海拉尔CTBTO地震台阵下方小尺度非均匀体研究
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摘要
利用国际禁核组织在海拉尔布设的小孔径地震台阵的16个深远地震波资料,分离出了P波波场中不相干的尾波.频率域中对波场扰动的研究表明,在0.5～3.0 Hz的频率范围内,观测到的波场扰动可以利用P波在随机介质中的散射进行解释.不同远震事件得到的稳定结果表明,在该台阵下方34 km厚的地壳和110 km厚的岩石层中可能存在相关长度为2.0～7.4 km的散射体.
Incoherent seismic wavefield fluctuations recorded by Hailaer CTBTO seismic array are separated from 16 deep teleseismic events.The frequency-dependent intensities of the mean and fluctuation wavefields are analyzed.The observed wavefield fluctuations in the frequency range 0.5～3.0 Hz can be explained by scattering of the teleseismic P-wave front at random media-type structures.The stable and narrow range of the fluctuation parameters from these teleseismic events indicates evidence for scattered seismic phases which are generated inside the crust and lithosphere.The reasonable structural models contain heterogeneities with 2.0～7.4 km correlation lengths in the 34 km thick crust and the 110 km thick lithosphere.
Incoherent seismic wavefield fluctuations recorded by Hailaer CTBTO seismic array are separated from 16 deep teleseismic events.The frequency-dependent intensities of the mean and fluctuation wavefields are analyzed.The observed wavefield fluctuations in the frequency range 0.5～3.0 Hz can be explained by scattering of the teleseismic P-wave front at random media-type structures.The stable and narrow range of the fluctuation parameters from these teleseismic events indicates evidence for scattered seismic phases which are generated inside the crust and lithosphere.The reasonable structural models contain heterogeneities with 2.0～7.4 km correlation lengths in the 34 km thick crust and the 110 km thick lithosphere.
引文
[1] Kasahars K.Computer program for a fault-plane solution.Bull.Seism.Soc.Am,1963,S3(1) :1～13
[2] Aki K,Christoffersson A,Husebye E S.Determination of the three-dimensional seismic structure of the lithosphere.J.Geophys.Res,1977,82:277 ～ 296
[3] Langston C A.Structure under Mount Rainier,Washington,inferred from teleseismic body waves.J.Geophys.Res.,1979,84( B4) :4749～4762
[4] Shen X Z,Zhou H L.Locating scatters in the bottom of the mantle beneath eastern Tibet with PKIKP precursors.Chinese Science Bulletin,2009,10． 1007/s11434-009-0382-1
[5] Sato H,Fehler M C.Seismic wave propagation and scattering in the heterogeneous earth.Springer-Verlag New York,1998
[6] Mack H.Nature of short-period P-wave signal variations at LASA.J.Geophys.Res.,1969,74:3161 ～ 3170
[7] Ritter J R R,Mai P M,Stoll G,Fuchs K.Scattering of teleseismic waves in the lower crust:observations in the Massif Central,France.Phys.Earth.Planet.Int.,1997,104:127 ～ 146
[8] Ritter J R R,Shapiro S A,Schechinger B.Scattering parameters of the lithosphere below the Massif Central,France,from teleseismic wavefield records.Geophys.J.Int.,1998,134:187 ～ 198
[9] Aki K.Scattering of P waves under the Montana Lasa.J.Geophys.Res.,1973,78:1334 ～ 1346
[10] Aki K,Chouet B.Origin of coda waves:source,attenuation,and scattering effects.J.Geophys.Res.,1975,80:3322～3342
[11] Flatte S M,Wu R S.Small-scale structure in the lithosphere and asthenosphere deduced from arrival time and amplitude fluctuations at NORSAR.J.Geophys.Res.,1988,93:6601 ～ 6614
[12] Langston C A.Scattering of teleseismic body waves under Pasadena,California.J.Geophys.Res.,1989,94:1935 ～1951
[13] Korn M.A modified energy-flux model for lithospheric scattering of teleseismic body waves.Geophys.J.Int.,1990,102:165 ～ 175
[14] Wagner G S,Langston C A.A numerical investigation of scattering effects for teleseismic propagation in a heterogeneous layer over a homogeneous half-space.Geophys.J.Int.,1992,110:486 ～ 500
[15] Korn M.Determination of site-dependent scattering Q from P-wave coda analysis with an energy-flux model.Geophys.J.Int.,1993,113:54 ～ 72
