东北地区660km间断面附近波速结构研究
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摘要
我国东北地区位于西北太平洋和达-贝尼奥夫俯冲带前缘,其深部速度结构对理解板块俯冲行为以及地幔物质的交换有重要意义.利用区域三重震相模拟方法,对中国地震观测台网记录到的两个深源地震P波和SH波波形数据,进行了相对到时和波形的拟合,获得了我国东北地区660km间断面附近波速结构.结果表明,研究区域下方的间断面没有发生明显下沉,间断面之上存在一个厚约130km的高速层,这可能对应了俯冲并滞留在间断面之上的西北太平洋板块;地幔过渡带整体呈现出S波低速异常和较高的vP/vS值,可能暗示了地幔转换带内含有较高的水.
Located at the front edge of the Wadati-Benioff zone of subducted northwestern Pacific plate,the velocity structure in the mantle transition zone beneath Northeastern China plays an important role in constraining the behavior of subducted slabs and material or energy exchange in mantle.By modeling P and SH triplicate waveforms from two deep events,recorded by a dense regional network stations,we show that a layer of fast anomaly,about 130 km thick,lies above the 660-km discontinuity with slight depression,which may be associated with the westward extension of the stagnant Pacific slab.The mantle transition zone,as a whole,is featured by low shear wave velocity and high vP/vS ratio,which may indicate the existence of a water-bearing mantle transition zone.
Located at the front edge of the Wadati-Benioff zone of subducted northwestern Pacific plate,the velocity structure in the mantle transition zone beneath Northeastern China plays an important role in constraining the behavior of subducted slabs and material or energy exchange in mantle.By modeling P and SH triplicate waveforms from two deep events,recorded by a dense regional network stations,we show that a layer of fast anomaly,about 130 km thick,lies above the 660-km discontinuity with slight depression,which may be associated with the westward extension of the stagnant Pacific slab.The mantle transition zone,as a whole,is featured by low shear wave velocity and high vP/vS ratio,which may indicate the existence of a water-bearing mantle transition zone.
引文
臧绍先,宁杰远.1996.西北太平洋俯冲带的研究及其动力学意义[J].地球物理学报,39(2):188-202.
郑秀芬,欧阳飚,张东宁,姚志祥,梁建宏,郑洁.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[J].地球物理学报,52(5):1412-1417.
Ai Y S,Zheng T Y,Xu W W,He Y M,Dong D.2003.A complex660km discontinuity beneath northeast China[J].Earth Planet Sci Lett,212(1-2):63-71.
Buland R,Chapman C H.1983.The computation of seismic travel times[J].Bull Seism Soc Amer,73(5):1271-1302.
Bijwaard H,Spakman W,Engdahl E R.1998.Closing the gap between regional and global travel time tomography[J].J Geophys Res,103(B12):30055-30078.
Bina C R,Helffrich G.1994.Phase-Transition Clapeyron slopes and transition zone seismic discontinuity topography[J].J Geophys Res,99(B8):15853-15860.
Castle J C,Creager K C.1998.Topography of the660-km seismic discontinuity beneath Izu-Bonin:Implications for tec-tonic history and slab deformation[J].J Geophys Res,103(B6):12511-12527.
Creager K C,Jordan T H.1984.Slab penetration into the lower mantle[J].J Geophys Res,89(NB5):3031-3049.
Creager K C,Jordan T H.1986.Slab penetration into the lower mantle beneath the Mariana and other island arcs of thenorthwest Pacific[J].J Geophys Res,91(B3):3573-3589.
Dziewonski A M,Chou T A,Woodhouse J H.1981.Determination of earthquake source parameters from waveform datafor studies of global and regional seismicity[J].J Geophys Res,86(B4):2825-2852.
Flanagan M P,Shearer P M.1998.Global mapping of topography on transition zone velocity discontinuities by stackingSS precursors[J].J Geophys Res,103(B2):2673-2692.
