TI介质中地震波旋转运动特性研究
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摘要
地震波的旋转运动研究是地球动力学中的一个新兴领域.本文基于弹性波理论推导出旋转速度与相速度的关系,通过Kelvin-Christoffel方程推导了TI介质中地震波相速度的计算公式,从而得到TI介质中的Thomsen参数与旋转速度之间关系;继而借助于几个典型的TI介质模型模拟了地震波旋转运动.模拟结果显示:qP波旋转速度随着ε、δ的增加逐渐增大;qSV波旋转速度随着ε的增大而减小,随δ增大而增大;qSH波旋转速度随γ、δ的增加而增大,且γ的影响更大.另外,从相速度与旋转速度对比发现:qP波和qSH波旋转速度即不是圆形也不是椭圆,相对于相速度更具有方向性,这说明相对于平移运动,旋转运动的信息更有方向性和各向异性.
Rotational motion of seismic wave is an emerging field of geodynamics.Based on elastic wave theory,this paper derived the relationship between rotation rate and phase velocity,and obtained the phase velocity of seismic wave in TI medium by solving Kelvin-Christoffel equation and relationship between Thomsen parameters of the elastic medium and rotation rate.We computed the peak rotation rates and phase velocity of qP-waves,qSV-waves,qSH-waves generated in different TI materials.The result indicate that qP rotation rates are higher with increasing values ofεandδ,qSH rotation rates are higher with increasing values ofγandδ,qSV rotation rates are higher with increasing values ofδ but decrease with increasing values ofε.Through the comparison of the phase velocity and rotational rate,pointed out rotational motion has better directivity and anisotropy than translation motion.
Rotational motion of seismic wave is an emerging field of geodynamics.Based on elastic wave theory,this paper derived the relationship between rotation rate and phase velocity,and obtained the phase velocity of seismic wave in TI medium by solving Kelvin-Christoffel equation and relationship between Thomsen parameters of the elastic medium and rotation rate.We computed the peak rotation rates and phase velocity of qP-waves,qSV-waves,qSH-waves generated in different TI materials.The result indicate that qP rotation rates are higher with increasing values ofεandδ,qSH rotation rates are higher with increasing values ofγandδ,qSV rotation rates are higher with increasing values ofδ but decrease with increasing values ofε.Through the comparison of the phase velocity and rotational rate,pointed out rotational motion has better directivity and anisotropy than translation motion.
引文
Bouchon M,Aki K.1982.Strain,tilt,and rotation associated with strong ground motion in the vicinity of earthquake faults[J].Bull.Seismol.Soc.Am.,72(5):1717-1738.
Droste Z,Teisseyre R.1976.Rotational and displacemental components of ground motion as deduced from data of the azimuth system of seismograph[J].Publ.Inst.Geophys.Pol.Acad.Sci.,97:157-167.
Ferrari G.2006.Note on the historical rotation seismographs[A].//Teisseyre R,Takeo M,Majewski E,eds.Earthquake Source Asymmetry,Structural Media and Rotation Effects[M].Berlin,Heidelberg:Springer-Verlag,367-376.
Galitzin B B.1912.Lectures on Seismometry,Russian Acad.Sci.,St.Petersburg(in Russian).
Guéguen Y,Sarout J.2009.Crack-induced anisotropy in crustal rocks:predicted dry and fluid-saturated Thomsen’s parameters[J].Physics of the Earth and Planetary Interiors,172(1-2):116-124.
Kharin D A,Simonov L I.1969.VBPP seismometer for separate registration of translational motion and rotations[J].Seismic Instruments,5:51-66(in Russian).
Lee V W,Trifunac M D.1987.Rocking strong earthquake accelerations[J].Soil Dyn.Earthq.Eng.,6(2):75-89.
Lee W H K,Huang B S,Langston C A,et al.2009.Review:progress in rotational ground-motion observations from explosions and local earthquakes in Taiwan[J].Bull.Seismol.Soc.Am.,99(2B):958-967.
Majewski E.2006.Seismic rotation waves:spin and twist solitons[A].//Teisseyre R,Takeo M,Majewski E,eds.Earthquake Source Asymmetry,Structural Media and Rotation Effects[M].Berlin,Heidelberg:Springer-Verlag,255-272.
Mallet R.1862.Great Neapolitan Earthquake of 1857[M].London:Chapman and Hall.
Nigbor R L.Six-degree-of-freedom ground-motion measurement[J].Bull.Seismol.Soc.Am.,84(5):1665-1669.
Pancha A,Webb T H,Stedman G E,et al.2000.Ring laser detection of rotations from teleseismic waves[J].Geophys.Res.Lett.,27(21):3553-3556.
Pham D N,Igel H,Wassermann J,et al.2009.Observations and modelling of rotational signals in the P-coda:constraints on crustal scattering[J].Bulletin of the Seismological Society of America,99(2B):1315-1332.
Pham D N,Igel H,de la Puente J,et al.2010.Rotational motions in homogeneous anisotropic elastic media[J].Geophysics,75(5):47-56.
