Tsunamis: The Giant Waves Caused by Underwater Earthquakes When there is an earthquake on the earth, the earth seems to tremble. But have you thought that earthquakes also occur under the sea? In this article we will learn the facts behind how ocean waves become tsunamis and how they are formed. The first question is What is meant by tsunami? A tsunami is a series of waves that are formed by a large volume of water after traveling a considerable distance, when there is an earthquake or volcanic eruption in the sea water. These waves can travel at speeds of up to 500 miles per hour and reach heights of over 100 feet, causing widespread destruction and loss of life. How Do Tsunamis occur? When an earthquake occurs under the sea with a magnitude greater than the normal ratio, then the sea water, which is apparently in a static condition, creates motion in itThe water that flows from it creates waves and here the waves carry energy with them. So, the more intense the earthq