汶川-映秀8.0级大地震的发生与岩石圈精细速度结构和动力机制
详细信息 本馆镜像全文    |  推荐本文 | | 获取馆网全文
摘要
汶川-映秀8.0级大地震发生在由3条NE向断裂带组成的龙门山逆冲走滑断裂系上,造成了以汶川、映秀为中心和其周边地域的严重破坏和人员的重大伤亡。然而强烈地震发生前却未见有可能的确切征兆或浅表层异常活动的迹象(相对于短期和临震预测),即浅层过程与地震发生的深层过程并不匹配。那么为什么在龙门山地区突然发生了这次大地震,它具有哪些特征?其成因机制又是什么?为此必须对这次强烈地震"孕育"、发生和发展的壳、幔速度结构以及其深层动力过程进行深入研究和探讨。通过对松藩-甘孜、龙门山造山带和四川盆地地域人工源地震深部探测以及天然地震层析成像、接收函数与面波频散反演研究分析,初步结果表明:1)在印度洋板块与欧亚板块陆-陆碰撞和挤压作用下,形成了喜马拉雅造山带和东构造结,该东构造结似一尖楔向NNE方向顶挤并插入青藏高原东北缘,故迫使高原深部物质向东流展,在受到以龙门山为西北边界的四川盆地高速"刚性"物质阻隔下,一部分物质则转而向东南侧向运移;2)龙门山造山带与其西北侧地带地形高差达3500±500m左右,地壳厚度在龙门山西北部为65±5km左右,四川盆地为40±2km左右,而龙门山地带与其东、西两侧相比则其地壳厚度变化幅度达15~20km,这里恰为应力作用的耦合与集中地带;3)下地壳和地幔盖层物质以上、中地壳(深20~25km)中的低速层为第一滑移面,以上地幔软流层顶面为第二滑移面,且在四川盆地深部"刚性"物质阻隔下,下地壳和上地幔盖层物质以高角度在龙门山断裂系与四川盆地的耦合地带向上运移(或称逆冲),且在龙门山地表3条断裂构成的断裂系向下收敛到15±5km左右深处汇聚,二者强烈碰撞、挤压和震源介质破裂;即在物质与能量的强烈交换下,高度集中的应力得到急速释放,故形成了这次8.0级大地震。为此通过该区的壳、幔速度结构变异,初步揭示了这次8.0级大地震"孕育"、发生和发展的深部介质和构造环境及其深层动力过程。
The 2008 Wenchuan M_S8.0 earthquake occurred in the Longmenshan fault system had no noticeable precursors.It might imply that the shallow process was matched with the deep process in this gigantic shock.Then why such a strong earthquake occurred in the Longmenshan fault system? What are the characteristics of this earthquake? What is its seismogenic mechanism? This article attempts preliminarily to answer some of these problems through method such as deep seismic sounding,nature earthquake tomography,receiver function,and surface wave dispassion.The India-Eurasia plate collision is the most important dynamic setting of major earthquakes in South Western China.The eastern end of the Himalayan chain is rapidly moving in NNE direction into the Tibetan Plateau,forcing the deep material to flow eastward.Owing to the obstruction of the NE trending Longmenshan fault system on the northwestern margin of the Sichuan Basin,a part of the flow material turns to southeast.The Longmenshan orogenic belt is a conspicuous boundary of topography and crust structure,across which the elevation difference is as large as 3500±500m,with crustal thickness 60±5km in its west and 40±2km in its east.Thus it must experience intense deformation and stress accumulation.It can be inferred from available data that there is the lower crust and upper mantle materials to flow eastward along two deep slide surfaces: one is a low velocity and low-resistivity layer(20~25km deep);the other is the top of the asthenosphere.Hindered by the high velocity rigid material beneath the Sichuan Basin,the lower crust and upper mantle materials move up by high angle overthrusting in Longmenshan.On the other hand,three thrust faults visible west of Longmenshan extend downward to the depth of 15±5km,where they converge,into one fault.Therefore the Longmenshan tectonic zone is a place of the intense exchange of material and energy.It is the sudden large-scale rupture of source medium beneath Longmenshan that released a huge amount of elastic strain and then resulted in the Wenchuan M_S8.0 earthquake.
