三维地震波速结构约束下的变黏度地幔对流及其动力学意义
|
摘要
建立了三维黏度扰动下的变黏度地幔对流模型,并提供了在引入地幔的三维地震波速度结构下相应的求解方法.依此反演了瑞利数Ra=106时,两种不同边界条件下的极、环型场对流图像,这有助于深化对地幔物质流动和大地构造运动的深部动力学过程的认识和理解.研究结果表明,不但地幔浅部的极型场对流图像显示出了与大地构造运动的相关性并揭示了其深部动力学过程,更重要的是,地幔浅部的环型场对流图像首次为我们认识和理解板块构造的水平与旋转运动提供了重要的信息:环型场速度剖面中在赤道附近存在一条大致南东东—北西西向的强对流条带,可能与环赤道附近大型剪切带的形成相关,进而表明可能是该带强震发生的深部动力学背景;在南北半球存在的旋转方向相反的对流环表明它们整体上可能存在差异旋转.
Mantle convection model with a 3-D lateral variable viscosity constrained by seismic wave velocity is developed and its corresponding solution is presented in this paper.The poloidal and toroidal convection patterns are presented at Rayleigh number Ra = 10~6 under two kinds of boundary conditions,respectively,which are helpful to further recognize and understand the behavior of mass motion in the mantle and the deep dynamic process of surface tectonic motion.Our results indicate that not only the poloidal convection patterns in uppermost mantle have good correlations to surface tectonic motion,but also the toroidal ones reveal important information of their horizontal motion and rotation for the first time.There is a SEE-NWW strong convection zone close to the equator in toroidal convection patterns,which probably correlates with the large-scale shear zone near the equator and is the deep dynamic background of strong earthquake occurrence in this zone.The opposite rotating large-scale convection rolls in the Southern and Northern hemispheres suggest that maybe there is differential rotation between them.
Mantle convection model with a 3-D lateral variable viscosity constrained by seismic wave velocity is developed and its corresponding solution is presented in this paper.The poloidal and toroidal convection patterns are presented at Rayleigh number Ra = 10~6 under two kinds of boundary conditions,respectively,which are helpful to further recognize and understand the behavior of mass motion in the mantle and the deep dynamic process of surface tectonic motion.Our results indicate that not only the poloidal convection patterns in uppermost mantle have good correlations to surface tectonic motion,but also the toroidal ones reveal important information of their horizontal motion and rotation for the first time.There is a SEE-NWW strong convection zone close to the equator in toroidal convection patterns,which probably correlates with the large-scale shear zone near the equator and is the deep dynamic background of strong earthquake occurrence in this zone.The opposite rotating large-scale convection rolls in the Southern and Northern hemispheres suggest that maybe there is differential rotation between them.
引文
[1]Hager B H,O’Connell R J.Subduction zone dips and flow driven bythe plates.Tectonophysics,1978,50:111~13
[2]Minister J B,Jordan T H.Present_day plate motion.J.Geophys.Res.,1978,83:5331~5354
[3]Forte A M,Peltier W R.Plate tectonics and aspherical Earthstructure:the importance of poloidal coupling.J.Geophys.Res.,1987,92:3645~3679
[4]Fu R S.Plate motions,earth’s geoid anomalies and mantleconvection.In:Cohen S C,Vanicek P eds.Slow Deformation andTransmission of Stress in the Earth.1989.47~54
[5]Hager B H,O’Connell R J.Kinemetic models of large_scale mantleflow.J.Geophys.Res.,1979,84:1031~1048
[6]Richard Y,Vigny C.Mantle dynamics with induced plate tectonics.J.Geophys.Res.,1989,94:17543~17560
[7]Gable C W,O’Connell R J.Convection in three dimensions withsurface plates:Generation of toroidal flow.J.Geophys.Res.,1991,96(B5):8391~8450
