An earthquake has just occurred. Seismic waves from the earthquake are detected at two recording stations. At Recording Station A, T = 45 s. At Recording Station B, T = 100 s. Which recording station is farther away from the epicenter?

Answer is: Recording Station B is farther from the epicenter than Recording Station A.

The distance between the beginning of the first P (pressure wave) and S wave (secondary waves), shows how many seconds the waves are apart.

This number is used to tell how far seismograph is from the epicenter of the earthquake.