What is a Tsunami?

The word Tsunami comes from Japan. It can be described as the wall of water that can challenge a jet plane in speed. The general way to pronounce Tsunami is su-NAH-mee. The meaning of tsu is harbor, and the word nami means wave in short harbor wave. It is used globally to refer to a series of waves traveling across the ocean with very long wavelengths and has enough strength to cause mass destruction of life and property.

What causes Tsunami form?
Seismic disturbances, volcanic activities, submarine faulting are the main reasons for occurrence of Tsunami. A seismic disturbance can move the seawater causing a rise or fall in the level of the ocean. The seismic disturbance occurs due to displacement of tectonic plate. This rise or fall in sea water level is the early formation of a tsunami wave. This wall of water sometime turns out to be more than 100 feet height. The earthquakes that take place on the seafloor or in coastal areas usually cause tsunamis. The energy produced by the earthquake is transmitted through the water causing violent movement of sea waves. There is also an example of Tsunami being caused due to huge explosion by nuclear bomb during World War I.

Physics behind Tsunamis
More correctly in geographical terms Tsunami is a series of waves of extremely long wavelength and long period generated in a body of water by an impulsive disturbance and displace the water body. They are primarily related with earthquakes in oceanic and coastal regions. After an earthquake occurs, the energy travels outward in all directions from the center of earthquakes. The amount of time between consecutive waves, called as the wave period, is only a few minutes to an hour. As the tsunami crosses the ocean, its length from crest to crest may be around hundred miles, and its vertical height from a few feet to more than 30 meter. In the deepest part of oceans, the waves will touch the speeds of 600 -750 miles per hour, traveling across the ocean in less than a day. Tsunamis can reach a maximum vertical height onshore above sea level, called a run-up height, of 30 meters.

Normal wave and tsunami wave
The waves at the shore are produced by wind blowing over the sea surface. The height of these waves when it is generated is very small. Tsunami waves resulting from physical mechanisms it is much different than wind waves. As the tsunami approaches land, their appearance and behavior become dependent on several factors, most important factors are the topography of the seafloor and shape of the shoreline.

Tsunami warning system
Many techniques have been developed to warn about tsunami. Pacific tsunami warning system (PTWS) is one of them which were established in 1948 for US and its territory. By 1965, it became an international system, with 26 nations as its member. Seismic stations operated by PTWS are used for detection and location of tsunami and other also provide the earthquake information.

In case of any tectonic activity satellite first monitors sends warning to PTWS. When information from tidal station reveals that a potentially destructive tsunami exists then an alert signal is passed on to all stations. This message is then on to the member nations and also warns the residents over TV and radio to inform about the devil.

What to do when a tsunami hits?
Early signs of Tsunami are aggressive vibrations of earth but as most of these earthquakes occur far away from the sea and they give little or no indication that a tsunami is on the way. If you are stay near by sea area, immediately turn off the water, gas, and electricity and swiftly move to higher ground. Born it well in your mind, once a Tsunami Warning is issued, it could be a case of minutes, or even seconds, before the devil wave hits. Tsunami is a chain of waves. In most cases the first wave proves to be less dangerous. These waves get more and worse as time passes. After the wave has hit, all food and water should be tested from hygienic point of view. Each building must be checked for gas leaks and electrical shorts before anyone entering.

Recently the Tsunami wave occurred in Indian Ocean which hit the islands of Indonesia, Srilanka, Thailand and Andaman and Nicobar, caused thousands of people to lose their life. The help provided by citizens of all the countries was amazing; just goes to show the unity of mankind to tackle the natural disasters.