汶川地震区绵远河流域泥石流形成区的崩塌滑坡特征
|
摘要
2008年汶川地震以后,四川省绵竹市清平乡表面覆盖了大量松散堆积物,这些物源在震后的几年中易受到暴雨激发,导致大量浅层崩塌、滑坡的形成,尤其在泥石流形成区。研究泥石流形成区崩塌、滑坡特征,有助于分析滑坡向泥石流转化的特点。2010-08-13绵远河流域发生强降雨致使数十条沟暴发泥石流,在统计了研究区内20条沟泥石流形成区内的386个崩塌、滑坡后,利用野外调查及高精度遥感影像,将386个崩塌、滑坡全部解译,并利用GIS分析统计出崩塌、滑坡在坡度、坡向、高程、沟道纵坡降、地层岩性、沟壑密度因子上的分布特征,得出在海拔1 700～2 400 m范围内崩塌、滑坡密度最大;坡度是影响崩塌、滑坡分布的重要因素,随着坡度的增加密度也越来越大,>70°时极易失稳;滑坡的方向垂直于发震断层明显多于平行于发震断层;纵坡降在500‰～600‰的区间内崩塌、滑坡大量分布;石炭系灰岩出露的地层容易产生大量崩塌、滑坡,尤其在下硬上软的岩层上面;在微度水土流失的区域,崩塌、滑坡分布集中,因此要加强该区域的监测预警。
After the 2008 Wenchuan earthquake,an abundance of loose co-seismic material sources were present in the Qingping town Mianzhu city of Sichuan province,where in later years served as source material for rainfall-induced shallow landslides,especially in forming region of debris flow.The characteristic of collapse and landslide in forming region of debris flow can help to analyze landslide transform to debris flow.A heavy rain occurred on August 13th along Mianyuan River,where a number of debris flow occurred.A spatial database,which included 386 landslides in forming region of 20 debris flows,was developed and analyzed using high precision image and field survey within the Mianyuan River basin.We also used GIS to census the rule of distribution of landslides in gradient,slope direction,elevation,and channel gradient,the lithology of stratum and drainage density factors. After analysis of the statistics in six evaluation factors,we find that the largest landslide density in the scope of 1 700~2 400 m,the slope is the important factor of landslide distribution,with the increase of slope,the density will increase. When landslide slope >70 °,it can is instabiliy.The aspect of perpendicular of the landslide significantly more than parallel to the seism genic faults;a lot of collapse landslides highly concentrated in the 500‰~600‰ slope of gully;the carboniferous strata of limestone can easily produce the large amount of collapse landslide,especially in the soft soil above the hard bedrock zone.The landslide concentrating distribute in micro degrees of soil erosion area,so we should strengthen the monitoring and warning system in this area.
After the 2008 Wenchuan earthquake,an abundance of loose co-seismic material sources were present in the Qingping town Mianzhu city of Sichuan province,where in later years served as source material for rainfall-induced shallow landslides,especially in forming region of debris flow.The characteristic of collapse and landslide in forming region of debris flow can help to analyze landslide transform to debris flow.A heavy rain occurred on August 13th along Mianyuan River,where a number of debris flow occurred.A spatial database,which included 386 landslides in forming region of 20 debris flows,was developed and analyzed using high precision image and field survey within the Mianyuan River basin.We also used GIS to census the rule of distribution of landslides in gradient,slope direction,elevation,and channel gradient,the lithology of stratum and drainage density factors. After analysis of the statistics in six evaluation factors,we find that the largest landslide density in the scope of 1 700~2 400 m,the slope is the important factor of landslide distribution,with the increase of slope,the density will increase. When landslide slope >70 °,it can is instabiliy.The aspect of perpendicular of the landslide significantly more than parallel to the seism genic faults;a lot of collapse landslides highly concentrated in the 500‰~600‰ slope of gully;the carboniferous strata of limestone can easily produce the large amount of collapse landslide,especially in the soft soil above the hard bedrock zone.The landslide concentrating distribute in micro degrees of soil erosion area,so we should strengthen the monitoring and warning system in this area.
引文
[1]Cui Peng,Wei Fangqiang,Cheng Xiaoqing,et al.Geo-hazanls inWenchuan earthquake area and countermeasures for disaster reduc-tion[J].Bulletin of Chinese Academy of Sciences 2008,23(4):317-323[崔鹏,韦方强,陈晓清,等.汶川地震次生山地灾害及其减灾对策[J].中国科学院院刊,200823(4):317-323]
[2]Yin Y,Wang F,Sun P.Landslide hazards triggered by the 2008Wenchuan earthquake,Sichuan,China[J].Landslide,2009(6):139-151
[3]Khattak G A,Owen L A,Kamp U,et al.Evolution of earthquake-triggered landslides in the Kashmir Himalaya,northern Pakistan[J].Geomorphology,2010,115:102-108
[4]Koi T,Hotta N,Ishigaki I,et al.Prolonged impact of earthquake-in-duced landslides on sediment yield in a mountain watershed,TheTanzawa region,Japan[J].Geomorphology,2008,101:692-702
[5]Tang C,van Asch T W J,Chang M,et al.Catastrophic Debris flowson 13 August 2010 in the Qingping area,southwestern China:Thecombined eflects of a strong earthquake and subsequent rainstorms[J].Geomorphology,2011,doi:10.1016/.
