taup

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.
More info and docs at https://www.seis.sc.edu/TauP