The secondary seismic wave, which travels more slowly than the P wave and consists of elastic vibrations transverse to the direction of travel. S waves cannot penetrate a liquid.
A type of seismic wave that is a transverse, or shear, wave, and which can travel only through rigid materials.
(abbreviation for secondary wave) body wave that causes the rocks along which it passes to move up and down perpendicular to the direction of its own movement. See also P wave.