April 21, 2011 RC2005 Cruise/project information ------------------------------------------------------------------------------------- Cruise Name RC2005 NGDC number 01010168 Platform Conrad Ship Operator LDEO Chief Scientist Charles Windisch (Conrad) Co-Chief Scentist Paul Stoffa (Conrad) Chief Scientist Manik Talwani (Vema) C0-Chief Scientist Peter Buhl (Vema) Principal Investigator Manik Talwani All collaborating LDEO Institutions Beginning date 09/25/76 Ending date 10/18/76 MCS start date 09/30/76 MCS end date 10/18/76 Cruise Report yes - paper Start Port Yokohama, Japan End Port Yokohama, Japan Project Name West Pacific Project Description Two ship reflection and refraction experiment to: 1) Continuously record depth to mantle. 2) Record sub-mantle reflections at designated points. Funding organization NSF Award # OCE 76-10081 Abstract NO ------------------------------------------------------------------------------------- navigation type: US Navy Transit Satellite CDP/SHOT navigation files in RC2005.nav.tar: One minute dayfiles are in RC2005.dayfiles.tar (times also local) I've included them since the nav for the COP lines is uncertain. Again, times in both sets of nav files are local. RC2005.line.start_end.nav Contains 1st and last entry for each of the CDP/SHOT navigation files. rc2005.37.cdpnav 34.537513 146.689629 42 1976 10 09 19 06 06 000 37 rc2005 34.169763 145.410604 2739 1976 10 10 10 26 26 000 37 rc2005 rc2005.38.cdpnav 33.804424 144.329251 28 1976 10 10 23 00 35 000 38 rc2005 31.336573 141.379813 7970 1976 10 12 20 10 16 000 38 rc2005 rc2005.39.cdpnav 31.202342 141.250352 28 1976 10 12 21 36 11 000 39 rc2005 31.293736 144.044870 5048 1976 10 14 04 42 13 000 39 rc2005 rc2005.41.cdpnav 31.773620 143.574692 28 1976 10 14 14 06 20 000 41 rc2005 30.347980 144.767170 3958 1976 10 15 12 27 22 000 41 rc2005 rc2005.43.cdpnav 30.492031 145.333468 28 1976 10 15 19 34 57 000 43 rc2005 30.375335 144.312513 1833 1976 10 16 05 50 51 000 43 rc2005 rc2005.44.cdpnav 30.396823 144.308341 28 1976 10 16 06 38 56 000 44 rc2005 30.351973 144.037702 664 1976 10 16 10 15 57 000 44 rc2005 rc2005.46.cdpnav 30.803420 143.480489 28 1976 10 16 17 30 02 000 46 rc2005 33.611735 140.667866 7658 1976 10 18 13 36 53 000 46 rc2005 rc2005.30.conrad.shotnav 39.486628 146.902196 31 1976 10 01 01 36 09 000 30 rc2005 38.346590 147.919787 2419 1976 10 01 19 32 31 000 30 rc2005 rc2005.33.conrad.shotnav 33.856273 153.649083 2 1976 10 05 21 27 40 000 33 rc2005 34.309299 146.675155 8900 1976 10 09 08 02 59 000 33 rc2005 rc2005.34.conrad.shotnav 34.345565 146.525732 3 1976 10 09 09 32 43 000 34 rc2005 34.431641 146.183200 326 1976 10 09 12 13 15 000 34 rc2005 rc2005.36.conrad.shotnav 34.476415 146.214201 2 1976 10 09 13 26 54 000 36 rc2005 34.542196 146.685858 702 1976 10 09 18 59 57 000 36 rc2005 rc2005.45.conrad.shotnav 30.367054 144.014681 2 1976 10 16 10 31 20 000 45 rc2005 30.760510 143.543053 472 1976 10 16 16 20 27 000 45 rc2005 CDP/SHOT Nav files are in UTIG distribution format. ------------------------------------------------------------------------------- For CDP Lines 37,38,39,41,43,44,46: These lines were processed as were earlier cruises so cdpnav could be defined as before Position_Correlation_Method: Position is at center of cmp bin and time is the time the ships's antenna was over that position. Trace_Position: trace Source_CMP_offsets_Applied: yes processed cdp data files: RC2005.37.stk.0042_2739 RC2005.38.stk.0025_7969 RC2005.39.stk.0024_5048 RC2005.39.stk.1660_3995.abrams RC2005.41.mig.1624_3591 