青藏高原东南缘瑞利波群速度分布特征及其构造意义探讨
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摘要
青藏高原东南缘是研究印度—欧亚板块碰撞过程、块体间相互作用和壳幔变形机制的重要地区.本文利用川滇地区流动地震台阵和固定地震台网共557个台站的连续波形数据,基于改进的背景噪声处理流程和分析方法得到了6023条瑞利波群速度频散曲线,反演获得了6~48s的瑞利波群速度分布图像.结果显示在四川盆地内部短周期群速度分布较好地揭示了盆地内沉积层厚度的横向变化.在30~48s周期,四川盆地西部群速度存在南低、北高的特征,推测是南部中下地壳和上地幔温度较高引起的.温度的增高降低了地壳的力学强度,在青藏高原东向挤压作用下盆地西南部地壳更易发生变形,并导致脆性上地壳在新生代产生地壳缩短和褶皱、断裂等地质活动.攀枝花及其周边地区从地壳浅部至上地幔深度的高速异常体,可能与基性和超基性岩的侵入有关.该高速体具有较大的介质强度,在一定程度上阻碍了青藏高原物质东南向的运移,这可能是造成丽江—小金河断裂两侧巨大高程差异的重要因素.自24s开始,南盘江盆地表现为明显的高速异常,与华南块体西南部其他区域的深部结构存在明显差异.反演的S波速度结构揭示,自中上地壳至上地幔,南盘江盆地的速度一直高于北侧其他区域.结合此地区的地壳运动模式,推测介质S波速度较高、力学强度较大的南盘江盆地对青藏高原物质的东南向逃逸具有一定的阻挡作用.
The southeastern margin of the Tibetan Plateau is an important area for the study of continental collisions between India and Eurasia plates,block interactions,and crust-mantle deformation mechanism.The study on the 3-D velocity structure of crust and mantle in the area helps us understand the formation mechanism and geodynamic process of the plateau.Although many seismological researches have been conducted in this region,high-resolution S-wave velocity structures are still in shortage due to the sparse distribution of seismic stations.Using dense seismic stations set up recently,high-resolution group velocity images of the crust and mantle inthis area are obtained with ambient noise tomography.The new results provide new insights for studying the mechanism of the crust-mantle coupling,deformations of the crust and mantle,and so on.We collected continuous waveform data recorded by 557 temporal and permanent stations in Chuan-Dian fragment region.After removing instrument responses,bandpass filtering,frequency-time normalization,cross-correlation and stacking,more than 50000 empirical Green′s functions were acquired.Furthermore,13972 Rayleigh wave fundamental mode dispersion curves of high signalto-noise ratio waveforms were measured with application of multiple filtering technique.To guarantee the validity of dispersion curves,we selected reliable dispersion curves according to the setting station-distance criteria and cluster analysis.At last,we determined group velocity structures of Rayleigh wave from periods of 6to 48 sin the study area with traditional surface wave tomography technique.From periods of 6to 20 s,group velocity in west and north of Sichuan basin is characterized as low velocity,while the central and southeast Sichuan basin is imaged as high velocity.From periods of 30 to 48s,the group velocity in Sichuan basin is obviously higher than that in the Tibetan Plateau and surrounding orogenic belts.In the meantime,the southwest part of the Sichuan basin is shown as relative low velocity.This phenomenon indicates the lateral variation of velocity structure in the lower crust and upper mantle.At 30 s,low group velocity is observed in Songpan-Ganzi fold belt,western Chuan-Dian fragment block and Xiaojiang fault zone.At Panzhihua and its surrounding area,a high-velocity anomaly exists at all periods.From 6sto24 s,this high-velocity anomaly is oriented in a nearly west-east direction,however between 30 s and 48 sin a northeast-southwest direction.Along with the growth of periods,the anomaly is concentrated to Panzhihua.At periods of 14 sand 20s,high group velocity anomaly exists at the south of Lijiang-Xiaojinhe Fault and the anomaly is parallel with the fault.Since 24 s,highvelocity anomaly shows up at the southeast of the study region and becomes larger with periods turning longer.At 30 s,the range of the high velocity anomaly is consistent with Nanpanjiang Basin.The S-wave velocity cross section reveals that the S-wave velocities of crust and upper mantle in the Nanpanjiang Basin are higher than those in other surrounding regions.High-resolution Rayleigh wave group velocity maps in the southeast of the Tibetan Plateau are obtained using ambient noise tomography based on intensive seismic observation data.Low velocities in Sichuan Basin at short periods reflect the sediments in the basin being younger than the surrounding blocks.In this basin,the different subsidence rate and sediments thickness since Jurassic result in the inhomegeneous distribution of low velocities.In the north and northwest of the basin,the sediments are thickest.For periods of 30 to 48 s,the low velocity in the northwestern margin of the Sichuan Basin may be related with high temperature in the lower crust and upper mantle.The high temperature decreases the mechanical strength of the crust in the southwestern basin,resulting in the crust deforming easier because of the pinching action of the Tibetan Plateau,and probably is the reason of Cenozoic folds,fault movements and crustal shortening in the brittle upper crust.High-velocity anomaly existing from the surface to upper mantle in Panzhihua and surrounding areas is probably caused by the intrusion of mafic-ultramafic magma in Emeishan magmatic activity.This high-velocity anomaly with strong medium strength impedes the material extrusion of Chuanxibei sub-block to some extent,bringing about the enormous difference of topography between the two sides of the Lijiang-Xiaojinhe Fault.The high group velocity anomaly in the southeast of the study area is consistent with the range of theNanpanjiang Basin.Having a higher S-wave velocity,the Nanpanjiang Basin has different deep structure comparing with other regions to the north of Nanpanjiang.Meanwhile,this high velocity anomaly may offer an impact of blocking the southeast extrusion of the plateau material.