[8]叶正仁,朱日祥.地幔对流与岩石圈板块的相互耦合及影响———(II)地幔混合对流理论及其应用.地球物理学报,1996,39(1):47~56Ye Z R,Zhu R X.Coupling between mantle circulation andlithospheric plates—(II)mix convection and its applications.Chinese J.Geophys.(in Chinese),1996,39(1):47~56
[9]Kirby S H,Kronenberg A K.Rheology of the lithosphere:selectedtopics.Rev.Geophys.,1987,25(6):1219~1244
[10]Kogan M G,McNutt M K.Gravity field over Northern Eurasia andvariations in the strength of the upper mantle.Science,1993,259:473~479
[11]Zhong S,Gurnis M.Role of plates and temperature_dependentviscosity in phase change dynamics.J.Geophys.Res.,1994,99(B8):15903~15917
[12]Zhong S,Zuber M T.Role of temperature_dependent viscosity andsurface plates in spherical shell models of mantle convection.J.Geophys.Res.,2000,105(B5):11063~11082
[13]Sunder_Plaβmann T,Christensen U.A test of approximations formodeling convection with temperature_dependent viscosity.Physics ofthe Earth and Planetary Interiors,2000,120:103~110
[14]Quareni F,Yuen D A,Sewell G,et al.High Rayleigh numberconvection with strongly variable viscosity:a comparison betweenmean field and two_dimensional solutions.J.Geophys.Res.,1985,90(B14):12633~12644
[15]Larsen T B,Yuen D A,Malevsky A V,et al.Dynamics of stronglytime_dependent convection with non_Newtonian temperature_dependent viscosity.Physics of the Earth and Planetary Interiors,1996,94:75~103
[16]Christensen U.Convection in a variable_viscosity fluid:Newtonianversus power_law rheology.Earth and Planetary Science Letters,1983,64:153~162
[17]Weinstein S A,Christenen U.Convection planforms in a fluid with atemperature_dependent viscosity beneath a stress_free upperboundary.Geophysical Research Letters,1991,18(11):2035~2038
[18]Hansen U,Yuen D A.High Rayleigh number regime of temperature_dependent viscosity convection and the Earth’s early thermal history.Geophysical Research Letters,1993,20(20):2191~2194
[19]Larsen T B,Yuen D A,Malevsky A V.Dynamical consequences onfast subducting slabs from a self_regulating mechanism due to viscousheating in variable viscosity convection.Geophysical Research Letters,1995,22(10):1277~1280
[20]Zhang S,Yuen D A.Intense local toroidal motion generated byvariable viscosity compressible convection in 3D spherical shell.Geophysical Research Letters,1996,23(22):3135~3138
[21]Balachandar S,Yuen D A,Reuteler D M,et al.Viscous dissipationin three_dimensional convection with temperature_dependent viscosity.Sicence,1995,267:1150~1153
[22]Balachandar S,Yuen D A,Reuteler D M.Localization of toroidalmotion and shear heating in 3_D high Rayleigh number convectionwith temperature_dependent viscosity.Geophysical Research Letters,1995,22(4):477~480
[23]Christensen U,Harder H.3_D convection with variable viscosity.Geophys.J.Int.,1991,104:213~226
[24]朱涛,冯锐.球层中的非线性自由热对流———变黏度模型.地震学报,2005,27(2):194~204Zhu T,Feng R.Nonlinear free thermal convection in a sphericalshell:A variable viscosity model.Acta Seismologica Sinica(inChinese),2005,27(2):194~204
[25]叶正仁,王建.上地幔变黏度小尺度对流的数值模拟.地球物理学报,2003,45(1):26~33Ye Z R,Wang J.A numerical research on the small_scale convectionwith variable viscosity in the upper mantle.Chinese J.Geophys.(inChinese),2003,46(3):335~339
[26]Koch D M,Ribe N M.The effect of lateral viscosity variations onsurface observations.Geophysical Research Letters,1989,16(1):535~538
[27]Richards M A,Hager B H.Effects of lateral viscosity variations onlong_wave_length geoid anomalies and topography.J.Geophys.Res.,1989,94(B8):10299~10313
