As a seismologist with extensive experience in the study of earthquakes and their effects, I can explain the impact of S waves on the ground. S waves, also known as secondary waves or shear waves, are one of the two main types of elastic waves that can travel through the Earth's interior, the other being P waves or primary waves. Unlike P waves, which can travel through both solids and liquids, S waves can only propagate through solids. When an earthquake occurs, S waves follow P waves and are typically slower. They cause the ground to shake in a side-to-side or up-and-down motion, which can be particularly damaging to structures not designed to withstand such movement. The shaking caused by S waves is responsible for much of the surface destruction during an earthquake. This is because, unlike P waves that cause the ground to compress and expand like a spring, S waves move through the ground in a shearing motion, which can topple buildings and other structures. The destructive power of S waves is also the reason why they are used to estimate the potential damage of an earthquake in seismic hazard assessments. S waves can also be associated with two types of surface waves: Love waves and Rayleigh waves. Love waves cause a horizontal back-and-forth movement, while Rayleigh waves produce both vertical and rotational movements. Both of these surface wave types contribute to the overall surface destruction caused by an earthquake. read more >>

Surface waves, in contrast to body waves can only move along the surface. They arrive after the main P and S waves and are confined to the outer layers of the Earth. They cause the most surface destruction. Earthquake surface waves are divided into two different categories: Love and Rayleigh.read more >>