引文
Allegre C J,Courtillot V,Tapponnier P,et al.1984.Structure andevolution of the Himalaya-Tibet orogenic belt.Nature,307(5946):17-22,doi:10.1038/307017a0.
    Bensen G D,Ritzwoller M H,Barmin M P,et al.2007.Processingseismic ambient noise data to obtain reliable broad-band surfacewave dispersion measurements.Geophys.J.Int.,169(3):1239-1260,doi:10.1111/j.1365-246X.2007.03374.x.
    Chen J H,Liu Q Y,Li S C,et al.2009.Seismotectonic study byrelocation of the Wenchuan Ms8.0earthquake sequence.ChineseJ.Geophys.(in Chinese),52(2):390-397.
    Chen Y,Badal J,Hu J F.2010.Love and Rayleigh wavetomography of the Qinghai-Tibet Plateau and surrounding areas.Pure Appl.Geophys.,167(10):1171-1203,doi:10.1007/s00024-009-0040-1.
    Chen Y,Zhang Z J,Sun C Q,et al.2013.Crustal anisotropy fromMoho converted Ps wave splitting analysis and geodynamicimplications beneath the eastern margin of Tibet and surroundingregions.Gondwana Res.,24(3-4):946-957.
    Cheng Y Q.2004.The Geology Map of China.2nd ed.(inChinese).Beijing:Geological Publishing House.
    Clark M K,Royden L H.2000.Topographic ooze:Building theeastern margin of Tibet by lower crustal flow.Geology,28(8):703-706,doi:10.1130/0091-7613(2000)28〈703:tobtem〉2.0.co;2.
    Deng W Z,Chen J H,Guo B,et al.2014.Fine velocity structure ofthe Longmenshan fault zone by double-difference tomography.Chinese J Geophys(in Chinese),57(4):1101-1110,doi:10.6038/cjg20140408.
    Ditmar P G,Yanovskaya T B.1987.A generalization of the BackusGilbert method for estimation of lateral variations of surface wavevelocities.Izv.Akad.Nauk.SSSR,Fiz.Zeml.(in Russian),6:30-60.
    Fang L H,Wu J P,Ding Z F,et al.2010.High resolution Rayleighwave group velocity tomography in North China from ambientseismic noise.Geophys.J.Int.,181(2):1171-1182,doi:10.1111/j.1365-246X.2010.04571.x.
    Fang L H,Wu J P,Wang W L,et al.2013.Love wave tomographyfrom ambient seismic noise in North-China.Chinese J.Geophys.(in Chinese),56(7):2268-2279,doi:10.6038/cjg20130714.
    Guo B,Liu Q Y,Chen J H,et al.2009.Teleseismic P-wavetomography of the crust and upper mantle in Longmenshan area,west Sichuan.ChineseJ.Geophys.(in Chinese),52(2):346-355.
    He H L,Fang Z J,Li P.1993.A preliminary approach to the faultactivity of southern segment on Xiaojiang west branch fault.Journal of Seismological Research(in Chinese),16(3):291-298.
    Herrmann R B,Ammon C J.2002.Computer Programs inSeismology version 3.20:Surface Waves,Receiver Functions,and Crustal Structure.Missouri:St.Louis University.
