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Program package ANRAY, version 4.40
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Ivan Psencik,

Geophysical Institute, Acad.Sci. of the Czech Rep.,
Bocni II, 141 31 Praha 4, Czech Republic

Main differences from the version 4.30
--------------------------------------
There are several new options offerred in this version. The most
important are the following:

(a) Examples of scripts for running ANRAY for various situations
are attached.
(b) Possibility to consider the surface water layer was introduced
(c) It is possible to record not only displacement but also pressure.
(d) Conversion coefficients can be evaluated not only at the free 
surface but also at internal interfaces
(e) Implementation of the graphical output using the software developed 
for the CRT package has been simplified.
(f) Many errors and problems have been removed and other small scale
modifications have been made. An error causing a shift (smaller than
time step in seismograms) of seismograms in the routine BPLOT was
removed. Problems with default input data were removed. I shall be 
grateful for indication of problems since with the new options, new 
bugs were surely introduced.


Description of the package
--------------------------
     Program package ANRAY can be used for computation of rays, 
travel times, ray amplitudes and ray synthetic seismograms (for qS 
waves also the QI approximation may be used) in 3-D laterally varying 
structures containing isotropic and/or anisotropic layers. 
Synthetic seismograms can be constructed at receivers distributed 
regularly or irregularly along surface, interfaces or vertical 
profiles.

    Program package consists of ten programs, basic program ANRAY 
and programs WEAKAN, ANRAYPL, SYNTAN, SEISPLOT, POLARPLOT, FRESAN, 
SYNFAN, BPLOT and VELPL.

    Program ANRAY is an updated version of program with the same 
name which has been used in packages ANRAY86 and ANRAY89 written by 
Gajewski & Psencik [1], [2]. It is 
designed for ray, travel time and ray amplitude computations. Two ways 
of approximation of distribution of elastic parameters are available. 
In the first, "B-spline approximation", elastic parameters in an 
arbitrary point of a layer are determined by B-spline approximation 
from values of parameters specified at grid points of a 3-D rectangular 
network. B-splines with tension by A.K.Cline [3] with 
additions by L.Klimes [4], are used. In the second 
way, "isosurface interpolation", elastic parameters are determined 
by vertical linear interpolation of values specified at interfaces, 
which represent surfaces of constant values of elastic parameters. 
Rays can be computed in two modes. In the first one, rays are specified 
by the point source location and the initial orientation of the 
slowness vector at the source: initial-value ray tracing. In 
the second mode, rays are specified by the point source location and 
a system of regularly or irregularly distributed receivers situated on 
surface or on an interface or on a vertical profile: two-point ray 
tracing. The point source can be situated at any point of the model. 
Polarization vectors, geometrical spreading and reflection, 
transmission and conversion coefficients may be evaluated along the rays. 

    Program ANRAY can produce seven files, one for plotting ray diagrams, 
travel times and ray amplitudes in program ANRAYPL, second for computation 
of synthetic seismograms in programs SYNTAN or SYNFAN, third for plotting 
plane sections of slowness, phase velocity or group velocity surfaces
in program VELPL. The remaining four files can be produced to generate 
a VRML file. Program ANRAY consists of 6 blocks of routines, ANRAY.FOR, 
A2.FOR, A3.FOR, A4.FOR, A5.FOR, and MODBS.FOR or MODIS.FOR, which must 
be linked together. If B-spline approximation is to be used, MODBS.FOR 
must be used, if isosurface interpolation is to be used, MODIS.FOR must 
be used. The selection can be made at the end of the file anray.for.
Default is the B-spline interpolation. Refer to the description of program 
ANRAY.

    The program WEAKAN is a first version of the program for the
calculation of qS waves in weakly anisotropic media and in qS wave
singular regions, based on the quasi-isotropic (QI) approximation,
[5]. The two coupled linear differential equations for the calculation 
of frequency-dependent amplitudes in the zero-order QI approximation 
are solved here along rays, which were calculated in the program ANRAY 
in a background isotropic medium. The results are stored in the file 
LU1. The frequency-dependent amplitudes are further used for the 
calculation of synthetic seismograms. At present, the program works 
only in the B-spline mode, i.e., it requires MODBS.FOR routines. 
The program WEAKAN generates a file to be further processed in 
program FRESAN and subsequent programs. Refer to the description 
of program WEAKAN.

    The program ANRAYPL can be used for plotting of horizontal and 
vertical ray diagrams, time-distance and amplitude-distance curves 
of individual elementary waves computed in the program ANRAY and
stored in the file LU1. Several types of point sources, namely explosive 
source, single force, double couple source can be considered. Program 
ANRAYPL is a modification of the program RAYPLOT from the package SEIS83 
[6]. Program ANRAYPL consists of routines: ANRAYPL.FOR, BORDER.FOR, 
SOURCE.FOR and CALCOPS.FOR. Refer to the description of program 
ANRAYPL.