Fuchs K,Müller G.1971.Computation of synthetic seismograms with the reflectivity method and comparison with ob-servations[J].Geophys J R astr Soc,23(4):417-433.
Fukao Y,Widiyantoro S,Obayashi M.2001.Stagnant slabs in the upper and lower mantle transition region[J].RevGeophys,39(3):291-323.
Gorbatov A,Kennett B L N.2003.Joint bulk-sound and shear tomography for Western Pacific subduction zones[J].Earth Planet Sci Lett,210(3-4):527-543.
Gudmundsson O,Sambridge M.1998.A regionalized upper mantle(RUM)seismic model[J].J Geophys Res,103(B4):7121-7136.
Higo Y,Inoue T,Li B S,Irifune T,Liebermann R C.2006.The effect of iron on the elastic properties of ringwoodite athigh pressure[J].Phys Earth Planet Interi,159(3-4):276-285.
Huang J L,Zhao D P.2006.High-resolution mantle tomography of China and surrounding regions[J].J Geophys Res,111(B9),doi:10.1029/2005jb004066.
Ito E,Takahashi E.1989.Postsphinel transformations in the system Mg2SiO4-Fe2SiO4and some geophysical implicai-tons[J].J Geophys Res,94(88):10637-10646.
Jacobsen S,Smyth J.2006.Effect of water on the sound velocities of ringwoodite in the transition zone[J].GeophysicalMonograph-American Geophysical Union,168:131.
Kennett B L N,Engdahl E R.1991.Traveltimes for global earthquake location and phase identification[J].Geophys JInt,105(2):429-465.
Karato S I.2011.Water distribution across the mantle transition zone and its implications for global material circulation[J].Earth Planet Sci Lett,301:413-423.
Li J,Chen Q F,Vanacore E,Niu F L.2008.Topography of the660-km discontinuity beneath northeast China:Implica-tions for a retrograde motion of the subducting Pacific slab[J].Geophys Res Lett,35(1):L01302,doi:10.1029/2007gl031658.
Li X Q,Yuan X H.2003.Receiver functions in northeast China-implications for slab penetration into the lower mantle innorthwest Pacific subduction zone[J].Earth Planet Sci Lett,216(4):679-691.
Niu F,Kawakatsu H.1996.Complex structure of mantle discontinuities at the tip of the subducting slab beneath North-east China:A preliminary investigation of broadband receiver functions[J].J Phys Earth,44(6):701-712.
Niu F,Li J.2011.Component azimuths of the CEArray stations estimated from P-wave particle motion[J].EarthquakeScience,24(1):3-13.
Revenaugh J,Sipkin S A.1994.Mantle Discontinuity Structure beneath China[J].J Geophys Res,99(B11):21911-21927.
Tajima F,Grand S P.1995.Evidence of high-velocity anomalies in the transition zone associated with Southern KurileSubduction Zone[J].Geophys Res Lett,22(23):3139-3142.
Tajima F,Nakagawa T.2006.Implications of seismic waveforms:Complex physical properties associated with stagnantslab[J].Geophys Res Lett,33(3):L03311,doi:10.1029/2005GL024314.
Tajima F,Katayama I,Nakagawa T.2009.Variable seismic structure near the660km discontinuity associated withstagnant slabs and geochemical implications[J].Phys Earth Planet Interi,172(3-4):183-198.
Vacher P,Mocquet A,Sotin C.1998.Computation of seismic profiles from mineral physics:The importance of the non-olivine components for explaining the660km depth discontinuity[J].Phys Earth Planet Interi,106(3-4):275-298.
van der Hilst R,Engdahl R,Spakman W,Nolet G.1991.Tomographic imaging of subducted lithosphere below North-west Pacific Island Arcs[J].Nature,353(6339):37-43.
Wang B,Niu F.2010.A broad660km discontinuity beneath northeast China revealed by dense regional seismic networksin China[J].J Geophys Res,115,B06308,doi:10.1029/2009JB006608.
