南海东北部及其邻近地区的Pn波速度结构与各向异性
|
摘要
利用中国地震台网和ISC台站1980~2004年的地震数据,反演了南海东北部及其邻近地区的Pn波速度结构和各向异性.上地幔顶部的速度变化揭示出区域地质构造的深部特征:华南地区速度较高并且变化平缓,具有构造稳定地区的岩石层地幔特征;华南沿海尤其是滨海断裂带附近出现低速异常,表明该断裂可能穿过壳幔边界深达上地幔顶部.南海北部至台湾海峡较高的速度与华南地区类似,反映出大陆边缘和陆架地区的岩石层地幔性质;西沙海槽附近较高的速度不仅反映了华南大陆向南的延伸,而且与海槽裂谷拉张引起的地幔上拱有关,整个南海北部没有发现大规模地幔热流的活动痕迹.相比之下,南海东部次海盆的上地幔顶部存在明显的低速异常,对应于海底扩张中心的地幔上涌区,表明岩石层地幔强烈减薄甚至缺失;台湾东部-吕宋-菲律宾北部的低速异常与地震、火山活动以及岩浆作用紧密相关,揭示了西太平洋岛弧俯冲带的活动特征;南海东北部的洋-陆边界清晰,南海东部和菲律宾海西部较高的速度代表了海洋岩石层地幔的性质.Pn波各向异性反映出区域性构造应力状态及岩石层地幔的变形痕迹:华南地区的各向异性较小,说明这一构造稳定地区的岩石层地幔变形程度较弱;南海北部的快波方向与地壳浅表层构造的伸展方向一致,主要反映了中、新生代以来的大陆边缘张裂和剪切作用对岩石层地幔结构的影响;琉球-台湾-吕宋岛弧两侧各向异性十分强烈,平行于海沟的快波方向表明菲律宾海板块和欧亚大陆的相互作用导致俯冲板块前缘的岩石层地幔强烈变形;台湾东南海域快波方向的变化可能与欧亚大陆和菲律宾海板块俯冲机制的转换以及岩石层被撕裂有关.
Using seismic data from Chinese and ISC stations between 1980～2004,we inverted Pn wave velocity and anisotropy of the northeastern South China Sea and adjacent region.The velocity variations at uppermost mantle reflect the features of regional geology and tectonics.The southeastern China region has fast velocities correspondent to the lithospheric mantle in tectonically stable regions.Slow velocities appear near the Binhai fault zone along the coast of southeastern China,which indicates a possible penetration of the fault zone into the uppermost mantle.Similar to southeastern China,fast velocities throughout the northern South China Sea and Taiwan Strait reveal a property of the continental lithospheric mantle,while fast velocities in the Xisha Trough reflect a southward extension of continental margin and a mantle upwarp produced by rifting.There is no evidence showing large-scale mantle heat flows in the northern South China Sea.However,pronounced slow velocities are observed in the eastern sub-basin of the South China Sea,which is thought to be an extinct mantle upwelling center with high heat flows,indicating a thinning or removal of lithospheric mantle.Along the eastern Taiwan,Luzon and northern Philippine,slow velocities are related to seismic and volcanic activity and magmatism in the arc zone,while fast velocities in the eastern South China Sea and western Philippine Sea reflect the oceanic lithospheric mantle.Pn velocity anisotropy also reveals the stress state in regional tectonics and the history of deformation of lithospheric mantle.Southeastern China has small anisotropy in response to less deformation there.Clear anisotropy is observed in the northern South China Sea,with fast directions of anisotropy aligned with shallow structures,which reflect the evidence of the Mesozoic-Cenozoic rifting and shear deformation in the lithospheric mantle.Strong anisotropy is also observed along the Ryukyu-Taiwan-Luzon arc zone and the fast directions parallel to those trenches indicate intense deformation in the lithospheric mantle of the leading edge of the Philippine Sea plate and Eurasian continent.The change of fast directions of anisotropy near eastern Taiwan is probably caused by a conversion of collision mechanisms between the Eurasian continent and the Philippine Sea plate,and the tear of the lithosphere mantle.
