Rayleigh Waves and Love Waves

This article will discuss Rayleigh Waves and Love Waves in detail that is a small but important part of the UPSC Syllabus of the Civil Services exam.

The earthquake which originates in the lithosphere propagates different seismic waves or earthquake waves which are basically of two types:

1. Body waves
2. Surface waves.

In this article, candidates will get relevant information on Surface waves which are classified into two types Rayleigh waves and Love Waves.

The information on Rayleigh waves and Love Waves will definitely be helpful to prepare for the upcoming IAS Exam.

What are Surface Waves?

1. When the body waves (explained below) interact with surface rocks, a new set of waves is generated called surface waves. They move along the earth’s surface and are the most damaging waves.
2. These are transverse waves wherein the particle movement is perpendicular to the wave propagation. Therefore, they create crests and troughs in the material through which they pass.
3. Rayleigh waves and Love waves are the two common surface waves.

What are Rayleigh Waves?

1. British physicist Lord Rayleigh demonstrated the Rayleigh Waves mathematically.
2. A Rayleigh wave is a seismic surface wave producing the sudden shake in an elliptical motion, with no crosswise or perpendicular motion.
3. It moves along the ground just like a wave moves across a lake or an ocean.
4. The greater part of the shaking felt from an earthquake is because of the Rayleigh wave, which can be considerably bigger than other waves.
5. Because it rolls, it moves the ground up and down and side-to-side in the same direction that the wave is moving.

What are Love Waves?

1. Much slower than Body Waves but are the fastest surface wave and moves the ground from side to side.
2. Love wave is also a seismic surface wave led to the horizontal shifting of the earth during an earthquake.
3. Confined to the surface of the crust Love waves always produce entirely horizontal motion.
4. They exist only in the presence of a semi-infinite medium overlain by an upper finite thickness.

Candidates can check the following related links to prepare for the upcoming UPSC exam-

What are Body Waves?

1. Body waves are generated due to the release of energy at the focus and move in all directions traveling through the interior of the earth.  Body waves are also of two types –
   1. P Waves – the longitudinal or compressional waves, analogous to sound waves, move faster and are the first to arrive at the surface.
   2. S Waves – the transverse or distortional waves, analogous to water ripples or light waves, arrive at the surface with some time lag. These are high-frequency waves and travel at varying velocities through the solid part of the Earth’s crust, mantle. Read more about the Structure of the Earth – Crust, Core, and Mantle on the linked page.

Question for the Day on the Topic

Consider the following statement

1. Rayleigh wave is a seismic surface wave in an elliptical motion.
2. Love wave always produces an entirely horizontal motion.

Select the correct ones.

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2

Answer: C

The above details would help candidates prepare for UPSC 2023.

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