青藏高原东北缘上地幔各向异性研究
|
摘要
通过分析位于青藏高原东北缘的区域数字地震台网30个台站的远震SKS波形资料,采用最小切向能量的网格搜索法和叠加分析方法求得每一个台站的SKS快波偏振方向和快、慢波的时间延迟,获得了青藏高原东北缘上地幔各向异性图像.从得到结果看,青藏高原东北缘的各向异性快波方向基本上呈NW-SE方向,并有一顺时针旋转趋势,快、慢波时间延迟是0·70~1·51s.青藏高原东北缘的SKS快波偏振方向与区域内主要构造断裂走向基本一致;各向异性快波偏振方向变化与区域内最小平均主压应力方向变化相似,也与由GPS测量得到的速度场方向变化相似.研究表明青藏高原东北缘上地幔物质在区域构造应力场的作用下,发生了顺时针旋转的形变以至流动,使得上地幔中橄榄岩的晶格排列方向平行于物质形变或流动方向,上地幔变形和上覆地壳变形可能存在垂直连贯变形特征.
Based on the polarization analysis of teleseismic SKS waveform data recorded at 30 seismic stations in the regional digital seismograph networks of the northeastern margin of the Tibetan Plateau,the SKS fast-wave direction and the delay time between the fast and slow shear waves at each station were determined by use of the grid searching method of minimum tangent energy and the stacking analysis method,and then we acquired the image of upper mantle anisotropy in the northeastern margin of the Tibetan Plateau. In the study region,the fast-wave polarization direction is basically in NW-SE direction with a clockwise rotation trend,and the delay time falls into the interval from 0.70 to 1.51 s. The fast-wave polarization direction is consistent with the strike of the major faults in the region. The variation of the fast-wave directions is similar to the variation of the minimum average principal compressional stress directions in the northeast margin of the Tibetan Plateau,and to the variation of GPS velocity directions. The research results imply that the regional tectonic stress field has resulted in deformation and flow of upper mantle material with clockwise rotation,and make the alignment of upper mantle peridotite lattice parallel to the direction of material deformation. The deformation of the crust and upper mantle is possibly vertically coherent deformation.
Based on the polarization analysis of teleseismic SKS waveform data recorded at 30 seismic stations in the regional digital seismograph networks of the northeastern margin of the Tibetan Plateau,the SKS fast-wave direction and the delay time between the fast and slow shear waves at each station were determined by use of the grid searching method of minimum tangent energy and the stacking analysis method,and then we acquired the image of upper mantle anisotropy in the northeastern margin of the Tibetan Plateau. In the study region,the fast-wave polarization direction is basically in NW-SE direction with a clockwise rotation trend,and the delay time falls into the interval from 0.70 to 1.51 s. The fast-wave polarization direction is consistent with the strike of the major faults in the region. The variation of the fast-wave directions is similar to the variation of the minimum average principal compressional stress directions in the northeast margin of the Tibetan Plateau,and to the variation of GPS velocity directions. The research results imply that the regional tectonic stress field has resulted in deformation and flow of upper mantle material with clockwise rotation,and make the alignment of upper mantle peridotite lattice parallel to the direction of material deformation. The deformation of the crust and upper mantle is possibly vertically coherent deformation.