Using seismic data from Chinese and ISC stations between 1980～2004,we inverted Pn wave velocity and anisotropy of the northeastern South China Sea and adjacent region.The velocity variations at uppermost mantle reflect the features of regional geology and tectonics.The southeastern China region has fast velocities correspondent to the lithospheric mantle in tectonically stable regions.Slow velocities appear near the Binhai fault zone along the coast of southeastern China,which indicates a possible penetration of the fault zone into the uppermost mantle.Similar to southeastern China,fast velocities throughout the northern South China Sea and Taiwan Strait reveal a property of the continental lithospheric mantle,while fast velocities in the Xisha Trough reflect a southward extension of continental margin and a mantle upwarp produced by rifting.There is no evidence showing large-scale mantle heat flows in the northern South China Sea.However,pronounced slow velocities are observed in the eastern sub-basin of the South China Sea,which is thought to be an extinct mantle upwelling center with high heat flows,indicating a thinning or removal of lithospheric mantle.Along the eastern Taiwan,Luzon and northern Philippine,slow velocities are related to seismic and volcanic activity and magmatism in the arc zone,while fast velocities in the eastern South China Sea and western Philippine Sea reflect the oceanic lithospheric mantle.Pn velocity anisotropy also reveals the stress state in regional tectonics and the history of deformation of lithospheric mantle.Southeastern China has small anisotropy in response to less deformation there.Clear anisotropy is observed in the northern South China Sea,with fast directions of anisotropy aligned with shallow structures,which reflect the evidence of the Mesozoic-Cenozoic rifting and shear deformation in the lithospheric mantle.Strong anisotropy is also observed along the Ryukyu-Taiwan-Luzon arc zone and the fast directions parallel to those trenches indicate intense deformation in the lithospheric mantle of the leading edge of the Philippine Sea plate and Eurasian continent.The change of fast directions of anisotropy near eastern Taiwan is probably caused by a conversion of collision mechanisms between the Eurasian continent and the Philippine Sea plate,and the tear of the lithosphere mantle.
引文
[1]刘光鼎.中国海地球物理场特征.地球物理学进展,2002,17(1):1~12Liu G D.The characteristics of geophysical fields on the China seas.Progress in Geophysics(in Chinese),2002,17(1):1~12
[2]Nissen S S,Hayes D E,Buhl P,Diebold J.Deep penetration seismicsoundings across the northern margin of the South China Sea.J.Geophys.Res.,1995,100(B11):22407~22433
[3]Qiu X L,Ye S Y,Wu S M,et al.Crustal structure across the XishaTrough,northwestern South China Sea.Tectonophysics,2001,341:179~193
[4]Yan P,Zhou D,Liu Z S,A crustal structure profile across the northerncontinental margin of the South China Sea.Tectonophysics,2001,338:1~21
[5]Qiu X L,Zhao M H,Ye C M,et al.Ocean bottom seismometer andonshore-offshore seismic experiment in northeastern South China Sea.Geotecton.Metallog.,2004,28(1):28~35
