NAME

     rnmo  - apply/remove residual normal moveout correction

SYNOPSIS

     rnmo [ -Nntap ] [ -Ootap ] [ -vvmod  ]  [  -sisclsiscl  ]  [
     -gisclgiscl ] [ -R ] [ -V ] [ -? ]

DESCRIPTION

     rnmo takes a set  of  traces  and  applies  the  gamma-based
     dynamic residual NMO correction:

     sqrt [ t0 **2 + (gamma **2 - 1) * (offset/2) **2 ]

     where t0 is the zero offset time or depth.

     Depending on the value of gamma (usually varying between  .9
     through  1.1)  under  or  over corrected events can be flat-
     tened. The gamma values actually represent a perturbation of
     the input velocity field. The input data and the gamma field
     can either be sampled in time  or  depth  (as  long  as  the
     header sample interval slot is correct).

     rnmo gets processing controls from the command  line.   Rea-
     sonable  defaults  are setup.  In addition, if no input file
     name is given, the binary trace data are expected to  be  on
     the  standard  input.  However, a gamma field must be speci-
     fied.

  Command line arguments
     -N ntap
          Enter the full path of the file containing the CRP data
          set.   If  not specified, input is expected to be stan-
          dard input.  If standard input  is  not  specified  and
          there  is  no  input,  e.g., program run in background,
          expect a termination. (default standard input )

     -O otap
          Enter the full path of the  output  NMO  corrected  CRP
          file.  If not specified, output is expected to be stan-
          dard output.  (default standard output )

     -v vmod
          Enter the full path of the file  containing  the  gamma
          field.   This file is in USP format and is gamma versus
          time or depth.  Program will stop if the gamma file  is
          not  given.  The  gamma field must have the same sample
          interval and number  of  samples  as  the  trace  data.
          There is either one gamma field record, consisting of a
          single gamma-depth trace, for each seismic record, or a
          single  gamma  trace  for the entire CRP data set.  The
          header of the vmod file must be consistent with that of
          the data file.

     -siscl siscl
          Enter optional input sample interval scale factor. This
          number  is multiplied by whatever is in the line header
          to get the internally used sample interval.  Default is
          1. Setting siscl to 0.0 forces the program to use what-
          ever is in the line header entry  UnitSc.  Try  a  test
          record forst.

     -giscl giscl
          Enter optional scale to use for the gamma values.  This
          number  is  divided into all the gamma values.  Default
          is 1. Setting giscl to 0.0 forces the  program  to  use
          whatever  is  in  the line header entry T_Unit.  If you
          picked gammas using rnmospec  then  these  scales  must
          correspond. Try a test record forst.

     -R   If present remove residual normal moveout correction

     -V   Verbose mode. List command line  and  lineheader  input
          parameters.

     -?   Query mode.  With this flag, rnmo will give a  descrip-
          tion  of  the  command line arguments and stop the pro-
          gram.

BUGS:

     none known at present.

SEE ALSO

     horvel, horvel3d, vi3d, vomit, rnmospec

AUTHOR

     Paul Gutowski, 1996 EPTG, pgutowski@amoco.com

COPYRIGHT

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