Back to SIOSEIS Examples.          Go to the list of seismic processes.          Go to SIOSEIS introduction.

Cruise report entry
Knudsen cruise report entry
Plot of some Knudsen chirp data.
Plot of MCS shot 5000.
Plot of MCS shot 5000 with 6x250 filter.
Plot of spectrum of MCS shot 5000.
Plot of dimples (chirp).
Plot of dimples (mcs brute stack).
Plot of dimples (fkmigr brute stack).
1) mount /Volumes/  # Bergen/Geometrics segy files
   mount /Volumes/     # Bergen/Geometrics log files (all lines)
   cd /Users/seismic/Data/MCS/Raw/shots
   mkcpy-shots XX

   Creates   /Users/seismic/Data/MCS/Raw/shots/Healy05$LINE
   Reads the last SEGY file on /Volumes/ 
   Writes all shots to /Users/seismic/Data/MCS/Raw/shots/Healy05$LINE/$FILE
       (This is the Coakley/Hopper archival data, which is in
        IEEE whereas the Geometrics file is IBM)
   Writes "latest_shot" to /Users/seismic/Data/MCS/Raw/latest_shot.
   Tries to get the log file and chmod 444 the segy files.

2)  Make sure /Users/seismic/Data/MCS/Raw/shots/Healy05XX has a log
    file for each sgy file.  (Control-c in step 1 (mkcpy-shots) prevents
    the script from finishing and doing the log copy).  If the logs
    are not proper, get them!  e.g.
    cp -p /Volumes/*.log
    chmod 444 *.log
  #  mkdir /Users/seismic/Data/Nav/Healy05XX
  #  cat H*.log > /Users/seismic/Data/Nav/Healy05XX/geometrics.log

    Run script   clean_logs   to remove all the '#BV' lines that
        are confusing sioseis.

    Get the first and last shots times from file geometrics.log

4)  Get the Seabeam or Knudsen file as:
    If the ship's data disk needs to be mounted, mount it as:
          mkdir /Volumes/Raw-data
          mount /Volumes/Raw-data
       cd /Users/seismic/Data/Seabeam
       ls -lt /Volumes/Raw-data/Datalog/seabeam_centerbeam | head
       cp the appropriate seabeam file,   e.g.
           cp -p /Volumes/Raw-data/Datalog/seabeam_centerbeam/Seabeam-Centerbeam_20050902-000004.RAW .
       cat the appropriate file to   > lineXX.raw
       or    ln -s  Seabeam-Centerbeam_20050820-000003.RAW lineXX.raw
       cd /Users/seismic/Data/Knudsen-depth
       ls -lt /Volumes/Raw-data/Datalog/knudsen | head
       cp the appropriate Knudsen file,   e.g.
          cp -p /Volumes/Raw-data/Datalog/knudsen/Knudsen_20050913-000004.RAW .
          ln -s /Users/seismic/Data/Knudsen-depth/Knudsen_20050913-000004.RAW line46.raw

5)  cd /Users/seismic/Data/MCS/Processed/Shots+nav
    mkshnav.sio XX > lineXX.stdout
       (This writes file Healy05$LINENO.segy which has the UDP
        long/lat and the Seabeam center depth in the SEG-Y trace

6)  cd /Users/seismic/Data/MCS/Processed/Shots+FK

The Bergen PCs were put on NTP during week 1, so the SEG-Y shot time is
the best time of the trigger (presumably the trigger is on one of these PCs).

The posmv navigation were transmitted from computer Healy-mx via "udp".
The Posmv is ~38m from the fantail (Consolidated survey: Posmv=-49.57,
aft fantail survey = -86.74, eyeball survey pt to end of fantail = -.8m)
Eyeball fantail to guns = 5m.  guns to trace 1 = 90m.
Therefore, distance from nav to first bin center = 38+5+45 = 88m

The seismic shot number (trigger counter) and the navigation were added
to the Geometrics log for each shot, along with the normal Geometrics
information. E.G. 
51920,084423.968,8018.32612,N,17425.62968,W,1,09 - Received at 08:45:25.57 for File 33262
 FFID   33262 (Stack  1, Shot Loc: 0 Meters) 08:45:25.47 08/22/2005 1546 KBytes SAVED IN 33262.SGY
51921,084443.967,8018.34381,N,17425.70720,W,1,09 - Received at 08:45:45.59 for File 33263
 FFID   33263 (Stack  1, Shot Loc: 0 Meters) 08:45:45.49 08/22/2005 1542 KBytes SAVED IN 33262.SGY

51920 is the shot number.
084423.968 is the fix time. 08 hours, 44 minutes, 23.968 seconds.
FFID is the count of the files written by the Geometrics

lsd of raw shot says:
     33262     1       0     0  1      0     0  16000  1000    5 234  8  45  25
     33263     1       0     0  1      0     0  16000  1000    5 234  8  45  45

lsd after healy nav:
     51920     1    8300     0  1    -90     0  16000  1000    5 234  8  45  25
     51921     1    8307     0  1    -90     0  16000  1000    5 234  8  45  45

0)  Low frequency (10Hz.) streamer noise due to heave or ship surges.
    Notice how successive streamer sections (8 traces) have reduced
    noise between traces 8/8 and 16/17.
    FK filter is very effective at reducing them.
1)  "Spikes".  Largish amplidutes (3x normal trace a few sec after
    water bottom).
    FK Filter sweeps or bleeds them into adjacent traces.  
    Hand editing.  FK bleeding problem?
2)  Traces and shots without seismic signals.  
    Short/long window based around the Seabeam water depth, with a ratio
    of .5, kills them.
3)  Traces go noisy after the water bottom.

SIOSEIS modifications for Healy05:
1)  REALTIME flag set in the PROCS list by the user.
2)  DISKIN looks at REALTIME flag and save the disk address of each
    trace read.  When end-of-file is detected, the segy file is closed
    and sioseis sleeps for a few seconds and the the file is reopened
    and positioned to the save disk address and the trace read is 
    tried again.  The program decides shooting ahs stopped after no
    shots are read after 120 seconds.  The file must be closed and
    reopened so that the OS resets the inode information for the file.
3)  GEOM module HEALY05 was added to read the Geometrics Log file with
    Bergen/LDEO nav and centerbeam info added.  The Geometrics log 
    file contains other stuff.  It may also miss shots, especially at
    the start or end of line.  The centerbeam is in a different file.
    The water depth from the first Seabeam entry for the same minute
    is used.  The Seabeam depth may be missing so the last good one
    is used (might be hours old!).  The Geometrics FFID is put into
    SEGY word 5 (energy source number) and the Bergen trigger counter
    is used as the shot number and put into SEGY word 3.
    The nav and water depth are put into the SEGY trace header as 
    per SEG standards.
4)  GEOM type 9 (realtime dfls (distance from last shot) ) was wrong
    on the shot after a missing shot.  (BUG).
5)  The maximum number of semblance velocities in VELAN was increased.
6)  PLOT rejected shots numbered 0 (a Knudsen quirk).
7)  Parameter ENDMUTE was added to despike/tredit to partially kill
    bad traces.
8)  Stack was "rewritten" to not count samples with zeroes.  (New 
    parameter NEW).
9)  SIOPLT doesn't work on 24bit displays (1,66.,... colors).  Works
    on 8 bit displays (256 colors) only.
10) Allow 32K ffts for large Knudsen files
11) Modify Healy05 to use Knudsen depth files because SeaBeam died.
Back to SIOSEIS Examples.          Go to the list of seismic processes.          Go to SIOSEIS introduction.