基于斜坡单元与信息量法结合的宝塔区黄土滑坡易发性评价

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

    • 摘要: 滑坡易发性评价对滑坡灾害的防治与管理具有重要意义。为了评价延安宝塔区黄土滑坡易发性,以斜坡为基本评价单元,选取斜坡坡度、坡高、坡向、坡形、斜坡结构类型、植被和人类工程活动7个指标作为评价因子,在ArcGIS平台下,利用信息量模型对研究区的黄土滑坡进行易发性分区评价。评价结果表明,宝塔区滑坡高易发区面积1092.39km2,占全区面积的30.81%,主要分布于宝塔区的中部及北部地区,低易发区集中于宝塔区南部汾川河流域。以斜坡作为评价单元提高了与实际地形地貌的吻合度。应用信息量模型进行滑坡易发性评价具有较高的预测精度,已有滑坡点落在很高易发区和高易发区中的比例为95.7%,较真实地反映了客观实际。

       

      Abstract: 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%.

       

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