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sioseis << !
procs segdin prout geom header output diskob gather nmo gains smute stack despike diskoa end

segdin
   ffilen 99999   # take all shots (this is the preset!)
   ftr 1 ltr 160  # skip the auxiliary channels - 161-172 and 161-180
   secs 16.0    # DMS-2000 has garbage from the even second to the end
   decimf 2     # decimate from 2 to 4 ms.  Little energy above Nyquist!
   offline yes  # eject after the rewind after EOT
   tr0 yes      # write trace 0 to tape
   newfile yes  # start a new SEG-Y file on every SEG-D tape
   iunit 3 end
end

geom
# shot spacing of 50 m (dfls), 12.5 m cdp bins, 25 group spacing
# range to closest trace varies.
# bird/depth sensors change on every deployment
  bgp 1 5 3 9 4 17 5 25 6 33 7 41 9 45 10 53 11 65 12 73
      13 85 14 98 15 106 16 118 17 125 18 133 8 141 2 149
  type 2 # increment the shot loaction based on the shot number
  fs 1 ls 999999  # all shot have the same parameters (preset)
  gxp 160 -138    # RESET the closest group only.  
  ggx -25         # Used to extrapolate gxp!
  dfls 50.0 dbrps 12.5 smear 12.5 end
end

despike
    fac 5 end    # Sutton/Trehu far-close average
end

output
   ontrcs 160 # reinforce that only 160 traces are to be written
   rewind 0   # leave the tape alone!  
   ounit 4 end
end

header 
#  geom started the line with negative rp numbers which some processes
#    don't like, so make them positive right away!
   l6 l6 + 200 fno 1 lno 9999999 end
end

smute          # "inner" mute
  addwb yes    # add in the water bottom time
  fno 1 lno 999999 xsets 163 1 16 2163 16 16 interp on end
end

diskob
# write every 15th shot to a "circular" file
   fno 1 lno 999999 noinc 15 rewind 1 opath shot.file end
 end

gather
# Scratch file parameters, really 2250 4 byte wrds, maxtrcs of 40, pad to be safe
# Roughly 150 MB scratch file
 maxrps 170 nwrds 4400 maxtrs 50 end
end

gains
#  Do spherical divergence.  
#  alpha .4 means range 263 is multiplied by 9, range 4263 by 30
#   type 8 alpha .4 end
#  alpha .5 means range 263 is multiplied by 15.7, range 4263 by 68.4
    type 8 alpha .5 end
end

nmo
# real time nmo, replace interpolation by RP to WB depth in Meters.
# If water depth changes by > 100 m, use previous value. Water-depth
# velocity functions supplied by Trine, interpolation by iso-velocity layering
 vtrkwb 1000 stretc 0.06
 fno  387 lno  387   vtp  1475 0.516
                           1623 0.867
                           1716 0.961
                           2022 1.272
                           2149 1.523
                           4029 3.007
                           4536 3.446
                           5375 4.385
                           6652 10.01 end                        
                                               
 fno  542 lno  542 stretc .06  vtp   1475 0.722
                           1912 1.423
                           2039 1.689
                           5537 3.935
                           6795 10.01 end                                             
                        
                        
 fno 1021 lno 1021 stretc .065   vtp 1475 1.361
                           1926 1.967
                           2074 2.201
                           2195 2.340
                           5537 4.352
                           6716 10.01 end
 
 fno 1475 lno 1475  stretc .07 vtp   1475 1.967
                           1761 2.373
                           1797 2.506
                           1878 2.640
                           2018 3.101
                           2047 3.340
                           2334 3.501
                           2880 3.646
                           5156 4.191
                           5715 5.325
                           6609 10.01 end
 
 fno 1688 lno 1688 stretc .075 vtp   1475 2.251
                           1696 2.862
                           1789 3.123
                           1912 3.301
                           2273 3.568
                           2736 3.846
                           3322 4.118
                           5024 5.441
                           6275 10.01 end
 
 fno 1721 lno 1721  vtp   1475 2.295
                           1535 2.612
                           1598 2.784
                           1659 3.018
                           1687 3.085
                           1772 3.318
                           1828 3.459
                           2014 3.635
                           2648 4.046
                           2822 4.135
                           4962 6.008
                           5537 6.725
                           6248 10.01 end
 
 fno 1817 lno 1817 stretc .08   vtp  1475 2.423
                           1561 2.990
                           1634 3.163
                           1659 3.296
                           1721 3.401
                           1792 3.596
                           2065 3.879
                           2621 4.352
                           2892 4.635
                           5156 5.975
                           6207 10.01 end
 
 fno 1871 lno 1871   vtp  1475 2.495
                           1584 2.918
                           1617 3.035
                           1636 3.212
                           1677 3.451
                           1721 3.596
                           1836 3.663
                           1895 3.718
                           1990 3.796
                           2321 4.141
                           2845 4.250
                           3686 4.597
                           5299 6.681
                           6118 10.01 end
                           
 fno 1995 lno 1995  stretc .09 vtp  1475 2.660
                           1555 3.193
                           1591 3.346
                           1708 3.760
                           1792 4.020
                           1989 4.392
                           2131 4.633
                           2309 4.879
                           2784 5.126
                           3718 6.513
                           4139 7.279
                           4472 8.526
                           5845 10.01 end                          
                           
 fno 2239 lno 2239  stretc .1  vtp  1475 2.986
                           1551 3.626
                           1618 3.866
                           1708 4.212
                           1776 4.366
                           1845 4.559
                           1940 4.719
                           2043 4.886
                           2243 5.079
                           2744 5.392
                           2794 5.492
                           6138 10.01 end
                                                                                                      
 fno 2434 lno 2434  vtp   1475 3.246
                           1533 3.792
                           1571 3.959
                           1585 4.132
                           1624 4.259
                           1734 4.479
                           1766 4.606
                           1842 4.746
                           1882 5.052
                           1950 5.306
                           2320 5.412
                           2764 5.759
                           3954 8.999
                           5545 10.01 end
                   
 fno 2574 lno 2574    vtp 1475 3.433
                           1672 4.572
                           1743 4.786
                           2096 5.452
                           2338 5.692
                           3204 6.559
                           5933 10.01 end
end

prout
# print the stacked trace number just so the light blink!
 fno 0 lno 99999 ftr 1 ltr 1 end
end

diskoa
# Write out disk file
  opath stacked/stack.line4 end
end

end
!
Go to the list of seismic processes.      Go to SIOSEIS introduction.