引文
[1]Hess HH.Seismic anisotropy of the uppermost mantle under oceans.Nature,1964,203:629~631
[2]Crampin S,Booth D C.Shear-wave polarization near the North Anatolian Fault,II.Interpretation in Terms of Crack-induced Anisotropy.Geophys.J.R.Astron.Soc.,1985,83:75~92
[3]Nicolas A,Christensen NI.Formation of anisotropy in upper mantle peridotites:Areview,in composition structure and dynamics of the lithosphere-asthenosphere system.Geodyn.Ser.,1987,16:111~123
[4]Silver P G,Chan W W.Implication for continental structure and evolutionfromseismic anisotropy.Nature,1988,335:34~39
[5]Silver P G,Chan W W.Share-wave splitting and subcontinental mantle deformation.J.Geophys.Res.,1991,96:16429~16454
[6]McNamara D,Owens T,Silver P G,et al.Shear-wave anisotropy beneaththe Tibetan Plateau.J.Geophys.Res.,1994,99:13655~13665
[7]Hirn A,Jiang M,Sapin M,et al.Seismic anisotropy as anindicator of mantle flowbeneath Himalayas and Tibet.Nature,1995,375:571~574
[8]丁志峰,曾融生.青藏高原横波分裂的观测研究.地球物理学报,1996,39(2):211~219Ding Z F,Zeng RS.Observation and study of shear wave anisotropy in Tibetan Plateau.Chinese J.Geophys.(Acta Geophysica Sinica)(in Chinese),1996,39(2):211~219
[9]姜枚,许志琴,Hirn A等.青藏高原及其部分邻区地震各向异性和上地幔特征.地球学报,2001,22(2):111~116Jiang M,Xu Z Q,Hirn A,et al.Eleseimic anisotropy and correspondig features of upper mantle in Tibetan Plateau and its neighboring areas.Acta Geoscientia Sinica(in Chinese),2001,22(2):111~116
[10]王椿镛,常利军,吕智勇等.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),2007,37(4):495~503Wang C Y,Chang L J,LZ Y,et al.Seismic anisotropy of upper mantle in eastern Tibetan Plateau and related crust-mantle couplingpattern.Science in China(Series D),2007,37(4):495~503
[11]常利军,王椿镛,丁志峰.云南地区SKS波分裂研究.地球物理学报,2006,49(1):197~204Chang LJ,Wang C Y,Ding Z F.Astudy on SKS splitting beneath the Yunnan region.Chinese J.Geophys.(in Chinese),2006,49(1):197~204
[12]吕庆田,马开义,姜枚.青藏高原南部下的横波各向异性.地震学报,1996,18(2):215~223LQT,Ma KY,Jiang M.Sismic anisotropy beneath Southern Tibet.Acta Seismologica Sinica(in Chinese),1996,18(2):215~223
[13]黄汲清,任纪舜,姜春发等.中国大陆构造及其演化.北京:科学出版社,1980Huang J Q,Ren J S,Jiang C F,et al.The Tectonic Evolution in China(in Chinese).Beijing:Science Press,1980
[14]田勤俭,丁国瑜.青藏高原东北隅似三联点构造特征.中国地震,1998,14(4):17~35Tian QJ,Ding G Y.The tectonic feature of a quasi trijunctioninthe northeastern corner of Qinghai Xizang Plateau.Earthquake Research in China(in Chinese),1998,14(4):17~35
[15]周民都,吕太乙,张元生等.青藏高原东北缘地质构造背景及地壳结构研究.地震学报,2000,22(6):645~653Zhou MD,LT Y,Zhang Y S,et al.The geological structure background and the crustal structure in northeastern margin of the Qinghai-Tibetan plateau.Acta Seismologica Sinica(in Chinese),2000,22(6):645~653
[16]Vinnik L P,Farra V,Romanowicz B.Azimuthal anisotropy in the Earthfrom observations of SKS at Geoscope and NARS broadband stations.Bull.Seismol.Soc.Am.,1989,79:1542~1558
[17]Wolfe CJ,Silver P G.Seismic anisotropy of oceanic upper mantle:Shear wave splitting methodologies and observations.J.Geophys.Res.,1998,103(B1):749~771
