基于信息量与集成学习的滑坡易发性评价——以新疆特克斯县为例

    Assessment of landslide susceptibility based on information and ensemble learning: A case study of Tekes County in Xinjiang Region

    • 摘要: 特克斯县地处天山北部,多为低山丘陵地区,区域滑坡灾害十分发育.因此选取高程、坡度、坡向、地形曲率、高差、工程地质岩组、断层、植被归一化指数、水系及道路共10个影响滑坡灾害发育的因子,构建特克斯县滑坡易发性评价指标.首先运用信息量模型进行滑坡易发性评价;其次以信息量模型的易发性分区结果随机选取与滑坡数量相同比例的非滑坡样本数据,将选取的非滑坡和滑坡样本相结合;最后采用集成学习算法的梯度提升决策树(GBDT)和极限梯度提升(XGBoost)模型进行滑坡易发性评价.根据易发性指数将研究区划分为极高、高、中、低及极低5个等级的易发分区.采用ROC曲线和滑坡密度对评价结果的精确度进行分析,结果表明结合信息量法的XGBoost模型预测准确度最高,AUC值为0.91,且易发分区的结果最为合理.极高、高易发区分布滑坡灾害144处,占滑坡总数的86.23%.极高、高易发区主要集中分布于特克斯县北部的低山丘陵区及人类工程活动强烈的地区.

       

      Abstract: Tekes County, located in northern Tianshan Mountains, is dominanted by low mountainous and hilly terrain, where regional landslide disasters are highly developed. In this study, 10 factors impacting the development of landslide disasters, including elevation, slope gradient, slope aspect, terrain curvature, relative relief, engineering geological rock group, fault, NDVI, river system and road, are selected to construct the susceptibility evaluation indexes of landslides in Tekes County. First, the information model is applied for landslide susceptibility assessment. Subsequently, based on the susceptibility zoning results from the information model, non-landslide sample data are randomly selected in a proportion equal to the number of landslides, which is then combined with the landslide samples. Finally, the ensemble learning algorithm, specifically the gradient boosting decision tree (GBDT) and extreme gradient boosting(XGBoost) models are employed for landslide susceptibility assessment. Based on the susceptibility indexes, the study area is divided into five susceptible zones, i.e. extremely low, low, medium, high and extremely high. The accuracy of evaluation results is analyzed using ROC curves and landslide density. The results indicate that the XGBoost model combined with information method achieves the highest prediction accuracy, with the AUC value of 0.91, and produces the most reasonable susceptibility zoning result. There are 144 landslide disasters(86.23% of the total) located within the high and extremely high susceptible zones which are mainly concentrated in the low mountainous and hilly areas of northern Tekes County and areas with intensive human engineering activities.

       

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