Surface waves are the waves or disturbances that travel on the surface of a body or along with the interface of two media. A surface wave is generally considered a mixture of both transverse and longitudinal waves. The particles of a transverse wave move perpendicular to the direction of propagation of the wave, whereas the particles of a longitudinal wave move parallel to the direction of propagation of the wave. Since a surface wave is a combination of transverse and longitudinal waves, when it travels through a medium, the particles of the medium tend to move in a circular direction.
Types of Surface Waves
1. Rayleigh Waves
Rayleigh waves are the surface waves that tend to move the particles of the medium in both horizontal and vertical direction along the vertical plane. These waves are quite slower than the body waves. Rayleigh waves are named after the British physicist Lord Rayleigh. He was the first person who mathematically demonstrated the existence of rayleigh waves.
2. Love Waves
Love waves, named after A.E.H. Love, a British mathematician, are the surface waves that tend to move the particles of the medium along a horizontal plane in a direction perpendicular to the direction of propagation of the wave. These type of waves exert a huge amount of pressure on the objects present on the surface of the earth such as tall buildings, thereby damaging the foundation of the structure.
Examples of Surface Waves
1. Water Waves
When a person throws a heavy object such as a stone in the water, or when a person dives into a water body, ripples get formed on the water surface. These ripples formed on the water surface are known as the water waves. The disturbance introduced on the still water surface travels from one point to another. In such cases, the propagation of the wave is easy to observe.
2. Seismic Waves
Seismic waves are the waves produced due to the movement of the tectonic plates of the earth or simply because of the earthquake. The seismic waves are a prominent example of surface waves as they exist on the surface of the earth and not inside the earth’s core. The seismic waves can be recorded on a seismograph with the help of a seismometer.
3. Gravity Waves
The gravity waves influence a lot of objects present on the earth’s surface. They help to hold the objects in place, and they are also responsible for the fall of the objects towards the ground. The gravity waves also occur within liquids and on the surface of fluids. The best example of gravity waves is the waves formed in the seas or oceans.
4. Wind Waves
The wind is also responsible to generate or form surface waves. The large surfing waves formed on the surface of an ocean or a sea are highly influenced by the winds. The wind flowing on the surface of the ocean or the sea in the direction opposite to the flow of the water produces huge surface waves.
5. Electromagnetic Waves
Some of the electromagnetic waves also act like surface waves. This is observed when an electromagnetic wave such as a radio wave is made to propagate along the surface of the earth for the purpose of communication and exchange of information between two points. The propagation of the wave is close to the surface of the earth, hence it is known as the ground wave propagation.