[28]Ribe N M.The dynamics of thin shells with variable viscosity and theorigin of toroidal flow in the mantle.Geophys.J.Int.,1992,110:537~552
[29]Cadek O,Richard Y,Martinec Z,Matyska C.Comparison betweenNewtonian and non_Newtanian flow driven by internal loads.Geophys.J.Int.,1993,112:103~114
[30]Zhang S,Christensen U.Some effects of lateral viscosity variations ongeoid and surface velocities induced by density anomalies in themantle.Geophys.J.Int.,1993,114:531~547
[31]Cˇadek O,Fleitout L.Effect of lateral viscosity variations in the top300 km on the geoid and dynamic topography.Geophys.J.Int.,2003,152:566~580
[32]傅容珊,黄建华,董树谦等.利用地震层析成像数据计算地幔新模型的探讨.地球物理学报,2003,46(6):772~778Fu R S,Huang J H,Dong S Q,et al.A new mantle convectionmodel constrained by seismic tomography data.Chinese J.Geophys.,2003,46(6):772~778
[33]傅容珊,董树谦,黄建华等.地震层析成像—地幔对流新模型的研究.地球物理学报,2002,45(增刊):136~142Fu R S,Dong S Q,Huang J H,et al.A new mantle convectionmodel constrained by seismic tomography.Chinese J.Geophys.(inChinese),2002,45(Suppl.):136~142
[34]Buckus G.A class of self_sustaining dissipative spherical dynamos.Ann.Phys,1958,4:381~384
[35]朱涛.全球地幔对流的数值模拟及其动力学意义[博士论文].北京:中国地震局地球物理研究所,2004Zhu T.The numerical modelling of whole mantle convection and itsdynamic implications[Ph.D.thesis](in Chinese).Beijing:Instituteof Geophysics,China Earthquake Administration,2004
[36]王家映.地球物理反演理论.武汉:中国地质大学出版社,1998.23~26Wang J Y.Theory of Geophysical Inversion(in Chinese).Wuhan:China University of Geosciences Press,1998.23~26
[37]Dziewonski A M.Mapping the Lower mantle:determination of lateralheterogeneity in P velocity up to degree and order 6.J.G.R.1984,89(B7):5929~5952
[38]Tanimoto T.Long_wavelength S_wave velocity structure throughout themantle.Geophys.J.Int.,1990,100:327~336
[39]傅容珊,黄建华,刘文忠.地震层析地球内部密度分布横向不均匀研究.地球物理学报,1993,36(6):740~751Fu R S,Huang J H,Liu W Z.Seismic tomography:Internalheterogeneity of mantle and its geodynamical inferences.Chinese J.Geophys.(in Chinese),36(6):740~751
[40]Su W J,Robert L W,Dziewonski A M.Degree 12 model of shearvelocity heterogeneity in the mantle.J.Geophys.Res.,1994,99(B4):6945~6980
[41]Zhao D P.Global tomographic imagies of mantle plumes andsubducting slabs:insight into deep earth dynamics.Phys.Earth andPlanetary Inter.,2004,146:3~34
[42]Dziewonski A M,Anderson D L.Preliminary reference earth model.Physics of the Earth and Planetary Interiors,1981,25:297~356
[43]Schubert G,Turcotte D L,Olson P.Mantle convection in the earthand planets.Cambridge,New York:Cambridge University Press,2001
[44]朱涛,冯锐.球层中高阶自由热对流格局及其变化的研究.地震学报,2005,27(1):11~24Zhu T,Feng R.The patterns of high_degree thermal free convectionand its features in a spherical shell.Acta Seismologica Sinica(inChinese),2005,27(1):11~24
[45]马宗晋.全球三大构造体系与板条构造.见:全球构造与固体地球多圈层相互作用.香山科学会议第143次学术讨论会,2000(143),14~16Ma Z J.The Earth’s three great tectonic systems and plate striptectonics.In:Coupling between Earth’s Tectonics and Multisphere(in Chinese).Xiangshan Scientific Convention,2000(143):14~16
[2]Minister J B,Jordan T H.Present_day plate motion.J.Geophys.Res.,1978,83:5331~5354
[3]Forte A M,Peltier W R.Plate tectonics and aspherical Earthstructure:the importance of poloidal coupling.J.Geophys.Res.,1987,92:3645~3679
[4]Fu R S.Plate motions,earth’s geoid anomalies and mantleconvection.In:Cohen S C,Vanicek P eds.Slow Deformation andTransmission of Stress in the Earth.1989.47~54
