Table 1:  Seismic Waves – S-wave                    Back

SShear, Secondary, Transverse

Particle Motion

Typical Velocity

Other Characteristics

Alternating transverse motions (perpendicular to the direction of propagation, and the ray path); commonly approximately polarized such that particle motion is in vertical or horizontal planes.

VS ~ 3 – 4 km/s in typical Earth’s crust; >~ 4.5 km/s in Earth’s mantle;  ~ 2.5-3.0 km/s in (solid) inner core.

S-waves do not travel through fluids, so do not exist in Earth’s outer core (inferred to be primarily liquid iron) or in air or water or molten rock (magma).  S waves travel slower than P waves in a solid and, therefore, arrive after the P wave.