    The program SYNTAN can be used for time domain computation of ray 
synthetic seismograms from the results computed in the program ANRAY 
and stored in the file LU2. Gabor wavelet is used as a source-time 
function. Hilbert transform of this wavelet is evaluated by approximate 
formula, see [7]. Several types of point sources, namely explosive source, 
single force, double couple source, can be considered. Program SYNTAN 
is a modification of the program SYNTPL from the program package SEIS83 
[6]. Program SYNTAN consists of routines: SYNTAN.FOR, SOURCE.FOR and CALCOPS.FOR.
Refer to the description of program SYNTAN.

    Programs FRESAN and SYNFAN can be used for frequency domain 
computation of ray synthetic seismograms. Frequency response is
computed in the program FRESAN from the data generated by the program 
ANRAY and WEAKAN (if the QI approximation is used) and stored in 
the files LU2 (ANRAY) and LU6 (WEAKAN). In the program SYNFAN it 
is multiplied by the spectrum of the considered source-time function. 
Inverse Fourier transform is then used to evaluate synthetic seismograms. 
Programs FRESAN and SYNTAN are modifications of the programs GB and 
SYNTGB from the package BEAM87 by V.Cerveny. Program FRESAN consists 
of routines FRESAN.FOR, BORDER.FOR, SOURCE.FOR and CALCOPS.FOR. Program 
SYNFAN consists of routines SYNFAN.FOR and CALCOPS.FOR. 
Refer to the description of program FRESAN.
Refer to the description of program SYNFAN.

    Programs SEISPLOT, BPLOT and POLARPLOT can be used for plotting 
results computed in progams SYNTAN and SYNFAN. Program SEISPLOT can 
be used for plotting synthetic seismograms generated by the program 
SYNTAN and stored in the file LU4, program BPLOT can be used for 
plotting synthetic seismograms generated by the program SYNFAN and 
stored in the file LU8. The program POLARPLOT serves for plotting 
particle motion diagrams and can be used with two (each file for one
component of the displacement vector) files LU4 generated by the 
program SYNTAN or BPLOT. Programs SEISPLOT and POLARPLOT are 
modifications of the programs with the same name from the package 
SEIS83, program BPLOT is a modification of the program with the same 
name from the package BEAM87. Program SEISPLOT consists of routines 
SEISPLOT.FOR, BORDER.FOR and CALCOPS.FOR. Program BPLOT consists of 
routines BPLOT.FOR, BORDER.FOR and CALCOPS.FOR. Program POLARPLOT 
consists of routines POLARPLOT.FOR, BORDER.FOR and CALCOPS.FOR.
Refer to the description of program SEISPLOT.
Refer to the description of program BPLOT.
Refer to the description of program POLARPLOT.

    Program VELPLOT can be used for plotting plane sections of
slowness, phase velocity and group velocity surfaces from the file
generated in the program ANRAY and stored in the file LU3. Plots in polar 
or Cartesian coordinates can be optionally generated. Program VELPLOT 
consists of routines VELPL.FOR and CALCOPS.FOR. Refer to the description of program 
VELPLOT.

    All files with the main programs (anray.for, weakan.for, anraypl.for, 
syntan.for, fresan.for, synfan.for, seispl.for, bplot.for, polar.for,
and velpl.for) contain, at their ends, Fortran 90 INCLUDE commands to 
include all subroutine files required. It is thus no need to compile 
subroutine files separately and to submit them to a linker.

    FORTRAN77 is used throughout the program package ANRAY. Modified 
CALCOMP routines, namely PLOTS, PLOTN, PLOT, SYMBOL and NUMBER are used 
in plotting programs (2-D graphics). Calcomp-PostScript interface containing 
the above listed routines and developed by L.Klimes, is a part of the 
package. This makes possible to generate the graphical output in the form 
of ASCII files coded in the PostScript level 2 language - encapsulated 
postscript file format version 3.0. The Calcomp-PostScript interface is 
a part of the block of routines CALCOPS.FOR. This block must be linked with 
each program of the package.

    The package is supplemented by a set of test input data.

