The CSG generated in the previous section is now migrated using PS transmission migration (equation 2.1). Migration of the unprocessed synthetic seismograms yields Figure 3.11e. No attempt was made to isolate the transmitted PS arrivals and no incidence angle or layer dip restrictions were used. It is clear that some parts of the salt flank boundary are well imaged despite the presence of coherent migration noise. Migrating additional shot gathers will increase the signal-to-noise ratio, causing the coherent noise to destructively interfere and the transmission PS energy at the diapir boundary to constructively interfere.
Next, the transmitted PS-wave traveltimes from the right salt flank were picked and the picked traveltimes were convolved with a source wavelet to generate traces containing only PS transmission events. These seismograms were then migrated to generate the migration image shown in Figure 3.11f. It is evident that the migration image of the transmitted PS waves corresponds well with the salt flank of the actual model. It should be noted that the exact velocity was used to generate the final migration section. Also, no incidence angle or dip constraints were imposed during migration, which would have reduced the migration artifacts. This test supports my conjecture that PS transmitted waves can be migrated to delineate salt flank boundaries.
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