3D P-wave seismograms computed using the first-order ray-based Born approximation in a 2D heterogeneous isotropic background model with a 2D heterogeneous perturbation are presented. The perturbed model contains 16 domains. We construct 16 partially perturbed models, in which the distribution of elastic parameters is the same as in the background model except for one domain where the P-wave velocity is perturbed. The Born seismograms are compared with the differences between the ray-theory seismograms computed in the partially perturbed models, or the complete perturbed model, and the background model. The seismograms are computed for a set of receivers in order to see how the seismograms change. The rays in the perturbed models are computed to be able to identify the wavegroups in the seismograms. Similarly, the travel times of the diffracted waves are computed and highlighted in the seismograms. The differences between the Born and ray-theory seismograms are studied.
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