[18]王良书,米宁,童蔚蔚等.鄂尔多斯西缘岩石圈结构和上地幔各向异性.中国地球物理学会第22届年会年刊,2006.589Wang LS,Mi N,Tong WW,et al.Lithospheric structure and upper mantle anisotropy of the western Ordos.Chinese Geophysical Society22Annual Meeting,2006.589
[19]陈九辉,刘启元,李顺成等.青藏高原东北缘—鄂尔多斯地块地壳上地幔S波速度结构.地球物理学报,2005,48(2):333~342Chen J H,Liu Q Y,Li S C,et al.Crust and upper mantle S wave velocity structure across northeastern Tibetan plateau and Ordos block.Chinese J.Geophys.(in Chinese),2005,48(2):333~342
[20]李松林,张先康,张成科等.玛沁—兰州—靖边地震测深剖面地壳速度结构的初步研究.地球物理学报,2002,45(2):210~217Li S L,Zhang X K,Zhang C K,et al.A preliminary study on the crustal velocitystructure of Maqin-Lanzhou-Jingbian by means of deep seismic sounding profile.Chinese J.Geophys.(in Chinese),2002,45(2):210~217
[21]李永华,吴庆举,安张辉.青藏高原东北缘地壳S波速度结构与泊松比及其意义.地球物理学报,2006,49(5):1359~1368Li Y H,Wu QJ,An Z H.The Poisson ratio and crustal structure across the NE Tibetan Plateau determined fromreceiver functions.Chinese J.Geophys.(in Chinese),2006,49(5):1359~1368
[22]Zhang ZJ,Klemperer S L.West-east variationin crustal thicknessin north Lhasa block,contral Tibet from deep seismic sounding data.Journal ofGeophysical Research Solid Earth,2005,110(B9),Art No.Bo9403
[23]Royden L,Burchfiel B C,King R W,et al.Surface deformation and lower crustal flowin eastern Tibet.Science,1997,276:788~790
[24]Ricard Y,Ricards M A,Lithgow-Nertelloni C,et al.A geodynamic model of mantle density heterogeneity.J.Geophys.Res.,1993,98:21895~21909
[25]Lithgow-Nertelloni C,Ricards M A.The dynamics of Cenozoic and Mesozoic plate motions.Rev.Geophys.,1998,36:27~78
[26]吴庆举,曾融生,赵文津.喜马拉雅-青藏高原的上地幔倾斜构造与陆-陆碰撞过程.中国科学(D辑),2004,34(10):919~925Wu QJ,Zeng RS,Zhao WJ.The upper mantle structure of Tibetan Plateau and implication for continent-continent collision.Science in China(Ser D)(in Chinese),2004,34(10):919~925
[27]Chen Z,Burchfiel B C,Liu Y,et al.Global Positioning System measurements from eastern Tibet and their implications for India/Eurasia intercontinental deformation.J.Geophys.Res.,2000,105:16215~16228
[28]Zhang P Z,Shen Z K,Wang M,et al.Continuous deformation of the Tibetan Plateaufromglobal positioning systemdata.Geology,2004,32(9):809~812
[29]丁国瑜.中国岩石圈动力学概论.北京:地震出版社,1991.438~445Ding G Y.Lithospheres Dynamics of China.Beijing:Seismological Press,1991.438~445
[30]许忠淮,汪素云,黄雨蕊等.由多个小震推断的青甘和川滇地区地壳应力场的方向特征.地球物理学报,1987,30:476~486Xu Z H,Wang S Y,Huang YR,et al.Directions of meanstress axes in southwestern China deduced from microearthquake data.Chinese J.Geophys.(in Chinese),1987,30:476~486
[31]许忠淮.东亚地区现今构造应力图的编制.地震学报,2001,23:492~501Xu Z H.Apresent-day tectonic stress map for eastern Asia region.Acta Seismologica Sinica(in Chinese),2001,23:492~501
[32]Wang Q,Zhang P Z,Frevmuller J T,et al.Present-day crustal deformation in China constrained by global positional system measurements.Science,2001,294:574~577
[33]甘卫军,沈正康,张培震等.青藏高原地壳水平差异运动的观测研究.大地测量与地球动力学,2004,24(1):29~35Gan WJ,Shen Z K,Zhang PZ,et al.Horizontal crustal movement of Tibetanfrom GPS measurements.J.Geodesy and Geodynamics(in Chinese),2004,24(1):29~35
