NOTES ON XINJIANG (CHINA) TEST SITES NUCLEAR EXPLOSIONS (BLACKNEST)
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                                     Version Date - 17th November 2004

   The file  README  contains this script and other relevant notes.

   The file  BKNAS  contains the definition of the BKNAS header and the
      description of the various fields within the header.

   The file  LIST  contains all the information required to organise,
      process, and digest Chinese nuclear explosions.

   The file  LINKS  contains links to generalise the naming of the
      nuclear explosion directories.


   Each year directory contains the files to process and beam-form the
      seismic data for each Chinese nuclear explosion that one or more
      recording exists.

   Each directory (Site_Date.Time) contains up to five sorts of files : -
      (a)  Original data defined (Date.Time_STN) by the name of the file
           and converted data in BKNAS, CSS, and IMS formats,
      (b)  Controlling files defined by date containing all necessary
           information for beam-forming by the APPLE program,
      (c)  Phase files defined by the phase code @ the station containing
           enough information for beam-forming by the APPLE program,
      (d)  PostScript files (I1_....ps,P1_....ps) containing information
           and the seismogram plot (output from the APPLE program),
      (e)  Four files (info,info.all,plot,file) which contain further
           information.

   Each controlling file (e.g. date_stn.input) and each phase file
   (e.g. P@STN.input, PcP@STN.input, etc.) contains up to 10 lines : -
      (1)  The word APPLE and the sampling rate,
      (2)  A title most of which is self-explanatory,
      (3)  A number in col.1 which defines the form of the hypocentre,
      (4)  The hypocentre information,
      (5)  The station code (YKA,WRA,EKA,GBA), the sensitivity number,
           and the form number for the PostScript files,
      (6)  The channel definition and position in the data file*,
      (7)  The instrument number (Blacknest code),
      (8)  Tape form number (20,21,32), number of channels, start time,
           and other 'useful' numbers,
      (+)  Onset time (UTC) corresponding to start time (if known);
           critical for original analogue data, optional for digital data,
      (9)  The name of the file of the original data.

   Zero length controlling files indicate no data is available or is not
      included.  Phase files which are not present indicate that either
      no data is available or considered not worth processing.

   Of the four further information files (info,info.all,plot,file) the
      most useful is  info  which contains a summary for each explosion.
      The fields are; station code (YKA,WRA,EKA,GBA), date, start sample
      (start time * sampling rate), onset time type, picked onset time,
      phase, depth, distance, given Mb, amplitude, period, distance
      factor, estimated magnitude Mb, maximum-likelihood magnitude M*,
      and magnitude difference.

   *  Channel definition and position requires further explanation : -
      (f)  Each channel is defined by four characters and its position
           in the line corresponds to its position in the data file,
      (g)  The first three characters define the pit code,
      (h)  The fourth character defines its use : -
             blank  for normal use,
           * display but do not use,
           ! glitches occur but outside arrival time window +/- 5s (say),
           + use irrespective of glitches, etc.,
           - invert and use irrespective of glitches, etc.,
      (j)  All four characters as **** indicate an unknown, a non-SP,
           a grossly over-loaded, or a blank channel,
      (k)  On original analogue data (tape form 21) the time channel is
           usually the next channel after the last defined channel and is
           not displayed.


   Suggested Processing : -
      (A)  Select the nuclear explosion of interest,
      (B)  View the selected  P1_....ps  file with a PostScript reader,
      (C)  Get the start sample number from the  info  file,
      (D)  Use appropriate tools to form a window and beam-form the event.



   YKA (YELLOWKNIFE ARRAY) SPECIFIC NOTES

   EVENT 19-DEC-1984
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      For this explosion the recording heads on the analogue tape deck
      were not aligned correctly.  The APPLE program allows for this
      'skewness' so correctly beamed seismograms are generated.
      For completeness, the original seismogram has been corrected and
      stored as BKNAS, CSS, and IMS format files.  The original raw data
      file is also included.