This is an example of Gaussian packet migration in the smoothed Marmousi model, based on the paper Zacek (2005). The migration uses uniform Gaussian packets, the output of the example Decomposition of the wave field into uniform Gaussian packets. To calculate stacked migrated sections of the "Marmousi model and dataset" run history file 'mar-gpmx.h'.
History file 'mar-gpmx.h' for 240 sources repeatedly runs another history file 'mar-gpm.h' and generates PostScript plots of migrated sections for each common-source gather. History file 'mar-gpm.h' computes positions of current source-receiver configuration and ray parameters for back-propagation of the wavefield using the program 'gpstep.for'. Then the history file 'mar-gpm.h' performs ray tracing from the source and computes multivalued travel times (incident wavefield). The final step, back-propagation of the wavefield from receivers and computation of migrated sections, is performed by program 'gpmig.for'. The programs 'gpstep.for' and 'gpmig.for' are located in the directory '/data/mar'. To compile the programs use command, e.g., 'perl f.pl gpstep'.
The output 'gpmsec.ps' of history file 'mar-gpmx.h' is the PostScript plot of stacked migrated sections of the "Marmousi model and dataset" in the smoothed Marmousi model 'mar-mod.dat' (see Smoothing the Marmousi model for Gaussian-packet migrations). Commented values of parameter MODEL in history file 'mar-gpm.h' allow to compute plots of stacked migrated sections that should be the same as Figures 7a and 7c in Zacek (2005).
To run the history file 'mar-gpmx.h' it is necessary to compile program 'gpmig.for' and program 'grdcal.for' with parameter MRAM=6000000. Include file 'ram.inc' is distributed with MRAM=4000000.
Zacek, K. (2005): Gaussian packet prestack depth migration, In: Seismic Waves in Complex 3-D Structures, Report 15, pp. 29-48.