Index of /data/reports/2005/05-005

[ICO]NameLast modifiedSizeDescription

[PARENTDIR]Parent Directory   -  
[   ]05-005_Mururoa.pdf 2013-05-14 08:36 261K 
[TXT]BKNAS 2005-03-30 09:56 25K 
[   ]LINKS 2005-03-30 09:56 40K 
[TXT]LIST 2005-03-30 09:56 80K 
[TXT]README 2005-03-30 09:56 6.9K 
[   ]TABLE 2005-03-30 09:56 9.5K 

                                             Version Date - 4th October 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 the French Mururoa and Fangataufa nuclear
      explosions (air burst and underground).

   The file  TABLE  contains the summary of the processing of the French
      Mururoa and Fangataufa underground nuclear explosions.

   The file  LINKS  contains links to generalise the naming of the event

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

   Each directory (year/date) 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 (date_stn.input) 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 (, containing information
           and the seismogram plot (output from the APPLE program),
      (e)  Three files (info,plot,file) containing further information.

   Each controlling file (e.g. date_stn.input) contains up to 10 lines : -
      (1)  The word APPLE and the sampling rate,
      (2)  A title some 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,GBA,EKA), 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)  Filename of original data.
   Zero length controlling files indicate no data is available or is not

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

   *  Channel definition and position requires further explanation : -
      (e)  Each channel is defined by four characters and its position in
           the line corresponds to its position in the BKNAS data file,
      (f)  The first three characters define the pit code,
      (g)  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.,
      (h)  All four characters as **** indicate an unknown, a non-SP,
           a grossly over-loaded, or a blank channel,
      (i)  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  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.


   ALL EVENTS IN 1985 AND 1986
      In 1985 and 1986 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 seismograms have been corrected and stored as BKNAS, CSS, and
   IMS format files.  The original raw data files are also included.

   EVENTS 19-JUL-1980 AND 25-MAY-1983
      The digitising settings for analogue to digital conversion were set
   low so any event over about Mb 5.8 is overloaded.  These two nuclear
   explosions being overloaded, no original data was transferred from
   analogue to digital tape.  However, VBB files exist for these two
   nuclear explosions and processed phase files are included with the
   YKB station code.

      A number of YKA analogue recordings were digitised with the VBB
   channel.  Some of the larger nuclear explosions which are overloaded
   or near overload have also been processed and phase files included
   with the YKB station code.


      The amplitudes recorded from Mururoa nuclear explosions really are
   about a magnitude down compared to those recorded at YKA.  As the
   amplitudes recorded from Fangataufa nuclear explosions compare favourably
   with those recorded at YKA it has been assumed that the Mururoa 'effect'
   is due to attenuation at source.


      The amplitudes recorded from Mururoa and Fangataufa nuclear explosions
   suffer from the same 'effect' as those recorded at WRA.  A further
   complication is that the recording distance is at the PKP triplication
   and the first arrival time is usually outside the travel time tables.
   The slow rise time on some first arrivals is thought to be due to fact
   that the signal is the Hilbert transform.


      EKA is not located at a suitable distance to record the small nuclear
   explosions.  All explosions over Mb 5.1 have been processed at fixed
   times and given a  PKP DETECTED  label if there is a positive correlation.
   However, most detections have to be dubious.  All the Fangataufa records
   have been processed but only 4 out of 10 nuclear explsions were detected.
   All other explosions except one (see below) have not been processed but
   are included for completeness.

   EVENT 6-MAY-1986
      The ISC did not report this nuclear explosion though it was clearly
   seen at YKA.  The detection is as clear as normal for EKA (i.e. not
   clearly seen) but is obviously from the right direction at the right speed.