DOCUMENTATION
SYNOPSIS
PERL PROGRAM NAME: SUFDMOD2 - Finite-Difference MODeling (2nd order) for acoustic wave equation
AUTHOR: Juan Lorenzo (Perl module only)
DATE:
DESCRIPTION:
Version: USE
NOTES
Examples
SEISMIC UNIX NOTES
SUFDMOD2 - Finite-Difference MODeling (2nd order) for acoustic wave equation
sufdmod2 <vfile >wfile nx= nz= tmax= xs= zs= [optional parameters]
Required Parameters:
<vfile file containing velocity[nx][nz]
SeismicUnixGui: data_in suffix_type= bin
>wfile file containing waves[nx][nz] for time steps
SeismicUnixGui: data_out suffix_type= bin
nx= number of x samples (2nd dimension)
nz= number of z samples (1st dimension)
xs= x coordinates of source, or, alternatively, the name
of a file that contains the x- and z-coordinates,
with the number of pairs as the first record and
the actual pairs of (x,z) locations following.
zs= z coordinates of source
tmax= maximum time
Optional Parameters:
sstrength=1.0 strength of source
pw=0 use point or extended source geometry parameters
=1 use horizontal plane wave source
pwt=20 amp taper on ends of line src (in grid points)
mono=0 use ricker wavelet as source function
=1 use single frequency src (freq=2*fpeak)
nt=1+tmax/dt number of time samples (dt determined for stability)
mt=1 number of time steps (dt) per output time step
dx=1.0 x sampling interval
fx=0.0 first x sample
dz=1.0 z sampling interval
fz=0.0 first z sample
fmax = vmin/(10.0*h) maximum frequency in source
fpeak=0.5*fmax peak frequency in ricker wavelet
dfile= input file containing density[nx][nz]
vsx= x coordinate of vertical line of seismograms
hsz= z coordinate of horizontal line of seismograms
vsfile= output file for vertical line of seismograms[nz][nt]
SeismicUnixGui: vsfile goes to $DATA_SEIMICS_BIN
hsfile= output file for horizontal line of seismograms[nx][nt]
SeismicUnixGui: hsfile goes to $DATA_SEIMICS_BIN
ssfile= output file for source point seismograms[nt]
SeismicUnixGui: ssfile goes to $DATA_SEIMICS_BIN
verbose=0 =1 for diagnostic messages, =2 for more
abs=1,1,1,1 absorbing boundary conditions on top,left,bottom,right
sides of the model.
=0,1,1,1 for free surface condition on the top
Notes:
This program uses the traditional explicit second order differencing
method.
Authors: CWP:Dave Hale
CWP:modified for SU by John Stockwell, 1993.
U Houston: added plane wave and monochromatic wave
source options. Chris Liner, 2010
Trace header fields set: sx, gx, ns, delrt, tracl, tracr, offset, d1, d2,
sdepth, trid
Modifications: Tony Kocurko (TK:)
Memorial University in Newfoundland and Labrador
- Allow user to supply the name of a file containing
shot point locations, rather than supplying them
as values to the xs= and zs= command line arguments.
- Correct the calculation of izs[is].
Technical reference:
Kelly, K. R., R. W. Ward, S. Treitel, and R. M. Alford (1976),
Synthetic Seismograms: A finite-difference approach,
Geophysics, Vol. 41. No. I (February, 1976), p. 2-27.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
sub boundary_conditions
sub dfile
sub dx
sub dz
sub fmax
sub fpeak
sub freq
sub fx
sub fz
sub hsfile
sub hsfile_out
sub hsz
sub mono
sub mt
sub nt
sub nx
sub nz
sub pw
sub pwt
sub seismogram_out
sub ssfile
sub sstrength
sub tmax
sub verbose
sub vsfile
sub vsfile_out
sub vsx
sub xs
sub zs
sub get_max_index
max index = number of input variables -1