[16] Shapiro S A,Kneib G.Seismic attenuation by scattering:theory and numerical results.Geophys.J.Int.,1993,114:373 ～ 391
[17] Shapiro S A,Schwarz R,Gold N.The effect of random isotropic inhomogeneities on the phase velocity of seismic waves.Geophys.J.Int.,1996,127:783 ～ 794
[18] Rothert E,Ritter J R R.Small-scale heterogeneities below the Graefenberg array,Germany,from seismic wavefield fluctuations of Hindu Kush events.Geophys.J.Int.,2000,140:175 ～ 184
[19] Hock S,Korn M,Ritter J R R,Rothert E.Mapping random lithospheric heterogeneities in northern and central Europe.Geophys.J.Int.,2004,157:251 ～ 264
[20] Shen X Z,Ritter J R R.Small-scale heterogeneities below the Lanzhou CTBTO seismic array,from seismic wavefield fluctuations.J,Seismo.,2009,10． 1007/sl0950-009-9177-8
[21] 郝春月,郑 重,郭燕平等.中国数字地震台网(CDSN)和IMS/PS台阵的监测定位能力评估.地震地磁观测与研究,2006,27(2) :56～63 Hao C Y,Zheng Z,Guo Y P,et al.The calculation of locating ability of China Digital Seismological Network (CDSN) and IMS/PS seismic array (in Chinese).Seismological and Geomagnetic Observation and Research,2006,27(2) :56 ～ 63
[22] Hao C Y,Zheng Z.Slowness-azimuth corrections of teleseismic events for IMS primary arrays in China.J.Seismo.,2009,doi:10． 1007/sl0950-008-9137-8
[23] 沈旭章,周蕙兰.接收函数近邻反演方法的改进和对海拉尔台下地壳速度结构的研究.中国科学院研究生院学报,2005,22(3) :322～328 Shen X Z,Zhou H L.Inversion of velocity structure under HLR seismic station with receiver function and NA method (in Chinese).Journal of the Graduate School of the Chinese Academy of Sciences,2005,22(3) :322 ～ 328
[24] Rost S,Thomas C.Array seismology:Methods and applications.Rev.Geophys.,2002,40:1 ～ 27
[25] Bannister S C,Husebye E S,Ruud B O.Teleseismic P-coda analyzed by three-component and array techniques:deterministic location of topographic P-to-Rg scattering near the NORESS array.Bull.Seism.Soc.Am.,1990,80:1969～1986
[26] Davies D,Kelly E J,Filson J R.Vespa process for the analysis of seismic signals.Nature Physical Science,1971,232:8 ～ 13
[27] Muirhead K J,Datt R.The Nth root process applied to seismic array data.Geophys.J.R.Astron.Soc.,1976,47:197 ～ 210
[28] An M J,Shi Y L.Lithospheric Thickness of the Chinese Continent.Phys.Earth Planet.Ints,2006,159:257 ～ 266
[29] Huang J L,Zhao D P.High-resolution mantle tomography of China and surrounding regions.J.Geophys.Res.,2006,111:B09305 doi:10． 1029/2005JB004066
[30] Korn M.Modelling the teleseismic P coda envelope:depth dependent scattering and deterministic structure,Special issue:Stochastic Seismic Wave Fields and Realistic Media,Neustadt,Germany,11-15 March 1996,guest eds Korn M,Sato H,ScherbaumF.Phys.Earth.Planet.Int.,1997,104:23 ～ 36
[31] Wessel P,Smith W H F.New version of the generic mapping tools released.Eos.Trans.Am.Geophys.Union.,1995,76:329
[2] Aki K,Christoffersson A,Husebye E S.Determination of the three-dimensional seismic structure of the lithosphere.J.Geophys.Res,1977,82:277 ～ 296
[3] Langston C A.Structure under Mount Rainier,Washington,inferred from teleseismic body waves.J.Geophys.Res.,1979,84( B4) :4749～4762
[4] Shen X Z,Zhou H L.Locating scatters in the bottom of the mantle beneath eastern Tibet with PKIKP precursors.Chinese Science Bulletin,2009,10． 1007/s11434-009-0382-1
[5] Sato H,Fehler M C.Seismic wave propagation and scattering in the heterogeneous earth.Springer-Verlag New York,1998
[6] Mack H.Nature of short-period P-wave signal variations at LASA.J.Geophys.Res.,1969,74:3161 ～ 3170
[7] Ritter J R R,Mai P M,Stoll G,Fuchs K.Scattering of teleseismic waves in the lower crust:observations in the Massif Central,France.Phys.Earth.Planet.Int.,1997,104:127 ～ 146
[8] Ritter J R R,Shapiro S A,Schechinger B.Scattering parameters of the lithosphere below the Massif Central,France,from teleseismic wavefield records.Geophys.J.Int.,1998,134:187 ～ 198