    Houseman G,England P.1986.Finite strain calculations ofcontinental deformation:1.Method and general results forconvergent zones.J.Geophys.Res.-Solid Earth,91(B3):3651-3663,doi:10.1029/JB091iB03p03651.
    Hu J F,Xu X Q,Yang H Y,et al.2011.S receiver functionanalysis of the crustal and lithospheric structures beneatheastern Tibet.Earth Planet.Sci.Lett.,306(1-2):77-85,doi:10.1016/j.epsl.2011.03.034.
    Huang J L,Zhao D P,Zheng S H.2002.Lithospheric structure andits relationship to seismic and volcanic activity in southwestChina.J.Geophys.Res.,107(B10):ESE 13-1-ESE 13-14,doi:10.1029/2000jb000137.
    Hubbard J,Shaw J H.2009.Uplift of the Longmen Shan andTibetan plateau,and the 2008 Wenchuan(M=7.9)earthquake.Nature,458(7235):194-197,doi:10.1038/nature07837.
    Jiménez-Munt I,Fernàndez M,Vergés J,et al.2008.Lithospherestructure underneath the Tibetan Plateau inferred from elevation,gravity and geoid anomalies.Earth Planet.Sci.Lett.,267(1-2):276-289,doi:10.1016/j.epsl.2007.11.045.
    Lei J S,Zhao D P,Su Y J.2009.Insight into the origin of theTengchong intraplate volcano and seismotectonics in southwestChina from local and teleseismic data.J.Geophys.Res.,114(B5):B05302,doi:10.1029/2008JB005881.
    Li C,van der Hilst R D,Meltzer A S,et al.2008.Subduction ofthe Indian lithosphere beneath the Tibetan Plateau and Burma.Earth Planet.Sci.Lett.,274(1-2):157-168,doi:10.1016/j.epsl.2008.07.016.
    Li Y,Yao H J,Liu Q Y,et al.2010.Phase velocity arraytomography of Rayleigh waves in western Sichuan from ambientseismic noise.Chinese J.Geophys.(in Chinese),53(4):842-852,doi:10.3969/j.issn.0001-5733.2010.04.009.
    Liu F T,Liu J H,Zhong D L,et al.2000.The subducted slab ofYangtze continental block beneath the Tethyan orogen inwestern Yunnan.Chinese Science Bulletin,45(5):466-472.
    Liu Q Y,Li Y,Chen J H,et al.2009.Wenchuan Ms8.0earthquake:preliminary study of the S-wave velocity structure ofthe crust and upper mantle.Chinese J.Geophys.(in Chinese),52(2):309-319.
    Liu Q Y,van der Hilst R D,Li Y,et al.2014.Eastward expansionof the Tibetan Plateau by crustal flow and strain partitioningacross faults.Nat.Geosci.,7(5):361-365,doi:10.1038/ngeo2130.
    Molnar P,Tapponnier P.1975.Cenozoic tectonics of Asia-effects ofa continental collision.Science,189(4201):419-426,doi:10.1126/science.189.4201.419.
    Molnar P,Tapponnier P.1978.Active tectonics of Tibet.J.Geophys.Res.-Solid Earth,83(B11):5361-5375,doi:10.1029/JB083iB11p05361.
    Royden L H,Burchfiel B C,King R W,et al.1997.Surfacedeformation and lower crustal flow in eastern Tibet.Science,276(5313):788-790,doi:10.1126/science.276.5313.788.
    Shapiro N M,Campillo M,Stehly L,et al.2005.High-resolutionsurface-wave tomography from ambient seismic noise.Science,307(5715):1615-1618,doi:10.1126/science.1108339.
    Shen Z K,LüJ N,Wang M,et al.2005.Contemporary crustaldeformation around the southeast borderland of the TibetanPlateau.J.Geophys.Res.-Solid Earth,110(B11):B1140,doi:10.1029/2004jb003421.
    Shen C B,Mei L F,Xu Z P,et al.2007.Architecture and tectonicevolution of composite basin-mountain system in Sichuan Basinand its adjacent areas.Geotectonica et Metallogenia(in Chinese),31(3):288-299.
    Shen Y,Ren Y,Gao H,et al.2012.An improved method toextract very-broadband empirical Green′s functions from ambientseismic noise.Bull.Seismol.Soc.Am.,102(4):1872-1877,doi:10.1785/0120120023.
    Tapponnier P,Xu Z Q,Roger F,et al.2001.Oblique stepwise riseand growth of the Tibet Plateau.Science,294(5547):1671-1677,doi:10.1126/science.105978.
