地形条件对次生山地灾害易发性分析
|
摘要
岷江上游河谷地带位于汶川地震极震区,是中国乃至世界上地震次生山地灾害最为活跃的地区之一,其频繁活动与复杂的地形条件密切相关。以岷江河谷汶川段为典型研究区,在分析了地理环境和地形条件的基础上,研究了地震次生山地灾害的类型、发育特征、分布状况和主要地形影响因素,并基于次生山地灾害形成因素贡献率,引入确定性系数,利用GIS和RS技术,定量分析了高程、坡度和坡向3个主要地形因子对次生山地灾害的易发程度,确定了最利于次生山地灾害发生的地形条件。研究结果表明:1)地震次生山地灾害具有点多面广、类型多样、分布集中、规模巨大等特征,并受地形条件控制;2)利于次生山地灾害发生的高程条件为1 000～1 600 m的高程范围,高程大于1 600 m的区域,山地灾害随海拔升高而越不易发生;3)坡度大于35°的中陡坡地带,均利于次生山地灾害的发生,且随坡度增大,灾害发生的可能性也增大;4)有利于次生山地灾害发生的坡向条件依次为东南、东、南和东北4个方向,其CF分别为0.169、0.1440、.135和0.023;5)利用GIS和统计分析方法,能定量进行地震次生山地灾害易发性分析。研究方法可以为灾区次生山地灾害风险评价与区划提供依据,研究成果对灾区山地灾害防治规划、保障重大工程建设安全和减少灾害损失等具有参考意义。
Taking the Minjiang River valley within Wenchuan county as a pilot site,the impact of geographic envi-ronment and topographic conditions on mountain hazards was discussed and the types,development and distribution of secondary mountain hazards in pilot site were explained.Based on the contribution of each topographic factor to mountain hazards development,the certainty factor of mountain hazards was introduced so as to quantitatively ana-lyze the susceptibility of secondary mountain hazards to three major topographic factors including altitude,slope and aspect.A case study with the technologies of geographical information system(GIS) and remote sensing(RS) was given and the most favorable topographic factors to secondary mountain hazards were probed.The results demonstra-ted that secondary mountain hazards induced by Wenchuan Earthquake scatter widely in pilot site with various types,concentrated distribution,large scale and serious damage and are under the control of topographic condi-tions.The altitude between 1 000 m and 1 600 m is favorable to secondary mountain hazard development and the altitude above 1 600 m is unfavorable to mountain hazard development with the altitude increasing but the hazard development decreasing.The mid and steep slopes above 35° are sensitive to secondary mountain hazards,while the more the slope degree is and the more probable the mountain hazard occurrence is.The susceptive aspects to secondary mountain hazards are southeast,east,south and northeast in turn and their corresponding certainty factors are 0.169,0.144,0.133,and 0.023,respectively.The susceptibility of mountain hazards to topographic factors can be quantitatively calculated by means of GIS and statistic analysis methods.The assessment method was essential for managing risks and developing mitigation efforts related to secondary mountain hazards.
Taking the Minjiang River valley within Wenchuan county as a pilot site,the impact of geographic envi-ronment and topographic conditions on mountain hazards was discussed and the types,development and distribution of secondary mountain hazards in pilot site were explained.Based on the contribution of each topographic factor to mountain hazards development,the certainty factor of mountain hazards was introduced so as to quantitatively ana-lyze the susceptibility of secondary mountain hazards to three major topographic factors including altitude,slope and aspect.A case study with the technologies of geographical information system(GIS) and remote sensing(RS) was given and the most favorable topographic factors to secondary mountain hazards were probed.The results demonstra-ted that secondary mountain hazards induced by Wenchuan Earthquake scatter widely in pilot site with various types,concentrated distribution,large scale and serious damage and are under the control of topographic condi-tions.The altitude between 1 000 m and 1 600 m is favorable to secondary mountain hazard development and the altitude above 1 600 m is unfavorable to mountain hazard development with the altitude increasing but the hazard development decreasing.The mid and steep slopes above 35° are sensitive to secondary mountain hazards,while the more the slope degree is and the more probable the mountain hazard occurrence is.The susceptive aspects to secondary mountain hazards are southeast,east,south and northeast in turn and their corresponding certainty factors are 0.169,0.144,0.133,and 0.023,respectively.The susceptibility of mountain hazards to topographic factors can be quantitatively calculated by means of GIS and statistic analysis methods.The assessment method was essential for managing risks and developing mitigation efforts related to secondary mountain hazards.
