Kirch_2d_depth - Kirchhoff 2D migration
Kirch_2d_depth <in.H >out.H tfile=tfile.H pars
File for input seismic traces (must be a sep3d file)
File for common offset migration output ( sep regular cube)
File for input traveltime tables. First axis is Z, second axis X, third
axis is regular spaced source locations. If not provided will be
calculated.
Velocity file (only needed if travel time file not provided).
[d3 of grid] Sampling interval of input midpoints
z-coordinate of first point in output trace
vertical spacing of output trace
number of points in output trace
[0.25/dt] frequency-highcut for input traces
[nxt*dxt/2] migration lateral aperature
[60] migration angle aperature from vertical
[1500](m/s) reference velocity value at surface
[0.0] reference velocity vertical gradient
[1] flag for line source
[0] Whether or not to be verbose
[100] Approximate maximum memory to use
Performs 2D Kirchoff depth migraion.
1. Output regular grid is the basis of the output cmp_x and offset_x
parameters. The input dataset should be sep3d gridded data.
Axis 1 - time, axis 2 - trace_in_bin, axis3-cmp_x, axis4 - offset_x .
The header keys offset_x and cmp_x must exist in the dataset.
2. This is SU's sukdmig2d code with only very slight modifications.
All credit belongs to CWP. If you use it in a paper
make sure to credit them.
3. Only works meters/feet for some reason???
4. Traveltime tables were generated by program rayt2d (or other ones)
on relatively coarse grids, with dimension ns*nxt*nzt. In the
migration process, traveltimes are interpolated into shot/gephone
positions and output grids. ',
5. If the offset value of an input trace is not in the offset array
of output, the nearest one in the array is chosen.
6. Memory requirement for this program is about
[ns*nxt*nzt+noff*nxo*nzo+4*nr*nzt+5*nxt*nzt+npa*(2*ns*nxt*nzt
+noff*nxo*nzo+4*nxt*nzt)]*4 bytes
where nr = 1+min(nxt*dxt,0.5*offmax+aperx)/dxo.
6. Amplitudes are computed using the reference velocity profile, v(z),
specified by the parameters v0= and dvz=.
Zhenyue Liu, 03/01/95, Colorado School of Mines
seis/image