引文
1 Yang Z X,Waldhauser F,Chen Y T et al.Double-difference relocation of earthquakes in central-Western China,1992-1999. Journal of Seismology,2005,9:241-264
    2滕艳.地震预测研究和抗震须并轨进行--访汶川地震专家委员会成员、中国科学院院士滕吉文.地质勘探导报,2008年5月29日,第4版:1-4 Teng Yan.Must combine track for study the earthquake prediction and earthquake protective measure-Visit the member of National committee of Wenchuan seismic specialists,Academician of the Academy of Science,Teng Jiwen.The Geological exploration Herald,May 29,2008,the fourth block:1-4
    3国家地震局地质研究所,云南省地震局.滇西北地区活动断裂.北京:地震出版社,1990. 1-321 Institute of Geology,China Seismological Bureau,Seismological Bureau of Yunnan Province.The Active Faults in North West Yunnan Province.Beijing:Seismological Press,1990. 1-321
    4徐锡伟,张培震,闻学泽等,川西及其邻近地区活动构造基本特征与强震复发模型.地震地质,2005,27(3) :446-461 Xu Xiwei,Zhang Peizhen,Wen Xueze et al.Features of active tectonics and recurrence behaviors of strong earthquakes in the western Sichuan Province and its adjacent regions.Seismology and Geology,2005,27 (3) :446-461
    5李传友,宋方敏,冉勇康.龙门山断裂带北段晚第四纪活动性讨论.地震地质,2004. 26(2) :248-258 Li Chuanyou,Song Fangmin,Ran Yongkang.Late Quaternary activity and age constraint of the Northern Longmenshan Fault zone.Seismology and Geology,2004,211 (2) :248-258
    6吕江宁,沈正康,王敏.川滇地区现代地壳运动速度场和活动块体模型研究.地震地质,2003,25(4) :543-554 Lau Jiangning,Shen Zhengkang,Wang Min.Contemporary crustal deformation and active tectonic block model of the Sichuan-Yunnan region,China.Seismology and Geology,2003,25 (4) :543-554
    7唐荣昌,韩渭滨主编.四川活动断裂与地震.北京:地震出版社,1993. 1-192 Tang Rongchang,Han Weibing eds.Active Faults and Earthquakes in Sichuan Province.Beijing:Seismological Press,1993. 1-192
    8闻学泽著.活动断裂地震潜势的定量评估.北京:地震出版社1995. 1-120 Wen Xueze.Quantitative Assessments of Earthquake Potential on Active Faults.Beijing:Seismological Press,1995. 1-120
    9 Densmore A L,Ellis M A,Li Yong et al.Active tectonics of the Beichuan and Pengguan faults at the eastern margin of the Tibetan Plateau.Tectonics,2007. 26:TC4005. 1-17
    10 李勇,周荣军,Densmore A L等著.青藏高原东缘大陆动力学过程与地质响应.北京:地质出版社,2006. 1-152 Li Yoag,Zhou Rongjun,Densmore A L et al.Continental Dynamics and Geological Responses of the Eastern Margin of Qinghai-Tibet Plateau.Beijing:Geological Publishing House,2006. 1-152
    11 张培震,闻学泽,徐锡伟等.2008年汶川8. 0级特大地震孕育和发生的多单元组合模式,科学通报,2009,54(7) :944-953 Zhang Peizhen,Wen Xueze,Xu Xiwei et al.Tectonic model of the great Wenchuan earthquake of May 12,2008,Sichuan,China.Chinese Science Bulletin,2009,54 (7) :944-953
    12 Burchfiel B C,Royden L H,Van der Hilst R D et al.A geological and geophysical context for the Wenchuan earthquake of 12 May 2008,Sichuan,People's Republic of China.GAS today,2008,18(7) :4-11
    13 丁国瑜主编.中国岩石圈动力学概论.北京:地震出版社,1991. 1-600 Ding Guoyu ed.Introduction of China Lithosphere Dynami Beijing:Seismological Press,1991. 1-600
    14 曹秋鹏,贾东,朱艾斓等.青藏高原东缘龙门山冲断带与四川盆地的现今构造表现:数字地形和地震活动证据.地质科学,2007,42(1) :31-44 Cao Qiupeng,Jia Dong,Zhu Ailan et al.Active tectonics in the Longmen thrust belt to the eastern Qinghai-Tibetan Plateau and Sichuan Basin:Evidence from topography and seismicity.Chinese Journal of Geology,2007,42 (1) :31-44
    15 张培震,王琪,马宗晋中国大陆现今构造运动的GPS速度场与活动地块.地学前缘,2002,9(2) :430-441 Zhang Peizhen,Wang Qi,Ma Zongjin.GPS velocity field and active crustal blocks of contemporary tectonic deformation in continental China.Earth Science Frontiers,2002,9 (2) :430-441
    16 Huang Jinli,Zhao Dapeng,Zheng Sihua.Lithospheric structure and its relationship to seismic and volcanic activity in South West China.Journal of Geophysical Research,2002,107 (B10) :2255,doi:10. 1029/2000JB000137
