disper - Computes dispersion curves for Rayleigh Waves in a plane layered elastic earth
disper [ infile ]
Compatible with Basic Seismic Utilities (BSU), this program computes Rayleigh wave dispersion curves in an elastic, 1-D layered earth. The input file is usually named disper.d and contains namelist parameters required by disper.
One begins by generating the input file first. Run the program gendis. The output of gendis is usually called disper.d and becomes the input to disper. The output of disper includes a file (typically named earth.crv) which contains the dispersion curve information for up to 9 modes. This file then becomes the input for the companion program, waves which computes synthetic Rayleigh wave seismic records. These seismic files are BSU compatible.
The model is described by control points. Between control points, a number of layers are generated, depending on the value of parameter deltz. Running disper will produce a file, model.m, which can be used to plot the model and confirm that the intended model was actually the one computed. Fortran 77 Version.
Namelist
Variables
nlay = number of control points
rho = density at control point (kg/m^3)
mu = shear modulus (Pa)
lame = Lame’s constant (Pa)
zi = depths (+down) specifying control points for properties
deltz = layer thickness to step between control points.
This parameter is important, and changes the model even when control points remain same. Always check the Octave plot file, model.m to make sure you are computing the intended model.
The meaning of this parameter changes if pvlcty not equal to zero. In that case, a previously determined solution is input (fixing the model), and deltz controls the spacing between points computed for the motion-stress vectors.
modemx = maximum number of
modes 1<=modemx<=9
nfreq = number of frequencies computed
flo = starting frequency (will be adjusted to a multiple of
delf)
delf = frequency increment ( reciprocal of aperture for
waves, 1/(N*dt)
)
jsmax = controls wave number increment in search. Set to
300.
ksw=0 plot phase velocity vs. frequency
ksw=1 plot wave number vs. frequency
pvlcty = 0 then compute dispersion
= phase velocity (m/s), switches from dispersion to compute motion-stress vector as function of depth (requires pfreq and zend to be specified)
pfreq = 0 compute dispersion
= value from previous dispersion run, must agree with pvlcty.
zend = maximum depth to compute
and plot motion-stress vectors (see
file mat2.m).
ofile = output listing file name to create (disper.tmp)
octav1 = dispersion plot Octave file name to create
(phase.m)
octav2 = motion-stress vector Octave plot file name to
create (mat2.m)
curve = dispersion curve file of frequency and wavenumbers
name to
create (earth.crv)
Options
infile This is the name of the file with the namelists.
Typically this file is called disper.d, it is easily
generated by the program gendis.
NOTE:
If invoked with no options, will prompt user for the input
file name only.
EXAMPLE:
disper disper.d
File disper.d is processed by disper.
earth.crv
name of file with dispersion curves. Name can be set in file disper.d
standard output
produces a listing on the fly of the dispersion curve
disper.tmp
Saved output very similar to standard output, gives input parameters and listing of the dispersion curve.
phase.m
phase velocity dispersion plotting procedure for execution by Octave
model.m
velocity model plotting procedure for execution by Octave
|
mat2.m |
motion-stress vector plot when pvlcty not zero |
gendis(1), genwave(1), waves(1), showmdl(1), halfsp(1)
no known bugs
Copyright © 2024 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. <[email protected]>