This is an example of Gaussian packet migration in the smoothed Marmousi model, based on the paper by Zacek (2005). The migration uses optimized Gaussian packets, the output of the example Decomposition of the wave field into optimized Gaussian packets. Run history file 'mgp-mig.h' to calculate stacked migrated sections of the "Marmousi model and dataset".
The distributed version of the history file 'mgp-mig.h' is set to compute migration for one common-shot gather (shot 77, at a horizontal coordinate of 4.9 km). It is the same shot used as example of decomposition of the wave field. To perform decomposition for other shots, enable the respective lines in the history file by removing the hashes.
History file 'mgp-mig.h' runs another history file 'mgp-mig1.h' that computes positions of current source-receiver configuration and ray parameters for back-propagation of the wavefield using the program 'gprpar.for'. Then the history file 'mgp-mig1.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 'gprpar.for' and 'gpmig.for' are located in the directory 'data/mar'. Use commands 'perl f.pl gprpar' and 'perl f.pl gpmig' to compile the programs.
The output of the default version of history file 'mgp-mig.h' is the PostScript plot 'gpms077.ps' of one migrated section. The output of complete version of history file 'mgp-mig.h' (with all commands enabled) is the PostScript plot 'gpmsec.ps' 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).
To run the history file 'mgp-mig.h' it is necessary to compile program 'gpmig.for' with parameter MRAM=12000000. 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.