Seismic waves

Notes from my study of Natural Sciences (S104) with the Open University.

There are two main types of seismic waves – body waves and surface waves.

Body waves travel through the interior of the earth, surface waves travel near the Earth’s surface only. Body waves travel faster than surface waves.

Body waves

Body waves consist of P waves and S waves.

P waves (or compressional waves) move back and forth compressing and stretching rock.

S waves (transverse wave) move up and down, moving the earth at right angles to the wave. S waves cannot travel through liquid, such as oceans.

P waves are faster than S waves.

Surface waves

There are two main types of surface waves, Love waves and Rayleigh waves.

Love waves move the earth side to side. They cannot travel through liquid. Motion reduces with depth (the greatest motion is at the surface).

Rayleigh waves move up and down. The motion reduces with depth, and are similar to waves in water. They are slower than Love waves but can persist for greater distances.

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