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 ¯24

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:  ¯IPD19865.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1551
      data length:  ¯6204 msec
  bytes per trace:  ¯6444
    bytes in file:  ¯137170584
   traces in file:  ¯21286
      first trace:  ¯51/37 FFID/trace
       last trace:  ¯496/10 FFID/trace


             file:  ¯IPD20087.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1551
      data length:  ¯6204 msec
  bytes per trace:  ¯6444
    bytes in file:  ¯137170584
   traces in file:  ¯21286
      first trace:  ¯496/11 FFID/trace
       last trace:  ¯839/32 FFID/trace


             file:  ¯IPD20309.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1551
      data length:  ¯6204 msec
  bytes per trace:  ¯6444
    bytes in file:  ¯137318796
   traces in file:  ¯21309
      first trace:  ¯939/33 FFID/trace
       last trace:  ¯383/29 FFID/trace

                             1


             file:  ¯IPD20531.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1551
      data length:  ¯6204 msec
  bytes per trace:  ¯6444
    bytes in file:  ¯137331684
   traces in file:  ¯21311
      first trace:  ¯383/30 FFID/trace
       last trace:  ¯827/28 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.

OB19821
OB19871
OB19921
OB19971
OB20021
OB20071
OB20121
OB20171
OB20221
OB20271
OB20321
OB20371
OB20421
OB20471
OB20521
OB20571
OB20621
OB20671
OB20721


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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