    17 Zhang Zhongjie,Yuan Xiaohui,Chen Yun et al.Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin.Earth and Planetary Science Letters,2010,292:254-264
    18宋仲和,安振强,陈里华.中国与邻近海域地壳与上地幔的P波速度结构.地震学报,1986,8(2) :263-274 Song Zhonghe,An Zhenqiang,Chea Lihua.P-wave velocity of the upper mantle on the mainland and the marginal seas of China.Acta Seismological Sinica,1986,8 (2) :263-274
    19刘启元,李昱,陈九辉等.汶川M_S8. 0地震:地壳上地幔S波速度结构的初步研究.地球物理学报,2009,52(2) :309-319 Liu Qiyuan,Li Yu,Chen Jiuhui et al.Wenchuan M_S8. 0 earthquake:Preliminary study of the S-wave velocity structure of the crust and upper mantle.Chinese Journal of Geophysics,2009,52(2) :309-319
    20朱介寿,李海丰,Jules G等.龙门山及青藏高原被动源地震剖面观测.地球探测与信息技术教育部与四川省重点实验室2007年学术年会论文集,2007. 1-8 Zhu Jieshou,Li Haifeng,Jules G et al.A Passive Seismological Profile Experiment in Eastern Margin of Tibetan Plateau and Longmenshan Region.Annual Academic Symposium Key Laboratory of Geoexploration & Information Technology of Ministry of Education& Sichuan Province,2007. 1-8
    21 Wang Chunyong,Han Weibin,Wu Jianping et al.Crust structure beneath the eastern margin of the Tibetan Plateau and its tectonic implications.Journal of Geophysical Research,2007,112 (B7) :B07307,doi:10. 1029/2005JB003873
    22朱介寿.汶川地震的岩石圈深部结构与动力学背景.成都理工大学学报(自然科学版),2008,35(4) :348-356 Zhu Jieshou.The Wenchuan earthquake occurrence background in deep structure and dynamics of lithosphere.Journal of Chengdu University of Technology (Science & Technology Edition),2008,35(4) :348-356
    23陈学波,吴铁强,杜平山等.龙门山构造带两侧地壳速度结构特征.见:国家地震局科技监测司编.中国大陋深部构造的研究与进展.北京:地质出版社,1988. 97-113 Chen Xuebo,Wu Tieqiang,Du Pingshan et al.Crustal velocity structure at the two sides of Longmenshan tectonic belt.In: Department of Scientific Programming and Earthquake Monitoring ed.Developments in the Research of Deep Structures of China's Continent.Beijing:Geological Publishing House,1988. 97-113
    24孙克忠,滕吉文.由长周期地震面波研究西藏高原地区地壳和上地幔的速度分布.地球物理学报,1985,28(增刊Ⅰ):42-53 Sun Kezhong,Teng Jiwen.The velocity distribution in the crust and upper mantle beneath the Xizang(Tibetan) Plateau from Long period surface waves.Acta Geophysica Siaica,1985,28 (Suppl.Ⅰ):42-53
    25刘启元,陈九辉,李顺成等.汶川8. 0级地震:川西流动地震台观测数据的初步分析.地震地质,2008,30(3) :584-596 Liu Qiyuan,Chen Jiuhui,Li Shuncheng et al.The M_ 8. 0 Wenchuan earthquake:Preliminary results from the Western Sichuan mobile seismic array observations.Seismology and Geology,2008,30 (3) :584-596
    26李立,金国元.攀西地区岩石圈的电性结构.见:张云湘主编.中国攀西裂谷文集(3) .北京:地质出版社,1988. 66-75 Li Li,Jin Guoyuan.Electrical conductivity structure of the Lithosphere in Panxi region.In:Zhang Yunxiang ed.Contribution to Panzhihua Xichang Rift,China (No.3) .Beijing:Geological Publishing House,1988. 66-75
    27滕吉文,白登海,杨辉等.2008汶川M_S8. 0强烈地震发生的深层过程和动力学响应.地球物理学报,2008,51(5) :1385-1402 Teng Jiwen,Bai Denghai,Yang Hui et al.Deep processes and dynamic responses associated with the Wenchuan M_ 8. 0 earthquake of 2008. Chinese Journal of Geophysics,2008,51 (5) :1385-1402
    28王椿镛,吴建平,楼海等.青藏高原东部壳幔速度结构和地幔变形场的研究.地学前缘,2006,13(5) :349-359 Wang Chunyong,Wu Jianping,Lou Hai et al.Study of crustal and upper mantle's structure and mantle deformation field beneath the Eastern Tibetan plateau.Earth Science Frontiers,2006,13 (5) :349-359
    29 熊熊,滕吉文.青藏高原东缘地壳运动与深层过程研究.地球物理学报,2002,45(4) :507-515 Xiong Xiong,Teng Jiwen.Study on crustal movement and deep process in Eastern Qinghai-Xizang Plateau.Chinese Journal of Geophysics,2002,45(4) :507-515
    30滕吉文,张中杰,胡家富等.青藏高原整体隆升与地壳短缩增厚的物理-力学机制研究(上).高校地质学报,1996,2(2) :121-133 Teng Jiwen,Zhang Zhongjie,Hu Jiafu et al.Physical-mechanical mechanism for the whole uplifting of the Qinghai-Xizang Plateau and the lateral shortening and vertical thickening of the crust (1st).Geological Journal of China Universities,1996,2 (2) :121-133
