Program Hypotable: iaspei-tau

The ./iaspei-tau directory has the source code and Makefile for the iaspei-tau traveltime table package (February 1996 version) and program Hypotable. The program ttimes differs from the one which comes with the iaspei-tau distribution in that it includes a few more options, like allowing distances in km, giving the take-off angle for each ray, and printing a detailed output file in parallel with the terminal output. The source language is Fortran 77, and, as written, compiles on two Sun Microsystems platforms, Sunos 4.1.4 and Solaris 2.x. The -Bstatic option has been used in producing the executables, which increases portability. Executables are put in subdirectory ../bin (defined relative to directory ./iaspei-tau).

The original 1991 release of the iaspei-tau package and its 1992 update are hard-wired to handle only the iasp91 velocity structure, which it did through polynomial fits within designated layers for the velocities and density. In 1991 I changed subroutine emdlv.f so that it could read in a v-z model from a file. (In 1992 I replaced the linear interpolation in this subroutine with cubic-spline interpolation.) File ./build-tables/iasp91.mod is the iasp91 model in the format expected by emdlv. The February 1996 version of the package added a few core phases and included a variant of my emdlv.f for reading velocity models from files. (It also includes model and table files for model ak135.) For more information about the iaspei-tau package, look at ./iaspei-tau/README_tau, written (mostly) by Ray Buland (USGS). The 1996 release for Unix and earlier releases for other operating systems can be gotten by anonymous ftp from the USGS. (The 1996 release used here is in the subdirectory experimental.)

Program Hypotable requires three input files: the ascii text velocity model file (xxx.mod), and two binary files produced by the iaspei-tau package (xxx.hed and xxx.tbl). If one simply wants to use the iasp91 model and iaspei-tau-package format tables, one can just use the files for the iasp91 model which come with this distribution. If one wants to use a different velocity structure, one follows the following procedure: First one creates an ascii model file in the same format as iasp91.mod. One then runs two program from the iaspei-tau package: first remodl and then setbrn. All other input comes from prompts. The output from this two-program sequence is two binary files: here IASP91.hed and IASP91.tbl. The code is optimized for the iasp91 model, so this procedure may not work for models which differ significantly from that model. (Using rsetbrn a stripped-down version of setbrn with only the main P and S branches, may help.) Cases for which this procedure has been applied by the authors have not used core phases, so the models differed from iasp91 only in the (two-layer) crust and the uppermost mantle.

Linking program Hypotable requires subroutines included in libiasp.a (which is produced by running the Makefile in ./iaspei-tau). As written, it requires that the the .tbl, .mod, and .hed files are all in the directory from which the program is being run.

The files (with their most recent modification dates) in directory ./iaspei-tau are as follows:

Modif.  date     name           comment
Jun 22  1992    emdlv.f	        jas/vt version of the iasp91 subroutine
Apr 29  2002    hypotable.f     source code in f77
Jun  5  1992    libsun.f        part of the iasp91 package
Oct 28  1998    libtau.f        part of the iasp91 package
Jun  5  1992      part of the iasp91 package
Apr 21  2001    Makefile        unix makefile for libiasp.a and all executables
Jun 17  1995    README_tau      Ray Buland's readme file for the iasp91 package
Jan 14  2000    remodl.f        source file in iasp91 package
Jan 14  2000    rsetbrn.f       source for stripped-down setbern (jas/vt)
Jan 14  2000    setbrn.f        source file in iasp91 package
Jun 22  1993	        man page realted to iasp91 package
Apr 26  2002    ttimes.f        source file for my version of ttimes
Jun  5  1992       part of iasp91 package

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