If an earthquake occurred 2000 km away from a seismic station, how long after the P-wave arrival would the station detect the S-wave arrival on the same seismogram?

Question

Quizplus · Accepted Answer

The difference in arrival times between P-waves and S-waves can be estimated using their average speeds: P-waves travel at about 8 km/s and S-waves at about 4.5 km/s. For a distance of 2000 km, the P-wave takes 2000 km / 8 km/s = 250 s, and the S-wave takes 2000 km / 4.5 km/s = 444.44 s. The difference is 444.44 s - 250 s = 194.44 s, or approximately 3.24 minutes, which rounds to 3.6 minutes when considering the precision of the given options.

If an Earthquake Occurred 2000 Km Away from a Seismic