| 汶川Ms8.0级地震后龙门山构造地貌及地表侵蚀过程研究——以湔江海子段河为例 |
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| 引用本文： | 赵国华,李 勇,闫 亮,等.汶川Ms8.0级地震后龙门山构造地貌及地表侵蚀过程研究——以湔江海子段河为例[J].四川地震,2014(1):15-23. |
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| 作者姓名： | 赵国华 李 勇 闫 亮 等 |
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| 作者单位： | [1]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [2]四川省地震局,四川成都610041 |
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| 基金项目： | 国家自然科学基金项目（41340005,41372114,41172162,40972083）. |
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| 摘 要： | 汶川Ms8.0级地震驱动的构造抬升作用和滑坡、泥石流剥蚀作用如何影响龙门山的地貌生长是目前争论的焦点。本文运用GIS技术,定量计算了湔江流域的坡度、地形起伏度、面积—高程积分等地貌参数,根据这些参数的计算结果,对湔江流域的构造地貌特征进行了量化分析;以汶川Ms8.0级地震重灾区湔江海子河右岸流域的滑坡、泥石流为例,并且利用野外实测资料、卫星照片及数字高程资料等,对于汶川地震驱动的构造抬升与滑坡、泥石流的表面侵蚀过程进行研究,获得以下初步认识:(1)湔江流域的映秀—北川断层以北地区地貌处于"壮年期",坡度、地形起伏度大;(2)汶川Ms8.0级地震后该地区发生了严重的同震滑坡及震后滑坡、泥石流灾害,海子河右岸流域的同震抬升量为5 339×104m3,同震滑坡量为3 852×104m3,同震抬升量大于同震滑坡量,地貌出现生长现象;(3)地震产生的泥石流量应略大于1 000×104m3,同震滑坡物质的30%转化为了泥石流量,因其海子沟右岸陡峻的坡度,绝大部分的泥石流冲入海子河,成为河道沉积物;(4)以目前湔江海子河流水搬运能力,在能够完全搬运出同震滑坡物质的前提下,同震滑坡物质搬运出龙门山至少需要283.2 a,表明在一个地震周期内,龙门山的同震滑坡物质可以搬运出龙门山;(5)准周期性相当震级地震引起的构造抬升及其均衡反弹作用也是龙门山的形成有重要作用的因素之一。
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| 关 键 词： | 汶川地震 构造抬升 同震滑坡 震后泥石流 河流卸载 山脉生长 海子河 湔江 龙门山 |
Tectonic geomorphology and surface erosion processes in the Longmenshan area after the 2008 Wenchuan Ms 8.0 Earthquake——Take Haizi river of Jiangjian for example |
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| ZHAO Guo-hua,LI Yong,YAN Liang,MA Chao,ZHANG Wei,YAN Zhao-kun,ZHENG Li-long,LI Jing-bo.Tectonic geomorphology and surface erosion processes in the Longmenshan area after the 2008 Wenchuan Ms 8.0 Earthquake——Take Haizi river of Jiangjian for example[J].Earthquake Research in Sichuan,2014(1):15-23. |
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| Authors: | ZHAO Guo-hua LI Yong YAN Liang MA Chao ZHANG Wei YAN Zhao-kun ZHENG Li-long LI Jing-bo |
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| Institution: | 1. National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Sichuan Chengdu 610059, China; 2. Sichuan Earthquake Administration, Sichuan Chengdu 610041, China) |
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| Abstract: | The effects of tectonic uplift, landslides, and debris-flow erosion driven by the 2008 Wenchuan Ms 8.0 Earthquake on the geomorphic growth of Longmen Mountain are one of current subjects. Based on GIS spatial analysis technology, the tectonic geomorphologic characteristics of the Jianjiang River Basin are studied by using the slope analysis, amplitude of landforms, hypsometric integral analysis. Taking tectonic uplifts, landslides, and debris-flow of the right bank of Haizi River of Jianjiang for example, we use field data, aerial photographs and digital elevation data to conduct quantitative analyses on the landslide, debris-flow erosion processes and effects over the geomorphic growth of Longmen Mountain. The preliminary results are the following： （ 1 ） The landform of the Jianjiang River Basin is in the mature stage that have large slopes along the north of Yingxiu-Beiehuan Fault. The 2008 Wenchuan MS. 0 Earthquake triggered co-seismic landslides and debris flow and caused very heavy loss. （2） The volume of co-seismic landslides in the fight bank of Haizi River is up to 3 852 x 104 m3 which is less than the equivalent volume of co-seismic uplift 5 339 × 10^4 m3 that we calculate. The difference mount will cause new uplift and geomorphie growth. （3） The volume of debris flow was a little bit more 1000 × 10^4 m3 that meant 30% volume of coseismic landslides was changed into debris flows after the earthquake. Debris flow discharged 1 000 × 10^4 m3 of solid materials into the Haizi River. （4） Assuming the Haizi River keeps a steady state of the present carrying capacity, it takes 280 years that the landslide mass caused by the 2008 Wenchuan M8.0 Earthquake to carry out from this region. And this time length is less than the recurrence interval of great seismic events. In other words, the coseismic landslide mass mount can be unloaded within the recurrence interval of great seismic event. （5） Tectonic uplift and iso-static rebound caused by repeated large seismic menshan mountain region. events play an important role on the uplift of Long-menshan mountain region. |
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| Keywords: | the 2008 Wenchuan M8 0 Earthquake tectonic uplift co-seismic landslide debris flow after earthquakes river unloading mountain growth Haizi River Jiangjian River Longmenshan Mountain |
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