Which waves are S waves characterized as?

S waves, or secondary waves, are indeed classified as transverse waves. This classification is based on the nature of how particles move in relation to the wave's direction of travel. In transverse waves, the particles of the medium move perpendicular to the direction of the wave. For S waves, as they propagate through a medium, they cause particles to oscillate up and down or side to side relative to their position, which is characteristic of transverse behavior.

Understanding this classification is crucial, especially in the context of seismic waves. S waves are generated during earthquakes and can travel through the Earth, but they are unable to move through liquids. This property further distinguishes them from other types of waves and highlights their specific behavior within different materials, making them vital in geological studies and analysis of the Earth's internal structure.