Explanation:

Tsunamis:
The seismic waves travelling through the ocean and sea water results into high sea waves which are known as tsunamis. ‘Tsunami’ is a Japanese term which has been universally adopted to describe a large seismically generated sea wave. These waves are responsible for causing considerable destruction in certain coastal areas where submarine earthquakes occur.
Pre – conditions for Tsunami:
For a Tsunami to occur, two conditions are required: There should be an earthquake from which energy can be transferred. There should be a vertical displacement of the water. i.e. during earthquake the crust should move vertically. That’s why Tsunamis are originated near oceanic trenches where plates are being subducted. In Atlantic Ocean, a number of earthquakes occur on Mid – Oceanic ridge but since there is no sudden vertical movement, Tsunamis are not formed. Tsunamis can also be triggered if seamounts break. This can cause vertical displacement of water.