NAME

Phase - Phaseshift migration (possibly split-step)


SYNOPSIS

Phase par=parfile.P D=input.H R=output.H S=slow.H


COORDINATE SYSTEM FOR DOWNWARD CONTINUATION DESCRIPTION PARAMETERS

amx_n (integer)
  Number of CMP in X (axis 1 of D,R and S)
amx_d (integer)
  Sampling of CMP in X
amx_o (integer)
  First CMP  X location
amy__n (integer)
  Number of CMP in X (axis 2 of D,R and S)
amy_d (integer)
  Sampling of CMP in Y
amy_o (integer)
  First CMP  Y location
ahx__n (integer)
  Number of half offsets in X (axis 3 of D and possibly R  )
ahx_d (integer)
  Sampling of half offsets in X
ahx_o (integer)
  First half offset  X location
ahy__n (integer)
  Number of half offsets in Y (axis 4 of D and possibly R)
ahy_d (integer)
  Sampling of half offset in Y
ahy_o (integer)
  First CMP  Y location


R/S DESCRIPTION PARAMETERS

az__n (integer) (axis 3 of S, axis 5 of R)
  Number of depth steps
az__d (integer)
  Sampling of depths
az__o (integer)
  First depth of model
image_real (logcal)
  Whether or not make the image real


DATA DESCRIPTION PARAMETERS

aw__n (integer) (axis 5 of D)
  Number of frequencies
aw__d (integer)
  Sampling of frequencies
aw__o (integer)
  First frequency of data


SLOWNESS PARAMETERS

velocity (logical)
 [.false.] whether or not S is velocity
nref (integer)
 [1] number of velocities for each depth step


PH GATHERS

pCIG (logical)
 [.false.] whether (.true.) or not (.false.) to create PH gathers
apx__n (integer)
  Number of PH in X (axis 3 of R)
apx_d (integer)
  Sampling of PH in X
apx_o (integer)
  First PH X location
apy__n (integer)
  Number of PH in Y (axis 4 of R)
apy_d (integer)
  Sampling of PH in Y
apy_o (integer)
  First PH  Y location
pcigeps (float)
  [.1] Epsilon parameter for Phgather construction


MEMORY MANAGEMET

nzs (integer)
Number of Z steps to do in memory

nws (integer)
Number of W to hold in memory


DESCRIPTION

 Perform split step phase shift migration/modeling


COMMENTS

anx_n,ahx_d,ahx_o and axis 1 of D and R must be the same
any_n,ahy_d,ahy_o and axis 2 of D and R must be the same
Slowness must contain entire span of X and Y
az__n,az__d,az__o , axis 3 of S and axis 5 of R must be the same
When doing ph gathers apx_n = ahx_n = n3 of D
When doing ph gathers apy_n = ahy_n = n4 of D
When doing offset gathers ahx_n,ahx_d,ahx_o = axis 3 of D and R
When doing offset gathers ahy_n,ahy_d,ahy_o = axis 4 of D and R
nzs must be a multiple of az__n
nws*nmpi_threads*nomp_threads must be a multiple of aw__n


CATEGORY

seis/image