Slowness vectors in viscoelastic anisotropic media. Part 2: Numerical examples

Vlastislav Cerveny, Ivan Psencik

Summary

The expressions based on the so-called mixed specification of the slowness vector of plane waves propagating in viscoelastic anisotropic media, derived by Cerveny and Psencik (2004), are used to illustrate behaviour of various characteristics of these plane waves. Studied characteristics are phase velocities, amplitude decay along the propagation direction, attenuation, attenuation angle and polarization vectors. Simple analytic expressions are used to describe behaviour of SH waves propagating in a plane of symmetry of a viscoelastic anisotropic medium. Characteristics of qP plane wave and qS plane waves are determined by solving a complex-valued algebraic equation of the sixth degree. Combined effects of attenuation and anisotropy predicted in Cerveny and Psencik (2004) are illustrated on two models of viscoelastic anisotropic media. The explanation of the so-called forbidden directions known from the directional specification of the slowness vector is given. Non-physical results related to forbidden directions do not arise in the mixed specification.

Keywords

Viscoelastic anisotropic media, inhomogeneous and homogeneous plane waves, mixed specification, inhomogeneity parameter, phase velocity, attenuation, attenuation angle, polarization.

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In: Seismic Waves in Complex 3-D Structures, Report 14, pp. 149-179, Dep. Geophys., Charles Univ., Prague, 2004.
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