[2]Crampin S,Booth D C.Shear-wave polarization near the North Anatolian Fault,II.Interpretation in Terms of Crack-induced Anisotropy.Geophys.J.R.Astron.Soc.,1985,83:75~92
[3]Nicolas A,Christensen NI.Formation of anisotropy in upper mantle peridotites:Areview,in composition structure and dynamics of the lithosphere-asthenosphere system.Geodyn.Ser.,1987,16:111~123
[4]Silver P G,Chan W W.Implication for continental structure and evolutionfromseismic anisotropy.Nature,1988,335:34~39
[5]Silver P G,Chan W W.Share-wave splitting and subcontinental mantle deformation.J.Geophys.Res.,1991,96:16429~16454
[6]McNamara D,Owens T,Silver P G,et al.Shear-wave anisotropy beneaththe Tibetan Plateau.J.Geophys.Res.,1994,99:13655~13665
[7]Hirn A,Jiang M,Sapin M,et al.Seismic anisotropy as anindicator of mantle flowbeneath Himalayas and Tibet.Nature,1995,375:571~574
[8]丁志峰,曾融生.青藏高原横波分裂的观测研究.地球物理学报,1996,39(2):211~219Ding Z F,Zeng RS.Observation and study of shear wave anisotropy in Tibetan Plateau.Chinese J.Geophys.(Acta Geophysica Sinica)(in Chinese),1996,39(2):211~219
[9]姜枚,许志琴,Hirn A等.青藏高原及其部分邻区地震各向异性和上地幔特征.地球学报,2001,22(2):111~116Jiang M,Xu Z Q,Hirn A,et al.Eleseimic anisotropy and correspondig features of upper mantle in Tibetan Plateau and its neighboring areas.Acta Geoscientia Sinica(in Chinese),2001,22(2):111~116
[10]王椿镛,常利军,吕智勇等.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),2007,37(4):495~503Wang C Y,Chang L J,LZ Y,et al.Seismic anisotropy of upper mantle in eastern Tibetan Plateau and related crust-mantle couplingpattern.Science in China(Series D),2007,37(4):495~503
[11]常利军,王椿镛,丁志峰.云南地区SKS波分裂研究.地球物理学报,2006,49(1):197~204Chang LJ,Wang C Y,Ding Z F.Astudy on SKS splitting beneath the Yunnan region.Chinese J.Geophys.(in Chinese),2006,49(1):197~204
[12]吕庆田,马开义,姜枚.青藏高原南部下的横波各向异性.地震学报,1996,18(2):215~223LQT,Ma KY,Jiang M.Sismic anisotropy beneath Southern Tibet.Acta Seismologica Sinica(in Chinese),1996,18(2):215~223
[13]黄汲清,任纪舜,姜春发等.中国大陆构造及其演化.北京:科学出版社,1980Huang J Q,Ren J S,Jiang C F,et al.The Tectonic Evolution in China(in Chinese).Beijing:Science Press,1980
[14]田勤俭,丁国瑜.青藏高原东北隅似三联点构造特征.中国地震,1998,14(4):17~35Tian QJ,Ding G Y.The tectonic feature of a quasi trijunctioninthe northeastern corner of Qinghai Xizang Plateau.Earthquake Research in China(in Chinese),1998,14(4):17~35
[15]周民都,吕太乙,张元生等.青藏高原东北缘地质构造背景及地壳结构研究.地震学报,2000,22(6):645~653Zhou MD,LT Y,Zhang Y S,et al.The geological structure background and the crustal structure in northeastern margin of the Qinghai-Tibetan plateau.Acta Seismologica Sinica(in Chinese),2000,22(6):645~653
[16]Vinnik L P,Farra V,Romanowicz B.Azimuthal anisotropy in the Earthfrom observations of SKS at Geoscope and NARS broadband stations.Bull.Seismol.Soc.Am.,1989,79:1542~1558
[17]Wolfe CJ,Silver P G.Seismic anisotropy of oceanic upper mantle:Shear wave splitting methodologies and observations.J.Geophys.Res.,1998,103(B1):749~771
