Journal ArticleDOI
Long-Wave Elastic Anisotropy Produced by Horizontal Layering
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TLDR
In this article, a horizontally layered inhomogeneous medium is considered, whose properties are constant or nearly so when averaged over some vertical height l′, and conditions on the five elastic coefficients of a homogeneous transversely isotropic medium are derived which are necessary and sufficient for the medium to be "long-wave equivalent" to a horizontally-layered inhomogenous medium.Abstract:
A horizontally layered inhomogeneous medium, isotropic or transversely isotropic, is considered, whose properties are constant or nearly so when averaged over some vertical height l′. For waves longer than l′ the medium is shown to behave like a homogeneous, or nearly homogeneous, transversely isotropic medium whose density is the average density and whose elastic coefficients are algebraic combinations of averages of algebraic combinations of the elastic coefficients of the original medium. The nearly homogeneous medium is said to be ‘long-wave equivalent’ to the original medium. Conditions on the five elastic coefficients of a homogeneous transversely isotropic medium are derived which are necessary and sufficient for the medium to be ‘long-wave equivalent’ to a horizontally layered isotropic medium. Further conditions are also derived which are necessary and sufficient for the homogeneous medium to be ‘long-wave equivalent’ to a horizontally layered isotropic medium consisting of only two different homogeneous isotropic materials. Except in singular cases, if the latter two-layered medium exists at all, its proportions and elastic coefficients are uniquely determined by the elastic coefficients of the homogeneous transversely isotropic medium. The observed variations in crustal P-wave velocity with depth, obtained from well logs, are shown to be large enough to explain some of the observed crustal anisotropies as due to layering of isotropic material.read more
Citations
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Journal ArticleDOI
3‐D radiation pattern of the drilling bit source in finely stratified media
TL;DR: In this paper, the radiation patterns for a vertical and a rotational loads distributed over a disk-shape surface placed in a finely stratified medium with a random distribution of elastic parameters were analyzed.
Journal ArticleDOI
TTI equivalent medium parametrization method for the seismic waveform modelling of heterogeneous media with coarse grids
Luqian Jiang,Wei Zhang +1 more
TL;DR: In this paper, a tilted transversely isotropic equivalent medium parametrization method was proposed to suppress the interface error and the artefact diffraction caused by the staircase approximation under the application of coarse grids.
DissertationDOI
Identification of damage in composite structures based on feature guided ultrasonic waves
TL;DR: In this article, a shear horizontal type bend-guided wave (SHB) mode has been identified, which is almost non-dispersive and non-leaky, with strong energy confinement in the bend region, which makes it attractive to be applied as a screening tool for composite bends.
Book ChapterDOI
Data Sensitivity Kernels
Po Chen,En-Jui Lee +1 more
TL;DR: In this paper, the authors introduce the concept of wavefield perturbation kernel (WPK) and give a general approach for deriving Frechet kernels of arbitrary data functionals.
Journal ArticleDOI
Comparisons of moveout approximations and inversions for P- and S-waves in acoustic transversely isotropic media with a vertical symmetry axis
Song Jin,Alexey Stovas +1 more
TL;DR: In this article, the authors considered four different traveltime approximations originally developed for P-wave and applied them for S-wave moveout in acoustic transversely isotropic medium with a vertical symmetry axis (acoustic VTI).
References
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Journal ArticleDOI
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Journal ArticleDOI
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Journal ArticleDOI
Elastic wave propagation in layered anisotropic media
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