2008年汶川大地震小鱼洞地表破裂带精细填图
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摘要
5.12汶川Mw7.9级地震为罕见的、地壳尺度位移配分于多条平行断裂的板内逆冲走滑型地震。在2条北东走向、近平行的主要地表破裂间,发育北西走向的小鱼洞地表破裂。介绍了对小鱼洞北西向地表破裂的精细填图。小鱼洞地表破裂空间上位于灌县-江油与映秀-北川断裂间,全长约8km,总体走向310°,为南西盘抬升、逆冲兼具左旋走滑性质。地表破裂在南东端走向变化较大,从300~310°变为南北向,并与灌县-江油地表破裂带的磁峰段相连。小鱼洞地表破裂的垂向位错自北西往南东方向递减,北西端陡坎高度最大3.4m,南东端则小于0.2m,衰减梯度约为0.5m/km。左旋走滑位移测量点较少,集中在中段的小鱼洞镇附近,所测最大左旋走滑位移约为2.2m,一般走滑位错与同处垂直位错具有同步变化的特征。小鱼洞断裂近地表的倾角较缓,为30°±15°。结合已有地貌、地球物理和地质研究结果,提出小鱼洞断裂是向下与灌县-江油断裂交会的侧向断坡,位于映秀-北川断裂中南段间的断面倾角差异的撕裂部位,连接映秀-北川和灌县-江油断裂。在运动学上,认为小鱼洞断裂是以斜向断坡为几何形态的撕裂断裂,调节了北东走向的主断裂的运动学横向差异。小鱼洞断裂上的同震位移矢量与N70°、80°E的区域主压应力场方向匹配。这一方向与龙门山高原边界斜交。
The 12th May 2008 Wenchuan earthquake is one of the very few reported continental oblique reverse-faulting events with crustal-scale co-seismic slip partitioning on parallel reverse faults.Between the two principal NE-striking ruptures,the NW-striking Xiaoyudong also broke during the quake.This paper reports a detailed mapping and coseismic slip measurements along the Xiaoyudong rupture.The generally N55°W-striking Xiaoyudong rupture extends for ~8km and accommodates a left-lateral and SWside up oblique motion.In the map view,the rupture zone has a relatively stable strike over the most part of the fault,but changes rapidly at its southeast end,where the strike changes from N55~65°W to nearly north-south southward,and then connects with the Cifeng section of the Pengguan fault.Fault scarp is highest in the northwest part,reaching 3.4m,and decreases southeastward to less than 0.2m at the southeastern end,with the average slip gradient of 6×10-3 along the strike.Left-lateral offset measurements are sparser than the vertical,and are concentrated in the middle reach near Xiaoyudong Town.The maximum observed left-lateral displacement is 2.2m.Left-lateral offsets co-vary with the vertical component.The near-surface fault has low to medium dip angle,being 30°± 15°.Geological and geophysical evidence suggests that the Xiaoyudong fault is likely a ~30°SW-dipping lateral ramp that soles into the Pengguan fault,and at its northwestern end intersects with the Beichuan fault,where the latter has a step in the fault plane.Kinematically,the Xiaoyudong fault likely functions as a tear and conjugate fault,connecting and transferring coseismic slip transfer between the Beichuan and Pengguan faults.Xiaoyudong rupture is a tear fault with the geometry of oblique ramp,adjusting the lateral variations of the northeast-trending main fault kinematics.Slip vector on the Xiaoyudong fault is compatible with the regional N70° and 80°E principal compressional stress direction,oblique to the current mountain front orientation.
引文
[1]Chen Ji.http://www.geol.ucsb.edu/faculty/ji/big_earthquakes/2008/05/12/Sichuan.heml,2008.
    [2]王卫民,赵连锋,李娟,等.四川汶川8.0级地震震源过程[J].地球物理学报,2008,51(5):1403-1410.
    [3]张勇,冯万鹏,许力生,等.2008年汶川大地震的时空破裂过程[J].中国科学(D辑),2008,38(10):1186-1194.
