…recording station faster than the secondary, or S, wave. P waves, also called compressional or longitudinal waves, give the transmitting medium—whether liquid, solid, or gas—a back-and-forth motion in the direction of the path of propagation, thus stretching or compressing the medium as the wave passes any one point in a…

…type of body wave, the S wave, travels only through solid material. With S waves, the particle motion is transverse to the direction of travel and involves a shearing of the transmitting rock.

…body: P waves (primary) and S waves (secondary). P waves are compressional waves and travel at the highest velocity; hence, they arrive first. S waves are shear waves that travel at a slower rate and are not able to pass through liquids that do not possess shear strength. In addition,…

…of earthquake waves exist: the S-wave, a transverse body wave; the P-wave, a longitudinal body wave; and the L-wave, which propagates along the boundary of stratified mediums. L-waves, which are of great importance in earthquake engineering, propagate in a similar way to water waves, at low velocities that are dependent…

… in the direction of propagation), S waves (transverse waves—that is, waves that vibrate at right angles to the direction of propagation), and surface waves (compression waves with no vertical or longitudinal components). In the case of distant earthquakes or of nearby very large earthquakes, the seismogram pattern is more complicated…