四川省雅安市泥石流灾害危险性评价

目的]对四川省雅安市泥石流灾害危险性进行评价,为科学合理地预测和应对该区泥石流的发生提供科学依据。方法]首先构建危险性评价指标体系,选取3类8个评价因子并进行量化分级,再用层次分析法(AHP)给指标赋权重,最后用危险性评价模型叠置分析评价因子,进行雅安市危险度区划,将雅安市范围的泥石流危险性级别分为轻度(Ⅰ)、中度(Ⅱ)、较高(Ⅲ)、高度(Ⅳ)。结果]宝兴县的Ⅳ区域占比(8.8%)最小,整体泥石流危险性最低。天全县危险性相对偏低。雨城区、芦山县、名山区的Ⅳ级都占比约20.0%,整体泥石流危险性居中;荥经县和汉源县整体泥石流危险性偏高,Ⅳ级占比约45.0%;石棉县的泥石流危险性最高,Ⅳ级区域占比高达57.4%,Ⅲ级区域占比高达24.4%。结论]加强预防高度危险区的泥石流灾害能力,警惕较高危险区泥石流潜在危险性。采用合理有效的措施(灾害监测,气象预报,植树种草)将雅安市泥石流危险性尽可能降低。

Evaluation of Debris Flow Hazard in Ya'an City of Sichuan Province

Objective] The risk of debris flow in Ya'an City was evaluated to provide scientific basis for predicting and dealing with debris flow scientifically and reasonably.Methods] Firstly,a quantitative-hierarchy factors assessing system,including nine factors of three categories,was established.The factors were weighted by method of analytic hierarchy process(AHP).Finally,assessment model of hazard was applied to the spatial overlay analysis and took debris flow hazard division in Ya'an City.The division map of debris flow hazard included low-risk zone(Ⅰ),risk zone(Ⅱ),high-risk zone(Ⅲ)and higher-risk zone(Ⅳ).Results] Baoxing county had the lowest risk,only 8.8％ was covered by Ⅳ zone.Risk of debris flow in Tianquan County was determined as fairly low as well.About 20.0％ of Yucheng,Lushan,Mingshan County are covered by Ⅳ zone,and the two counties have moderate level risk.Risk of debris flow in Yingjing and Hanyuan County is fairly high,Ⅳ zone covered 45.0 ％ approximately.The debris flow risk in Shimian County hits the top.The percent of Ⅳ going up to 57.4％,and the percent of Ⅲll up to 24.4％.Conclusion] The capacity of debris flow disaster should be enhanced in prevention of Ⅳ grade risk,be alert to the potential danger in Ⅲ.The measures have monitoring,weather forecast,tree and grass plantation.