Incorporated Research Institutions for Seismology, IRIS, provides an educational visualization tool to aid in teaching about global seismology. Specifically it simulates how P-waves and S-waves travel from the epicenter on the surface of the Earth as well as through Earth’s interior.
It also provides annotations of each travelling ray as it reflects or refracts through the different layers along with their corresponding seismograms. Check it out here (opens in a new tab).
If you are a student, teacher, or just interested I invite you to check out the various learning and teaching resources available from IRIS.