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 ¯08

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:  ¯IPD3579.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯138866736
   traces in file:  ¯21576
      first trace:  ¯680/16 FFID/trace
       last trace:  ¯28/15 FFID/trace


             file:  ¯IPD3753.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯137264172
   traces in file:  ¯21327
      first trace:  ¯28/16 FFID/trace
       last trace:  ¯372/14 FFID/trace


             file:  ¯IPD3925.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯12283488
   traces in file:  ¯1908
      first trace:  ¯403/1 FFID/trace
       last trace:  ¯743/30 FFID/trace

                             1

             file:  ¯IPD3940.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯135867560
   traces in file:  ¯21327
      first trace:  ¯372/15 FFID/trace
       last trace:  ¯402/62 FFID/trace


             file:  ¯IPD4111.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯136629428
   traces in file:  ¯21073
      first trace:  ¯743/31 FFID/trace
       last trace:  ¯83/23 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.

OB3531
OB3581
OB3631
OB3681
OB3731
OB3781
OB3831
OB3881
OB3931
OB3981
OB4031
OB4081
OB4131
OB4181
OB4231
OB4281



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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