雅砻江中游卡拉地区泥石流危险性区划

Hazard zoning of debris flow in Kala region in middle reaches of Yalong River

以雅砻江中游卡拉地区为研究区,根据泥石流形成条件,基于GIS平台选取坡度、岩性、崩滑坡点密度、地质构造缓冲区及归一化植被指数等5个泥石流危险性评价因子,采用AHP法确定其权重,结合信息量法完成了研究区泥石流灾害危险性区划。结果表明:在极低度危险区内泥石流沟面积仅占危险等级面积的3.71%,而中度危险及以上的区域包含的泥石流沟面积占研究区泥石流沟总面积的75.24%,与实际泥石流发育规律相一致,说明在泥石流危险性区划中,运用AHP-信息量法并结合GIS的空间分析功能的定量评价方法具有较高的可信度。

To Kala region in middle reaches of Yalong River,according to the forming conditions of debris flow,five indexes including slope,lithology,density of collapsing and sliding point,buffer zone of geological structures and NDVI were selected to evaluate the hazard degree of debris flow based on GIS. AHP combined with information value method is used to determine the weight of the five indexes and hence divide the region into zones of different hazard degree. The results show： the area of debris flow valley in extremely low dangerous zone only accounts for 3. 71% of all dangerous zones while in moderately dangerous zone and above,the area of debris flow valley accounts for 75. 24% of the total area of debris flow valley in the whole region,corresponding well with the practical development condition,which proves that the quantitative analysis by the spatial analysis function of GIS combined with AHP and information value method is reliable in hazard zoning of debris flow.