Seismic Wave Types Explained

This question requires matching different types of seismic waves (P waves, L waves, S waves) with their corresponding wave characteristics (Longitudinal waves, Transverse waves, Surface waves). Let's break down each wave type:

Understanding P Waves

P waves, also known as Primary waves, are the fastest seismic waves generated during an earthquake. They are classified as longitudinal waves. In longitudinal waves, the particles of the medium (like rock or soil) vibrate back and forth parallel to the direction the wave is travelling. Imagine compressing and expanding a spring; the compression travels along the spring's length. This property allows P waves to travel through solids, liquids, and gases.

Based on this, P waves match with Longitudinal waves (ii).

Understanding S Waves

S waves, or Secondary waves, are slower than P waves and arrive at seismic stations after the P waves. They are characterized as transverse waves. In transverse waves, the particles of the medium move in an up-and-down or side-to-side motion, perpendicular to the direction the wave is propagating. Think of the wave pattern created by shaking a rope vertically; the wave travels horizontally, but the rope segments move vertically. S waves can only travel through solid materials because liquids and gases cannot support shear forces.

Therefore, S waves match with Transverse waves (i).

Understanding L Waves

L waves, commonly known as Surface waves (like Love waves and Rayleigh waves), are generated when seismic waves reach the Earth's surface. They travel slower than both P and S waves but often have larger amplitudes and are responsible for most earthquake damage. As their name suggests, they are surface waves, meaning their motion is confined to the near-surface layers of the Earth. Love waves cause horizontal shearing of the ground, while Rayleigh waves create a rolling motion.

Thus, L waves match with Surface waves (iii).

Matching Summary

Let's summarize the matches:

Correct Option Derivation

Based on the detailed explanation of each seismic wave type:

• P waves are longitudinal waves. So, (a) matches with (ii).
• L waves are surface waves. So, (b) matches with (iii).
• S waves are transverse waves. So, (c) matches with (i).

Combining these matches, the correct option is (a)-(ii), (b)-(iii), (c)-(i).