DOCUMENTATION
SYNOPSIS
PERL PROGRAM NAME: SUFDMOD1 - Finite difference modelling (1-D first order) for the
AUTHOR: Juan Lorenzo (Perl module only)
DATE:
DESCRIPTION:
Version: USE
NOTES
Examples
SEISMIC UNIX NOTES
SUFDMOD1 - Finite difference modelling (1-D 1rst order) for the
acoustic wave equation "
sufdmod1 <vfile >sfile nz= tmax= sz= [optional parameters]
Required parameters :
L_SU checks to make sure only <vfile and >sfile=is used
<vfile binary file containing velocities[nz]
>sfile SU file containing seimogram[nt]
nz= number of z samples
tmax= maximum propagation time
sz= z coordinate of source
Optional parameters :
dz=1 z sampling interval
fz=0.0 first depth sample
rz=1 coordinate of receiver
sz=1 coordinate of source
dfile= binary input file containing density[nz]
wfile= output file for wave field (snapshots in a SU trace panel)
abs=0,1 absorbing conditions on top and bottom
styp=0 source type (0: gauss, 1: ricker 1, 2: ricker 2)
freq=15.0 approximate source center frequency (Hz)
nt=1+tmax/dt number od time samples (dt determined for numerical
stability)
zt=1 trace undersampling factor for trace and snapshots
zd=1 depth undersampling factor for snapshots
press=1 to record the pressure field; 0 records the particle
velocity
verbose=0 =1 for diagnostic messages
Notes :
This program uses a first order explicit velocity/pressure finite
difference equation.
The source function is applied on the pressure component.
If no density file is given, constant density is assumed
Wavefield can be easily viewed with suximage, user must provide f2=0
to the ximage program in order to get correct time labelling
Seismic trace is shifted in order to get a zero phase source
Source begins and stop when it's amplitude is 10^-4 its maximum
Time and depth undersampling only modify the output trace and snapshots.
These parameters are useful for keeping snapshot file small and
the number of samples under SU_NFLTS. CHANGES and their DATES
sub Step
collects switches and assembles bash instructions by adding the program name
sub note
collects switches and assembles bash instructions by adding the program name
sub clear
sub abs
boundary conditions
sub boundary_conditions
boundary conditions
sub density_file_bin
sub dfile
sub dz
sub freq
sub fz
sub nt
sub nz
sub press
sub receiver_depth
sub rz
sub source_depth
sub seismogram_out
sub sfile
sub source_type
sub styp
sub sz
sub tmax
sub velocity_file_bin
sub verbose
sub vfile
sub vfile
sub wfile
sub zd
sub zt
sub get_max_index
max index = number of input variables -1