四川省石棉县县城泥石流灾害风险评估

四川省石棉县县城及周边地区泥石流灾害频发，通过石棉县泥石流地质灾害调查资料，以一级分水岭为分界线，采用单沟泥石流风险评估方法对县城及周边地区34条泥石流沟分析，确定了泥石流地质灾害危险性和易损性的主要影响因素，逐一对研究区内的34条泥石流沟分析其危险性、易损性和风险性评价。然后采用由点至面的方法得到了泥石流风险性分布图，进而确定了各风险区的分布范围。结果表明:石棉县城及周边地区泥石流以轻度危险为主，中度危险次之；泥石流承载体为高易损性，泥石流的风险性以中度风险为主，并有一定的分布特征。研究果可为该县汛期地质灾害预警预报及今后治理次序提供参考依据。

Risk Evaluation of Debris Flows in Urban Area of Shimian County of Sichuan Province

There are the frequent occurrences of debris flows in and the urban and surrounding areas of Shimian county. Based on detailed investigation of geological hazards in Shimian county, the 34 debris flows are evaluated with single gully debris flow risk assessment method by using a watershed as the segmentation borderline. The main influence factors were determined in terms of debris flow hazard and vulnerability evaluation. Then the hazard and vulnerability of the 34 debris flow gullies were calculated. The results show that the main hazard of debris flow of the study area is light risk, the second is moderate hazard. There is high vulnerability of debris flow bearing body. The main risk of debris flow is moderate, and there are certain distribution characteristics of risk. Finally, the debris flow risk distribution map is made through the analysis from dot to surface. And distribution range of each risk area is determined. The analysis results could provide reference bases for the geological disaster warning and forecasting during the flood season in this county.