    [4]徐锡伟,闻学泽,叶建青,等.汶川Ms8.0地震地表破裂带及其发震构造[J].地震地质,2008,30(3):597-629.
    [5]张培震,徐锡伟,闻学泽,等.2008年汶川8.0级地震发震断裂的滑动速率、复发周期和构造成因[J].地球物理学报,2008,51(4):1066-1073.
    [6]何宏林,孙昭民,王世元,等.汶川Ms8.0地震地表破裂带白沙河段破裂及其位移特征[J].地震地质,2008,30(3):658-673.
    [7]刘静,张智慧,文力,等.汶川8级大地震同震破裂的特殊性及构造意义[J].地质学报,2008,82(12):1707-1722.
    [8]李海兵,付小方,Jér觝me VAN DER WOERD,等.汶川地震(Ms8.0)地表破裂及其同震右旋斜向逆冲作用[J].地质学报,2008,82(12):1623-1643.
    [9]国家重大科学工程“中国地壳运动观测网络”项目组测定的2008年汶川Ms8.0级地震的同震位移场[J].中国科学(D辑),2008,38(10):1195-1206.
    [10]朱艾澜,徐锡伟,刁桂苓,等.汶川Ms8.0地震部分余震重新定位及地震构造初步分析[J].地震地质,2008,30(3):759-767.
    [11]黄媛,吴建平,张天中,等.汶川8.0级大地震及其余震序列重定位研究[J].中国科学(D辑),2008,38(10):1242-1249.
    [12]付碧宏,时丕龙,张之武.四川汶川Ms8.0大地震地表破裂带的遥感影像解析[J].地质学报,2008,82(12):1679-1687.
    [13]陈九辉,刘启元,李顺成,等.汶川Ms8.0地震余震序列重新定位及其地震构造研究[J].地球物理学报,2009,52(2):390-397.
    [14]郑勇,马宏生,吕坚,等.汶川地震强余震(Ms≥5.6)的震源机制解及其与发震构造的关系[J].中国科学(D辑),2009,39(4):413-426.
    [15]Xu X,Wen X,Yu G,et al.Coseismic reverse-and oblique-slipsurface faulting generated by the 2008 Mw 7.9 Wenchuan earth-quake,China[J].Geology,2009,37(6):515-518.
    [16]Liu-Zeng J,Zhang Z,Wen L,et al.Co-seismic ruptures of the 12May 2008,Ms 8.0 Wenchuan earthquake,Sichuan:East-West crustalshortening on oblique,parallel thrusts along the eastern edge of Tibet[J].Earth and Planetary Science Letters,2009,286(3/4):355-370.
    [17]李海兵,吴富崓,司家亮,等.2008年汶川地震同震滑移特征、最大滑移量及构造意义[J].第四纪研究,2009,29(3):387-402.
    [18]陈桂华,李峰,郑荣章,等.逆冲型断裂同震地表变形定量分析的几个问题——以汶川Ms8.0地震为例[J].地震地质,2008,30(3):674-682.
    [19]陈桂华,徐锡伟,于贵华,等.2008年汶川Ms8.0地震多断裂破裂的进地表滑移及滑移分解[J].地球物理学报,2009,52(5):1384-1394.
    [20]Wesnousky S G.Displacement and Geometrical Characteristics ofEarthquake Surface Ruptures:Issues and Implications for Seismic-Hazard Analysis and the Process of Earthquake Rupture[J].Bulletinof the Seismological Society of America,2008,98(4):1609-1632.
    [21]Clark M M.Surface rupture along the Coyote Creek fault,the Bor-rego Mountain Earthquake of April 9,1968[J].U.S.Geol.Surv.Profess,1972,787:55-86.
    [22]卢华复等.前龙门山前陆盆地推覆构造的类型和成因[J].南京大学学报,1989,25(4):18-24.
