Seismic waves

Seismic waves move at different speeds depending on the materials they are encountering. Earthquakes cause different types of seismic waves: BODY WAVES and SURFACE WAVES. The surface waves can only travel through Earth’s surface while body waves, on the other hand, can travel through the inner layers of the Earth.

Waves travelling through Earth’s surface are the surface waves. The surface waves are the slowest travelling seismic waves and arrive after the body waves. They are responsible for the damage and destruction related with earthquakes. There are two types of surface waves: LOVE WAVES and RAYLEIGH WAVES. The love waves are the fastest surface waves and cause the ground to move from side to side while Rayleigh waves are the slowest of the seismic waves and cause the ground to roll like ocean wave.

(Please see the figure above for clear details)

There are two types of body waves. The first type of body wave is the P (Primary) wave. P waves are the fastest travelling seismic wave, push and pull the materials they encounter, the first wave you feel in an earthquake and can move through solids and liquids.

The second type of body wave is the S (Secondary) wave. S waves move slower than P waves but faster than the surface waves, move the materials they encounter up and down, arrive after the P waves and can move only through solids.

(Please see the figure above for clear details)

The waves of energy that travel through the Earth because of earthquakes enable scientists to tell us a lot about the internal structure of the Earth. Seismic waves move at different speeds when they travel through different types of materials they are encountering. As the body waves travel through the Earth, the waves are bent by the different materials that make up the Earth. The bending of waves is similar to the bending of light waves as they travel through a prism.