PROCESS SMUTE
                               ------- -----

Parameters, alphabetically:
addwb     fno       interp    lno       lprint
tsets     ttp       type      xtp       xsets

DOCUMENT DATE: 20 April 2007
Modifications:
    3 September 2005 - Add parameter TYPE 2 to find and mute to a
                       zero crossing rather than using a taper.
    20 April 2007 - Allow ADDWB 2X.
                    

PROCESS SMUTE performs either a surgical mute or a tail mute to the 
seismic traces.  A surgical mute zeroes a portion of the trace according
to user given start and end times.  A tail mute zeroes the end or tail
of the trace starting at a user given time.  SMUTE is similar to process
MUTE except that MUTE always zeroes the front or beginning of the trace.

SMUTE was designed for zeroing areas that are occasionally bad, so 
spatial interpolation is turned off except when using tail muting 
(parameter XTP, which is similar to process MUTE parameter XTP).

Surgical mutes are used to zero out spike while tail mutes are often
applied to the traces closest to the source (and are then called
inner mutes).

As with process MUTE, a 5 sample linear ramp is applied to the mute zone
edges in order to reduce "edge effects".

Traces not specified are muted according to interpolation and 
extrapolation of the mute times of adjacent traces and shots/rps, unless
the INTERP parameter is used.

Surgical muting and tail muting may not be perform simultaneously.  i.e.
XTP, TTP, XSETS, TSETS are all mutually exclusive.
   
Each parameter list must be terminated with the word END.  Spatial 
variation is obtained by giving multiple lists or control points.  (See
doc/syntax).  The spatial variation may be turned off by using the
INTERP parameter.


THE PARAMETER DICTIONARY
--- --------- ----------

FNO    - The first shot (or RP) to apply the mutes to.  Shot (RP)
         numbers must increase monotonically.
         PRESET=1

LNO    - The last shot (RP) number to apply the mutes to.  LNO must be
         larger than FNO in each list and must increase list to list.
         DEFAULT=FNO

XTP    - RANGE-TIME-PAIRS.  A list of range and tail mute time pairs.
         Mute times for ranges not specified are obtained through linear
         interpolation.  If the range is between two ranges specified.
         traces with a range less than the smallest given range will be
         muted to the mute time of the smallest given range.  Likewise,
         ranges larger than the largest given range will be muted to the
         mute time of the largest given range.  XTP must be given with
         increasing ranges. The program computes the absolute value of
         both user ranges and data ranges.  e.g. xtp 1000 3.0 2000 4.0
         traces with ranges less than 1000 will be muted to 3 seconds,
         traces with ranges greater than 2000 will be muted to 4 seconds,
         and traces with range between 1000 and 2000 will be muted
         proportionately between 3 and 4 seconds.
         PRESET=NONE

TTP    - Trace number-time-pairs.  A list of trace numbers (of a shot or
         RP) and tail mute times (listed in pairs).  The mute time for a
         trace between two traces that are specified is obtained through
         linear interpolation of the mute times of the specified traces.
         Traces with a trace number less than the smallest given will be
         muted to the mute time of the smallest trace number.  Likewise,
         traces with a trace number larger than the largest given will
         be muted to the mute time of the largest given.  TTP must be
         given in increasing trace numbers. e.g. ttp 4 2. 20 5. 
         traces 1 thru 4 will be muted to 2 seconds, traces 20 and up 
         will be muted to 5 seconds, and traces 5 thru 19 will be muted
         proportionately between 2 and 5 seconds.
         PRESET=NONE

XSETS  - Range-start time-end time triples.  A list of range and mute 
         window times.  Only those traces actually specified are muted.
         Sets must be given so that the ranges increase.  The sign of the
         range is ignored since the program uses the absolute value of 
         the trace ranges as well as the ranges specified by the user. 
         e.g.  xsets 1000 2.5 3.0 2000 3.990 4.000  
         Traces with a range of 1000 will be muted from time 2.5 To 3.0
         and traces with a range of 2000 will be muted from time 3.99 to
         4.0 seconds.
         PRESET=NONE 

TSETS  - Trace number-start time-end time triples.  A list of trace
         number and mute window times.  Only those traces actually
         specified are muted.  TSETS must be given so that the trace
         numbers increase.  e.g.  tsets 5 0.9 1.0 15 3.0 4.0
         Trace number 5 will be muted from time .9 to time 1.0 and trace
         15 will be muted from 3 to 4 seconds.
         PRESET=NONE.

ADDWB  - Indicates that the mute times given via XSETS or TSETS will be
         added to the water bottom time of the trace. (Water bottom
         times may be entered via process wbt).
       = YES,  The water bottom time will be added.
       = 2X,  Two times.  The water bottom time will be added twice to 
         XSETS and TSETS.  This is useful for describing "inner mutes"
         where the mute starts at the water bottom multiple.
         PRESET = NO     e.g.  addwb yes

INTERP - A yes/no switch indicating that the start and end 
         times for traces not specified via XSETS/TSETS and XTP/TTP 
         should be calculated by interpolation or "extension".  Traces
         between specified traces will be muted using times linearly
         interpolated.  Traces not between specified traces will be muted
         using the "closest" trace (times held constant).  Shots/rps not
         specified will be calculated through interpolation and
         "extension" in a similar manner.
         Preset = yes for xsets/tsets   e.g.   interp no
         Preset = no for xtp/ttp       e.g    interp yes
 
END    - Terminates each parameter list.

NOTE *****

1)   Either XSETS, TSETS, XTP, or TTP must be given.
2)   All times are in seconds.


Written and copyrighted (C) by: Paul Henkart, 
Scripps Institution of Oceanography, March 1982
All rights reserved.