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 Ż22

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:  ŻIPD17465.SGY
      sample rate:  4000.0 microsec
samples per trace:  Ż1301
      data length:  Ż5204 msec
  bytes per trace:  Ż5444
    bytes in file:  Ż131269328
   traces in file:  Ż24112
      first trace:  Ż252/48 FFID/trace
       last trace:  Ż755/15 FFID/trace


             file:  ŻIPD17717.SGY
      sample rate:  4000.0 microsec
samples per trace:  Ż1301
      data length:  Ż5204 msec
  bytes per trace:  Ż5444
    bytes in file:  Ż132363572
   traces in file:  Ż24313
      first trace:  Ż755/16 FFID/trace
       last trace:  Ż261/40 FFID/trace


             file:  ŻIPD17970.SGY
      sample rate:  4000.0 microsec
samples per trace:  Ż1301
      data length:  Ż5204 msec
  bytes per trace:  Ż5444
    bytes in file:  Ż131301992
   traces in file:  Ż24118
      first trace:  Ż261/41 FFID/trace
       last trace:  Ż765/14 FFID/trace

                             1
             file:  ŻIPD18222.SGY
      sample rate:  4000.0 microsec
samples per trace:  Ż1301
      data length:  Ż5204 msec
  bytes per trace:  Ż5444
    bytes in file:  Ż132298244
   traces in file:  Ż24301
      first trace:  Ż765/15 FFID/trace
       last trace:  Ż271/27 FFID/trace


             file:  ŻIPD18475.SGY
      sample rate:  4000.0 microsec
samples per trace:  Ż1301
      data length:  Ż5204 msec
  bytes per trace:  Ż5444
    bytes in file:  Ż131155004
   traces in file:  Ż24091
      first trace:  Ż271/28 FFID/trace
       last trace:  Ż773/22 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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