Notes on Seismic Waves

Seismic Waves

Introduction to Seismic Waves

• When an earthquake occurs, its energy moves through the Earth as seismic waves.

Types of Seismic Waves

Primary Wave (P Wave)

• Definition: A primary wave, commonly referred to as a P wave, is the fastest seismic wave.
• Characteristics:
  • First wave to arrive at a seismograph station after an earthquake.
  • Type of wave: Longitudinal.
  • Nature of disturbance: Moves parallel to the direction of wave motion.
  • Medium of travel: Capable of traveling through any type of medium:
  • Solid
  • Liquid
  • Gas (air)

Secondary Wave (S Wave)

• Definition: A secondary wave, known as an S wave, travels slower than the primary wave.
• Characteristics:
  • Type of wave: Transverse.
  • Nature of disturbance: The disturbance moves perpendicular to the wave motion.
  • Medium of travel: Unlike primary waves, secondary waves can only travel through solid mediums.
  • Unable to travel through liquids and gases.