    [23]潘桂棠,王桂生,徐耀荣,等.青藏高原新生代构造演化[M].北京:地质出版社,1990:1-190
    [24]潘桂棠,陈智樑,李兴振,等.东特提斯地质构造形成演化[M].北京:地质出版社,1997:1-218
    [25]罗志立.龙门山造山带岩石圈演化的动力学模式[J].成都地质学院学报,1991,18(1):1-7.
    [26]宋鸿彪,刘树根.龙门山中北段重磁场特征与深部构造关系[J].成都地质学院学报,1991,18(1):74-82.
    [27]刘和甫,梁慧社.川西龙门山冲断系构造样式与前陆盆地演化[J].地质学报,1994,6(8):101-118
    [28]许志琴,侯立玮,王宗秀,等.中国松潘-甘孜造山带的造山过程[M].北京:地质出版社,1992.
    [29]刘树根.龙门山冲断带与川西前陆盆地的形成演化[M].成都:成都科技大学出版社,1993:17-21.
    [30]王懋基.黑水-泉州地学断面的重磁解释[J].地球物理学报,1994,37(3):321-329.
    [31]崔作舟,陈纪平,吴苓.花石峡-邵阳深部地壳结构和构造[M].中华人民共和国地质矿产部地质专报五,构造地质、地质力学,第21号.北京:地质出版社,1996.
    [32]Li Y,Allen PA,Densmore,et al.Evolution of the Longmen ShanForeland Basin(western Sichuan,China)during the Late Triassic In-dosinian Orogeny[J].Basin Research,2003,15,117-138.
    [33]李勇,周荣军,Densmore A L,等.青藏高原东缘龙门山晚新生代走滑-逆冲作用的地貌标志[J].第四纪研究,2006,26(1):40-51.
    [34]李勇,周荣军,Densmore A L,等.龙门山断裂带走滑方向的反转及其沉积与地貌标志[J].矿物与岩石,2006,26(4):26-34.
    [35]王有学,Mooney W D,韩果花,等.台湾-阿尔泰地学断面阿尔金-龙门山剖面的地壳纵波速度结构[J].地球物理学报,2005,48(1):98-106.
    [36]贾东,陈竹新,贾承造,等.龙门山前陆褶皱冲断带构造解析与川西前陆盆地的发育[J].高校地质学报,2003,9(3):402-409.
    [37]张季生,高锐,曾令森,等.龙门山及邻区重、磁异常特征及与地震关系的研究[J].地球物理学报,2009,52(2):572-578.
    [38]Chen S,Wilson C J L.Emplacement of the Longmen Shan Thrust-Nappe Belt along the eastern margin of the Tibetan Plateau[J].Jour-nal of Structural Geology,1996,18:413-430.
    [39]Jia D,Wei G,Chen Z,et al.Longmen Shan fold–thrust belt andits relation to the western Sichuan Basin in central China:New in-sights from hydrocarbon exploration[J].AAPG Bulletin 2006,90,1425-1447.
    [40]唐荣昌,立德华.松潘-龙门山地区主要活动断裂带第四纪活动特征[J].中国地震,1991,7(3):64-71.
    [41]邓起东,陈社发,赵小麟.龙门山及其邻区的构造和地震活动及动力学[J].地震地质,1994,16(4):389-403.
    [42]赵小麟,邓启东,陈社发.龙门山逆断裂带的构造地貌学研究[J].地震地质,1994,16(4):422-428
    [43]马保起,苏刚,侯治华,等.利用岷江阶地的变形估算龙门山断裂带中段晚第四纪滑动速率[J].地震地质,2005,27(2):234-242.
    [44]周荣军,李勇,Densmore A L,等.青藏高原东缘活动构造[J].矿物岩石,2006,26(2):40-51.
    [45]Densmore A L,Ellis M A,Li Y,et al.Active tectonics of the Be-ichuan and Pengguan faults at the eastern margin of the TibetanPlateau[J].Tectonics,2007,TC4005,doi:10.1029/2006TC001987.