[5]Hager B H,O’Connell R J.Kinemetic models of large_scale mantleflow.J.Geophys.Res.,1979,84:1031~1048
[6]Richard Y,Vigny C.Mantle dynamics with induced plate tectonics.J.Geophys.Res.,1989,94:17543~17560
[7]Gable C W,O’Connell R J.Convection in three dimensions withsurface plates:Generation of toroidal flow.J.Geophys.Res.,1991,96(B5):8391~8450
[8]叶正仁,朱日祥.地幔对流与岩石圈板块的相互耦合及影响———(II)地幔混合对流理论及其应用.地球物理学报,1996,39(1):47~56Ye Z R,Zhu R X.Coupling between mantle circulation andlithospheric plates—(II)mix convection and its applications.Chinese J.Geophys.(in Chinese),1996,39(1):47~56
[9]Kirby S H,Kronenberg A K.Rheology of the lithosphere:selectedtopics.Rev.Geophys.,1987,25(6):1219~1244
[10]Kogan M G,McNutt M K.Gravity field over Northern Eurasia andvariations in the strength of the upper mantle.Science,1993,259:473~479
[11]Zhong S,Gurnis M.Role of plates and temperature_dependentviscosity in phase change dynamics.J.Geophys.Res.,1994,99(B8):15903~15917
[12]Zhong S,Zuber M T.Role of temperature_dependent viscosity andsurface plates in spherical shell models of mantle convection.J.Geophys.Res.,2000,105(B5):11063~11082
[13]Sunder_Plaβmann T,Christensen U.A test of approximations formodeling convection with temperature_dependent viscosity.Physics ofthe Earth and Planetary Interiors,2000,120:103~110
[14]Quareni F,Yuen D A,Sewell G,et al.High Rayleigh numberconvection with strongly variable viscosity:a comparison betweenmean field and two_dimensional solutions.J.Geophys.Res.,1985,90(B14):12633~12644
[15]Larsen T B,Yuen D A,Malevsky A V,et al.Dynamics of stronglytime_dependent convection with non_Newtonian temperature_dependent viscosity.Physics of the Earth and Planetary Interiors,1996,94:75~103
[16]Christensen U.Convection in a variable_viscosity fluid:Newtonianversus power_law rheology.Earth and Planetary Science Letters,1983,64:153~162
[17]Weinstein S A,Christenen U.Convection planforms in a fluid with atemperature_dependent viscosity beneath a stress_free upperboundary.Geophysical Research Letters,1991,18(11):2035~2038
[18]Hansen U,Yuen D A.High Rayleigh number regime of temperature_dependent viscosity convection and the Earth’s early thermal history.Geophysical Research Letters,1993,20(20):2191~2194
[19]Larsen T B,Yuen D A,Malevsky A V.Dynamical consequences onfast subducting slabs from a self_regulating mechanism due to viscousheating in variable viscosity convection.Geophysical Research Letters,1995,22(10):1277~1280
[20]Zhang S,Yuen D A.Intense local toroidal motion generated byvariable viscosity compressible convection in 3D spherical shell.Geophysical Research Letters,1996,23(22):3135~3138
[21]Balachandar S,Yuen D A,Reuteler D M,et al.Viscous dissipationin three_dimensional convection with temperature_dependent viscosity.Sicence,1995,267:1150~1153
[22]Balachandar S,Yuen D A,Reuteler D M.Localization of toroidalmotion and shear heating in 3_D high Rayleigh number convectionwith temperature_dependent viscosity.Geophysical Research Letters,1995,22(4):477~480
[23]Christensen U,Harder H.3_D convection with variable viscosity.Geophys.J.Int.,1991,104:213~226
[24]朱涛,冯锐.球层中的非线性自由热对流———变黏度模型.地震学报,2005,27(2):194~204Zhu T,Feng R.Nonlinear free thermal convection in a sphericalshell:A variable viscosity model.Acta Seismologica Sinica(inChinese),2005,27(2):194~204
[25]叶正仁,王建.上地幔变黏度小尺度对流的数值模拟.地球物理学报,2003,45(1):26~33Ye Z R,Wang J.A numerical research on the small_scale convectionwith variable viscosity in the upper mantle.Chinese J.Geophys.(inChinese),2003,46(3):335~339
