S wave

An S wave, or secondary wave, is a type of seismic wave that moves through the Earth during an earthquake. Unlike the faster primary (P) waves that push and pull material back and forth, S waves move the ground side to side or up and down perpendicular to the wave's direction. They cannot travel through liquids, only solids. This movement causes significant shaking and damage during seismic events. S waves usually arrive after P waves and are crucial in helping scientists understand Earth's interior and assess earthquake hazards.