Answer:
arrival times
Explanation:
P waves (Primary waves) and S waves (Secondary waves) are the two types of mechanical waves emitted during an earthquake. The main difference between the two waves is their speed: in fact, P waves are much faster than S waves. Moreover, P waves can travel through solids and liquids, while S waves can travel through solids only. Because of their difference in speed, the S waves take more time than the P waves to go from the epicenter to the seismograph, therefore their arrival time is different and this difference in arrival time can be used to estimate the distance of the epicenter.
