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 ¯15

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:  ¯IPD9810.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯132276468
   traces in file:  ¯24297
      first trace:  ¯841/16 FFID/trace
       last trace:  ¯342/24 FFID/trace


             file:  ¯IPD10063.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯132336352
   traces in file:  ¯24308
      first trace:  ¯347/25 FFID/trace
       last trace:  ¯853/44 FFID/trace


             file:  ¯IPD10316.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯132200252
   traces in file:  ¯24283
      first trace:  ¯853/45 FFID/trace
       last trace:  ¯360/39 FFID/trace

                             1


             file:  ¯IPD10569.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯132352684
   traces in file:  ¯24311
      first trace:  ¯360/40 FFID/trace
       last trace:  ¯867/14 FFID/trace

             file:  ¯IPD10823.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯19825204
   traces in file:  ¯3641
      first trace:  ¯867/15 FFID/trace
       last trace:  ¯943/7 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.

OB9771
OB9821
OB9871
OB9921
OB9971
OB10021
OB10071
OB10121
OB10171
OB10221
OB10271
OB10321
OB10371
OB10421
OB10440
OB10440G
OB10490
OB10540
OB10590
OB10640
OB10690
OB10740
OB10790
OB10840

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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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