Reid H F.1910.The mechanics of the earthquake[R].The California Earthquake of April 18,1906,Report of the State Earthquake Investigation Commission,Vol.2,1910,Carnegie Institution of Washington,43-47.
Takeo M.1998.Ground rotational motions recorded in near-source region of earthquakes[J].Geophys.Res.Lett.,25(6):789-792.
Thomsen L.1986.Weak elastic anisotropy[J].Geophysics,51(10):1954-1966.
Trifunac M D.1982.A note on rotational components of earthquake motions on ground surface for incident body waves[J].International Journal of Soil Dynamics and Earthquake Engineering,1(1):11-19.
Trifunac M D.2009.Review:rotations in structural response[J].Bull.Seismol.Soc.Am.,99(2B):968-979.
程玖兵,康玮,王腾飞.2013.各向异性介质qP波传播描述I:伪纯模式波动方程[J].地球物理学报,56(10):3474-3486,doi:10 .6038/cjg20131022.
董兴朋,彭愿,吴阿丹,等.2013.日本和台湾近场区地面旋转运动研究[J].地球物理进展,28(5):2300-2308,doi:10.6038/pg20130512.
杜世通.2008.地震波动力学理论与方法[M].东营:中国石油大学出版社.
张伯军,刘财,冯晅,等.2010.弹性动力学简明教程[M].北京:科学出版社.
Droste Z,Teisseyre R.1976.Rotational and displacemental components of ground motion as deduced from data of the azimuth system of seismograph[J].Publ.Inst.Geophys.Pol.Acad.Sci.,97:157-167.
Ferrari G.2006.Note on the historical rotation seismographs[A].//Teisseyre R,Takeo M,Majewski E,eds.Earthquake Source Asymmetry,Structural Media and Rotation Effects[M].Berlin,Heidelberg:Springer-Verlag,367-376.
Galitzin B B.1912.Lectures on Seismometry,Russian Acad.Sci.,St.Petersburg(in Russian).
Guéguen Y,Sarout J.2009.Crack-induced anisotropy in crustal rocks:predicted dry and fluid-saturated Thomsen’s parameters[J].Physics of the Earth and Planetary Interiors,172(1-2):116-124.
Kharin D A,Simonov L I.1969.VBPP seismometer for separate registration of translational motion and rotations[J].Seismic Instruments,5:51-66(in Russian).
Lee V W,Trifunac M D.1987.Rocking strong earthquake accelerations[J].Soil Dyn.Earthq.Eng.,6(2):75-89.
Lee W H K,Huang B S,Langston C A,et al.2009.Review:progress in rotational ground-motion observations from explosions and local earthquakes in Taiwan[J].Bull.Seismol.Soc.Am.,99(2B):958-967.
Majewski E.2006.Seismic rotation waves:spin and twist solitons[A].//Teisseyre R,Takeo M,Majewski E,eds.Earthquake Source Asymmetry,Structural Media and Rotation Effects[M].Berlin,Heidelberg:Springer-Verlag,255-272.
Mallet R.1862.Great Neapolitan Earthquake of 1857[M].London:Chapman and Hall.
Nigbor R L.Six-degree-of-freedom ground-motion measurement[J].Bull.Seismol.Soc.Am.,84(5):1665-1669.
Pancha A,Webb T H,Stedman G E,et al.2000.Ring laser detection of rotations from teleseismic waves[J].Geophys.Res.Lett.,27(21):3553-3556.
Pham D N,Igel H,Wassermann J,et al.2009.Observations and modelling of rotational signals in the P-coda:constraints on crustal scattering[J].Bulletin of the Seismological Society of America,99(2B):1315-1332.
Pham D N,Igel H,de la Puente J,et al.2010.Rotational motions in homogeneous anisotropic elastic media[J].Geophysics,75(5):47-56.
Reid H F.1910.The mechanics of the earthquake[R].The California Earthquake of April 18,1906,Report of the State Earthquake Investigation Commission,Vol.2,1910,Carnegie Institution of Washington,43-47.
Takeo M.1998.Ground rotational motions recorded in near-source region of earthquakes[J].Geophys.Res.Lett.,25(6):789-792.
Thomsen L.1986.Weak elastic anisotropy[J].Geophysics,51(10):1954-1966.
Trifunac M D.1982.A note on rotational components of earthquake motions on ground surface for incident body waves[J].International Journal of Soil Dynamics and Earthquake Engineering,1(1):11-19.
Trifunac M D.2009.Review:rotations in structural response[J].Bull.Seismol.Soc.Am.,99(2B):968-979.
程玖兵,康玮,王腾飞.2013.各向异性介质qP波传播描述I:伪纯模式波动方程[J].地球物理学报,56(10):3474-3486,doi:10 .6038/cjg20131022.
董兴朋,彭愿,吴阿丹,等.2013.日本和台湾近场区地面旋转运动研究[J].地球物理进展,28(5):2300-2308,doi:10.6038/pg20130512.
杜世通.2008.地震波动力学理论与方法[M].东营:中国石油大学出版社.
张伯军,刘财,冯晅,等.2010.弹性动力学简明教程[M].北京:科学出版社.
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