sftahmute (2.0-git)
index
user/karl/Mtahmute.c
Read Trace And Header (tah) from standard input, MUTE.

 
Synopsis
        sftahmute < in.rsf > out.rsf xmute= tmute= verbose=1 ntaper=12

tah is the abbreviation of Trace And Header. Madagascar programs
that begin with sftah are a designed to:
1- read trace and headers from separate rsf files and write them to
standard output (ie sftahread)
2- filter programs that read and write standard input/output and
process the tah data (eg sftahnmo, sftahstack)
3- read tah data from standard input and write separate rsf files for
the trace and headers data (ie sftahwrite)

These programs allow Seismic Unix (su) like processing in Madagascar.
Some programs have su like names.

Some programs in this suite are sftahread, sftahgethw, ftahhdrmath,
and sftahwrite.

The sftahmute program is designed to mute data. Trace and header data
(tah) are read from standard input (usually a pipe). The trace xmute
and tmute parameter define the mute start time. They are interpolated
to determine the start time for the trace using the trace header
offset. The ntaper defines the length in samples of the taper.

EXAMPLE:

sftahsort input=shots-receivers-23900_headfix.rsf \
sort="xline:600,601 offset" \
| sftahnmo tnmo=0,2,6,10.5,16 vnmo=1500,1500,2250,3250,3700 \
| sftahmute \
xmute=0,20000 tmute=0,20 ntaper=25 \
| sftahnmo \
tnmo=0,2,6,10.5,16 \
vnmo=1500,1500,2250,3250,3700 \
inv=y \
| sftahmakeskey pkey=xline skey=cdpt \
| sftahwrite \
verbose=1 \
label2=cdpt o2=1 n2=100 d2=1 \
label3=xline o3=600 n3=1 d3=1 \
output=mutecmps.rsf \
>/dev/null

sfgrey
In this example the shot organized prestack data in the file
shots-receivers-23900_headfix.rsf are read in xline offset order by
sftahsort program. The headers are in the file
shots-receivers-23900_headfix_hdr.rsf, the headers parameter default.
The headers are merged with the trace amplitudes and the tah data sent
down the pipe for nmo, mute, and inverse nmo. This sequence was used
to apply the mute using times that were selected from a prestack
gather with moveout applied.

The sftahnmo program uses the velocity function defined by the tnmo,
vnmo parameters and the offset header to apply normal moveout to
the traces.

sftahmute zeros the shallow data. TLhe time samples above the line
through (time,offset) pairs (0,0)(20,20000), are set to zero. There
is a 25 point taper applied below the zero portion of the traces.

A second sftahnmo execution applied inverse nmoout. Other than inv=yes
the parameters are the same as in the first sftahnmo.

The program sftahmakeskey is used to create a secondary key used
in the following sftahwrite to define the location to wrte the trace
in the output file. Sftahmakeskey makes a secondary key (skey=cdpt)
the count the traces starting in the a primary key gather (pkey=xline).
The input traces gathered by xline by sftahsort. Sftahmakeskey sets
cdpt to 1 when the trace has a new xline. If the trace has the same
xline as the previous trace cdpt is incremented

Sftahwrite writes the the trace data to mutecmp.rsf and the headers are
written to the file mutecmp_hdr.rsf. The order of the data in the output
file is defined by the cdpt and xline trace headers, so the data order
is (time,cmpt,xline). Finally, the output volume is displayed using
sfgrey.

 
Parameters
       
 
int ntaper=12


number of samples in the taper of the mute.

 
floats tmute=


List of floats the same length as list of floats in the xmute
parameter. The (xmute,tmute) pairs are interpolated using the
trace headers offset to determine trace start time. The mute is
NOT moved based on the first live sample.

[numtmute]
 
int verbose=1


flag to control amount of print
0 terse, 1 informative, 2 chatty, 3 debug

 
floats xmute=


List of floats the same length as list of floats in the tmute
parameter. The (xmute,tmute) pairs are interpolated using the
trace headers offset to determine trace start time. The mute is
NOT moved based on the first live sample.

[numxmute]

 
Used In
       

 
DATA
        teapotdome/firstlook
teapotdome/scdecon
teapotdome/vels
teapotdome/zomig