FAST
3-D First Arrival Seismic Tomography programs

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

A new program package for 3-D (and 2-D) first arrival traveltime tomography can be obtained by using anonymous FTP from 128.42.14.7 in czelt, or click on one of the buttons below. The key features of the method are:

  • sources and receivers may be anywhere in the model
  • traveltimes and raypaths calculated efficiently using an eikonal solver that is valid for strongly contrasted media
  • regularized inversion using a user-specified combination of smallest, flattest, and smoothest perturbation constraints relative to a background model
  • different grid sizes for forward and inverse parameterization
  • efficient solution of sparse linear system using LSQR variant of conjugate gradient technique
  • interface may be specified above which model remains fixed
  • size of velocity update may be bounded at each iteration
  • interactive plotting of raypaths, models, time files, interfaces, etc., and GMT scripts for plotting models

    The package is one compressed tar file (4.3 Mb). There are 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. 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.

    Zelt and Barton (1998) describes the forward traveltime calculation and most of the tomography methodology; citing this paper would be appropriate.

    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 fast package, I like to keep track of where it has gone. Thanks.

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

  • Download gzip-compressed fast package (4 Mb)

  • Download uncompressed fast package (20 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 fast, and what type of data you plan to apply fast to.

  • Map of fast sites

    ZPLOT

    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.

    OTHER RELATED SOFTWARE AND WEB SITES

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

  • Patch to install FAST under Linux is available here. Thanks to Drew Brenders for creating this.
  • A fortran-based interactive program for viewing slices through 2-D and 3-D FAST files, such as velocity models, as well as 2-D GMT grd files, 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