Finding the path of a simple ray, from arbitrary source and receiver positions, reflecting from a dipping interface can be accomplished by the method of images. This method can be extended to converted (P-S) waves, for the small offset case, by scaling the distance of the image receiver from the interface by the α/β value (the P-wave to S-wave velocity ratio). This moves the conversion point closer to the receiver position. The technique can be further generalized by introducing anisotropy (weak vertical transverse isotropy). Anisotropy perturbs the conversion point toward the receiver when Thomsen's (1986) 2δ-ε parameter is positive and toward the source when it is negative.
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