    Wang C Y,Chan W W,Mooney W D.2003.Three-dimensionalvelocity structure of crust and upper mantle in southwesternChina and its tectonic implications.J.Geophys.Res.,108(B9):2442,doi:10.1029/2002jb001973.
    Wang C Y,Chang L J,LüZ Y,et al.2007.The anisotrophy of theupper mantle in eastern Tibetan Plateau and related crust-mantlecoupling model.Science in China(Series D)(in Chinese),37(4):495-503.
    Wang C Y,Lou H,LüZ Y,et al.2008.S-wave crustal and uppermantle′s velocity structure in the eastern Tibetan Plateau-deepenvironment of lower crustal flow.Science in China Series D:Earth Sciences(in Chinese),51(2):263-274.
    Wang C Y,Zhu L P,Lou H,et al.2010a.Crustal thicknesses andPoisson′s ratios in the eastern Tibetan Plateau and their tectonicimplications.J.Geophys.Res.-Solid Earth,115(B11):B11301,doi:10.1029/2010jb007527.
    Wang C Y,Lou H,Yao Z X,et al.2010.Crustal thicknesses andPoisson′s ratios in Longmenshan mountains and adjacentregions.Quaternary Sciences(in Chinese),30(4):652-661,doi:10.3969/j.issn.1001-7410.2010.04.02.
    Wang W L,Wu J P,Fang L H,et al.2014.S wave velocitystructure in southwest China from surface wave tomography andreceiver functions.J.Geophys.Res.Solid Earth,119(2):1061-1078,doi:10.1002/2013jb010317.
    Wang Z,Zhao D P,Wang J.2010b.Deep structure andseismogenesis of the north-south seismic zone in southwestChina.J.Geophys.Res.,115(B12):B12334,doi:10.1029/2010jb007797.
    Wu J P,Ming Y H,Wang C Y.2001.The S wave velocitystructure beneath digital seismic stations of Yunnan provinceinferred from teleseismic receiver function modelling.Chinese J.Geophys.(in Chinese),44(2):228-237,doi:10.3321/j.issn:0001-5733.2001.02.010.
    Wu J P,Yang T,Wang W L,et al.2013.Three dimensional Pwave velocity structure around Xiaojiang fault system and itstectonic implications.Chinese J.Geophys.(in Chinese),56(7):2257-2267,doi:10.6038/cjg20130713.
    Xu Y G,Chung S L,Jahn B M,et al.2001.Petrologic andgeochemical constraints on the petrogenesis of Permian-TriassicEmeishan flood basalts in southwestern China.Lithos,58(3-4):145-168,doi:10.1016/S0024-4937(01)00055-X.
    Xu Y G,Chung S L.2001.The Emeishan large igneous province:Evidence for mantle plume activity and melting conditions.Geochimica(in Chinese),30(1):1-9.
    Xu L L,Rondenay S,van der Hilst R D.2007.Structure of thecrust beneath the southeastern Tibetan Plateau from teleseismicreceiver functions.Phys.Earth Planet.Inter.,165(3-4):176-193,doi:10.1016/j.pepi.2007.09.002.
    Xu M,Zhu C Q,Tian Y T,et al.2011.Borehole temperaturelogging and characteristics of subsurface temperature in SichuanBasin.Chinese J.Geophys.(in Chinese),54(4):1052-1060,doi:10.3969/j.issn.0001-5733.2011.04.020.
    Yang T,Wu J,Fang L,et al.2014.Complex structure beneath theSoutheastern Tibetan Plateau from teleseismic P-wave tomography.Bull.Seismol.Soc.Am.,104(3):1056-1069,doi:10.1785/0120130029.
    Yanovskaya T B,Ditmar P G.1990.Smoothness criteria in surfacewave tomography.Geophys.J.Int.,102(1):63-72,doi:10.1111/j.1365-246X.1990.tb00530.x.
    Yao H J,Beghein C,van der Hilst R D.2008.Surface wave arraytomography in SE Tibet from ambient seismic noise and twostation analysis—II.Crustal and upper-mantle structure.Geophys.J.Int.,173(1):205-219,doi:10.1111/j.1365-246X.2007.03696.x.
    Yao H J,van der Hilst R D,Montagner J P.2010.Heterogeneityand anisotropy of the lithosphere of SE Tibet from surface wavearray tomography.J.Geophys.Res.Solid Earth,115(B12):B12307,doi:10.1029/2009jb007142.
