地貌信息熵是判断地貌发育演化阶段的量化指标,常用以表示流域地貌面的受侵蚀程度,是地形地貌因子的反映。以GIS技术为操作平台,利用芦山地震滑坡体积作为泥石流物质来源数据,采用地貌信息熵方法,对55条泥石流沟进行了基于滑坡物源的泥石流危险性区划研究,期望能为即将来临的雨季做好泥石流危险区规划和防灾工程部署提供参考。研究结果表明:研究区泥石流沟谷流域地貌信息熵值变化范围为0.003 2-0.938 1,沟谷地貌演化从幼年期至老年期均有分布;泥石流危险区面积自极高危险区至极低危险区基本呈现递减趋势,80.77%研究区面积的泥石流沟谷比较活跃,处于幼年期—壮年期的泥石流沟谷增加了泥石流发生的危险性;泥石流沟谷流域斜坡物质响应率变化范围为0-133.24mm,低度和极低度物源敏感区面积共占研究区沟谷流域面积的72.93%,表明近3/4的泥石流沟谷流域对滑坡物源不敏感;基于滑坡物源的泥石流危险性评价结果表明,2/5以上的泥石流沟谷流域处于中度及以上危险区,泥石流活动较为活跃。
Geomorphic information entropy is a quantitative indicator used to determine the evolutionary stage and express the erosion degree of watershed geomorphic surface,which is a reflection of topography factors. In order to do a better job for the upcoming rainy season's debris-flow hazard zone planning and provide a reference for disaster prevention,with GIS technology as a platform and the Lushan seismic landslides' volume data as source material of debris flow, and by combining geomorphic information entropy method,the paper carries out debris-flow hazard evaluation for 55 debris flows based on landslide material sources. The results show that: The range of the value of geomorphic information entropy is between 0.003 2 - 0.938 1 in debris-flow valley basin of the study area,and valley geomorphic evolution is distributed from childhood to old age; the area of debris-flow hazard zone shows a decreasing trend basically from high to low hazard zone,with 80.77% of the study region locating in the debris flow prone area,and the presence of debris-flow valley in its juvenile to mature stage increases the risk of debris flow. The response rate of seismic slope mass movement( RRSSMM) of the debris flow basin varies from 0 - 133.24 mm,and the area of material source sensitive area of low and very low degree accounts for 72.93% of the valley basin area of the study area,which indicates that nearly 3/4 of debris-flow valley basins are insensitive to landslides material source. The result of debris-flow hazard evaluation based on landslides material source indicates that more than 2/5 of the debris flow valley basin is located in moderate or above hazard zone,where debris flow activity seems more active.