Loess landslide susceptibility evaluation based on slope unit and information value method in Baota District, Yan’an

Susceptibility evaluation of landslide has important significance for landslide hazard prevention and management. In this paper, the authors tried to assess the susceptibility of loess landslide in Baota District of Yan’an by using slope unit and information value method. Landslide locations were identified in Baota District from maps of topography and field survey. These data were collected to construct a spatial database with the help of ArcGIS. Using slope section as the basic evaluation unit, and selecting the seven factors of slope gradient, slope height, slope aspect, slope pattern, slope structure type, vegetation and human engineering activity, the authors carried out an ArcGIS-based assessment to evaluate loess landslide susceptibility with information value method. The assessment shows that high-class susceptibility places with a total area of 1092.39km2 account for 30.81% of the whole district, which are mainly distributed in the central and northern parts of Baota District. Low-class susceptibility places are mainly distributed in Fenchuan River basin in southern Baota District. With the slope section as the basic evaluation unit, the assessments are consistent with topography and geomorphology. The landslide susceptibility with information value method is more reasonable and effective, and has higher prediction accuracy. It is shown that existing landslides in very high and high-class susceptibility areas possess the proportion of 95.7%.