[18]王良书,米宁,童蔚蔚等.鄂尔多斯西缘岩石圈结构和上地幔各向异性.中国地球物理学会第22届年会年刊,2006.589Wang LS,Mi N,Tong WW,et al.Lithospheric structure and upper mantle anisotropy of the western Ordos.Chinese Geophysical Society22Annual Meeting,2006.589
[19]陈九辉,刘启元,李顺成等.青藏高原东北缘—鄂尔多斯地块地壳上地幔S波速度结构.地球物理学报,2005,48(2):333~342Chen J H,Liu Q Y,Li S C,et al.Crust and upper mantle S wave velocity structure across northeastern Tibetan plateau and Ordos block.Chinese J.Geophys.(in Chinese),2005,48(2):333~342
[20]李松林,张先康,张成科等.玛沁—兰州—靖边地震测深剖面地壳速度结构的初步研究.地球物理学报,2002,45(2):210~217Li S L,Zhang X K,Zhang C K,et al.A preliminary study on the crustal velocitystructure of Maqin-Lanzhou-Jingbian by means of deep seismic sounding profile.Chinese J.Geophys.(in Chinese),2002,45(2):210~217
[21]李永华,吴庆举,安张辉.青藏高原东北缘地壳S波速度结构与泊松比及其意义.地球物理学报,2006,49(5):1359~1368Li Y H,Wu QJ,An Z H.The Poisson ratio and crustal structure across the NE Tibetan Plateau determined fromreceiver functions.Chinese J.Geophys.(in Chinese),2006,49(5):1359~1368
[22]Zhang ZJ,Klemperer S L.West-east variationin crustal thicknessin north Lhasa block,contral Tibet from deep seismic sounding data.Journal ofGeophysical Research Solid Earth,2005,110(B9),Art No.Bo9403
[23]Royden L,Burchfiel B C,King R W,et al.Surface deformation and lower crustal flowin eastern Tibet.Science,1997,276:788~790
[24]Ricard Y,Ricards M A,Lithgow-Nertelloni C,et al.A geodynamic model of mantle density heterogeneity.J.Geophys.Res.,1993,98:21895~21909
[25]Lithgow-Nertelloni C,Ricards M A.The dynamics of Cenozoic and Mesozoic plate motions.Rev.Geophys.,1998,36:27~78
[26]吴庆举,曾融生,赵文津.喜马拉雅-青藏高原的上地幔倾斜构造与陆-陆碰撞过程.中国科学(D辑),2004,34(10):919~925Wu QJ,Zeng RS,Zhao WJ.The upper mantle structure of Tibetan Plateau and implication for continent-continent collision.Science in China(Ser D)(in Chinese),2004,34(10):919~925
[27]Chen Z,Burchfiel B C,Liu Y,et al.Global Positioning System measurements from eastern Tibet and their implications for India/Eurasia intercontinental deformation.J.Geophys.Res.,2000,105:16215~16228
[28]Zhang P Z,Shen Z K,Wang M,et al.Continuous deformation of the Tibetan Plateaufromglobal positioning systemdata.Geology,2004,32(9):809~812
[29]丁国瑜.中国岩石圈动力学概论.北京:地震出版社,1991.438~445Ding G Y.Lithospheres Dynamics of China.Beijing:Seismological Press,1991.438~445
[30]许忠淮,汪素云,黄雨蕊等.由多个小震推断的青甘和川滇地区地壳应力场的方向特征.地球物理学报,1987,30:476~486Xu Z H,Wang S Y,Huang YR,et al.Directions of meanstress axes in southwestern China deduced from microearthquake data.Chinese J.Geophys.(in Chinese),1987,30:476~486
[31]许忠淮.东亚地区现今构造应力图的编制.地震学报,2001,23:492~501Xu Z H.Apresent-day tectonic stress map for eastern Asia region.Acta Seismologica Sinica(in Chinese),2001,23:492~501
[32]Wang Q,Zhang P Z,Frevmuller J T,et al.Present-day crustal deformation in China constrained by global positional system measurements.Science,2001,294:574~577
[33]甘卫军,沈正康,张培震等.青藏高原地壳水平差异运动的观测研究.大地测量与地球动力学,2004,24(1):29~35Gan WJ,Shen Z K,Zhang PZ,et al.Horizontal crustal movement of Tibetanfrom GPS measurements.J.Geodesy and Geodynamics(in Chinese),2004,24(1):29~35
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