RC2005.41.stk.0024_3958 RC2005.43.stk.0024_1833 RC2005.44.stk.0024_0664 RC2005.46.stk.0025_3080.abrams RC2005.46.stk.0025_7658 processing system LDEO MCS Inhouse processing: Lines 37,38,39,41,46 processed in 1980-81 spherical divergence, burg decon, bandpass, nmo Lines 43,44 processed in 1977 nmo Lew Abrams reprocessed parts of line 39 and 46. Processing is unknown. Note: There are some incorrect time entries in the segy headers. These errors have been corrected as best we could in the cdpnav files. cdp spacing 50 meters field data: cdp gathers on tape at LDEO - not yet in database. ********************************************************** For COP Lines 30,31, 33,34,36,45: 'Stack' tapes exist for these lines and indeed they look like reflection profiles. Except for the 2 files labelled 'vema' they are stacks of the Conrad shots. I do not know how these files were made. The cdp numbering convention and the times in the headers do not follow the convention of the normal cdp lines. The times at the beginning of the lines are are more like the times of the corresponding shots. Further into the lines they are further from the shot times. I believe that there was some editing of non shots and then a renumbering so that there would be no missing ones. So the nav files for these lines are the cdp (shot?) number, the time in the header and the ship's position at that time. Exactly how that relates to the trace I do not know but at least you have a general idea of where it is. As for the Vema shots I don't know the ship to ship range they were trying to maintain or whether the Vema was in front of or behind the Conrad. You may not want to include the line 45 Vema shots - too confusing. RC2005.30.stk.0001_2419 RC2005.31.stk.0002_0988 RC2005.33.stk.0002_8900 RC2005.34.stk.0003_0326 RC2005.36.stk.0002_0702 RC2005.45.stk.0002_0472 RC2005.45.stk.0003_0261.vema (Rselect range= 16 km, vel=6.7 km/sec) RC2005.45.stk.0004_0261.vema (vel = 8.2 km/sec) ------------------------------------------------------------------------------------ The delays and number of samples may vary within a line. Header info from the first and last traces in each file is in: RC2005.processed.segy.files.index. Fields are as follows: LINE CDP SHOT SOURCE DATE TIME REC_DELAY SAMPLES SAMP_INT POINT ********************************************************** RC2005 Seismic Acquisition Parameters ********************************************************** Number of Channels 24 Group Spacing 100 meters Source to Near Channel 300 meters (Not precise but typical for the Conrad at this time) Antenna to Source 40 meters " " " " Near Channel Number 24 Cable Depth UNKNOWN Acquisition System Name DFSIV Conrad Source Volume 1864 cu. in. (probably) Conrad Source Pressure 2000 psi Conrad Source Type Bolt 1500C Conrad Source Number 4 Conrad Source Depth UNKNOWN meters Vema (no recording) Vema shot expolsives - details unknown Shot Control Time : (cdp lines: every 20 seconds for approximately 50 meters) Time : (cop lines: varies - sometimes 20, secs, 40sec, 20secs, etc so Conrad shot twice per minute and Vema once per minute. (e.g. Conrad shot at ~10 secs and ~30 secs, Vema at ~50 secs.) Acquisition Sample Interval 4000 microseconds: Record Length 12 seconds Compass No Active Tail Buoy No Recording Delay Yes Acquisition System Analog 2 or more ships No ********************************************************** ********************************************************** **********************************************************