[6]赵明辉,丘学林,叶春明等.南海东北部深地震联测与滨海断裂带两侧地壳结构分析.地球物理学报,2004,47(5):845~852Zhao M H,Qiu X L,Ye C M,et al.Analysis on deep crustalstructure along the onshore-offshore seismic profile across the Binhai(Littoral)Fault Zone in northeastern South China Sea.Chinese J.Geophys.(in Chinese),2004,47(5):845~852
[7]Wang T K,Chen M K,Lee C S,et al.Seismic imaging of thetransitional crust across the northeastern margin of the South ChinaSea.Tectonophysics,2006,412:237~254
[8]Bautista B C,Bautista M L P,Oike K,et al.A new insight on thegeometry of subducting slabs in northern Luzon,Philippines.Tectonophysics,2001,339:279~310
[9]刘建华,吴华,刘福田.华南及其海域三维速度分布特征与岩石层结构.地球物理学报,1996,39(4):483~492Liu J H,Wu H,Liu F T.Features of 3-D velocity distribution andlithosphere structure in South China and its contiguous sea area.Chinese J.Geophys.(in Chinese),1996,39(4):483~492
[10]郑月军,黄忠贤,刘福田等.中国东部海域地壳上地幔瑞利波速度结构研究.地球物理学报,2000,43(4):480~487Zheng Y J,Huang Z X,Liu F T,et al.Rayleigh wave velocity andstructure of the crust and upper mantle beneath the seas in easternChina.Chinese J.Geophys.(in Chinese),2000,43(4):480~487
[11]曹小林,朱介寿,赵连锋等.南海及邻区地壳上地幔三维S波速度结构的面波波形反演.地震学报,2001,23(2):113~124Cao X L,Zhu J S,Zhao L F,et al.Three dimensional shear wavevelocity structure of crust and upper mantle in South China Sea and inits adjacent regions by surface waveform inversion.Acta SeismologicaSinica(in Chinese),2002,23(2):113~124
[12]Huang Z X,Su W,Peng Y J,et al.Rayleigh wave tomography ofChina and adjacent regions.J.Geophys.Res.,2003,108(B2),2073,doi:10.1029/2001JB001696
[13]蔡学林,朱介寿,曹家敏等.中国东南大陆边缘带岩石圈三维结构-动力学型式.海洋地质与第四纪地质,2005,25(3):25~34Cai X L,Zhu J S,Cao J M,et al.,Three-dimensional structural anddynamic types of the continental margin lithosphere in southeastChina.Marine Geology&Quaternary Geology(in Chinese),2005,25(3):25~34
[14]Wang S Y,Hearn TM,Xu Z H,et al.Velocity structure of uppermostmantle beneath China continent from Pn tomography.Science inChina(Series D),2002,45(2):143~150
[15]Liang C,Song X D,Huang J L.Tomographic inversion of Pn traveltimes in China.J.Geophys.Res.,2004,109,B11304,doi:10.1029/2003JB002789
[16]Hearn T M,Wang S,Ni J F,et al.Uppermost mantle velocitiesbeneath China and surrounding regions.J.Geophys.Res.,2004,109,B11301,doi:10.1029/2003JB002874
[17]Hearn T M.Anisotropic Pn tomography in the western United States.J.Geophys.Res.,1996,101(B4):8403~8414
[18]Laske G,Masters G,Reif C.Crust2.0:a new global crustal model at2×2 degrees.http://mahi.ucsd.edu/Gabi/rem.dir/crust2.html
[19]Paige C C,Saunders M A.LSQR:An algorithm for sparse linearequations and least squares problems.ACM Trans.Math.Software,1982,8(1):43~71
[20]李立.中国大陆地壳上地幔电性特征.地球物理学报,1996,39(增刊):130~140Li L.Geoelectrical characteristic of crust and upper mantle in thecontinental region of China.Chinese J.Geophys.(in Chinese),1996,39(Suppl.):130~140
[21]Wang Y.Heat flow pattern and lateral variations of lithospherestrength in China mainland:constraints on active deformation.Phys.Earth Planet.Int.,2001,126:121~146
