The term tsunami was derived from two Japanese word, “Tsu” which means Harbour and “Nami” which stands for Wave. Tsunami also known as in the Tamil language, the word is aazhi peralai. In the Acehnese language, it is ië beuna or alôn buluëk. Note that in the fellow Austronesian language of Tagalog, a major language in the Philippines, alon means "wave". On Simeulue island, off the western coast of Sumatra in Indonesia, in the Defayan language the word is smong, while in the Sigulai language it is emong.
Regardless of the origin of name for tsunami, this natural phenomenon is commonly related to disaster. Since, its series of waves could swept-off along any things that came across its way. Tsunamis cause damage by two mechanisms either the smashing force of a wall of water travelling at high speed or the destructive power of a large volume of water draining off the land and carrying all with it, even if the wave did not look large.
But how Tsunami occurs? There are several theories that suggest by scientist worldwide regarding to the creation of this natural disaster. The principal generation mechanism (or cause) of a tsunami is the displacement of a substantial volume of water or perturbation of the sea. This displacement of water is usually attributed to earthquakes, landslides, volcanic eruptions, or more rarely by meteorites and nuclear tests. The waves formed in this way are then sustained by gravity. It is important to note that tides do not play any part in the generation of tsunamis.
Any warning or prediction can be done/sensed? First on the list the drawback. Drawback is a phenomenon which can serve as a brief warning for the tsunami. A drawback occurs because the water propagates outwards with the trough of the wave at its front. Drawback begins before the wave arrives at an interval equal to half of the wave's period. Drawback can exceed hundreds of metres, and people unaware of the danger sometimes remain near the shore to satisfy their curiosity or to collect fish from the exposed seabed.
A tsunami cannot be precisely predicted, even if the magnitude and location of an earthquake is known. Geologists, oceanographers, and seismologists analyse each earthquake and based on many factors may or may not issue a tsunami warning. However, there are some warning signs of an impending tsunami, and automated systems can provide warnings immediately after an earthquake in time to save lives. One of the most successful systems uses bottom pressure sensors that are attached to buoys.
Besides that, some zoologists hypothesise that some animal species have ability to sense subsonic Rayleigh waves from an earthquake or a tsunami. If correct, monitoring their behaviour could provide advance warning of earthquakes, tsunami etc. However, the evidence is controversial and is not widely accepted.
What we can do to minimize the effect of Tsunami? A report published by the United Nations Environment Programme (UNEP) suggests that the tsunami of 26th December 2004 caused less damage in the areas where natural barriers were present, such as mangroves, coral reefs or coastal vegetation. A Japanese study of this tsunami in Sri Lanka used satellite imagery modelling to establish the parameters of coastal resistance as a function of different types of trees.
As a conclusion, nature always provides remedy for its own caused disaster. There is always a way to prevent or for worst, minimize the effect of the natural disaster. As a human, we can always play our role to sustain the environment for the future of the next generations. GO GREEN!
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