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Datum correction for the Triton XTF towfish

lsd paul.segy 1 1 1
      SHOT   TR       RP    TR ID  RANGE DELAY NSAMPS    SI   YR DAY HR MIN SEC
         1     1       0     0  1      0     0   1024   519 2006 118 17  23  35
  shot           1  tr           1  src           0  rp           0  tr           0  id      1  eog           0
  fold      0  range           0  relev   0.0000000      selev   0.0000000      sdep   887.75000      wdep   51.770000    
  time switch or shot time millisecond       0
  source long            0           1   18.927999    
  source lat.            0           0  0.55599999    

Comments:
1)  The receiver depth (negative elevation) is not given.
2)  The source depth is given as cm rather than m.
    The SEGY trace header long word 13 is source depth, scaled by short word 35 
    (minus means divisor), thus 88775 / 100 = 887.75, which should be 8.8775
3)  Unusual sample interval of 519us (.000519s).


sioseis script #1 calculating the shift in process header.
sioseis script #2 using process shift paramteres datume 0 datumv 1520
*****     Process shift handled the datum correction incorrectly (wrong sign) from Feb 2010 - Feb 2011
*****    USE SIOSEIS ver 2011.2.4 (18 Feb. 2011)  or later

On the sioseis depth plot, the first ping (on the right)
the water depth in the segy trace header is 51.77.  The SEGY header for the last ping is 61.5



SEGY trace header dump:

69>dutil
  Enter the disk file pathname.
paul.segy
  The file is opened on unit            8
  Enter an option: he, rd, dr, da, de, dz, di, dl, dm, dd, dv,
   dw, d1, po, pw, qu, s1, s3, s6, co, wr, op, cu, rk, ad, fz
rd 3600
  Read         3600  bytes
  Enter an option: he, rd, dr, da, de, dz, di, dl, dm, dd, dv,
   dw, d1, po, pw, qu, s1, s3, s6, co, wr, op, cu, rk, ad, fz
rd 240
  Read          240  bytes
  Enter an option: he, rd, dr, da, de, dz, di, dl, dm, dd, dv,
   dw, d1, po, pw, qu, s1, s3, s6, co, wr, op, cu, rk, ad, fz
s3 60
  Enter an option: he, rd, dr, da, de, dz, di, dl, dm, dd, dv,
   dw, d1, po, pw, qu, s1, s3, s6, co, wr, op, cu, rk, ad, fz
dl 60
          0          1          1          1          0
          0          0      65536          0          0
          0          0      88775          0          0
       5177          0   -6489064     -78928        556
     -78928        556     131072          0          0
          0          0          0       1024   34013440
          0          0          0          0          0
          0          0          0          0  131465334
    1114135    2293760          0          0          0
          0          0          0  973606272          0
          0          0          0          0          0
          0          0          0          0          0
  Enter an option: he, rd, dr, da, de, dz, di, dl, dm, dd, dv,
   dw, d1, po, pw, qu, s1, s3, s6, co, wr, op, cu, rk, ad, fz
s3 60
  Enter an option: he, rd, dr, da, de, dz, di, dl, dm, dd, dv,
   dw, d1, po, pw, qu, s1, s3, s6, co, wr, op, cu, rk, ad, fz
s1 120
  Enter an option: he, rd, dr, da, de, dz, di, dl, dm, dd, dv,
   dw, d1, po, pw, qu, s1, s3, s6, co, wr, op, cu, rk, ad, fz
di 120
       0       0       0       1       0       1       0       1       0       0
       0       0       0       0       1       0       0       0       0       0
       0       0       0       0       1   23239       0       0       0       0
       0    5177       0       0    -100   -1000      -2  -13392       0     556
      -2  -13392       0     556       2       0       0       0       0       0
       0       0       0       0       0       0       0    1024     519     256
       0       0       0       0       0       0       0       0       0       0
       0       0       0       0       0       0       0       0    2006     118
      17      23      35       0       0       0       0       0       0       0
       0       0       0       0       0       0   14856    3456       0       0
       0       0       0       0       0       0       0       0       0       0
       0       0       0       0       0       0       0       0       0       0