Seismic Waves: the Physics of How Earthquakes Travel Through Our Planet

Seismic waves are energy waves that travel through the Earth’s interior and across its surface during an earthquake. Understanding how these waves move helps scientists learn about the Earth’s structure and the behavior of earthquakes.

Types of Seismic Waves

There are two main types of seismic waves: body waves and surface waves. Body waves travel through the Earth’s interior, while surface waves move along the Earth’s surface.

Body Waves

Body waves include Primary (P) waves and Secondary (S) waves. P-waves are compressional and travel fastest, moving through solids, liquids, and gases. S-waves are shear waves that move slower and only travel through solids.

Surface Waves

Surface waves travel along the Earth’s surface and typically cause the most damage during earthquakes. They include Love waves and Rayleigh waves, which move in different patterns and affect the ground differently.

Wave Propagation and Earth’s Structure

Seismic waves change speed and direction depending on the materials they pass through. These variations help scientists map the Earth’s layers, such as the crust, mantle, and core.