    Yokoyama M,Liu Y Y,Halim N,et al.2001.Paleomagnetic studyof Upper Jurassic rocks from the Sichuan basin:tectonic aspectsfor the collision between the Yangtze Block and the North ChinaBlock.Earth Planet.Sci.Lett.,193(3-4):273-285,doi:10.1016/s0012-821x(01)00498-8.
    Zhang Z J,Yuan X H,Chen Y,et al.2010.Seismic signature ofthe collision between the east Tibetan escape flow and theSichuan Basin.Earth Planet.Sci.Lett.,292(3-4):254-264,doi:10.1016/j.epsl.2010.01.046.
    Zhang P Z.2013.A review on active tectonics and deep crustalprocesses of the Western Sichuan region,eastern margin of theTibetan Plateau.Tectonophysics,584:7-22,doi:10.1016/j.tecto.2012.02.021.
    Zheng X F,Ouyang B,Zhang D N,et al.2009.Technical systemconstruction of Data Backup Centre for China SeismographNetwork and the data support to researches on the Wenchuanearthquake.Chinese J.Geophys.(in Chinese),52(5):1412-
    1417,doi:10.3969/j.issn.0001-5733.2009.05.031.
    Zheng X F,Yao Z,Liang J,et al.2010.The role played andopportunities provided by IGP DMC of China National SeismicNetwork in Wenchuan earthquake disaster relief and researches.Bull.Seismol.Soc.Am.,100(5B):2866-2872,doi:10.1785/0120090257.
    陈九辉,刘启元,李顺成等.2009.汶川Ms8.0地震余震序列重新定位及其地震构造研究.地球物理学报,52(2):390-397.
    程裕淇.2004.中国地质图(第二版).北京:地质出版社.
    邓文泽,陈九辉,郭彪等.2014.龙门山断裂带精细速度结构的双差层析成像研究.地球物理学报,57(4):1101-1110,doi:10.6038/cjg20140408.
    房立华,吴建平,王未来等.2013.华北地区勒夫波噪声层析成像研究.地球物理学报,56(7):2268-2279,doi:10.6038/cjg20130714.
    郭飚,刘启元,陈九辉等.2009.川西龙门山及邻区地壳上地幔远震P波层析成像.地球物理学报,52(2):346-355.
    何宏林,方仲景,李玶.1993.小江断裂带西支断裂南段新活动初探.地震研究,16(3):291-298.
    李昱,姚华健,刘启元等.2010.川西地区台阵环境噪声瑞利波相速度层析成像.地球物理学报,53(4):842-852,doi:10.3969/j.issn.0001-5733.2010.04.009.
    刘福田,刘建华,何建坤等.2000.滇西特提斯造山带下扬子地块的俯冲板片.科学通报,45(1):79-84.
    刘启元,李昱,陈九辉等.2009.汶川Ms8.0地震:地壳上地幔S波速度结构的初步研究.地球物理学报,52(2):309-319.
    沈传波,梅廉夫,徐振平等.2007.四川盆地复合盆山体系的结构构造和演化.大地构造与成矿学,31(3):288-299.
    王椿镛,常利军,吕智勇等.2007.青藏高原东部上地幔各向异性及相关的壳幔耦合型式.中国科学(D辑:地球科学),37(4):495-503.
    王椿镛,楼海,吕智勇等.2008.青藏高原东部地壳上地幔S波速度结构—下地壳流的深部环境.中国科学(D辑:地球科学),38(1):22-32.
    王椿镛,楼海,姚志祥等.2010.龙门山及其邻区的地壳厚度和泊松比.第四纪研究,30(4):652-661,doi:10.3969/j.issn.1001-7410.2010.04.02.
    吴建平,明跃红,王椿镛.2001.云南数字地震台站下方的S波速度结构研究.地球物理学报,44(2):228-237,doi:10.3321/j.issn:0001-5733.2001.02.010.
    吴建平,杨婷,王未来等.2013.小江断裂带周边地区三维P波速度结构及其构造意义.地球物理学报,56(7):2257-2267.
    徐明,朱传庆,田云涛等.2011.四川盆地钻孔温度测量及现今地热特征.地球物理学报,54(4):1052-1060,doi:10.3969/j.issn.0001-5733.2011.04.020.
    徐义刚,钟孙霖.2001.峨眉山大火成岩省:地幔柱活动的证据及其熔融条件.地球化学,30(1):1-9.
    郑秀芬,欧阳飚,张东宁等.2009.“国家数字测震台网数据备份中心”技术系统建设及其对汶川大地震研究的数据支撑.地球物理学报,52(5):1412-1417,doi:10.3969/j.issn.0001-5733.2009.05.031.

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