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 ¯09

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:  ¯IPD4414A.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯135204652
   traces in file:  ¯21007
      first trace:  ¯83/24 FFID/trace
       last trace:  ¯19/33 FFID/trace


             file:  ¯IPD4281.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1549
      data length:  ¯6196 msec
  bytes per trace:  ¯6436
    bytes in file:  ¯139330128
   traces in file:  ¯21648
      first trace:  ¯20/34 FFID/trace
       last trace:  ¯349/22 FFID/trace


             file:  ¯IPD4583.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯131900832
   traces in file:  ¯24228
      first trace:  ¯349/1 FFID/trace
       last trace:  ¯739/48 FFID/trace

                             1

             file:  ¯IPD4779.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯130044428
   traces in file:  ¯23887
      first trace:  ¯739/49 FFID/trace
       last trace:  ¯125/3 FFID/trace


             file:  ¯IPD4972.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯58717140
   traces in file:  ¯10785
      first trace:  ¯125/4 FFID/trace
       last trace:  ¯298/62 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.

OB4281
OB4331
OB4381
OB4410A
OB4410G
OB4431
OB4460
OB4510
OB4560
OB4610
OB4660
OB4710
OB4760
OB4810
OB4860
OB4910
OB4960
OB5010


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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