SUDATUMFD - 2D zero-offset Finite Difference acoustic wave-equation
DATUMing
sudatumfd stdout [optional parameters]
Required parameters:
nt= number of time samples on each trace
nx= number of receivers per shot gather
nsx= number of shot gathers
nz= number of downward continuation depth steps
dz= depth sampling interval (in meters)
mx= number of horizontal samples in the velocity model
mz= number of vertical samples in the velocity model
vfile1= velocity file used for thin-lens term
vfile2= velocity file used for diffraction term
dx= horizontal sampling interval (in meters)
Optional parameters:
dt=.004 time sampling interval (in seconds)
buff=5 number of zero traces added to each side of each
shot gather as a pad
tap_len=5 taper length (in number of traces)
x_0=0.0 x coordinate of leftmost position in velocity model
Notes:
The algorithm is a 45-degree implicit-finite-difference scheme based
on the one-way wave equation. It works on poststack (zero-offset)
data only. The two velocity files, vfile1 and vfile2, are binary
files containing floats with the format v[ix][iz]. There are two
potentially different velocity files for the thin-lens and
diffraction terms to allow for the use of a zero-velocity layer
which allows for datuming from an irregular surface.
Source and receiver locations must be set in the header values in
order for the datuming to work properly. The leftmost position of
of the velocity models given in vfile1 and vfile2 must also be given.
Author: Chris Robinson, 10/16/00, CWP, Colorado School of Mines
References:
Beasley, C., and Lynn, W., 1992, The zero-velocity layer: migration
from irregular surfaces: Geophysics, 57, 1435-1443.
Claerbout, J. F., 1985, Imaging the earth's interior: Blackwell
Scientific Publications.