龙溪河流域震后次生地质灾害分布与地形及河床演变关系  

Relationship Between the Topography,Riverbed Evolution and the Secondary Geological Disasters after the Earthquake in the Longxi River Basin

作　　者：郭碧云[1,2] 傅旭东[2] 张正峰[3] 

机构地区：[1]浙江海洋学院海洋科学与技术学院,浙江舟山316004 [2]清华大学水沙科学与水利水电工程国家重点实验室,北京100084 [3]中国人民大学公共管理学院,北京100872

出　　处：《应用基础与工程科学学报》2013年第6期1005-1017,共13页Journal of Basic Science and Engineering

基　　金：科技部973课题(2011CB409901);国家自然科学基金项目(51209119);浙江海洋学院科研启动经费资助

摘　　要：以龙溪河流域为研究区,分别选用"5·12"地震前后QuickBird全色遥感影像及DEM数据,辅以差分GPS和激光测距仪等现场实测数据,运用地理信息系统技术,对地震引发的次生地质灾害与地形关系及河床演变进行研究.结果表明:流域内次生地质灾害面积为11.11km2,占流域总面积的14.29%,主要分布在坡度20°—50°之间,占灾害总面积的86.59%;阳坡比阴坡发生地质灾害的比率大,东南坡向地质灾害发生面积比率最大,达到灾害总面积的23.97%;1100—2300m高程范围内地质灾害比较集中,占灾害总面积的80.23%,是研究区灾害分布的主要高程范围;地质灾害沿河流分布规律明显,距主河道越近灾害点分布越密集.泥石流引发龙溪河河床形态变化,上游、下游河床剖面和比降变化较大.次生地质灾害空间分布与地形因素关系密切.该文的研究可为震后防灾减灾和预警提供依据.This study is aimed at explanation of relationship between the secondary geological disasters triggered by the earthquake and the topography,and the consequences on the evolution of the riverbed.Based on the remote sensed interpretation of two QuickBird panchromatic images on and comparison between two DEMs of different periods of time,while assisted with the field survey by the differential GPS and laser rangefinder,the secondary geological disasters triggered by ＂5 · 12＂ earthquake was delineated across the Longxi Rvier Basin.The afterearthquake distribution of disaster was statistically analyzed with topographic factors for the relationship between them.The results showed an area of 11.11 km2 for the secondary geological disasters accounted for 14.29％ of the total area.It mainly distributed in a gradient range of 20°-50° for the disaster,accounted for 86.59％ of the total area of the total disaster.Higher frequency of the disaster was suggested on the sunny slope than on the shady slope,especially in the southeast aspect,it experienced with the highest fraction of 23.97％ of the secondary disaster.Geological disasters in elevation range of 1100-2300m were relatively concentrated,accounting for 80.23％ of the total area of disaster.The significant feature of geological disaster in the basin was featuring approximately same with the pattern along the river,the closer to the main river,the more intensive occurence.There was a close relationship between the secondary geological disasters and the topography in space.The mudslides caused the morphology changes in the Longxi River Basin,led to sharp changes of the riverbed profiles and the slope in the upper and lower reaches of the Longxi river.The study may provide basis for post-earthquake disaster prevention,mitigation and early warning.

关 键 词：次生地质灾害 空间分布 地形因素 河床演变 

分 类 号：P642.22[天文地球—工程地质学]