芦山“4·20”震后地质灾害危险性评价

Hazard assessment of geological disaster after "4·20" earthquake in Lushan County

芦山"4·20"地震之后,滑坡、崩塌、泥石流等次生地质灾害频发,新增地质灾害点365处,严重影响当地经济建设与灾后重建工作。在分析地质灾害孕灾环境条件的基础上,选取地层岩性、断裂带、坡度、相对高程、年平均降雨量、地震动峰值加速度、土地利用类型等7个因子作为评价指标,建立基于灾害熵的地质灾害危险性评价方法,并将该方法应用于芦山县地质灾害危险性评价。结果表明,芦山县49.89%的区域处于中度和高度危险区,其中高危险区占总面积的29.99%,这些高危险区位于正河、玉溪河、灵关河流域,受地形、人类活动、地震影响,地质灾害破坏性极大,在后期建设与防灾减灾中应当给予高度关注。

After the ＂4·20＂ earthquake in Lushan County, secondary geological disasters such as landslides, collapses and debris flows occurred frequently. There are 365 new geological hazard spots which seriously impact local economic construction and post- disaster reconstruction. This paper selects lithology, fault zone, slope, relative elevation, annual rainfall, peak ground acceleration, and the type of land use based on geological disasters environmental conditions to build up a geological disasters hazard evaluation methodology of entropy,which has been applied to Lushan＇s geological disasters risk assessment. The results show that 49.89% of Lushan＇s area belong to a medium and high dangerous region, among which 29.99% are in high dangerous region situated in Zheng River, Yuxi River and Lingguan River drainage basin. Impacted by terrain, human activities and earthquake, the geological disasters always damage heavily, so we should pay more attention to it during subsequent construction and disaster prevention and mitigation.