An S wave, also known as a secondary wave or shear wave, is a type of elastic wave that occurs in solid media. It is characterized by its particle motion, which is perpendicular to the direction of wave propagation. S waves are slower than primary waves (P waves) and cannot travel through liquids or gases, only through solids. They are produced by and carry information about shear stresses within the material through which they pass. During an earthquake, S waves are responsible for the side-to-side shaking that can cause significant damage to structures. read more >>

S-wave. noun. The definition of an S wave, or secondary wave, is a wave motion in a solid medium where the medium moves perpendicular to the direction of the travel of the wave. An example of an S wave is when pieces of rock in an earthquake vibrate at right angles to the direction of the seismic wave.read more >>