Seismic waves in the Earth. Surface seismic waves generated by an earthquake arrive at a...

Seismic waves in the Earth. Surface seismic waves generated by an earthquake arrive at a distant observer after the arrival of P waves and S waves (Fig. 12.27B), partly because surface waves travel more slowly than both P and S waves. Even if all these waves had the same velocities, however, the surface waves would still arrive last. Explain why.