长江上游地区泥石流灾害敏感性量化评价研究

泥石流敏感性分析对灾害分析评价预测具有重要作用。文章以长江上游为研究区,选择坡度、相对高差、地层岩性、年降雨量、地震烈度等5方面因素为评价因子,探讨运用GIS技术管理分析泥石流灾害信息和区域泥石流敏感性分析的方法。量化评价因子的作用分值大小,有效表达泥石流敏感性指数(DFSI),进而,结合空间分析与条件概率模型,实现了区域泥石流敏感性分析并制作了泥石流敏感性专题图。长江上游地区泥石流敏感性区域具有一定的规律性,高度敏感区主要分布在第一级阶梯与第二级阶梯的过渡地带,比较集中的区域有雅砻江中下游、安宁河、小江、普渡河、大渡河中下游、理塘河、白龙江、岷江上游、涪江上游等干支流的5～10 km范围内;中度敏感区主要分布在高度敏感区的外围约10～30 km范围内。利用历史泥石流资料验证,表明已经发生的泥石流主要分布在泥石流敏感性指数较高地区,说明敏感性分析的结果基本反映出研究区泥石流敏感性特性。

Quantitative Evaluation for Susceptibility of Debris Flow in Upper Yangtze River Basin

It is very important to analyze the debris flow susceptibility for hazard analysis,evaluation and prediction.Based on GIS technology,the debris flow susceptibility for the upper Yangtze River basin was evaluated,with slope,relative elevation,stratum lithology,annual rainfall and earthquake intensity as evaluation factors.Through quantitatively analyzing the potential probability of triggering factors,visualizing the debris flow susceptibility index(DFSI) and applying spatial analysis and conditional probability model,susceptibility analysis and topic mapping for regional debris flow were studied.Analysis result showed that the susceptive regions of debris flow have some distribution characteristics in the upper Yangtze River basin.High sensitive area is the transition area between the first stepped landform and second stepped landform in China,mainly within a 5 to 10 km distance of artery of Anning River,Xiaojiang River,Pudu River,mid and lower reaches of Dadu River,Bailong River,Litang River,the upper reaches of Min River and Fujiang River.Middle sensitive area is within a distance of 10~30 km around high sensitive area.According to historical data,it shows the debris flows that have happened distribute in high DFSI area and topic map can express the characteristics of debris flows in the upper Yangtze River basin.