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 Biondi, B., and Symes, W., 2004, Angledomain commonimage gathers for migration velocity analysis by wavefieldcontinuation imaging: Geophysics, 69, no. 5, 12831298.

 Biondi, B., 2005, Angledomain common image gathers for anisotropic migration: SEP120, 77104.

 BrandsbergDahl, S., de Hoop, M. V., and Ursin, B., 1999, The sensitivity transform in the common scatteringangle/azimuth domain: 61st Ann. Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts, 15381541.

 de Bruin, C. G. M., Wapenaar, C. P. A., and Berkhout, A. J., 1990, Angledependent reflectivity by means of prestack migration: Geophysics, 55, no. 9, 12231234.

 Fomel, S., and Prucha, M., 1999, Anglegather time migration: SEP100, 141150.

 Fomel, S., 1996, Migration and velocity analysis by velocity continuation: SEP92, 159188.

 Prucha, M., Biondi, B., and Symes, W., 1999, Angledomain commonimage gathers by waveequation migration: 69th Ann. Internat. Meeting, Soc. of Expl. Geophys., Expanded Abstracts, 824827.

 Rickett, J., and Sava, P., 2002, Offset and angledomain common imagepoint gathers for shotprofile migration: Geophysics, 67, 883889.

 Rosales, D., and Rickett, J., 2001a, pswave polarity reversal in angle domain commonimage
gathers: SEP108, 3544.

 Rosales, D., and Rickett, J., 2001b, PSwave polarity reversal in angle domain commonimage gathers: 71st Annual Internat. Mtg., Expanded Abstracts, 18431846.

 Sava, P., and Fomel, S., 2000, Anglegathers by Fourier Transform: SEP103, 119130.

 Sava, P., and Fomel, S., 2003, Angledomain commonimage gathers by wavefield continuation methods: Geophysics, 68, no. 3, 10651074.

A
In this part, we obtain the relation to transform subsurface offsetdomain
commonimage gathers into angledomain commonimage gathers for the
case of PS data.
To perform this derivation, we use the geometry in Figure
in order to obtain the parametric equations for migration on a constant
velocity medium.
Following the derivation of Fomel (1996) and
Fomel and Prucha (1999),
and applying simple trigonometry and geometry to Figure ,
we obtain parametric equations for migrating an impulse recorded at time t_{D},
midpoint m_{D} and surface offset h_{D} as follows:
angles2 Figure 9 Parametric formulation of the
impulse response.

 
 

 
 (14) 
where the total path length is:
 

 (15) 
From that system of equations, Biondi (2005) shows that the total path length is
 
(16) 
Appendix A shows that we can rewrite system (14) as:
 

 
 (17) 
where and follow the same definition as in equation (3).
where,
L in terms of the angles and is:
 
(18) 