半干旱区具有植被稀少、松散堆积物源丰富的特征,为泥石流的形成提供了有利条件。以金沙江上游奔子栏—昌波河段为例,通过野外调查及遥感影像数据分析,研究了半干旱区的区域泥石流发育特征;选取地层岩性、断裂构造、斜坡坡度、流域相对高差、年平均降雨量和植被归一化指数等6项评价指标,利用GIS技术与AHP层次分析法相结合,建立半干旱区泥石流易发性评价模型,得到研究区泥石流易发性评价栅格图。对研究区进行小流域划分,以小流域为单元,进行区域统计分析并分类,制作基于流域单元的泥石流易发性分区图。分区结果表明:研究区泥石流高易发区和偏高易发区主要分布在金沙江沿岸的东北部、中部和西南部,面积约1 040.9 km2,占研究区总面积的35.7%。最后,构建检验曲线对泥石流易发性评价结果进行检验,高易发区和偏高易发区内实际发育的泥石流面积为651.4 km2,占泥石流总面积的51.1%,表明易发性评价分区效果良好。 Semi-arid area has the characteristics of rare vegetation and rich source of loose accumulation, which provides favorable conditions for the formation of debris flow. Taking the Benzhang-Changbo section in the upper reaches of the Jinsha River as an example, the authors analyzed the development characteristics of regional debris flow in the semi-arid region through the field investigation and remote sensing image data analysis. The stratigraphic lithology, fault structure, slope gradient, relative elevation difference , Average annual rainfall and normalized index of vegetation, and so on. By using GIS technology and AHP AHP, the evaluation model of debris flow vulnerability in semi-arid area was established and the raster flow vulnerability evaluation grid map of the study area was obtained. The study area is divided into small watersheds, and the small watersheds are used as a unit to carry out regional statistical analysis and classification, and to make the easy-to-partition map of debris flow based on basin units. The results of zoning showed that the areas prone to mud-rock flow and high-prone areas were mainly located in the northeast, central and southwest of the Jinsha River, with an area of ​​about 1040.9 km 2, accounting for 35.7% of the total area of ​​the study area. Finally, the test curve was constructed to test the evaluation of debris flow susceptibility. The actual developed debris flow area in high-prone areas and high-prone areas was 651.4 km2, accounting for 51.1% of the total debris flow area, indicating that the evaluation of susceptibility to divisions was effective.