NAME
hspec91p - evaluate F(f,p) for plane wave (tau-p) elastic
modeling
VERSION
(2.0) - New Formulation
(3.0) - Added Kjartansson (1979) constant Q operator
AUTHOR
R. B. Herrmann, Saint Louis University, 1991
LANGUAGE
FORTRAN 77
LIBRARY REQUIRED
None
Computations are performed in complex double precision. The
following non-standard double precision complex routines are
required: zsqrt(), zabs(), dcmplx(), and zlog().
SYNOPSIS
hspec91p
[-O name4 ]
[-tmax tmax ]
[-dt delt ]
[-pmax pmax ]
[-pmin pmin ]
[-pnum pnum ]
[-F fref ]
[-K]
[-SD]
[-SU]
[-SPUP]
[-SPDN]
[-SSUP]
[-SSDN]
[-RD]
[-RU]
[-RPUP]
[-RPDN]
[-RSUP]
[-RSDN]
[-?]
DESCRIPTION
The purpose of this program is to evaluate the medium p-t
response for sixteen basic Green's functions as a function
of distance and frequency. The Green's functions are for a
point vertical downward force, a point horizontal force, a
point explosion, and double couple earthquake sources.
The meaning the the command line arguments are as follow:
-F fref
Set the reference frequency for causal Q. (fref = 1.0
is the default).
[-K ]
Use Kjartansson Constant Q operator instead of the
Futterman operator (default = Futterman). Causal Q
means that the layer velocity is complex.
[-SD]
Perform wavefield separation at source to consider only
downgoing waves from the source. Default no separation
done at the source.
[-SU]
Perform wavefield separation at source to consider only
upgoing waves from the source. Default no separation
done at the source.
[-SPUP]
[-SPDN]
[-SSUP]
[-SSDN]
These permit wavefield separation at the source for
upgoing and downgoing P and upgoing and downgoing S,
respectively. The values are logically additive. The
-SUP is equivalent to -SPUP -SSUP together. Default no
separation done at the source. Due to the nature of the
wavefield at low frequencies mathematically correct
linear trends may be seen if the P-wave contribution is
desired independently of the corresponding S-wave.
[-RD]
Perform wavefield separation at receiver to consider
only downgoing waves from the source. Default no
separation done at the receiver.
[-RU]
Perform wavefield separation at receiver to consider
only upgoing waves from the source. Default no separa-
tion done at the receiver.
[-RPUP]
[-RPDN]
[-RSUP]
[-RSDN]
These permit wavefield separation at the receiver for
upgoing and downgoing P and upgoing and downgoing S,
respectively. The values are logically additive. The
-SUP is equivalent to -RPUP -RSUP together. Default no
separation done at the source. Due to the nature of the
wavefield at low frequencies mathematically correct
linear trends may be seen if the P-wave contribution is
desired independently of the corresponding S-wave.
Note that this may not be too useful for receivers at
the free surface since these options do not permit
separation of the wavefield for free surface motion for
incident P or incident S because of the difficulty of
separating the composite reflected P and S wavefields.
The use of these flags is a filtering operation applied
to the true motion. These receiver flags may have value
for receivers at depth, as for VSP.
[-?]
Do not run the program. Provide online help for command
line arguments.
MODEL INPUT (UNIT 05)
The control input for the model and the source and receiver
depths is on UNIT LIN:
-Oname4
Enter the name of output file containing the F(f,r)
spectra. No default.
-alphaalpha
Enter the time domain damping.
-dtdelt
Enter the sampling interval in ms. No default.
-tmaxtmax
Enter the maximum trace time (ms). No default.
-pminpmin
Enter the minimum ray parameter. Default = .0000001
-pmaxpmax
Enter the maximum ray parameter. No default.
-pnumpnum
Enter the number of ray parameters desired. No default.
-typeieqex
Enter the control for Green's functions computed. The
choices are as follows:
= 0 : earthquake and explosion
= 1 : point force and explosion
= 2 : earthquake, explosion and point force
= 3 : explosion only
= 4 : earthquake only
= 5 : force only
-surfisurf
Enter the surface flag (see explanation below). Default
= 1
-halfihalf
Enter the half space flag (see explanation below).
Default = 0
surface = 0 - elastic
1 - free
2 - rigid
halfspace = 0 - elastic
1 - free
2 - rigid
e.g., surf = 1, half = 1 consists of a model with both
surfaces free, and surf = 0, half = 0 consists of a
model inserted into a wholespace, with the property of
the upper halfspace equal to that of the first layer in
the model, and that of the lower halfspace equal to
that of the last layer of the model.
LINE 1
read(LIN,*)mmax
mmax - number of layers in the model
LINE 2 (mmax lines)
read(LIN,*)
(d(i),a(i),b(i),rho(i),qa(i),qb(i),i=1,mmax)
d - layer thickness - if d(mmax) is zero, the layer
thickness will be internal increased to permit sources
at deeper depths, however, this may not be what is
desired if the base boundary condition is not that of
an elastic halfspace.
a - compressional wave velocity
b - shear wave velocity
rho - layer density
qa - compressional wave quality factor, or its inverse,
for the layer. The program ASSUMES Q $ >=$ 1. If a
smaller value is input, it is ASSUMED to be inverse Q.
qb - shear wave quality factor, or its inverse, for the
layer. The program ASSUMES Q $ >=$ 1. If a smaller
value is input, it is ASSUMED to be inverse Q.
LINE 3
read(LIN,*)mdpths
mdpths
- number of source depths for which synthetics are
desired
LINE 4 (mdpths lines)
do 2008 i=1,mdpths
read(LIN,*)depths(i)
2008 continue
depths(i)
- depth of source
LINE 5
read(LIN,*)mdpthr
mdpthr
- number of receiver depths for which systhetics are
desired
LINE 6 (mdpthr lines)
do 2009 i=1,mdpthr
read(LIN,*)depthr(i)
2009 continue
depthr(i)
- depth of receiver
LINE 7
THEORY
(see hardcopy available on request):
DIAGNOSTIC OUTPUT
Diagnostic output is placed on UNIT 06. The desired spectra
are written onto UNIT 04 in unformatted, sequential access.
SEE ALSO
hspec91(1), rhfoc(1)
SAMPLE DATA SET
Plane Wave Response to Simple Layer Over 1/2-Space
Below is a script that computes the plane wave resopnse for
a simple layer ober a 1/2-space. The thickness is 2500
(units), the p-wave speeds are 8000 and 8500 in the layer
and 1/2-space respectively. The corresponding s-wave speeds
are 2300 and 3063 and the densities are 2.3 and 2.4. The
inverse p and s Qs are .001 and The ray parameters go from
normal incidence to .0005 in 20 steps.
# SITE RESPONSE
#!/bin/sh
cat > hspec91.dat << EOF
2
0.2500E+04 0.7000E+04 0.2300E+04 0.2300E+01 0.1000E-02
0.1000E-02
0.0000E+00 0.8500E+04 0.3063E+04 0.2400E+01 0.1000E-02
0.1000E-02
1
100
1
50
EOF
hspec91p -Oswae -tmax2000 -dt4 -pmax.0005 -pnum20 <
hspec91.dat > outssup.sed
rhfoc -fswae-t -l8 -P \|
gasp -Ojunk11 -rec
Man(1) output converted with
man2html