Among the greatest natural disasters in the world, tsunami can be rated in the top lists.
What is tsunami? It is a Japanese term that is used to describe a semicircular sea wave that is large enough to cause a great destruction usually at the coastal region.
Once occurrences like volcanic eruption, nuclear weapon testing, large meteorites impact, massive movements, landslides or underwater earthquakes take place displacement of water occurs due to the slippage of boundaries between two tectonic plates. For long it has been taken to be simply tidal waves which are simply small water waves as a result of gravitational pull between the moon and the sun.
The largest tsunami is referred to as megatsunami or iminami or wave of purification that rises to heights of more than 90 meters; they even gain greater heights when they experience the impact of the earth.
Below are some Facts about tsunami:
I. Usually it is a series of waves and the first waves occurs to be the least in intensity among all.
II. Before any occurrence of a tsunami, the shore line always recedes like never before exposing the bed of the ocean, this is a great warning to stay far away from the region.
III. Animals are least affected by tsunami for they somehow detect it earlier and take cover or run away. That’s why you will always hear fewer animals are reported in this occurrences compared to human beings. This can also be a great clue to us that something MIGHT happen soon.
IV. There is also a device that can also detect a tsunami earlier called Tsunameter which detects any approaching tidal wave. The devise is too expensive thus found only in super power countries.
V. Tsunami have greatest effect on shallow waters like at the coast and least in the deep waters, in deep waters it is only a normal but large tidal wave. As it is said it can be 1 meter high as in the deep open sea but rises to 30 meters or more as it approaches the shallow shores of oceans.
VI. It has caused not hundreds of thousands but millions of deaths of human beings in its history. In destruction perspective it can be rated among the highest natural disasters.
VII. Just like a jet airliner, it can reach an average speed of about 400 to 500 and above miles per hour. This is the force that causes the great destruction of lives and property on land.
Signs that Tsunami is Approaching:
I. A loud roar resembling that of an aircraft or even a diesel train is heard.
II. In case of an occurrence of an earthquake near water body a tsunami follows shortly mostly.
III. Animals especially the large ones like elephants move in the opposite detection once they detect the vibrations. Elephants are known to be good detectors of any slight movements.
IV. The water around the shore recedes drastically to a point of exposing even the base of the ocean or sea like never before. This is known as the tsunami trough which is followed by crest.
Tsunami Warning System:
As said earlier the systems are too expensive thus found in only some few countries, but the few that are available can serve the purpose for the whole world. The principle used is based on facts like, tsunami moves at a speed of 0.3 kilometers per second [km/sec] thus there is a sufficient time to confirm its occurrence once one of its causes like earthquake or volcanic eruption takes place.
Once the network detects tsunamis, a communication alarm system used globally is raised for instant evacuation of people around the coastal region.
How an the Effect of Tsunami be Reduced?
Unfortunately, tsunami cannot be fully controlled or evaded, some few measures are undertaken to prepare for its occurrence any time and of any magnitude. The measures taken include: –
I. A high wall can be created along the coast. Taking Japan as an example, they have creates a wall of 4.5 meters along the highly populated coastal region. This wall only reduces the magnitude.
II. Flood gates or channels are created to direct the water to some more safe places other than destroying property and lives, these channels also absorb part of the water or the lesser waves.
III. A tree cover can also be made along the coast to serve the purpose of the wall.
Just like any other natural disaster, tsunami can occur anytime, anywhere and of any magnitude. Being prepared is the only solution.