摘要
2008年5月12日,中国四川省龙门山地区发生M S8.0大地震,诱发了大量的斜坡地质灾害。全面、准确的地质灾害编录和对其发育规律分析是灾害防治研究的基础。因此,本文选取同震地质灾害典型发育的绵远河流域作为研究区,利用2期震后的SPOT5卫星遥感影像,结合震前航拍影像,进行了同震地质灾害图斑的自动识别,并结合影像目视检核和灾害野外验证精确地编录了斜坡地质灾害。针对先前学者在此研究区的研究成果,对比分析本次地质灾害提取方法的优势与成果的完整性与精确性。在此解译成果基础上,进行了地质灾害发育规律的空间分析,得出了一些有别于前人的认识:(1)遥感影像是提取地震地质灾害的有效手段,但需要注意遥感影像的时相选择和期次的对比,这样才能获取完整且准确的解译结果;(2)提取的研究区地质灾害总面积为85.5km2,约为前人研究结果的两倍;解译结果显示,灾害主要集中分布于北川—映秀地表破裂带附近和绵远河主河道两侧的斜坡;(3)流域地处地形、地貌过渡带,高程、坡度、坡形、断裂及地表破裂和地层岩性是汶川地震地质灾害分布的主控因素;在高程1500m和4100m附近灾害面积百分比最大,分别为31%和25%以上;灾害分布主要集中在50°附近,面积百分比与坡度呈正相关;在凹形陡坡单元灾害面积分布最大,其次为凸型中坡单元;灾害分布与该地区断层的活动特征相关性很大;硬岩、上硬下软地层是地质灾害的主要发生区域,占49.6%。
On May 12, 2008, a Ms8.0 earthquake occurred in the Longmenshan fault zone in Sichuan province of China. It induced large amounts of geo-hazards. Comprehensive and accurate disasters catalog and the development pattern analysis are the foundation of research in disaster prevention and control. The Mianyuan river basin is one of the typical areas where seismic disasters well developed. This paper used two SPOT5 remote sensing images which took alter the earthquake, combined with the aerial image took before the earthquake, automatically identified the geo-hazards spots and connected with the field investigation and visual cheek. It catalogued the slope geological disasters accurately. By comparison and contrast between the results of the previous researches in the study area and the method used in this paper, this geological disasters extraction method has a lot of advantages. The results are more completely and accurately. On the basis of the disaster development regularity of spatial analysis, we obtained some new understanding different from the previous ones. （1） Paying more attention to the choice and contrast of the times when RS images took and using RS image are an effective method for extraction of eoseismie geological disasters, so as so obtain accurate and complete interpretation results; （2） the extracted area of disasters is 85.5km2,about two times the research by predecessors. Visual results show that the area of disasters mainly distribute in Beiehuan-Yingxiu surface rupture zone and along the both sides of the Mianyuan river; （3）the main factors influencing the distribution of geological disasters in Wenehuan earthquake are elevation, slope, slope- shape, surface ruptures and stratigraphic lithology. Near the elevation of 1500m and 4100m, the geo-hazards area percentages are large, above 31% and 25% respectively. The distribution is positively related to the slope. The geo- hazards area percentage is mainly concentrated in the vicinity of 50°. Disasters mainly distribute in the concave slope units, followed by convex slopes. The disasters have big relationships with the active faults complexity characteristics of activity in the region. On the hard rock or the soft stratums with hard under is the main sliding area of disasters, it.s area percentage up to 49.6%.
出处
《工程地质学报》
CSCD
北大核心
2014年第1期46-55,共10页
Journal of Engineering Geology
基金
科技支撑项目(2011BAK12B09)
自然科学基金项目(40902059)
中国地质调查局工作项目(1212010914025
1212011120372)资助
关键词
汶川地震
地震地质灾害
绵远河流域
地质灾害提取
灾害分布特征
Wenehuan earthquake, Seismic geo-hazards, Mianyuan river basin, Identification of geo-hazards,Distribution characteristics of geo-hazards
