Kirchhoff prestack depth migration in velocity models with and without vertical gradients: Comparison of triclinic anisotropy with simpler anisotropies

Vaclav Bucha

Summary

The Kirchhoff prestack depth migration is used to calculate migrated sections in simple heterogeneous and homogeneous anisotropic velocity models in order to demonstrate the impact of anisotropy and simple inhomogeneity on migrated images. We generate the recorded wave field in velocity models composed of two layers separated by a non-inclined curved interface. The anisotropy of the upper layer is triclinic and the layer has a constant vertical gradient of elastic moduli. The bottom layer is isotropic and homogeneous. We apply the Kirchhoff prestack depth migration to both heterogeneous and homogeneous single-layer velocity models with different types of anisotropy: a triclinic anisotropic medium, transversely isotropic media with a horizontal symmetry axis and a vertical symmetry axis. We show and discuss the errors of the migrated interface caused by inaccurate velocity models used for migration. The study is limited to P-waves.

Keywords

3-D Kirchhoff prestack depth migration, anisotropic velocity model, velocity gradient

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In: Seismic Waves in Complex 3-D Structures, Report 23, pp. 45-59, Dep. Geophys., Charles Univ., Prague, 2013.