Reflection moveout approximation for a converted P-SV wave in a moderately anisotropic homogeneous VTI layer

Veronique Farra & Ivan Psencik

Summary

We present and test an approximate formula for the reflection moveout of converted waves in a homogeneous VTI (transversely isotropic with the vertical axis of symmetry) layer. For its derivation, we use the weak-anisotropy approximation, i.e., we expand the square of the reflection traveltime in terms of weak-anisotropy (WA) parameters. Travel times are calculated along reference rays of converted waves reflected in reference isotropic media. This requires the determination of the point of reflection of the reference ray, at which the corresponding wave converts. Presented tests indicate that the accuracy of the formula is comparable with the accuracy of formulae derived in a similar way for unconverted waves. The tests also indicate that the formula can be applied not only to weakly, but also to moderately anisotropic VTI media.

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Seismic Waves in Complex 3-D Structures, 27 (2017), 51-58 (ISSN 2336-3827, online at http://sw3d.cz).