The name Tsunami comes from a Japanese word meaning harbour wave. It is the world’s most powerful and destructive wave that occurs in a large body of water. These waves speed across the ocean as fast as a jet plane and can cause large scale destruction swallowing up islands and wiping out villages.
It is caused by some sudden activity on the seabed, like earthquake, underwater volcanic eruption, or landslides, releasing the vast amount of energy in the water. This released energy travels up to the water surface, displacing large amount of water rapidly and raising it above the sea level. The gravity of the earth tries to pull the water down causing the wave to swell outwards horizontally, creating the giant Tsunami waves.
Learn more about Tsunami in this video