[22]He L,Wang K,Xiang L,et al.Heat flow and thermal history of theSouth China Sea.Phys.Earth Planet.Int.,2001,126:211~220
[23]郝天珧,刘建华,宋海斌等.华南及其相邻边缘海域一些重要断裂的地球物理证据.地球物理学进展,2003,17(1):13~23Hao T Y,Liu J H,Song H B,et al.Geophysical evidences of someimportant faults in Huanan block and adjacent marginal sea region.Progess in Geophysics(in Chinese),2003,17(1):13~23
[24]丘学林,曾钢平,胥颐等.南海西沙石岛地震台下的地壳结构研究.地球物理学报,2006,49(6):1720~1729Qiu X L,Zeng G P,Xu Y,et al.The crustal structure beneath theShidao station on Xisha islands of South China Sea.Chinese J.Geophys.(in Chinese),2006,49(6):1720~1729
[25]Taylor B,Hayes D E.The tectonic evolution of South China Basin.In:Hayes D E ed.The Tectonic and Geologic Evolution of SoutheastAsian Seas and Islands.Geophys.Monogr.Ser.,AGU,Washington,D.C.,1980,23:89~104
[26]Taylor B,Hayes D E.Origin and history of the South China SeaBasin.In:Hayes D E ed.The Tectonic and Geologic Evolution ofSoutheast Asian Seas and Islands.Geophys.Monogr.Ser.,AGU,Washington,D.C.,1983,27:23~56
[27]胥颐,刘建华,郝天珧等.中国东部海域及邻区岩石层地幔的P波速度结构与构造分析.地球物理学报,2006,49(4):1053~1061Xu Y,Liu J H,Hao T Y,et al.P wave velocity structure and tectonicanalysis of lithospheric mantle in eastern China seas and adjacentregions.Chinese J.Geophys.(in Chinese),2006,49(4):1053~1061
[28]Besana G M,Shibutani T,Hirano N,et al.The shear wave velocitystructure of the crust and upper mantle beneath Tagaytay,Philippinesinferred from receiver function analysis.Geophys.Res.Lett.,1995,22(23):3143~3146
[29]Nakamura Y,Shibutani T.Three-dimensional shear wave velocitystructure in the upper mantle beneath the Philippine Sea region.Earth Planets Space,1998,50:939~952
[30]Okino K,Fujioka K.The Central Basin Spreading Center in thePhilippine Sea:Structure of an extinct spreading center andimplications for marginal basin formation.J.Geophys.Res.,2003,108(B1),2040 doi:10.1029/2001GB001095
[31]Huang Z,Peng Y,Luo Y,et al.Azimuthal anisotropy of Rayleighwaves in East Asia.Geophys.Res.Lett.,2004,31,L15617,doi:10.1029/2004GL020399
[32]Huang B S,Huang W G,Liang W T,et al.Anisotropy beneath anactive collision orogen of Taiwan.Geophys.Res.Lett.,2006,33,L24302,doi:10.1029/2006GL027844
[33]Lallemand S,Font Y,Bijwaard H,et al.New insights on 3-D platesinteraction near Taiwan from tomography and tectonic implication.Tectonophysics,2001,335:229~253
[34]Kim K H,Qiu J M,Pujol J,et al.Three dimensionalVp andVsstructural models associated with the active subduction and collisiontectonics in the Taiwan region.Geophys.J.Int.,2005,162:204~220
[35]陈学波,李金森,王恩福等.汕头-吕宋岛岩石圈速度结构与震源构造-台湾浅滩7.3级地震构造之一.地球物理学进展,1996,11(1):28~41Chen X B,Li J S,Wang E F,et al.The velocity structure and thefocal structure of the lithosphere on Shantou-Luzon Island.Progressin Geophysics(in Chinese),1996,11(1):28~41
[2]Nissen S S,Hayes D E,Buhl P,Diebold J.Deep penetration seismicsoundings across the northern margin of the South China Sea.J.Geophys.Res.,1995,100(B11):22407~22433
[3]Qiu X L,Ye S Y,Wu S M,et al.Crustal structure across the XishaTrough,northwestern South China Sea.Tectonophysics,2001,341:179~193