[9] Aki K.Scattering of P waves under the Montana Lasa.J.Geophys.Res.,1973,78:1334 ～ 1346
[10] Aki K,Chouet B.Origin of coda waves:source,attenuation,and scattering effects.J.Geophys.Res.,1975,80:3322～3342
[11] Flatte S M,Wu R S.Small-scale structure in the lithosphere and asthenosphere deduced from arrival time and amplitude fluctuations at NORSAR.J.Geophys.Res.,1988,93:6601 ～ 6614
[12] Langston C A.Scattering of teleseismic body waves under Pasadena,California.J.Geophys.Res.,1989,94:1935 ～1951
[13] Korn M.A modified energy-flux model for lithospheric scattering of teleseismic body waves.Geophys.J.Int.,1990,102:165 ～ 175
[14] Wagner G S,Langston C A.A numerical investigation of scattering effects for teleseismic propagation in a heterogeneous layer over a homogeneous half-space.Geophys.J.Int.,1992,110:486 ～ 500
[15] Korn M.Determination of site-dependent scattering Q from P-wave coda analysis with an energy-flux model.Geophys.J.Int.,1993,113:54 ～ 72
[16] Shapiro S A,Kneib G.Seismic attenuation by scattering:theory and numerical results.Geophys.J.Int.,1993,114:373 ～ 391
[17] Shapiro S A,Schwarz R,Gold N.The effect of random isotropic inhomogeneities on the phase velocity of seismic waves.Geophys.J.Int.,1996,127:783 ～ 794
[18] Rothert E,Ritter J R R.Small-scale heterogeneities below the Graefenberg array,Germany,from seismic wavefield fluctuations of Hindu Kush events.Geophys.J.Int.,2000,140:175 ～ 184
[19] Hock S,Korn M,Ritter J R R,Rothert E.Mapping random lithospheric heterogeneities in northern and central Europe.Geophys.J.Int.,2004,157:251 ～ 264
[20] Shen X Z,Ritter J R R.Small-scale heterogeneities below the Lanzhou CTBTO seismic array,from seismic wavefield fluctuations.J,Seismo.,2009,10． 1007/sl0950-009-9177-8
[21] 郝春月,郑 重,郭燕平等.中国数字地震台网(CDSN)和IMS/PS台阵的监测定位能力评估.地震地磁观测与研究,2006,27(2) :56～63 Hao C Y,Zheng Z,Guo Y P,et al.The calculation of locating ability of China Digital Seismological Network (CDSN) and IMS/PS seismic array (in Chinese).Seismological and Geomagnetic Observation and Research,2006,27(2) :56 ～ 63
[22] Hao C Y,Zheng Z.Slowness-azimuth corrections of teleseismic events for IMS primary arrays in China.J.Seismo.,2009,doi:10． 1007/sl0950-008-9137-8
[23] 沈旭章,周蕙兰.接收函数近邻反演方法的改进和对海拉尔台下地壳速度结构的研究.中国科学院研究生院学报,2005,22(3) :322～328 Shen X Z,Zhou H L.Inversion of velocity structure under HLR seismic station with receiver function and NA method (in Chinese).Journal of the Graduate School of the Chinese Academy of Sciences,2005,22(3) :322 ～ 328
[24] Rost S,Thomas C.Array seismology:Methods and applications.Rev.Geophys.,2002,40:1 ～ 27
[25] Bannister S C,Husebye E S,Ruud B O.Teleseismic P-coda analyzed by three-component and array techniques:deterministic location of topographic P-to-Rg scattering near the NORESS array.Bull.Seism.Soc.Am.,1990,80:1969～1986
[26] Davies D,Kelly E J,Filson J R.Vespa process for the analysis of seismic signals.Nature Physical Science,1971,232:8 ～ 13
[27] Muirhead K J,Datt R.The Nth root process applied to seismic array data.Geophys.J.R.Astron.Soc.,1976,47:197 ～ 210
[28] An M J,Shi Y L.Lithospheric Thickness of the Chinese Continent.Phys.Earth Planet.Ints,2006,159:257 ～ 266
[29] Huang J L,Zhao D P.High-resolution mantle tomography of China and surrounding regions.J.Geophys.Res.,2006,111:B09305 doi:10． 1029/2005JB004066
[30] Korn M.Modelling the teleseismic P coda envelope:depth dependent scattering and deterministic structure,Special issue:Stochastic Seismic Wave Fields and Realistic Media,Neustadt,Germany,11-15 March 1996,guest eds Korn M,Sato H,ScherbaumF.Phys.Earth.Planet.Int.,1997,104:23 ～ 36
[31] Wessel P,Smith W H F.New version of the generic mapping tools released.Eos.Trans.Am.Geophys.Union.,1995,76:329
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