What are Tsunami waves? How they are different from other oceanic waves.

What are Tsunami waves? How they are different from other oceanic waves.
  • Introduce your answer while defining what are tsunami waves
  • Explain what are oceanic waves
  • Differentiate between Tsunami waves and other oceanic waves
  • Conclude appropriately
Model Answer :
Tsunamis, also known as seismic sea waves, are a series of enormous waves created by an underwater (sea) disturbance caused by an earthquake, landslide, volcanic eruption, or even meteorite. In the open ocean, tsunamis have extremely long wavelengths. When the tsunami wave enters shallow waters, its length shortens and its height rises, thus the wave is forced upward into a towering wall of water sometimes as much as 30 meters in height.
Ocean waves are upper layer waves which are caused by wind moving across the surface of the water. The friction between the air molecules and the water molecules causes energy to be transferred from the wind to the water.
Difference between Tsunami wave and other oceanic waves:
  • Causes: Normal ocean waves are caused by the wind, whereas tsunamis are powered by a geological force like earthquake.
  • Wavelength: In the open ocean, tsunamis have extremely long wavelengths which can be between 100 and 300 km, whereas normal ocean waves have wavelengths of only 30 or 40 meters.
  • Magnitude: Tsunami involves movement of the entire water column from surface to seafloor. Normal wind waves only involve motion of the uppermost layer of the water.
  • Speed: Typically a tsunami wave travel across a deep ocean at an average speed of 800 km per hour, whereas normal ocean waves travel at speeds of 8-100 km per hour.
  • Direction: Tsunami waves radiate across the ocean from the source, like ripples on a pond. Ocean waves are usually powered by the wind direction.
  • Behaviour on Shore: Tsunami waves can change their path around land masses, whereas a normal wave generally breaks at shore.
Tsunamis are natural disasters that can cause major damage to life and property, as seen frequently in the Indo-Pacific region. As a result, early warning systems have been put in place along with public awareness to minimize the damage, especially to life, from these events.

Subjects : Geography