摘要
岩石圈内部间断面的精细结构隐含了岩石圈形成、增生和改造及破坏等重要的动力学信息.文章发展了地震光照成像新方法以探测岩石圈内部间断面小尺度结构.该方法使用了高频段0.5~4Hz的远震事件地震P波初至及其尾波信号,其对岩石圈间断面的分辨能力达到2km.该方法的基本原理是在台站下方垂直入射透射波响应的自相关等价于震源和地震台站均位于自由地表的反射波响应.透射波响应包括在台站下方穿过间断面到达自由地表的初至P波及其在自由地表和间断面之间反射的多次波.本研究将该方法垂直入射情况进一步拓展到倾斜入射,这提升了该方法的适用性.通过合成理论地震图验证了地震光照成像方法理论的正确性和可行性,探讨了影响成像结果的一些因素,并给出了该方法的数据处理步骤以及成果解释准则.文章利用该方法并结合瞬时频率等结果确定了华北克拉通东部两个固定台站的岩石圈精细结构,发现在两个台站下方岩石圈地幔分别在52和75km的深度存在明显的间断面.西澳大利亚克拉通MBWA固定台站下方,地震光照成像和接收函数揭示的岩石圈结构较为一致,存在明显的岩石圈内部间断面.高频地震光照成像结果可揭示岩石圈精细结构,但其波形更为复杂,建议充分利用层析反演速度和接收函数等已有的地震学信息并作为参考.
引文
孙伟家,符力耘,姚振兴.2009.基于耦合反射/透射系数单程波传播算子的地震波模拟研究.地球物理学报,52:2558-2565
滕吉文.2006.地球深部壳-幔边界的层束精细结构与物理属性研究.吉林大学学报:地球科学版,36:1-23
王椿镛,吴庆举,张先康.1994.冀中拗陷内深地震反射剖面揭示的滑脱构造.科学通报,39:625-628
徐佩芬,李世豪,凌甦群,郭慧丽,田宝卿.2013.利用SPAC法估算地壳S波速度结构.地球物理学报,56:3846-3854
杨文采.2009.东亚古特提斯域大地构造物理学.北京:石油工业出版社
赵俊猛,刘国栋,赵国泽,卢造勋,张先康.2001.天山造山带与准噶尔盆地壳幔过渡带及其动力学含义.中国科学D辑:地球科学,31:272-282
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.地球物理学报,52:1412-1417
郑天愉,段永红,许卫卫,艾印双,陈凌,赵亮,张耀阳,徐小兵.2017.华北地区地壳-上地幔地震波速度结构模型v2.0.http://www.craton.cn/data
郑晓东.1991.Zoeppritz方程的近似及其应用.石油地球物理勘探,26:129-144
朱日祥,陈凌,吴福元,刘俊来.2011.华北克拉通破坏的时间,范围与机制.中国科学:地球科学,41:583-592
Abt D L,Fischer K M,French S W,Ford H A,Yuan H,Romanowicz B.2010.North American lithospheric discontinuity structure imaged by Ps and Sp receiver functions.J Geophys Res,115:B09301
Aki K,Chouet B.1975.Origin of coda waves:Source,attenuation,and scattering effects.J Geophys Res,80:3322-3342
Artemieva I M.2009.The continental lithosphere:Reconciling thermal,seismic,and petrologic data.Lithos,109:23-46
Barnes A E.2007.A tutorial on complex seismic trace analysis.Geophysics,72:W33-W43
Bostock M G.1998.Mantle stratigraphy and evolution of the slave province.J Geophys Res,103:21183-21200
Chen L.2017.Layering of subcontinental lithospheric mantle.Chin Sci Bull,62:1030-1034
Chen L,Jiang M,Yang J,Wei Z,Liu C,Ling Y.2014.Presence of an intralithospheric discontinuity in the central and western north china craton:Implications for destruction of the craton.Geology,42:223-226
Claerbout J F.1968.Synthesis of a layered medium from its acoustic transmission response.Geophysics,33:264-269
Diehl T,Ritter J R R.2005.The crustal structure beneath SE Romania from teleseismic receiver functions.Geophys J Int,163:238-251
Farra V,Vinnik L.2000.Upper mantle stratification by P and S receiver functions.Geophys J Int,141:699-712
Fischer K M,Ford H A,Abt D L,Rychert C A.2010.The lithosphereasthenosphere boundary.Annu Rev Earth Planet Sci,38:551-575
Ford H A,Fischer K M,Abt D L,Rychert C A,Elkins-Tanton L T.2010.The lithosphere-asthenosphere boundary and cratonic lithospheric layering beneath Australia from Sp wave imaging.Earth Planet Sci Lett,300:299-310
Frasier C W.1970.Discrete time solution of plane P-Sv waves in a plane layered medium.Geophysics,35:197-219
Gorbatov A,Saygin E,Kennett B L N.2012.Crustal properties from seismic station autocorrelograms.Geophys J Int,192:861-870
Griffin W L,O’Reilly S Y.1987.Is the continental Moho the crustmantle boundary?Geology,15:241
Hales A L.1969.A seismic discontinuity in the lithosphere.Earth Planet Sci Lett,7:44-46
He L J.2015.Thermal regime of the North China Craton:Implications for craton destruction.Earth-Sci Rev,140:14-26
Houston H.2001.Influence of depth,focal mechanism,and tectonic setting on the shape and duration of earthquake source time functions.J Geophys Res,106:11137-11150
Kennett B L N,Engdahl E R,Buland R.1995.Constraints on seismic velocities in the Earth from traveltimes.Geophys J Int,122:108-124
Kennett B L N.2001.The Seismic Wavefield:Volume 1,Introduction and Theoretical Development.Cambridge:Cambridge University Press
Kennett B L N.2002.The Seismic Wavefield:Volume 2,Interpretation of Seismograms on regional and Global Scales.Cambridge:Cambridge University Press
Kennett B L N.2015.Lithosphere-asthenosphere P-wave reflectivity across australia.Earth Planet Sci Lett,431:225-235
Kennett B L N,Furumura T.2008.Stochastic waveguide in the lithosphere:Indonesian subduction zone to australian craton.Geophys J Int,172:363-382
