*********************************** Program package ANRAY, version 4.10 *********************************** Ivan Psencik, Geophysical Institute, Acad.Sci. of the Czech Rep., Bocni II, 141 31 Praha 4, Czech Republic *************************************** Working version, not yet fully debugged *************************************** Main differences from the version 4.01 -------------------------------------- There are several new options offerred in this version. The most basic are the following: (a) The first test version of program WEAKAN based on the zero-order quasi-isotropic (QI) approximation for calculation of coupled qS waves in weakly anisotropic media or in singular regions of qS waves was developed. (b) The input data are read in by list-directed input (free format). (c) Many errors and problems have been removed and other small scale modifications have been made. Substantial changes were made in program VELPL for plotting various velocity surfaces, smaller changes were also made in the program ANRAYPL. Tests were indroduced, which guarantee that polarization vectors vary smoothly along a ray and do not jump by 180 degrees. The x- and y-components of displacement, which were incorrectly called "radial" and "transverse" in previous versions are called x- and y-components. Possibility to rotate horizontal axis, to which displacement is projected, was introduced to SYNTAN. 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, also used in [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 three files, one for plotting ray diagrams, travel times and ray amplitudes, second for computation of synthetic seismograms and third for plotting plane sections of slowness, phase velocity or group velocity surfaces. 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 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. As input file, it requires a file generated in program ANRAY (for background isotropic medium). 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. 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. 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). 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, program BPLOT can be used for plotting synthetic seismograms generated by the program SYNFAN. The program POLARPLOT serves for plotting particle motion diagrams and can be used in both cases. 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. 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. 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 'ani' 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.ani 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.ani 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.ani, synfan.ani and bplot.ani are input data for programs FRESAN, SYNFAN and BPLOT. They generate the postscript file seisanv.ps with section of ray synthetic seismograms of a vertical component. The data polar.dat generate the postscript file polatv.ps with projections of particle motion diagrams into the transverse-vertical plane if files with ray synthetic seismograms generated by BPLOT for vertical and transverse components are available. The data with extension 'qi' are data for the same experiment as the data above ('ani') 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 'ani'. 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.qi, synfan.qi and bplot.qi are input data for programs FRESAN, SYNFAN and BPLOT. They generate the postscript file seisqiv.ps with section of synthetic seismograms of a vertical component in the QI approximation. The data polar.dat may generate the postscript file polqtv.ps with projections of particle motion diagrams into the transverse-vertical plane if files with QI synthetic seismograms generated by BPLOT for vertical and transverse components are available and if the name "polqtv.ps" is specified in the input data. 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 porgram 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 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 'ani', 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, September 1998 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.,1997. Green functions for inhomogeneous weakly anisotropic media. In: Seismic Waves in Complex 3-D Structures, Report 6, Dept.of Geophysics, Charles University Prague, pp.263-282. [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.