    The data with extension 'an' are data for a VSP experiment in 
a vertically inhomogeneous model of HTI medium with axis of symmetry 
45 degrees out of the plane containing the source and the borehole. 
The data anray.an are specified for B-spline approximation, 
i.e. for the program ANRAY linked with MODBS. Program ANRAY with these 
data generates "anisotropic" ray results for two qS waves. The data 
anraypl.an are input data for the program ANRAYPL. They generate 
postscript files anrpl1.ps and anrpl2.ps with ray diagrams, 
travel-time and amplitude curves of the two qS waves. The data fresan.ant and 
fresan.anv are input data for 
computation of transverse (t) and vertical components (v) in program 
FRESAN. The data synfan.an are input data for program SYNFAN. 
The data bplot.ant and bplot.anv are input data for plotting
transverse (t) and vertical components (v) in program BPLOT. BPLOT 
generates the postscript files seisant.ps and seisanv.ps with sections 
of ray synthetic seismograms of transverse and vertical components. 
The data polar.an generate the postscript file polatv.ps with 
projections of particle motion diagrams into the transverse-vertical 
plane.

   The data with extension 'qi' are data for the same experiment as
the data above ('an') but the computations are based on the QI 
approximation. The data anray.qi are specified for an isotropic model 
forming a background of the model 'an'. Again, B-spline approximation 
is used. Program ANRAY with these data generates "isotropic" ray 
results for an S wave. The data anraypl.qi are input data for the 
program ANRAYPL. They generate postscript file anrplis.ps with ray 
diagram, travel-time and amplitude curves of the S wave. The data 
weak.qi are the input data for the program WEAKAN, in which the two 
coupled differential equations of the QI approximation are solved. 
The data fresan.qit and fresan.qiv
are input data for computation of transverse (t) and vertical components (v)
in program FRESAN. The data synfan.qi 
are input data for program SYNFAN. The data and bplot.qit
and bplot.qiv are input data for plotting
transverse (t) and vertical components (v) in program BPLOT. BPLOT
generates the postscript files seisqit.ps and seisqit.ps with section of 
synthetic seismograms of transverse and vertical components in the QI 
approximation. The data polar.qi generate 
the postscript file polqtv.ps with projections of particle motion 
diagrams into the transverse-vertical plane.

   The data with extension 'chs' are data for another VSP experiment
based on the ray computations in a model, in which isosurface 
approximation is used. It means that the program ANRAY must be 
linked with MODIS in this case. Program ANRAY with the data 
anray.chs generates "anisotropic" ray results for a qP wave and 
two qS waves. The data syntan.chs and seispl.chs 
are input data for programs SYNTAN and SEISPL. They generate the postscript file 
seischs.ps with section of ray synthetic seismograms of a vertical 
component of displacement vector.

   The data with extension 'rfr' are data for a refraction/reflection 
experiment based on the ray computations in a model, in which isosurface 
approximation is used. It means that the program ANRAY must be 
linked with MODIS. Program ANRAY with the data anray.rfr 
generates a VRML file rfr.wrl for 3-D image of model and rays of qP 
refracted and reflected waves. 

    The data anray.vel are the input data for the ANRAY program, 
generating a file for plotting a section of the phase velocity 
surface in the program VELPL. The section is calculated in the 
above model 'an', close to the model surface. The data velpl.vel 
are the input data for the program VELPL. They generate a postscript 
file phvel.ps.

    In case of publication of results obtained with the program        
package ANRAY, the users are asked kindly to refer to this report.

Good luck!

Praha, May 2002


REFERENCES
                                                        
[1] Gajewski,D., Psencik,I., 1986. Numerical modelling of seismic
    wave fields in 3-D laterally varying layered anisotropic
    structures - Program ANRAY86, Internal Report Inst.of Earth and
    Planet.Phys., University of Alberta, Edmonton.
                                                        
[2] Gajewski,D.,  Psencik,I.,1989. Ray  synthetic seismograms  in 3-D
    laterally inhomogeneous anisotropic structures - Program ANRAY89,
    Internal  Report   Centre  for  Computational   Seismology,  LBL,
    Berkeley.
                                                        
[3] Cline,A.K.,1981. FITPACK, Dept. of Computer Sciences, Univ. of 
    Texas at Austin.
                                                        
[4] Cerveny,V., Klimes,L., Psencik,I.,1988. Complete seismic ray
    tracing in three-dimensional structures. In: Seismological
    Algorithms, D.J.Doornbos edit., Academic Press, New York, pp.89-168.
                                                        
[5] Psencik,I.,1998. 1998.  Green's functions for inhomogeneous weakly 
    anisotropic media. Geophys.J. Int., 135, 279-288.
                                                        
[6] Cerveny,V., Psencik,I.,1984. Documentation of earthquake
    algorithms. SEIS83 - Numerical modeling of seismic wave fields
    in 2-D laterally varying layered structures by the ray method.
    E.R.Engdahl, edit., Report SE-35, Boulder, 36-40.
                                                        
[7] Cerveny,V., Molotkov,I.A., Psencik,I.,1977. Ray method in seismology,
    Univerzita Karlova, Praha.