The TauP Toolkit is a seismic travel time calculator. In addition to travel times, it can calculate derivative information such as ray paths through the earth, pierce and turning points. It handles many types of velocity models and can calculate times for virtually any seismic phase with a phase parser. It is written in Java so it should run on any Java enabled platform. Unfortunately, gjc, which comes with many Linux distributions, is not quite Java and prevents TauP from finding its model files. Please use Java from Sun on Linux instead.
We have released the next version of TauP, TauP-2.3.0, which is more accurate for long phases like PKPPKP and allows receivers at depth.
The documentation for TauP is available as a PDF document. You can download the zip file or the tar.gz version containing a draft and the source images of our paper submitted to the Seismological Research Letters.
If you would like TauP and would like to cite it, please use the following: Crotwell, H. P., T. J. Owens, and J. Ritsema (1999). The TauP Toolkit: Flexible seismic travel-time and ray-path utilities, Seismological Research Letters 70, 154–160.
The TauP Toolkit source code is hosted on github here: https://github.com/crotwell/TauP.