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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