[4]Yan P,Zhou D,Liu Z S,A crustal structure profile across the northerncontinental margin of the South China Sea.Tectonophysics,2001,338:1~21
[5]Qiu X L,Zhao M H,Ye C M,et al.Ocean bottom seismometer andonshore-offshore seismic experiment in northeastern South China Sea.Geotecton.Metallog.,2004,28(1):28~35
[6]赵明辉,丘学林,叶春明等.南海东北部深地震联测与滨海断裂带两侧地壳结构分析.地球物理学报,2004,47(5):845~852Zhao M H,Qiu X L,Ye C M,et al.Analysis on deep crustalstructure along the onshore-offshore seismic profile across the Binhai(Littoral)Fault Zone in northeastern South China Sea.Chinese J.Geophys.(in Chinese),2004,47(5):845~852
[7]Wang T K,Chen M K,Lee C S,et al.Seismic imaging of thetransitional crust across the northeastern margin of the South ChinaSea.Tectonophysics,2006,412:237~254
[8]Bautista B C,Bautista M L P,Oike K,et al.A new insight on thegeometry of subducting slabs in northern Luzon,Philippines.Tectonophysics,2001,339:279~310
[9]刘建华,吴华,刘福田.华南及其海域三维速度分布特征与岩石层结构.地球物理学报,1996,39(4):483~492Liu J H,Wu H,Liu F T.Features of 3-D velocity distribution andlithosphere structure in South China and its contiguous sea area.Chinese J.Geophys.(in Chinese),1996,39(4):483~492
[10]郑月军,黄忠贤,刘福田等.中国东部海域地壳上地幔瑞利波速度结构研究.地球物理学报,2000,43(4):480~487Zheng Y J,Huang Z X,Liu F T,et al.Rayleigh wave velocity andstructure of the crust and upper mantle beneath the seas in easternChina.Chinese J.Geophys.(in Chinese),2000,43(4):480~487
[11]曹小林,朱介寿,赵连锋等.南海及邻区地壳上地幔三维S波速度结构的面波波形反演.地震学报,2001,23(2):113~124Cao X L,Zhu J S,Zhao L F,et al.Three dimensional shear wavevelocity structure of crust and upper mantle in South China Sea and inits adjacent regions by surface waveform inversion.Acta SeismologicaSinica(in Chinese),2002,23(2):113~124
[12]Huang Z X,Su W,Peng Y J,et al.Rayleigh wave tomography ofChina and adjacent regions.J.Geophys.Res.,2003,108(B2),2073,doi:10.1029/2001JB001696
[13]蔡学林,朱介寿,曹家敏等.中国东南大陆边缘带岩石圈三维结构-动力学型式.海洋地质与第四纪地质,2005,25(3):25~34Cai X L,Zhu J S,Cao J M,et al.,Three-dimensional structural anddynamic types of the continental margin lithosphere in southeastChina.Marine Geology&Quaternary Geology(in Chinese),2005,25(3):25~34
[14]Wang S Y,Hearn TM,Xu Z H,et al.Velocity structure of uppermostmantle beneath China continent from Pn tomography.Science inChina(Series D),2002,45(2):143~150
[15]Liang C,Song X D,Huang J L.Tomographic inversion of Pn traveltimes in China.J.Geophys.Res.,2004,109,B11304,doi:10.1029/2003JB002789
[16]Hearn T M,Wang S,Ni J F,et al.Uppermost mantle velocitiesbeneath China and surrounding regions.J.Geophys.Res.,2004,109,B11301,doi:10.1029/2003JB002874
[17]Hearn T M.Anisotropic Pn tomography in the western United States.J.Geophys.Res.,1996,101(B4):8403~8414
[18]Laske G,Masters G,Reif C.Crust2.0:a new global crustal model at2×2 degrees.http://mahi.ucsd.edu/Gabi/rem.dir/crust2.html
[19]Paige C C,Saunders M A.LSQR:An algorithm for sparse linearequations and least squares problems.ACM Trans.Math.Software,1982,8(1):43~71
[20]李立.中国大陆地壳上地幔电性特征.地球物理学报,1996,39(增刊):130~140Li L.Geoelectrical characteristic of crust and upper mantle in thecontinental region of China.Chinese J.Geophys.(in Chinese),1996,39(Suppl.):130~140
