Elastic wave propagation features in tilted ellipsoidal anisotropic media
Liang Kai1,2, Cao Danping1,2, Yin Xingyao1,2, Wu Guochen1,2
1. School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 266580, China; 2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Sciences and Technology, Qingdao, Shandong 266071, China
Abstract：The propagation features of elastic wave include velocity and polarization.They are important parameters in the researches of seismic wave propagation,and play important roles in the theory and application.The tilted ellipsoidal anisotropic (TEA) media is a special case of transversely isotropic media.Based on stiffness matrix of TEA media in the observation coordinate system,we derive analytic expressions of velocity and polarization for elastic wave in TEA media with Christoffel equation.Results of theoretical analysis and numerical examples indicate:①In TEA media,iso-surfaces of phase velocity for qP wave and SH wave are anisotropic,but not ellipsoidal,and their iso-surfaces of group velocity are both ellipsoidal with the tilted symmetry axis; phase velocity and group velocity of qSV wave are the same,and isotropic; ②The polarization of qP wave,qSV wave and SH wave are perpendicular to each other,and the polarization of qP wave and qSV wave is related to anisotropic parameters; the polarization of SH wave is independent of the anisotropic parameters and is perpendicular to the plane determined by the propagation direction and the symmetry axis.
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