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 ¯29

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:  ¯IPD24392.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯137334968
   traces in file:  ¯21338
      first trace:  ¯785/1 FFID/trace
       last trace:  ¯229/26 FFID/trace


             file:  ¯IPD24614.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯137309224
   traces in file:  ¯21334
      first trace:  ¯229/27 FFID/trace
       last trace:  ¯673/48 FFID/trace


             file:  ¯IPD24836.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯136292336
   traces in file:  ¯21176
      first trace:  ¯674/1 FFID/trace
       last trace:  ¯115/8 FFID/trace

                             1

             file:  ¯IPD25057.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯27755632
   traces in file:  ¯4312
      first trace:  ¯115/9 FFID/trace
       last trace:  ¯204/48 FFID/trace

             file:  ¯IPD25102.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯137920644
   traces in file:  ¯21429
      first trace:  ¯205/1 FFID/trace
       last trace:  ¯651/21 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.

OB24350
OB24400
OB24450
OB24500
OB24550
OB24600
OB24650
OB24700
OB24750
OB24800
OB24850
OB24900
OB24950
OB25000
OB25050
OB25100
OB25150
OB25200
OB25250
OB25300



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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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