SYNOPSIS
PERL PROGRAM NAME:
AUTHOR: Juan Lorenzo (Perl module only)
DATE:
DESCRIPTION:
Version:
USE
NOTES
Examples
SYNOPSIS
SEISMIC UNIX NOTES SUSTATICRRS - Elevation STATIC corrections, apply corrections from
headers or from a source and receiver statics file,
includes application of Residual Refraction Statics
sustaticrrs <stdin >stdout [optional parameters]
Required parameters:
none
Optional Parameters:
v0=v1 or user-defined or from header, weathering velocity
v1=user-defined or from header, subweathering velocity
hdrs=0 =1 to read statics from headers
=2 to read statics from files
sign=1 =-1 to subtract statics from traces(up shift)
Options when hdrs=2:
sou_file= input file for source statics (ms)
rec_file= input file for receiver statics (ms)
ns=240 number of sources
nr=335 number of receivers
no=96 number of offsets
Options when hdrs=3:
blvl_file= base of the near-surface model file (sampled
at CMP locations)
refr_file= horizontal reference datum file (sampled at
CMP locations)
nsamp= number of midpoints on line
fx= first x location in velocity model
dx= midpoint interval
V_r= replacement velocity
mx= number of velocity model samples in
lateral direction
mz= number of velocity model samples in
vertical direction
dzv= velocity model depth interval
vfile= near-surface velocity model
Options when hdrs=4:
nsamp= number of midpoints on line
fx= first x location in velocity model ",
dx= midpoint interval ",
Options when hdrs=5:
none
Notes:
For hdrs=1, statics calculation is not performed, statics correction
is applied to the data by reading statics (in ms) from the header.
For hdrs=0, field statics are calculated, and
input field sut is assumed measured in ms.
output field sstat equals 10^scalel*(sdel - selev + sdepth)/swevel
output field gstat equals sstat - sut/1000.
output field tstat equals sstat + gstat + 10^scalel*(selev - gelev)/wevel
For hdrs=2, statics are surface consistently obtained from the
statics files. The geometry should be regular.
The source- and receiver-statics files should be unformated C binary
floats and contain the statics (in ms) as a function of surface location.
For hdrs=3, residual refraction statics and average refraction statics
are computed. For hdrs=4, residual refraction statics are applied,
and for hdrs=5, average refraction statics are applied (Cox, 1999).
These three options are coupled in many data processing sequences:
before stack residual and average refraction statics are computed but
only residual refractions statics are applied, and after stack average
refraction statics are applied. Refraction statics are often split
like this to avoid biasing stacking velocities. The files blvl_file
and refr_file are the base of the velocity model defined in vfile and
the final reference datum, as described by Cox (1999), respectively.
Residual refraction statics are stored in the header field gstat, and
the average statics are stored in the header field tstat. V_r is the
replacement velocity as described by Cox (1999). The velocity file,
vfile, is designed to work with a horizontal upper surface defined in
refr_file. If the survey has irregular topography, the horizontal
upper surface should be above the highest topographic point on the
line, and the velocity between this horizontal surface and topography
should be some very large value, such as 999999999, so that the
traveltimes through that region are inconsequential.
Credits:
CWP: Jamie Burns
CWP: Modified by Mohammed Alfaraj, 11/10/1992, for reading
statics from headers and including sign (+-) option
CWP: Modified by Timo Tjan, 29 June 1995, to include input of
source and receiver statics from files.
CWP: Modified by Chris Robinson, 11/2000, to include the splitting
of refraction statics into residuals and averages
Trace header fields accessed: ns, dt, delrt, gelev, selev,
sdepth, gdel, sdel, swevel, sut, scalel
Trace header fields modified: sstat, gstat, tstat
References:
Cox, M., 1999, Static corrections for seismic reflection surveys:
Soc. Expl. Geophys.User's notes (Juan Lorenzo) untested
CHANGES and their DATES
Import packages
instantiation of packages
Encapsulated hash of private variables
sub 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 V_r
sub blvl_file
sub dx
sub dzv
sub fx
sub hdrs
sub mx
sub mz
sub no
sub nr
sub ns
sub nsamp
sub rec_file
sub refr_file
sub sign
sub sou_file
sub v0
sub v1
sub vfile
sub get_max_index
max index = number of input variables -1