芦山地震区泥石流易发性评价

发布时间：2018-03-20 13:39

本文选题：芦山地震　切入点：泥石流　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：泥石流是一种经常发生于山区小流域的地质灾害,顷刻之间往往导致极其严重的生命财产损失。为更加准确表达芦山地震后丰富的物源变化以及得到真实可靠的泥石流易发性评价结果,文章基于地理信息系统、遥感、地质学及统计学等技术方法理论,在人机交互提取泥石流沟谷流域前提下,选用确定性系数法以及地貌信息熵法共同开展基于滑坡物源的震区泥石流易发性评价研究工作。主要研究成果如下:(1)结合Arc GIS水文分析模块与Google Earth遥感影像,采用人机交互的提取方法,在研究区范围内共圈划出453个泥石流沟谷流域,总面积为4481.22km2。(2)芦山地震产生了大量的滑坡碎屑物质,这些滑坡碎屑物常常堆积于坡体或坡角。地震斜坡物质响应率变化范围为0~14.79mm,低度和极低度物源敏感区面积共占研究区泥石流沟谷流域面积的91.84%,表明超过90%的泥石流沟谷流域对震区滑坡堆积物不敏感。(3)采用确定性系数法对泥石流进行空间分布规律分析,结果显示,所选择的6个环境影响因子(高程、坡度、坡向、地质年代、岩性和NDVI)有利于泥石流发生的区间依次为2000 m以上的高程,20o以上的坡度,北、北东、东、南东、南和北西的坡向,南华系、奥陶系等年代地层,富含石灰岩、白云岩等碳酸盐岩以及火山碎屑岩等岩石出露地区,-1~0.2的NDVI。(4)根据6个环境影响因子构建有利于泥石流发生的不同因子组合,并对其所生成的索引图进行成功率检验,以得出有利于泥石流发生的最优因子组合;成功率检验结果显示,地形、地貌与地质因子组合(高程、坡度、坡向、年代地层、岩性和NDVI)的AUC值为88.93%,该组合的泥石流易发性评价结果与其它因子组合相比更为准确。(5)引入滑坡物源,进行基于确定性系数法的泥石流易发性评价,评价结果表明,研究区泥石流中度及以上易发区面积占泥石流沟谷流域总面积的7.76%,泥石流极为不活跃。(6)研究区泥石流沟谷流域地貌信息熵值变化于0.0001~0.8976之间,地貌演化从幼年期至老年期均有分布,但大多数仍介于幼年期至壮年期的地貌演化阶段。高度及高度以上易发区面积为4284.30km2,为研究区面积的49.25%,说明近1/2的泥石流沟谷流域比较活跃。但如若引入滑坡物源进行基于地貌信息熵法的泥石流易发性评价,评价结果显示出不足5%的泥石流沟谷流域处于中度及以上易发区,泥石流活动极为不活跃。
[Abstract]:Debris flow is a geological hazard that often occurs in small mountain basins. In order to more accurately express the rich source changes after the Lushan earthquake and obtain the true and reliable results of debris flow vulnerability evaluation, this paper is based on GIS, remote sensing, Based on the theory of geology and statistics and other technical methods, under the premise of human-computer interactive extraction of debris flow valley, The deterministic coefficient method and geomorphological information entropy method are used to study the vulnerability of debris flow in seismic area based on landslide source. The main research results are as follows: 1) combining with Arc GIS hydrological analysis module and Google Earth remote sensing image. By using the method of man-machine interaction extraction, 453 debris flow gully basins with a total area of 4481.22km2 路m ~ (2 / 2) were delineated in the study area. The Lushan earthquake produced a large amount of landslide debris. The material response rate of seismic slope varies from 0 to 14.79 mm, and the sensitive area of low and very low source accounts for 91.84 of the valley area of debris flow in the study area, indicating that more than 90% mudstone. Liugougu valley is insensitive to landslide deposits in earthquake area. The deterministic coefficient method is used to analyze the spatial distribution of debris flow. The results show that the selected six environmental impact factors (elevation, slope, slope direction, geological age, lithology and NDVI) are favorable to the slope above 20 o of elevation above 2000 m, north, north, east, east and south. The slope in the south and north west, the South China system, the Ordovician and other chronostratigraphic strata are rich in limestone. The carbonate rocks such as dolomite and pyroclastic rock outcrop area (NDVI.Q4) are constructed according to six environmental impact factors, and the success rate of the index map generated by them is tested. The results of success rate test show that the combination of terrain, geomorphology and geological factors (elevation, slope, direction of slope, chronostratigraphy, etc.). The AUC value of lithology and NDVI is 88.93, and the result of debris flow vulnerability evaluation of this combination is more accurate than other factors combination.) the landslide source is introduced to evaluate the vulnerability of debris flow based on deterministic coefficient method. The evaluation results show that, In the study area, the area of middle and above debris flow area accounts for 7.76% of the total area of debris flow valley, and the debris flow is extremely inactive. 6) the geomorphologic information entropy of debris flow gully valley in the study area varies from 0.0001 to 0.8976. The geomorphologic evolution was distributed from infancy to old age. However, most of them are still in the stage of geomorphologic evolution from infancy to maturity. The area of prone area above height is 4284.30km2, which is 49.25km ~ 2 of the studied area, indicating that nearly 1/2 debris flow valley basin is active. But if the landslide source is introduced, The vulnerability evaluation of debris flow based on geomorphological information entropy method is carried out. The evaluation results show that less than 5% debris flow valley is in moderate or higher prone areas, and debris flow activity is extremely inactive.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.23

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