[21]Wang Y.Heat flow pattern and lateral variations of lithospherestrength in China mainland:constraints on active deformation.Phys.Earth Planet.Int.,2001,126:121~146
[22]He L,Wang K,Xiang L,et al.Heat flow and thermal history of theSouth China Sea.Phys.Earth Planet.Int.,2001,126:211~220
[23]郝天珧,刘建华,宋海斌等.华南及其相邻边缘海域一些重要断裂的地球物理证据.地球物理学进展,2003,17(1):13~23Hao T Y,Liu J H,Song H B,et al.Geophysical evidences of someimportant faults in Huanan block and adjacent marginal sea region.Progess in Geophysics(in Chinese),2003,17(1):13~23
[24]丘学林,曾钢平,胥颐等.南海西沙石岛地震台下的地壳结构研究.地球物理学报,2006,49(6):1720~1729Qiu X L,Zeng G P,Xu Y,et al.The crustal structure beneath theShidao station on Xisha islands of South China Sea.Chinese J.Geophys.(in Chinese),2006,49(6):1720~1729
[25]Taylor B,Hayes D E.The tectonic evolution of South China Basin.In:Hayes D E ed.The Tectonic and Geologic Evolution of SoutheastAsian Seas and Islands.Geophys.Monogr.Ser.,AGU,Washington,D.C.,1980,23:89~104
[26]Taylor B,Hayes D E.Origin and history of the South China SeaBasin.In:Hayes D E ed.The Tectonic and Geologic Evolution ofSoutheast Asian Seas and Islands.Geophys.Monogr.Ser.,AGU,Washington,D.C.,1983,27:23~56
[27]胥颐,刘建华,郝天珧等.中国东部海域及邻区岩石层地幔的P波速度结构与构造分析.地球物理学报,2006,49(4):1053~1061Xu Y,Liu J H,Hao T Y,et al.P wave velocity structure and tectonicanalysis of lithospheric mantle in eastern China seas and adjacentregions.Chinese J.Geophys.(in Chinese),2006,49(4):1053~1061
[28]Besana G M,Shibutani T,Hirano N,et al.The shear wave velocitystructure of the crust and upper mantle beneath Tagaytay,Philippinesinferred from receiver function analysis.Geophys.Res.Lett.,1995,22(23):3143~3146
[29]Nakamura Y,Shibutani T.Three-dimensional shear wave velocitystructure in the upper mantle beneath the Philippine Sea region.Earth Planets Space,1998,50:939~952
[30]Okino K,Fujioka K.The Central Basin Spreading Center in thePhilippine Sea:Structure of an extinct spreading center andimplications for marginal basin formation.J.Geophys.Res.,2003,108(B1),2040 doi:10.1029/2001GB001095
[31]Huang Z,Peng Y,Luo Y,et al.Azimuthal anisotropy of Rayleighwaves in East Asia.Geophys.Res.Lett.,2004,31,L15617,doi:10.1029/2004GL020399
[32]Huang B S,Huang W G,Liang W T,et al.Anisotropy beneath anactive collision orogen of Taiwan.Geophys.Res.Lett.,2006,33,L24302,doi:10.1029/2006GL027844
[33]Lallemand S,Font Y,Bijwaard H,et al.New insights on 3-D platesinteraction near Taiwan from tomography and tectonic implication.Tectonophysics,2001,335:229~253
[34]Kim K H,Qiu J M,Pujol J,et al.Three dimensionalVp andVsstructural models associated with the active subduction and collisiontectonics in the Taiwan region.Geophys.J.Int.,2005,162:204~220
[35]陈学波,李金森,王恩福等.汕头-吕宋岛岩石圈速度结构与震源构造-台湾浅滩7.3级地震构造之一.地球物理学进展,1996,11(1):28~41Chen X B,Li J S,Wang E F,et al.The velocity structure and thefocal structure of the lithosphere on Shantou-Luzon Island.Progressin Geophysics(in Chinese),1996,11(1):28~41
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