Seismic reflections. Seismic waves will be reflected at “discontinuities” in elastic properties A new ray emerges, heading back to the surface Energy. - ppt download
Updates to the Regional Seismic Travel Time (RSTT) Model: 2. Path-dependent Travel-time Uncertainty | Pure and Applied Geophysics
Travel time curves
Remote Sensing | Free Full-Text | An Envelope Travel-Time Objective Function for Reducing Source–Velocity Trade-Offs in Wave-Equation Tomography
geophysics - How does multiple layer seismic reflection work? How do we distinguish arrivals from different layers and their velocities? - Earth Science Stack Exchange
Geophysics: Seismic - the critical refraction - YouTube