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 ¯07

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:  ¯IPD2882.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1550
      data length:  ¯6200 msec
  bytes per trace:  ¯6440
    bytes in file:  ¯140228160
   traces in file:  ¯21774
      first trace:  ¯165/1 FFID/trace
       last trace:  ¯516/12 FFID/trace


             file:  ¯IPD3057.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1550
      data length:  ¯6200 msec
  bytes per trace:  ¯6440
    bytes in file:  ¯78185200
   traces in file:  ¯12140
      first trace:  ¯516/13 FFID/trace
       last trace:  ¯711/62 FFID/trace


             file:  ¯IPD3103.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯136942372
   traces in file:  ¯21277
      first trace:  ¯607/1 FFID/trace
       last trace:  ¯950/11 FFID/trace

                              1

             file:  ¯IPD3274.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯139027636
   traces in file:  ¯21601
      first trace:  ¯950/12 FFID/trace
       last trace:  ¯336/36 FFID/trace


             file:  ¯IPD3407.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯137135452
   traces in file:  ¯21307
      first trace:  ¯336/37 FFID/trace
       last trace:  ¯680/15 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 for the file names given below.

OB2850
OB2900
OB2950
OB3000
OB3050
OB3100
OB3150
OB3200
OB3240A
OB3250
OB3290
OB3340
OB3390
OB3431
OB3431G
OB3481
OB3531


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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