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 ¯22

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:  ¯IPD17465.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯131269328
   traces in file:  ¯24112
      first trace:  ¯252/48 FFID/trace
       last trace:  ¯755/15 FFID/trace


             file:  ¯IPD17717.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯132363572
   traces in file:  ¯24313
      first trace:  ¯755/16 FFID/trace
       last trace:  ¯261/40 FFID/trace


             file:  ¯IPD17970.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯131301992
   traces in file:  ¯24118
      first trace:  ¯261/41 FFID/trace
       last trace:  ¯765/14 FFID/trace

                             1
             file:  ¯IPD18222.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯132298244
   traces in file:  ¯24301
      first trace:  ¯765/15 FFID/trace
       last trace:  ¯271/27 FFID/trace


             file:  ¯IPD18475.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯131155004
   traces in file:  ¯24091
      first trace:  ¯271/28 FFID/trace
       last trace:  ¯773/22 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.

OB17431
OB17481
OB17531
OB17581
OB17631
OB17681
OB17731
OB17781
OB17831
OB17881
OB17981
OB18031
OB18081
OB18131
OB18181
OB18231
OB18281
OB18331
OB18381
OB18431
OB18481
OB18531
OB18581
OB18631
OB18681

                             2


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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