2-D traveltime inversion and amplitude modeling programs

Written by Colin Zelt (Department of Earth Science, Rice University, Houston, TX)

The latest package of programs for 2-D ray tracing, traveltime inversion, amplitude calculation and synthetics can be obtained using anonymous FTP from our public directory here at Rice University (, or click on one of the buttons below. It is one compressed tar file (0.3 Mb) in the directory rayinvr. There are read.me files, examples and documentation with the programs that should explain everything. Also, there are make files to generate x-windows graphics versions of all programs that also produce (color) postscript files (as well as UNIRAS versions as before). There is a new version of dmplstsqr (called smoothlsqr) that uses first-derivative smoothing regularization.

All programs in this package are written in Fortran 77 except one program in the pltlib directory for x-windows graphics which is written in C. For the five main graphics programs, rayinvr, tramp, vmodel, pltsyn and rayplot, there is a makefile (for unix users) to make two versions of each program. The first is for users who have access to the commercial graphics package called Uniras. The second version, prefaced by the letter x (i.e., xrayinvr for rayinvr), is intended for users who have access to the X11 graphics libraries. This version of each program will allow screen graphics and generation of black & white or color postscript files. Alternatively, a read.me file explains how to attach your own local graphics system.

Zelt and Smith (1992) describes the methodology and citing this would be appropriate. Zelt and Ellis (1988) presents the original forward modeling code and the method of amplitude calculation used by tramp. Zelt and Forsyth (1994) present many new features of the programs, such as floating reflectors and combining amplitude modeling with traveltime inversion. Zelt (1999) is a review-style paper on modeling strategies and model assessememt which may be helpful for anyone working with wide-angle data. Zelt et al. (2003) presents four real data case studies which apply the two main methods advocated in Zelt (1999).

If you have any questions, suggestions, or bugs, let me know by e-mail. Do not distribute the code to anyone outside your immediate group, but refer interested persons to me directly. None of the programs in any form provided in this package are to be used by you, or transferred to someone, for financial gain or used in a private company as part of its business.

Please let me know if you take a copy of the rayinvr package, I like to keep track of where it has gone. Thanks.

Note: the input parameter "iroute" is out of date; it should be ignored. To obtain a postscript file (called p.out), use iplot=0 or 2.

FLOWCHART summarizing the programs and input/output files of the intended rayinvr modeling steps is available here.

Please do not ask me questions about installing rayinvr on a specific computer platform, since I have no experience with this other than on a Sun Unix system.

  • Download gzip-compressed rayinvr package (0.3 Mb)

  • Download uncompressed rayinvr package (1.6 Mb)

  • If you cannot download for some reason, send a message to czelt@rice.edu and I will e-mail the package to you. In your e-mail, please include your name, position, institute, location, how you heard about rayinvr, and what type of data you plan to apply rayinvr to.

  • Map of rayinvr sites


    I also have a program package called zplot for interactive plotting and picking of seismic data. It is specifically designed for 2-D and 3-D wide-angle data. You must convert your data from segy format to z-format using the program provided called sgy2z. Documentation and an example are provided, however the documentation is not very detailed, so you will have to look carefully at the codes, example and documentation to figure it out. Please e-mail me if you take a copy of this code.

  • Download gzip-compressed zplot package (0.4 Mb)

  • Download uncompressed zplot package (0.8 Mb)

  • If you cannot download for some reason, send a message to czelt@rice.edu and I will e-mail the package to you. In your e-mail, please include your name, position, institute, location, how you heard about zplot, and what type of data you plan to apply zplot to.


    Note: please contact the authors directly with questions about their software.

  • Patch to install rayinvr under Linux and Max OS X is available here. Thanks to Scott Pearse for creating this.
  • A fortran-based interactive editor for rayinvr velocity model files is available here.
  • A graphical user interface (RayGUI) for interfactive ray tracing is available here. The manual for this is available here.
  • A version of rayinvr that works in spherical coordinates to allow for earth curvature is available from Andrew Gorman.
  • GRAVMOD: a 2D gravity modeling program is available here.

    Rice University
    Department of Earth Science, MS-126
    P.O. Box 1892
    Houston, TX 77251-1892

    (713) 348-4757 (office)
    (713) 348-5214 (fax)

    e-mail: czelt@rice.edu