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 ¯10

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:  ¯IPD5059.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯133588472
   traces in file:  ¯24538
      first trace:  ¯299/1 FFID/trace
       last trace:  ¯694/48 FFID/trace


             file:  ¯IPD5256.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯133621136
   traces in file:  ¯24544
      first trace:  ¯694/49 FFID/trace
       last trace:  ¯90/40 FFID/trace


             file:  ¯IPD5454.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯133163840
   traces in file:  ¯24460
      first trace:  ¯90/41 FFID/trace
       last trace:  ¯485/10 FFID/trace

                               1

             file:  ¯IPD5652.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯133779012
   traces in file:  ¯24573
      first trace:  ¯485/25 FFID/trace
       last trace:  ¯881/45 FFID/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 with the file names given below.

OB5010
OB5060
OB5110
OB5160
OB5260
OB5310
OB5360
OB5410
OB5460
OB5510
OB5560
OB5610
OB5660
OB5710
OB5760
OB5810


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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