[6]Huang Runqiu,Li Weile.Research on development and distributionof geo-hazards induced by the Wenchuan earthquake on 12th May,2008[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(12):2585-2592[黄润秋,李为乐.“5.12”汶川大地震触发地质灾害的发育分布规律研究[J].岩石力学与工程学报,2008,27(12):2585-2592]
[7]Li Weile,Huang Runqiu,Tang Chuan,et al.Landslides triggered by“5.12”Wenchuan earthquake in the Mianyuan River Basin,China[J].Journal of Mountain Science,2011,29(4):483-492[李为乐,黄润秋,唐川,等.汶川地震触发的绵远河流域崩塌、滑坡的特征[J].山地学报,2011,29(4):483-492]
[8]Tang Chunan,Zuo Yujun,Qin Sifeng,et al.Spalling and slingingpattern of shallow slope and dynamics explanation in the2008Wenchuan earthquake[C]//Proceedings of the 10th conferenceon Rock Mechanics and engineering,China.2009:258-262[唐春安,左宇军,秦泗凤,等.汶川地震中的边坡浅层散裂与抛射模式及其动力学解释[C]//第十届全国岩石力学与工程学术大会论文集,2009:258-262]
[9]C Tang,T W J van Asch,M Chang,et al.Catastrophic Debris flowson 13 August 2010 in the Qingping area,southwestern China:thecombined effects of a strong earthquake and subsequent rainstorms[J].Geomorphology,2011:1-65
[10]Zhao X H,Chang Ming,Huang X C.Disaster feature analysis ofWenjia Gully debris flow in Qingping,Wenchuan Earthquake Area[J].South-to-North Water Diversion and Water Science&Technology,2011,9(5):107-110[赵学宏,常鸣,黄翔超.汶川震区清平乡文家沟泥石流灾害特征分析[J].南水北调与水利科技,2011,9(5):107-110]
[2]Yin Y,Wang F,Sun P.Landslide hazards triggered by the 2008Wenchuan earthquake,Sichuan,China[J].Landslide,2009(6):139-151
[3]Khattak G A,Owen L A,Kamp U,et al.Evolution of earthquake-triggered landslides in the Kashmir Himalaya,northern Pakistan[J].Geomorphology,2010,115:102-108
[4]Koi T,Hotta N,Ishigaki I,et al.Prolonged impact of earthquake-in-duced landslides on sediment yield in a mountain watershed,TheTanzawa region,Japan[J].Geomorphology,2008,101:692-702
[5]Tang C,van Asch T W J,Chang M,et al.Catastrophic Debris flowson 13 August 2010 in the Qingping area,southwestern China:Thecombined eflects of a strong earthquake and subsequent rainstorms[J].Geomorphology,2011,doi:10.1016/.
[6]Huang Runqiu,Li Weile.Research on development and distributionof geo-hazards induced by the Wenchuan earthquake on 12th May,2008[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(12):2585-2592[黄润秋,李为乐.“5.12”汶川大地震触发地质灾害的发育分布规律研究[J].岩石力学与工程学报,2008,27(12):2585-2592]
[7]Li Weile,Huang Runqiu,Tang Chuan,et al.Landslides triggered by“5.12”Wenchuan earthquake in the Mianyuan River Basin,China[J].Journal of Mountain Science,2011,29(4):483-492[李为乐,黄润秋,唐川,等.汶川地震触发的绵远河流域崩塌、滑坡的特征[J].山地学报,2011,29(4):483-492]
[8]Tang Chunan,Zuo Yujun,Qin Sifeng,et al.Spalling and slingingpattern of shallow slope and dynamics explanation in the2008Wenchuan earthquake[C]//Proceedings of the 10th conferenceon Rock Mechanics and engineering,China.2009:258-262[唐春安,左宇军,秦泗凤,等.汶川地震中的边坡浅层散裂与抛射模式及其动力学解释[C]//第十届全国岩石力学与工程学术大会论文集,2009:258-262]
[9]C Tang,T W J van Asch,M Chang,et al.Catastrophic Debris flowson 13 August 2010 in the Qingping area,southwestern China:thecombined effects of a strong earthquake and subsequent rainstorms[J].Geomorphology,2011:1-65
[10]Zhao X H,Chang Ming,Huang X C.Disaster feature analysis ofWenjia Gully debris flow in Qingping,Wenchuan Earthquake Area[J].South-to-North Water Diversion and Water Science&Technology,2011,9(5):107-110[赵学宏,常鸣,黄翔超.汶川震区清平乡文家沟泥石流灾害特征分析[J].南水北调与水利科技,2011,9(5):107-110]
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