statistical analysis, we bring about the landslide susceptibility zonation of the Geheyan reservoir area of the Qingjiang River. According to the landslide susceptibility, the area is divided into three classes： the high class covers 15.65%, which contains 73. 17% of known landslides; the moderate class covers 41.54%, which contains 17. 81% of known landslides; whereas the low class covers 42. 81% and only 9. 02% of known landslides in this area.