U.S. DEPARTMENT OF THE INTERIOR / U.S. GEOLOGICAL SURVEY
                                
                                
        U.S. GEOLOGICAL SURVEY DIGITAL DATA SERIES DDS-13
                                
              International Phase of Ocean Drilling
                Seismic Line 1 Demultiplexed Data
               Cape Hatteras to Mid-Atlantic Ridge
                                
                            DISC ¯06

Demultiplexed Seismic Data

     Each file of seismic data is the disc-image of a SEG-Y
format tape output during the demultiplexing of the original
field data.  The data were written to tape using the 32 bit IBM
floating point format (Barry, and others, 1975).  As the data
were copied bit-for-bit to the CD-ROM file, this format was
preserved.  Each file of sesimic data is named IPD{number}, where
{number} is the first shotpoint in the file.  NOTE: FFID
indicates the Field File Identification Number assigned each shot
as it was recorded.

             file:  ¯IPD2348.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯2250
      data length:  ¯9000 msec
  bytes per trace:  ¯9240
    bytes in file:  ¯148434960
   traces in file:  ¯16064
      first trace:  ¯98/43 FFID/trace
       last trace:  ¯357/48 FFID/trace


             file:  ¯IPD2478.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯2250
      data length:  ¯9000 msec
  bytes per trace:  ¯9240
    bytes in file:  ¯123302160
   traces in file:  ¯13344
      first trace:  ¯357/49 FFID/trace
       last trace:  ¯572/62 FFID/trace


             file:  ¯IPD2587.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1800
      data length:  ¯7200 msec
  bytes per trace:  ¯7440
    bytes in file:  ¯142613520
   traces in file:  ¯19168
      first trace:  ¯573/1 FFID/trace
       last trace:  ¯882/10 FFID/trace

                             1

             file:  ¯IPD2740.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1800
      data length:  ¯7200 msec
  bytes per trace:  ¯7440
    bytes in file:  ¯130471440
   traces in file:  ¯17536
      first trace:  ¯882/11 FFID/trace
       last trace:  ¯164/62FFID/trace



Observer Logs

     The following files are digitized versions of the original
observer's log sheets.  Each file is named OB{number}.{format},
where {number} is the first shot point on the page, and {format}
is the graphic format of the file: PCX, TIF, or GIF.  No {format}
extension is shown for the file names given below.

OB2300A
OB2300AG
OB2311
OB2350
OB2361
OB2400
OB2450
OB2500
OB2550
OB2600
OB2650
OB2700
OB2750
OB2800
OB2850



REFERENCE

Barry, K.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended
     standards for digital tape formats: Geophysics, v. 40, p.
     344-352.


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