Harbor waves, commonly known as a tsunami when translated in Japanese is a series of strong and huge waves rushing at the ocean beds and sea shores of coastal areas causing havoc and disrupting life and property. The waves can be as high as 15 km in height.
Tsunamis can be caused by earthquakes, volcanic eruptions, or underwater landslides. Tsunamis are most commonly caused by earthquakes. When a sudden movement is caused under the sea beds, it disrupts the stability of the water and causes huge waves which travel with high speeds as the displaced water, which acts under the influence of gravity, tries to find equilibrium. These waves are so strong that they can destruct anything which comes their way. They cause economical and social damage. In some cases, when the vertical movement of the plates is not big, the water finds equilibrium quickly without causing a tsunami. With this we can conclude that not all underwater earthquakes cause tsunamis. Height of tsunami waves is directly proportional to the vertical movement of the plates.
Tsunamis have great impacts on life and environment. They cause land degradation and salinity of the soils which has great impacts on the harvests. This in turn causes economical crisis as all basic commodities like food, fresh drinking water and shelter is destroyed by this disaster. It has a great impact on the tourism industry as well as the affected area gets totally damaged which takes years to rebuild.
Among the most devastating tsunami incidences that have occurred earlier, the tsunami of the Indian Ocean which occurred on the 26th day of December 2004 was caused by the second largest earthquake underwater ever recorded with a magnitude of 9.1 and 9.3 .It lasted for about 8 to 10 minutes killing 225,000 people over 11 different countries of southeast Asia and the most affected areas were of Indonesia, India, Sri Lanka, and Thailand. Despite a lag of up to several hours between the earthquake and the impact of the tsunami, nearly all of the victims were taken completely by surprise. There were no tsunami warning systems in the Indian Ocean to detect tsunamis or to warn the general populace living around the ocean. In the aftermath of the disaster, there is now an awareness of the need for a tsunami warning system for the Indian Ocean. Many health professionals and aid workers have reported widespread psychological trauma associated with the tsunami.
When a tsunami is going to occur, the water receeds away from the shore showing the sea bed and shells and corals. This is a natural warning which gives us some time to run away to higher lands.