NAME

     spike  - module to compute simple synthetic traces

SYNOPSIS

     spike [ -Ootap ] [ -t0t0t ] [ -vvel ] [ -x0x0 ] [ -gigi ]  [
     -ntrntr  ] [ -sinsi ] [ -ampamp ] [ -Llength ] [ -Rl ] [ -Rf
     ] [ -Du ] [ -Dd ] [ -v2 ] [ -dip ] [ -V ] [ -? ]

DESCRIPTION

     spike computes simple stick-o-grams based on an input  velo-
     city, group interval, and near trace offset. spike  computes
     either a refraction or a  reflection.   Dipping  events  are
     also handled.  In the case of dipping events and refraction,
     either updip  or  downdip  refraction  trajectories  may  be
     specified.  If refraction is chosen using none zero dip then
     a velocity below the refractor must be entered to facilitate
     the  calculation  of the critical angle.  The output of this
     program may be used as input to any other sis program,  e.g.
     sctvf.   Although spike produces only one event per run more
     complicated records may be built up using other sis programs
     such as vstak.

     spike gets both its data and  its  parameters  from  command
     line arguments.

  Command line arguments
     -O otap
          Enter the output data  set  name  or  file  immediately
          after typing -O.  This output file is not required when
          piping the output to another process.  The output  data
          set also requires the full path name.

     -t0 t0
          Enter the normal incidence start time (ms).

     -v vel
          Enter the desired velocity in ft/s or m/s

     -x0 x0
          Enter the near trace offset in ft or m

     -gi gi
          Enter the group interval in ft or m

     -ntr ntr
          Enter the number of groups desired  (default = 10)

     -si nsi
          Enter the sample interval in ms  (default = 4)

     -amp amp
          Enter the amplitude of the spikes, e.g. 307 for 15%  of
          2047   (default = 1).  Note that if in the calculations
          the spike time happens to  fall  between  2  samples  a
          linear interpolation is done spreading the amplitude of
          the spike over the 2 sample points.

     -L length
          Enter the total trace time in ms

     -Rf  Enter the command line argument '-Rf' to get a  refrac-
          tion event

     -Rl  Enter the command line argument '-Rl' to get a  reflec-
          tion event

     -Du  Enter the command line argument '-Du' to get  an  updip
          refraction event

     -Dd  Enter the command line argument '-Dd' to get a  downdip
          refraction event

     -v2 v2
          Enter the velocity below the refractor for non-zero dip
          refractors

     -dip dip
          Enter the dip in degrees of the reflector/refractor

     -V   Enter the command line argument '-V' to get  additional
          printout.

     -?   Enter the command line  argument  '-?'  to  get  online
          help.  The  program terminates after the help screen is
          printed.

DISCUSSION

     The program interprets any sample interval greater  than  32
     as microseconds and applies the appropriate velocity correc-
     tion.  The equations used for the updip and downdip  refrac-
     tion  arrival  calculations  are  from  Applied  Geophysics,
     pp.282.  Should you require a dipping horizon with the dip =
     critical angle, this routine will not accomodate you.

BUGS

     Phylum unknown.

AUTHOR

     Paul G. Gutowski: TRC Mods  by  Paul  G.A.  Garossino:  TRC,
     Jan/91

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved

          an affiliate of BP America Inc.