引文
[1]Han Yongshun,Cui Peng,Zhu Yingyan,et al.Remote sens-ing monitoring and assessment of traffical damage by Wen-chuan Earthquake—a case study in Du-Wen highway[J].Journal of Sichuan University:Engineering Science Edition,2009,41(3):273-283.[韩用顺,崔鹏,朱颖彦,等.汶川地震危害道路交通及其遥感监测与评估[J].四川大学学报:工程科学版2,009,41(3):273-283.]
[2]Yin Yueping.Features of landslides triggered by the Wen-chuan earthquake[J].Journal of Engineering Geology,2009,17(1):29-38.[殷跃平.汶川八级地震滑坡特征分析[J].工程地质学报2,0091,7(1):29-38.]
[3]Liu Chuanzheng.Disasters induced by the Wenchuan earth-quakes,Sichuan,China,and geo-environmental safety[J].Geological Bulletin of China,2008,27(11):1907-1912.[刘传正.四川汶川地震灾害与地质环境安全[J].地质通报2,0082,7(11):1907-1912.]
[4]Han Yongshun.Research on theory and key technologies ofdebris flow risk management[D].Chengdu:Institute ofMountain Hazards and Environment,Chinese Academy ofSciences2,008.[韩用顺.泥石流灾害风险管理理论与关键技术[D].成都:中国科学院成都山地灾害与环境研究所,2008.]
[5]Lan Hengxing,Wu Faquan,Zhou Chenghu,et al.Analysison susceptibility of GIS-based landslide triggering factors inYunnan Xiaojiang watershed[J].Chinese Journal of RockMechanics and Engineering,2002,21(10):1500-1506.[兰恒星,伍法权,周成虎,等.基于GIS的云南小江流域滑坡因子敏感性分析[J].岩石力学与工程学报,2002,21(10):1500-1506.]
[6]Shortliffe E H,Buchanan B G.A model of inexact reasoningin medicine[J].Math Biosci,1975,23(2):351-379.
[7]Heckerman D.Probabilistic interpretations for MYCIN’scertainty factors[J].Uncertainty in Artificial Intelligence,19861,67-196.
[2]Yin Yueping.Features of landslides triggered by the Wen-chuan earthquake[J].Journal of Engineering Geology,2009,17(1):29-38.[殷跃平.汶川八级地震滑坡特征分析[J].工程地质学报2,0091,7(1):29-38.]
[3]Liu Chuanzheng.Disasters induced by the Wenchuan earth-quakes,Sichuan,China,and geo-environmental safety[J].Geological Bulletin of China,2008,27(11):1907-1912.[刘传正.四川汶川地震灾害与地质环境安全[J].地质通报2,0082,7(11):1907-1912.]
[4]Han Yongshun.Research on theory and key technologies ofdebris flow risk management[D].Chengdu:Institute ofMountain Hazards and Environment,Chinese Academy ofSciences2,008.[韩用顺.泥石流灾害风险管理理论与关键技术[D].成都:中国科学院成都山地灾害与环境研究所,2008.]
[5]Lan Hengxing,Wu Faquan,Zhou Chenghu,et al.Analysison susceptibility of GIS-based landslide triggering factors inYunnan Xiaojiang watershed[J].Chinese Journal of RockMechanics and Engineering,2002,21(10):1500-1506.[兰恒星,伍法权,周成虎,等.基于GIS的云南小江流域滑坡因子敏感性分析[J].岩石力学与工程学报,2002,21(10):1500-1506.]
[6]Shortliffe E H,Buchanan B G.A model of inexact reasoningin medicine[J].Math Biosci,1975,23(2):351-379.
[7]Heckerman D.Probabilistic interpretations for MYCIN’scertainty factors[J].Uncertainty in Artificial Intelligence,19861,67-196.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心