Fig. \ref{803142} shows the main processing workflow applied to both  tapes 20 and 21. For this case, we read (DSIN)  the data pre-processed and sorted them in CMP gathers. Next we used the interactive velocity analysis (VELDEF)  module to pick the moveout velocities from the reflections. Then,  the saved velocity file is used to perform NMO. After that the data was stacked (STACK) and a frequency wavenumber  (FXDECON) deconvolution applied to sharpen the data. Finally we used the Kirchhoff migration module (MIGTX)  to  obtain the final image.