    [46]陈国光,计凤桔,周荣军,等.龙门山断裂带晚第四纪活动性分段的初步研究[J].地震地质,2007,29(3):657-673.
    [47]王振荣.四川彭灌地区推覆构造及其成因[J].成都理工大学学报(自然科学版),1984,(4).
    [48]李远图.龙门山南西段飞来峰构造的形成特征[J].四川地质学报,1984.
    [49]李远图.龙门山南西段飞来峰构造的基本特征[J].地质通报,1989,03:247-249.
    [50]韩建辉.论龙门山飞来峰群[J].沉积与特提斯地质,2006,26(1):54-59.
    [51]Shen Z K,Sun J B,Zhang P Z,et al.Slip maxima at fault junctionsand rupturing of barriers during the 2008 Wenchuan earthquake[J].Nature Geoscience,2009,2:718-724
    [52]四川省地质局第二区域地质测量队.四川省地质图灌县幅,1976.
    [53]张智慧,刘静,许强,等.逆冲断裂的视走滑位移分析及其在5.12汶川大地震同震破裂调查中的应用[J].地质学报,2008,82(12):1723-1732.
    [54]李勇,黄润秋,Densmore,A.L,等.龙门山小鱼洞断裂在汶川地震中的地表破裂及地质意义[J].第四纪研究,2009,29(3):502-512.
    [55]冉勇康,陈立春,陈桂华,等.汶川Ms8.0地震发震断裂大地震原地重复现象初析[J].地震地质,2008,30(3):630-643.
    [56]Chang C,Chen G,Xu X,et al.Influence of the pre-existing Xi-aoyudong salient in surface rupture distribution of the Mw7.9Wenchuan earthquake,China[J].Tectonophysics,2012,530:240-250.
    [57]Tan X B,Yuan R M,Xu X W,et al.Surface rupture near Xi-aoyudong area produced by 2008 Mw 7.9 Wenchuan Earthquake[J].Journal of Asian Earth Sciences,2012,http://dx.doi.org/10.1016/j.jseaes.2012.06.005.
    [58]Kuo Y,Chen Y,Huang M,et al.Fault geometry based on coseis-mic ground displacements from satellite images for the 2008Wenchuan earthquake,Sichuan,China.EOS.Transactions of theAmerican Geophysical Union,2009,90(52)(Fall Meet.Suppl.,AbstractT11A-1769).
    [59]Aagaard B T,Heaton TH,Hall JF.Dynamic earthquake ruptures inthe presence of lithostatic normal stresses:Implications for frictionmodels and heat production[J].Bulletin of the Seismological Societyof America,2001,91:1765-1796.
    [60]Liu-Zeng J,Heaton T.The effect of slip variability on earthquakeslip-length scaling[J].Geophysical Journal International,2005,1163(3):841-849.
    [61]何宏林,孙昭民,魏占玉,等.汶川MS8.0地震地表破裂带白沙河段破裂及其位移特征[J].地震地质,2008,30(3):658-673.
    [62]Housner G W.Properties of strong ground motion earthquakes[J].Bulletin of the Seismological Society of America,1955,45(3):197-218.
    [63]Brune J N.Tectonic Stress and the Spectra of Seismic Shear Wavesfrom Earthquakes[J].Journal of Geophysical Research,1970,75(26):4997-5009.
    [64]Brune J N.The physics of earthquake strong motion,in SeismicRisk and Engineering Decisions[M].Lomnitz,C.&Rosenblueth eds,E.,Elsevier,New York,1976:140-177.
    [65]Heaton T H.Evidence for and implications of self-healing pulses ofslip in earthquake rupture[J].Physics of the Earth and Planetary Inte-riors,1990,64:1-20.
    [66]Dietrich J H.Modeling of rock friction,1,Experimtal results andconstitutivc equations[J].Journal of Geophysical Research,1979,84(B5):2161-2168.
