NAME

     backus - module for applying a Backus  3-pt  dereverberation
     operator to trace data

SYNOPSIS

     backus [ -Nntap ] [ -Ootap ] [ -nsns ] [ -nene ] [ -rsirs  ]
     [  -reire ] [ -rr ] [ -velv ] [ -Ccfile ] [ -GIngi ] [ -ffmt
     ] [ -V ] [ -? ]

DESCRIPTION

     backus applies a 3-point dereverberation operator  to  trace
     data.

     Backus gets both its data and its  parameters  from  command
     line  arguments.  These arguments specify the input, output,
     the water bottom reflection coefficient, an override for the
     water  velocity, and three parameters to optionally override
     the water depths encoded in the trace headers.   These  last
     three  parameters  include the name of a card file where the
     water depths are stored, the number of water depths  in  the
     file (1 per GI), and the format of the file.

  Command line arguments
     -Nntap
          Enter input data set name  or  file  immediately  after
          typing  -N;  entering  nothing  specifies a stdin pipe.
          This file should include the complete path name if  the
          file   resides   in  a  different  directory.   Example
          -n/b/vsp/dummy tells  the  program  to  look  for  file
          'dummy' in subdirectory 'vsp' stored in directory b.

     -Ootap
          Enter output data set name or  file  immediately  after
          typing  -O.  This output file is not required when pip-
          ing the output to another process.  The output data set
          also requires the full path name (see above).

     -rs irs
          (integer)    Enter    first    record    to    process.
          (default = 1)

     -re ire
          (integer)    Enter    last    record    to     process.
          (default = all)

     -ns ns
          Enter first trace in record to process. (default = 1)

     -ne ne
          Enter last trace in record to process.  (default = all)


     -r r Enter water bottom reflection coefficient.  (default  =
          0.3)

     -vel v
          Enter water velocity.  (default = value in line header)

     -Ccfile
          Enter file name that contains the water  depths.   This
          parameter  is  used  only  to override the water depths
          posted in the trace  headers.   (OPTIONAL)  (default  =
          values in trace headers)

     -GI ngi
          Enter number of water depths in the card file  (e.g.  1
          per GI). (OPTIONAL)

     -ffmt
          Enter  format   of   the   card   file.    (default   =
          (5x,12f5.0,15x)  ) (OPTIONAL)

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

     -?   Enter this (or '-?' if you are running in  c-shell)  to
          get  online  help.   The  program  will terminate after
          printing a list of parameters.

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved
          an affiliate of BP America Inc.