[26]Koch D M,Ribe N M.The effect of lateral viscosity variations onsurface observations.Geophysical Research Letters,1989,16(1):535~538
[27]Richards M A,Hager B H.Effects of lateral viscosity variations onlong_wave_length geoid anomalies and topography.J.Geophys.Res.,1989,94(B8):10299~10313
[28]Ribe N M.The dynamics of thin shells with variable viscosity and theorigin of toroidal flow in the mantle.Geophys.J.Int.,1992,110:537~552
[29]Cadek O,Richard Y,Martinec Z,Matyska C.Comparison betweenNewtonian and non_Newtanian flow driven by internal loads.Geophys.J.Int.,1993,112:103~114
[30]Zhang S,Christensen U.Some effects of lateral viscosity variations ongeoid and surface velocities induced by density anomalies in themantle.Geophys.J.Int.,1993,114:531~547
[31]Cˇadek O,Fleitout L.Effect of lateral viscosity variations in the top300 km on the geoid and dynamic topography.Geophys.J.Int.,2003,152:566~580
[32]傅容珊,黄建华,董树谦等.利用地震层析成像数据计算地幔新模型的探讨.地球物理学报,2003,46(6):772~778Fu R S,Huang J H,Dong S Q,et al.A new mantle convectionmodel constrained by seismic tomography data.Chinese J.Geophys.,2003,46(6):772~778
[33]傅容珊,董树谦,黄建华等.地震层析成像—地幔对流新模型的研究.地球物理学报,2002,45(增刊):136~142Fu R S,Dong S Q,Huang J H,et al.A new mantle convectionmodel constrained by seismic tomography.Chinese J.Geophys.(inChinese),2002,45(Suppl.):136~142
[34]Buckus G.A class of self_sustaining dissipative spherical dynamos.Ann.Phys,1958,4:381~384
[35]朱涛.全球地幔对流的数值模拟及其动力学意义[博士论文].北京:中国地震局地球物理研究所,2004Zhu T.The numerical modelling of whole mantle convection and itsdynamic implications[Ph.D.thesis](in Chinese).Beijing:Instituteof Geophysics,China Earthquake Administration,2004
[36]王家映.地球物理反演理论.武汉:中国地质大学出版社,1998.23~26Wang J Y.Theory of Geophysical Inversion(in Chinese).Wuhan:China University of Geosciences Press,1998.23~26
[37]Dziewonski A M.Mapping the Lower mantle:determination of lateralheterogeneity in P velocity up to degree and order 6.J.G.R.1984,89(B7):5929~5952
[38]Tanimoto T.Long_wavelength S_wave velocity structure throughout themantle.Geophys.J.Int.,1990,100:327~336
[39]傅容珊,黄建华,刘文忠.地震层析地球内部密度分布横向不均匀研究.地球物理学报,1993,36(6):740~751Fu R S,Huang J H,Liu W Z.Seismic tomography:Internalheterogeneity of mantle and its geodynamical inferences.Chinese J.Geophys.(in Chinese),36(6):740~751
[40]Su W J,Robert L W,Dziewonski A M.Degree 12 model of shearvelocity heterogeneity in the mantle.J.Geophys.Res.,1994,99(B4):6945~6980
[41]Zhao D P.Global tomographic imagies of mantle plumes andsubducting slabs:insight into deep earth dynamics.Phys.Earth andPlanetary Inter.,2004,146:3~34
[42]Dziewonski A M,Anderson D L.Preliminary reference earth model.Physics of the Earth and Planetary Interiors,1981,25:297~356
[43]Schubert G,Turcotte D L,Olson P.Mantle convection in the earthand planets.Cambridge,New York:Cambridge University Press,2001
[44]朱涛,冯锐.球层中高阶自由热对流格局及其变化的研究.地震学报,2005,27(1):11~24Zhu T,Feng R.The patterns of high_degree thermal free convectionand its features in a spherical shell.Acta Seismologica Sinica(inChinese),2005,27(1):11~24
[45]马宗晋.全球三大构造体系与板条构造.见:全球构造与固体地球多圈层相互作用.香山科学会议第143次学术讨论会,2000(143),14~16Ma Z J.The Earth’s three great tectonic systems and plate striptectonics.In:Coupling between Earth’s Tectonics and Multisphere(in Chinese).Xiangshan Scientific Convention,2000(143):14~16
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