Wang R.1999.A simple orthonormalization method for stable and efficient computation of Green’s functions[J].BullSeism Soc Amer,89(3):733-741.
Wang T,Chen L.2009.Distinct velocity variations around the base of the upper mantle beneath northeast Asia[J].PhysEarth Planet Interi,172(3-4):241-256.
Wang Y,Wen L X,Weidner D,He Y M.2006.SH velocity and compositional models near the660-km discontinuity be-neath South America and northeast Asia[J].J Geophys Res,111(B7),doi:10.1029/2005jb003849.
Widiyantoro S,Kennett B L N,van der Hilst R D.1999.Seismic tomography with P and S data reveals lateral variationsin the rigidity of deep slabs[J].Earth Planet Sci Lett,173(1-2):91-100.
Ye L,Li J,Tseng T L,Yao Z X.2011.A stagnant slab in a water-bearing mantle transition zone beneath northeast Chi-na:Implications from regional SH waveform modeling[J].Geophys J Inter,186(2):706-710.
郑秀芬,欧阳飚,张东宁,姚志祥,梁建宏,郑洁.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[J].地球物理学报,52(5):1412-1417.
Ai Y S,Zheng T Y,Xu W W,He Y M,Dong D.2003.A complex660km discontinuity beneath northeast China[J].Earth Planet Sci Lett,212(1-2):63-71.
Buland R,Chapman C H.1983.The computation of seismic travel times[J].Bull Seism Soc Amer,73(5):1271-1302.
Bijwaard H,Spakman W,Engdahl E R.1998.Closing the gap between regional and global travel time tomography[J].J Geophys Res,103(B12):30055-30078.
Bina C R,Helffrich G.1994.Phase-Transition Clapeyron slopes and transition zone seismic discontinuity topography[J].J Geophys Res,99(B8):15853-15860.
Castle J C,Creager K C.1998.Topography of the660-km seismic discontinuity beneath Izu-Bonin:Implications for tec-tonic history and slab deformation[J].J Geophys Res,103(B6):12511-12527.
Creager K C,Jordan T H.1984.Slab penetration into the lower mantle[J].J Geophys Res,89(NB5):3031-3049.
Creager K C,Jordan T H.1986.Slab penetration into the lower mantle beneath the Mariana and other island arcs of thenorthwest Pacific[J].J Geophys Res,91(B3):3573-3589.
Dziewonski A M,Chou T A,Woodhouse J H.1981.Determination of earthquake source parameters from waveform datafor studies of global and regional seismicity[J].J Geophys Res,86(B4):2825-2852.
Flanagan M P,Shearer P M.1998.Global mapping of topography on transition zone velocity discontinuities by stackingSS precursors[J].J Geophys Res,103(B2):2673-2692.
Fuchs K,Müller G.1971.Computation of synthetic seismograms with the reflectivity method and comparison with ob-servations[J].Geophys J R astr Soc,23(4):417-433.
Fukao Y,Widiyantoro S,Obayashi M.2001.Stagnant slabs in the upper and lower mantle transition region[J].RevGeophys,39(3):291-323.
Gorbatov A,Kennett B L N.2003.Joint bulk-sound and shear tomography for Western Pacific subduction zones[J].Earth Planet Sci Lett,210(3-4):527-543.
Gudmundsson O,Sambridge M.1998.A regionalized upper mantle(RUM)seismic model[J].J Geophys Res,103(B4):7121-7136.
Higo Y,Inoue T,Li B S,Irifune T,Liebermann R C.2006.The effect of iron on the elastic properties of ringwoodite athigh pressure[J].Phys Earth Planet Interi,159(3-4):276-285.
Huang J L,Zhao D P.2006.High-resolution mantle tomography of China and surrounding regions[J].J Geophys Res,111(B9),doi:10.1029/2005jb004066.
