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 ¯16

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:  ¯IPD10861.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯128977404
   traces in file:  ¯23691
      first trace:  ¯943/8 FFID/trace
       last trace:  ¯438/34 FFID/trace


             file:  ¯IPD11108.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯4783432
   traces in file:  ¯878
      first trace:  ¯438/35 FFID/trace
       last trace:  ¯456/48 FFID/trace


             file:  ¯IPD11118.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯128797752
   traces in file:  ¯23658
      first trace:  ¯457/1 FFID/trace
       last trace:  ¯417/42 FFID/trace

                             1

             file:  ¯IPD11328.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯132156700
   traces in file:  ¯24275
      first trace:  ¯417/43 FFID/trace
       last trace:  ¯923/29 FFID/trace


             file:  ¯IPD11581.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯128890300
   traces in file:  ¯23675
      first trace:  ¯923/30 FFID/trace
       last trace:  ¯416/40 FFID/trace

             file:  ¯IPD11827.SGY
      sample rate:  4000.0 microsec
samples per trace:  ¯1301
      data length:  ¯5204 msec
  bytes per trace:  ¯5444
    bytes in file:  ¯129042732
   traces in file:  ¯23703
      first trace:  ¯416/41 FFID/trace
       last trace:  ¯910/31 FFID/trace
























                             2
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.

OB10840
OB10890
OB10940
OB10990
OB11040
OB11090
OB11120A
OB11140
OB11170
OB11220
OB11270
OB11320
OB11370
OB11420
OB11470
OB11520
OB11570
OB11620
OB11670
OB11720
OB11770
OB11820
OB11870
OB11920
OB11970
OB12020
OB12070



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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