    31滕吉文,张中杰,胡家富等.青藏高原整体隆升与地壳短缩增厚的物理-力学机制研究(下).高校地质学报,1996,2(3) :307-323 Teng Jiwen,Zhang Zhongjie,Hu Jiafu et al.Physical-mechanical mechanism for the whole uplifting of the Qinghai-Xizang Plateau and the lateral shortening and vertical thickening of the crust (2nd).Geological Journal of China Universities,1996,2 (3) :307-323
    32滕吉文,王谦身,王光杰等.喜马拉雅"东构造结"地区的特异重力场与深部地壳结构.地球物理学报,2006,49(4) :1045-1052 Teng Jiwen,Wang Qianshen,Wang Guangjie et al.Specific gravity field and deep crustal structure of the ' Himalayas east structural knot'.Chinese Journal Geophysics,2006,49 (4) :1045-1052
    33 Teng Jiwen.Characteristics of the geophysical fields and plate tectonics of the Qinghai-Xizang Plateau and its neighbouring regions.Proceedings of Symposium on Qinghai-Xizang (Tibet) Plateau (Beijing China).Geological and Ecological Studies of Qinghai-Xizang Plateau(Vol.1) .Beijing:Science Press,1981. 633-650
    34 Meng Qingren,Hu Jianmin,Wang Erchie et al.Late Cenozoic denudation by large magnitude landslides in the eastern edge of Tibetan Plateau.Earth and Planetary Science Letters,2006,243:252-267
    35 Burchfiel B C,Zhang P,Wang Y et al.Geology of the Haiyuan fault zone,Ningxia Autonomous region,China,and its relation to the evolution of the northeastern margin of the Tibetan Plateau.Tectonics,1991,10(6) :1091-1110
    36 Wang Qi,Zhang Peizhen,Fregmuelier J T et al.Present-day crustal deformation in China constrained by global positioning system measurements.Science,2001,294:574-577
    37苏有锦,秦嘉政.川滇地区强地震活动与区域新构造运动的关系.中国地震,2001,17(1) :24-34 Su Youjin,Qin Jiazheng.Strong earthquake activity and relation to regional neotectonic movement in Sichuan-Yunnan region.Earthquake Research in China,2001,17(1) :24-34
    38张国民,李丽,黎凯武等.强震成组活动与潮汐力调制触发.中国地震,2001,17(2) :110-120 Zhang Guomin,Li Li,Li Kaiwu et al.Group strong earthquakes and triggering by tidal stress.Earthquake Research in China,2001,17(2) :110-120
    39 Clark M K,Bush J W M,Royden L H.Dynamic topography produced by lower crustal flow against rheological strength heterogeneities bordering the Tibetan Plateau.Geophysical Journal International,2005,162:575-590
    40 Meng Qingren,Wang Erchie,Hu Jianmin.Mesozoic sedimentary evolution of the north West Sichuan Basin:Implication for continued clockwise rotation of the South China block.Geological Society of America Bulletin,2005,117 (3-4) :396-410
    41 Beaumont C,Jamieson R A,Nguyen M H et al.Crustal channel flows:1. Numerical models with application to the tectonics of the Himalayan-Tibetan orogen.Journal of Geophysical Research,2004,109:B06406,doi:10. 1029/2003JB002809
    42 Jamieson R A,Beaumont C,Medvedev Set al.Crustal channel flows:2. Numerical models with implications for metamorphism in the Himalayan-Tibetan orogen.Journal of Geophysical Research,2004,109:B06407,doi:10. 1029/2003JB002811
    43陈运泰.汶川特大地震的震级和断层长度.科技导报,2008,26(10) :26-27 Chen Yuntai.On the magnitude and the fault length of the great Wenchuan earthquake.Science & Technology Review,2008,26(10) :26-27
    44李海兵,王宗秀,付小方等.2008年5月12日汶川地震(M_S8. 0) 地表破裂带的分布特征中国地质,2008,35(5) :803-813 Li Haibing,Wang Zongxiu,Fu Xiaofang et al.The surface rupture zone distribution of the Wenchuan earthquake(M_S8. 0) happened on May 12th,2008. Geology in China,2008,35 (5) :803-813
    45 滕吉文,张永谦,闫雅芬.强烈地震震源破裂和深层过程与地震短临预测探索.地球物理学报,2009,s2(2) :428-443 Teng Jiwen,Zhang Yongqian,Yan Yafen.Deep process of the rupture of strong earthquakes and exploration for the impending earthquake prediction.Chinese Journal of Geophysics,2009,52(2) :428-443

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