bdat - BSU program datums refraction data for easier first break picking (C-Language Version)
bdat [ -h | infile | vel | iapply ]
Basic Seismic Utilities (BSU) program computes and applies static shifts to refraction data in order to make first break picking easier. The shot charge is corrected to the surface elevation of the shot hole, sz, by applying an overburden velocity over the shot depth, sd (no shot correction if a surface source). The geophone correction will adjust times so that the record will appear as if the geophone were at the same elevation as the surface of the shot hole, sz. The intended use is to make refractor arrivals easier to identify and pick. On rough terrain, first arrivals will undulate, and this program tends to straighten the data. If the datumed data are picked for first arrivals, and the picks stored in the headers with program bpic (also see header value hd.mst in c_bsegy.h), then the reverse application will restore the data to recorded time, and the picks will also be adjusted in the headers. This assumes that the same overburden velocity is used for both datuming and restoring the data. C-Language Version.
Options
|
-h |
Online help giving details on command line arguments | ||
|
infile |
Input file name | ||
|
vel |
Overburden velocity. For p-waves, this will be typically in the range of 500 to 1000 m/s in partially saturated soils. Examine the uphole times for a good value. | ||
|
iapply |
Application direction switch |
1=adjust data to shot elevation datum.
-1=restore data back to original time.
NOTE:
If invoked with no options, will prompt user for input
parameters. The static shift is computed as follows:
sz=shot hole elevation
sd=shot depth
gz=geophone elevation
static=(sz-sd-rz)/vel
EXAMPLE:
bdat w001.seg 600. 1
File w001.seg is processed by bdat. Data are shifted to datum with overburden velocity of 600 m/s.
bdatxxxx.seg
named according to convention (first 4char bdat, the next 4char are the first 4char of the input file name, suffix .seg)
standard output
produces a progress bar
bdatxxxx.lst
Echo check of input parameters in listing file, plus a table of statics applied.
bdatxxxx.dat
File with trace number and static shift in seconds.
bhelp(1), bpic(1), c_bsegy(5)
no known bugs
Copyright © 2017 by Paul Michaels
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
P. Michaels, PE. <pm@cgiss.boisestate.edu>