基于地理信息系统和信息量模型的滑坡危险性评价——以重庆万州为例

LANDSLIDE HAZARD EVALUATION OF WANZHOU BASED ON GIS INFORMATION VALUE METHOD IN THE THREE GORGES RESERVOIR

针对滑坡危险性评价,以重庆万州滑坡地质灾害为例,采用地理信息系统技术,选取高程、地层岩性、坡向、坡度、距离河流的远近、距离道路的远近、建筑物分布和到遂宁组和沙溪庙组地层的距离等8个指标作为评价因子,利用信息量模型对万州研究区的滑坡地质灾害进行危险性评价。评价结果表明,地理信息系统和信息量模型能够很好地为滑坡灾害的危险性研究服务,可用来解决过去地质灾害危险性评价中效率低、精度差、费时、费力等问题,从而实现滑坡地质灾害的信息化和科学化。

This paper tries to assess the hazard of landslide of Wanzhou in Three Gorges Reservoir by using geographical information system（GIS） and information value method. Landslide locations were identified in the Wanzhou Region from interpretation of aerial photographs, maps of the topography and field surveys. Those data were collected and constructed into a spatial database with the help of GIS. Using the eight factors of elevation, slope gradient, slope aspect, lithology, proximity to rivers, proximity to roads, building distribution and the proximity to dividing line of Shaximiao Formation and Suining Formation, a GIS-based assessment process is made to evaluate landslide hazard with information value method. Elevation, slope gradient, slope aspect data were derived from contour map. Lithology data were extracted from the geological map. Proximities to rivers, to roads and to dividing line of Shaximiao Formation and Suining Formation were analyzed from river map, road map and geology map using buffer analysis function of GIS. Building distribution data were classified from the Landsat ETM＋ satellite image. All above data were organized into spatial database for next works. The model of information value is used to produce a map of slope instability. With the help of GIS, remote sensing and information value model, the probability of landslide occurring can be predicted. The results of the analysis were verified using the landslide location data. By the comparison between the result predicted and the actual distribution of landslide, the high consistency between them can be found. At last, some characteristics of Wanzhou landslide have been summarized.