S waves shake the ground in a shearing, or crosswise, motion that is perpendicular to the direction of travel. These are the shake waves that move the ground up and down or from side to side. S waves are called secondary waves because they always arrive after P waves at seismic recording stations.

What motion do S waves move?

S waves produce vertical and horizontal motion in the ground surface. Particle motion consists of alternating transverse motion. Particle motion is perpendicular to the direction of propagation (transverse).

Do S waves move horizontally?

S waves, or secondary waves, are the waves directly following the P waves. ... S waves are the more dangerous type of waves because they are larger than P waves and produce vertical and horizontal motion in the ground surface. Both P and S waves are called body-waves because they move within the Earth's interior.