what are seismic waves

Seismic waves are mechanical waves of acoustic energy that travel through the Earth or other planetary bodies. They can result from various events such as earthquakes, volcanic eruptions, magma movement, large landslides, and large man-made explosions that produce low-frequency acoustic energy. Seismic waves are studied by seismologists, who record the waves using seismometers, hydrophones (in water), or accelerometers. These waves are distinguished from seismic noise, which is persistent low-amplitude vibration arising from various natural and anthropogenic sources. Seismic waves are used to study the Earths internal structure, locate earthquake hypocenters, and investigate shallow subsurface structures. There are three basic types of seismic waves: P-waves, S-waves, and surface waves. P-waves, also known as primary waves or pressure waves, travel at the greatest velocity through the Earth, while S-waves, known as secondary waves, cannot travel through liquids and only move through solids. Surface waves, which travel along the ground, are the slowest of all seismic waves and can be the most destructive type of seismic wave.