    [67]Ruina A.Slip instability and state variable friction laws[J].Journal ofGeophysical Research,1983,88(B12):10359-10370.
    [68]Rice J R.Spation-temporal complexity of slip on a fault[J].Journalof Geophysical Research,1993,98(B6):9885-9907.
    [69]Marone C.Laboratory-derived friction laws and their application toseismic faulting[J].Annual Review of Earth and Planetary Sciences,1998,26:643-696.
    [70]Cochard A,Madariaga R.Dynamic faulting under rate-dependentfriction[J].Pure and Applied Geophysics,1994,142:419-445.
    [71]Shaw BE.Frictional weakening and slip complexity on earthquakefaults[J].Journal of Geophysical Research,1995,100:6769-6788.
    [72]Andrews DJ.Fault geometry and earthquake mechanics[J].Annali DiGeofisca,1994,37:1341-1348.
    [73]Aki K.Interrelation between fault zone structures and earthquakeprocesses[J].PAGEOPH,1995,145:647-676.
    [74]Densmore A L,Li Y,Richardson N J,et al.The Role of LateQuaternary Upper-Crustal Faults in the 12 May 2008 WenchuanEarthquake[J].Bulletin of the Seismological Society of America,2010,100:2700-2712.
    [75]Fletcher J,Rockwell T,Teran O,et al.The surface ruptures associ-ated with the El Mayor-Borrego earthquake sequence[M].GSA meet-ing,May 27-29,2010,Anaheim,California,abstract LB1-5.
    [76]Dahlstrom C D A.Structural geology in the eastern margin of theCanadian Rocky Mountains[J].Bulletin of Canadian Petroleum Ge-ology,1970,18(3):332-406
    [77]McClay K R.Glossary of thrust tectonics terms[C]//McClay K R,ed.Thrust Tectonics.New York:Chapman Hall,1992:419-433.
    [78]郑勇,马宏生,吕坚,等.汶川地震强余震(Ms≥5.6)的震源机制解及其与发震构造的关系[J].中国科学(D辑),2009,39(4):413-426.
    [79]杜义,谢富仁,张效亮,等.汶川MS8.0级地震断层滑动机制研究[J].地球物理学报,2009,52(2):464-473.
    [80]谢富仁,崔效锋,赵建涛,等.中国大陆及邻区现代构造应力场分区[J].地球物理学报,2004,47(4):654-662.
    [81]Jones TD,Nur A.The nature of seismic reflections from deepcrustal fault zones[J].Journal of Geophysical research,1984,89(NB5):3153-3171.
    [82]崔效锋,谢富仁,赵建涛.中国及邻区震源机制解的分区特征[J].地震地质,2005,27(2):298-307.
    [83]徐纪人,赵志新.青藏高原及其周围地区区域应力场与构造运动特征[J].中国地质,2006,33(2):275-285.
    [84]Avouac J P,Tapponnier P.Kinematic model of active deformationin central Asia[J].Geophysical Research Letters,1993:20,895-898.
    [85]Zhang P Z,et al.Continuous deformation of the Tibetan Plateaufrom global positioning system data[J].Geology,2004,32:809-812.
    [86]Shen Zhengkang,Lu J,Wang M et al.Contemporary crustal defor-mation around the southeast borderland of the Tibetan Plateau[J].Journal of Geophysical research,2005,110,B11409,doi:10.1029/2004JB003421.
    [87]徐锡伟,闻学泽,陈桂华,等.巴颜喀拉地块东部龙日坝断裂带的发现及其大地构造意义[J].中国科学(D辑),2008,38(5):529-542.
    [88]王二七,陈智梁.龙门山断裂带印支期左旋走滑运动及其大地构造成因[J].地学前缘,2001,8(2):375-384.
    [89]England P,Molnar P.Right-lateral shear and rotation as the expla-nation for strike-slip faulting in eastern Tibet[J].Nature,1990,344:140-142.

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