DOCUMENTATION
SYNOPSIS
PROGRAM NAME: sunmo
AUTHOR: Chang Liu
DATE: Dec 1 2013
DESCRIPTION:
Version: 0.0.1
0.0.2 July 15, 2015 (JML)
0.0.3 Jan 14, 2020 (DLL)
0.0.4 Feb 06, 2020 (DLL)
=head2 USENOTES
Examples
SEISMIC UNIX NOTES
SUNMO - NMO for an arbitrary velocity function of time and CDP
sunmo <stdin >stdout [optional parameters]
Optional Parameters:
tnmo=0,... NMO times corresponding to velocities in vnmo
vnmo=1500,... NMO velocities corresponding to times in tnmo
cdp= CDPs for which vnmo & tnmo are specified (see Notes)
smute=1.5 samples with NMO stretch exceeding smute are zeroed
lmute=25 length (in samples) of linear ramp for stretch mute
sscale=1 =1 to divide output samples by NMO stretch factor
invert=0 =1 to perform (approximate) inverse NMO
upward=0 =1 to scan upward to find first sample to kill
voutfile= if set, interplolated velocity function v[cdp][t] is
output to named file.
Notes:
For constant-velocity NMO, specify only one vnmo=constant and omit tnmo.
NMO interpolation error is less than 1 0.000000or frequencies less than 600f
the Nyquist frequency.
Exact inverse NMO is impossible, particularly for early times at large
offsets and for frequencies near Nyquist with large interpolation errors.
The "offset" header field must be set.
Use suazimuth to set offset header field when sx,sy,gx,gy are all
nonzero.
For NMO with a velocity function of time only, specify the arrays
vnmo=v1,v2,... tnmo=t1,t2,...
where v1 is the velocity at time t1, v2 is the velocity at time t2, ...
The times specified in the tnmo array must be monotonically increasing.
Linear interpolation and constant extrapolation of the specified velocities
is used to compute the velocities at times not specified.
The same holds for the anisotropy coefficients as a function of time only.
For NMO with a velocity function of time and CDP, specify the array
cdp=cdp1,cdp2,...
and, for each CDP specified, specify the vnmo and tnmo arrays as described
above. The first (vnmo,tnmo) pair corresponds to the first cdp, and so on.
Linear interpolation and constant extrapolation of 1/velocity^2 is used
to compute velocities at CDPs not specified.
The format of the output interpolated velocity file is unformatted C floats
with vout[cdp][t], with time as the fast dimension and may be used as an
input velocity file for further processing.
Note that this version of sunmo does not attempt to deal with anisotropy.
The version of sunmo with experimental anisotropy support is "sunmo_a
Credits:
SEP: Shuki Ronen, Chuck Sword
CWP: Shuki Ronen, Jack, Dave Hale, Bjoern Rommel
Modified: 08/08/98 - Carlos E. Theodoro - option for lateral offset
Modified: 07/11/02 - Sang-yong Suh -
added "upward" option to handle decreasing velocity function.
CWP: Sept 2010: John Stockwell
1. replaced Carlos Theodoro's fix
2. added the instruction in the selfdoc to use suazimuth to set
offset so that it accounts for lateral offset.
3. removed Bjoren Rommel's anisotropy stuff. sunmo_a is the
version with the anisotropy parameters left in.
4. note that scalel does not scale the offset field in
the segy standard.
Technical Reference:
The Common Depth Point Stack
William A. Schneider
Proc. IEEE, v. 72, n. 10, p. 1238-1254
1984
Trace header fields accessed: ns, dt, delrt, offset, cdp, scalelCHANGES and their DATES
Juan Lorenzo July 15 2015
introduced "par" subroutine
V0.0.3 Jan 14 2020 automatic use of scalelsub Step
collects switches and assembles bash instructions by adding the program name
sub note
collects switches and assembles bash instructions by adding the program name
sub clear
sub _get_data_scale
get scalco or scalel from file header
instantiate class
sub cdp
sub invert
sub lmute
sub par V0.0.3 1-14-2020 DLL automatic use of data_scale
read par file (assume in m/s or ft/s) scale a new output par file * data-scale assign new output par file
A typical parfile does only handles one gather at a time
instantiate classes
declare local variables
private definitions
read i/p file
scale par file values
write new par file
cat scaled par files
Declare
local variablesSet up a list of files for action
my $file_name_list_in
my $file_name_list_out
my @file_name_list Set up FLOW
RUN FLOW
LOG FLOW(s)
to screen and FILEsend to sunmo
sub par V0.0.3 1-14-2020 DLL automatic use of data_scale
read par file (assume in m/s or ft/s) scale a new output par file * data-scale assign new output par file
A typical parfile does only handles one gather at a time
instantiate classes
declare local variables
private definitions
read i/p file
scale par file values
write new par file
send to sunmo
sub smute
sub sscale
sub set_base_file_name
sub tnmo
sub upward
sub vnmo
sub vnmo_mps
sub voutfile
sub get_max_index
max index = number of input variables -1