Question

Why does the difference in arrival times of P and S waves increase at seismograph recording stations that are farther away from the epicenter?

Answer 1

This difference increases because p-waves travel faster than s-waves. Therefore, if a seismograph is far from the epicenter, readings of the p-waves will arrive first, but since those waves travel faster than s-waves, it might be a bit longer before readings of the s-waves appear.