Kennett B L N,Furumura T.2016.Multiscale seismic heterogeneity in the continental lithosphere.Geochem Geophys Geosyst,17:791-809
Kennett B L N,Salmon M.2012.AuSREM:Australian seismological reference model.Aust J Earth Sci,59:1091-1103
Kennett B L N,Saygin E,Salmon M.2015.Stacking autocorrelograms to map moho depth with high spatial resolution in southeastern Australia.Geophys Res Lett,42:7490-7497
Kennett B L N,Yoshizawa K,Furumura T.2017.Interactions of multiscale heterogeneity in the lithosphere:Australia.Tectonophysics,717:193-213
Kumar M R,Bostock M G.2006.Transmission to reflection transformation of teleseismic wavefields.J Geophys Res,111:B08306
Langston C A.1979.Structure under mount rainier,Washington,inferred from teleseismic body waves.J Geophys Res,84:4749-4762
Mancinelli N J,Fischer K M,Dalton C A.2017.How sharp is the cratonic lithosphere-asthenosphere transition?Geophys Res Lett,44:10,189-10,197
Pham T S,Tkal?i?H.2017.On the feasibility and use of teleseismic Pwave coda autocorrelation for mapping shallow seismic discontinuities.J Geophys Res-Solid Earth,122:3776-3791
Rickett J,Claerbout J.1999.Acoustic daylight imaging via spectral factorization:Helioseismology and reservoir monitoring.Lead Edge,18:957-960
Ruigrok E,Wapenaar K.2012.Global-phase seismic interferometry unveils P-wave reflectivity below the Himalayas and Tibet.Geophys Res Lett,39:L11303
Saygin E,Cummins P R,Lumley D.2017.Retrieval of the P wave reflectivity response from autocorrelation of seismic noise:Jakarta Basin,Indonesia.Geophys Res Lett,44:792-799
Schuster G T,Yu J,Sheng J,Rickett J.2004.Interferometric/daylight seismic imaging.Geophys J Int,157:838-852
Selway K,Ford H,Kelemen P.2015.The seismic mid-lithosphere discontinuity.Earth Planet Sci Lett,414:45-57
Sun W,Fu L Y.2012.Compensation for transmission losses based on one-way propagators in the mixed domain.Geophysics,77:S65-S72
Sun W,Kennett B L N.2016a.Receiver structure from teleseisms:Autocorrelation and cross correlation.Geophys Res Lett,43:6234-6242
Sun W,Kennett B L N.2016b.Uppermost mantle P wavespeed structure beneath eastern china and its surroundings.Tectonophysics,683:12-26
Sun W,Kennett B L N.2016c.Uppermost mantle structure beneath eastern china and its surroundings from Pn and Sn tomography.Geophys Res Lett,43:3143-3149
Sun W,Kennett B L N.2017.Mid-lithosphere discontinuities beneath the western and central North China Craton.Geophys Res Lett,44:1302-1310
Sun W,Fu L Y,Saygin E,Zhao L.2018.Insights into layering in the cratonic lithosphere beneath Western Australia.J Geophys ResSolid Earth,123:1405-1418
Taner M T,Koehler F,Sheriff R E.1979.Complex seismic trace analysis.Geophysics,44:1041-1063
Vinnik L P.1977.Detection of waves converted from P to SV in the mantle.Phys Earth Planet Inter,15:39-45
Vinnik L P,Avetisjan R A,Mikhailova N G.1983.Heterogeneities in the mantle transition zone from observations of P-to-SV converted waves.Phys Earth Planet Inter,33:149-163
Wang Q,Song X D,Ren J Y.2017.Ambient noise surface wave tomography of marginal seas in east Asia.Earth Planet Phys,1:13-25
Wang T,Song X,Xia H H.2015.Equatorial anisotropy in the inner part of Earth’s inner core from autocorrelation of earthquake coda.Nat Geosci,8:224-227
Wilson D C,Angus D A,Ni J F,Grand S P.2006.Constraints on the interpretation of S-to-P receiver functions.Geophy J Int,165:969-980
Wirth E A,Long M D.2014.A contrast in anisotropy across midlithospheric discontinuities beneath the central United States-Arelic of craton formation.Geology,42:851-854
Yoshizawa K,Kennett B L N.2015.The lithosphere-asthenosphere transition and radial anisotropy beneath the Australian continent.Geophys Res Lett,42:3839-3846
Yuan H,Romanowicz B.2010.Lithospheric layering in the North American craton.Nature,466:1063-1068
Yuan X,Kind R,Li X,Wang R.2006.The S receiver functions:Synthetics and data example.Geophys J Int,165:555-564
1)国家测震台网数据备份中心. 2007. 国家测震台网地震波形数据. 中国地震局地球物理研究所, doi:10.11998/SeisDmc/SN, http://www.seisdmc.ac.cn