## Flexi Says: The speed of S-waves varies slightly depending on the rock types that the seismic waves are moving through. Typical S-wave speeds are about 1-8 km/sec. S-waves are slower than P-waves, and scientists can determine the location of an earthquake epicenter using the difference in the arrival time of S-waves and P-waves at three different seismograph stations. If the epicenter location is known, the speed of S-waves between the epicenter and a seismograph station can be calculated using the formula Speed = Distance/Time, using the distance between the epicenter and the station and the time it took for the S-waves to arrive at the station.