What is a travel-time curve that shows the relationship between the travel time of a given type of wave?

A travel-time curve is a graphical representation that illustrates the relationship between the travel time of seismic waves and their distance from a seismic source. It typically plots the travel time on the vertical axis against the distance on the horizontal axis, showing how different types of waves (such as P-waves and S-waves) propagate through various geological materials. The curve helps geologists and seismologists determine the depth and location of seismic events by analyzing the arrival times of these waves at various monitoring stations. Each wave type has a distinct slope on the curve, reflecting its speed and the medium it travels through.