Ito E,Takahashi E.1989.Postsphinel transformations in the system Mg2SiO4-Fe2SiO4and some geophysical implicai-tons[J].J Geophys Res,94(88):10637-10646.
Jacobsen S,Smyth J.2006.Effect of water on the sound velocities of ringwoodite in the transition zone[J].GeophysicalMonograph-American Geophysical Union,168:131.
Kennett B L N,Engdahl E R.1991.Traveltimes for global earthquake location and phase identification[J].Geophys JInt,105(2):429-465.
Karato S I.2011.Water distribution across the mantle transition zone and its implications for global material circulation[J].Earth Planet Sci Lett,301:413-423.
Li J,Chen Q F,Vanacore E,Niu F L.2008.Topography of the660-km discontinuity beneath northeast China:Implica-tions for a retrograde motion of the subducting Pacific slab[J].Geophys Res Lett,35(1):L01302,doi:10.1029/2007gl031658.
Li X Q,Yuan X H.2003.Receiver functions in northeast China-implications for slab penetration into the lower mantle innorthwest Pacific subduction zone[J].Earth Planet Sci Lett,216(4):679-691.
Niu F,Kawakatsu H.1996.Complex structure of mantle discontinuities at the tip of the subducting slab beneath North-east China:A preliminary investigation of broadband receiver functions[J].J Phys Earth,44(6):701-712.
Niu F,Li J.2011.Component azimuths of the CEArray stations estimated from P-wave particle motion[J].EarthquakeScience,24(1):3-13.
Revenaugh J,Sipkin S A.1994.Mantle Discontinuity Structure beneath China[J].J Geophys Res,99(B11):21911-21927.
Tajima F,Grand S P.1995.Evidence of high-velocity anomalies in the transition zone associated with Southern KurileSubduction Zone[J].Geophys Res Lett,22(23):3139-3142.
Tajima F,Nakagawa T.2006.Implications of seismic waveforms:Complex physical properties associated with stagnantslab[J].Geophys Res Lett,33(3):L03311,doi:10.1029/2005GL024314.
Tajima F,Katayama I,Nakagawa T.2009.Variable seismic structure near the660km discontinuity associated withstagnant slabs and geochemical implications[J].Phys Earth Planet Interi,172(3-4):183-198.
Vacher P,Mocquet A,Sotin C.1998.Computation of seismic profiles from mineral physics:The importance of the non-olivine components for explaining the660km depth discontinuity[J].Phys Earth Planet Interi,106(3-4):275-298.
van der Hilst R,Engdahl R,Spakman W,Nolet G.1991.Tomographic imaging of subducted lithosphere below North-west Pacific Island Arcs[J].Nature,353(6339):37-43.
Wang B,Niu F.2010.A broad660km discontinuity beneath northeast China revealed by dense regional seismic networksin China[J].J Geophys Res,115,B06308,doi:10.1029/2009JB006608.
Wang R.1999.A simple orthonormalization method for stable and efficient computation of Green’s functions[J].BullSeism Soc Amer,89(3):733-741.
Wang T,Chen L.2009.Distinct velocity variations around the base of the upper mantle beneath northeast Asia[J].PhysEarth Planet Interi,172(3-4):241-256.
Wang Y,Wen L X,Weidner D,He Y M.2006.SH velocity and compositional models near the660-km discontinuity be-neath South America and northeast Asia[J].J Geophys Res,111(B7),doi:10.1029/2005jb003849.
Widiyantoro S,Kennett B L N,van der Hilst R D.1999.Seismic tomography with P and S data reveals lateral variationsin the rigidity of deep slabs[J].Earth Planet Sci Lett,173(1-2):91-100.
Ye L,Li J,Tseng T L,Yao Z X.2011.A stagnant slab in a water-bearing mantle transition zone beneath northeast Chi-na:Implications from regional SH waveform modeling[J].Geophys J Inter,186(2):706-710.
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