A Tsunami is a chain of fast moving waves caused by sudden trauma in the ocean. Earthquakes, volcanic eruptions, or even the impact of meteorites can generate them. Tsunamis are also incorrectly known as tidal waves, but unlike tidal waves they are not caused by changes in the tides.

There is a sense of fear and helplessness after the latest tsunami (Dec 26, 2004) that killed more than 2000,000 people and caused material damage worth of many billion dollars. Therefore it is very important to device a new technology or a device not only to prevent massive loss of lives but also their properties and environmental hazards caused by tsunamis. In order to device such technologies, one should have thorough knowledge about tsunamis' wave power and type of damages caused to human beings, properties and environment.

Wave power

Tsunamis aren't like wind-generated waves that rhythmically roll onto beaches. A tsunami can have a wavelength (i.e. distance between wave crests) in excess of 100km (60 miles) and there may be an hour between them. They travel at great speeds across an ocean with hardly any energy losses and are barely noticeable out at sea. Waves are a dense form of energy compared, for example, to the wind. Because water is much denser than air, so the energy required moving a heavy volume of water is far greater than that needed to move the same volume of air.

As a tsunami leaves the deep water of the ocean and travels into the shallower water near the coast, it behaves like a normal wave - only with more force. While shallow water slows the tsunami, its height increases. Tsunamis batter the coast with tremendous amounts of energy. They can strip sand from beaches, tearing up vegetation, and even raising whole towns and villages to the ground.

We, so called advanced civilizations capable of collecting data from moon or distance planets such as Saturn are incapable to study and judge any natural events, occurring in the neighbourhoods.

However it is a foremost duty of world citizens to save our lives and properties. We should find new ways and means for our survival or existence on this planet.

Egyptians studied astronomy to predict hazards caused by Nile River. So did other civilizations. Many civilizations avoided occupying hazardous places by the knowledge gained and passed generation to generations or by instinct. We are disabled by the modern technology. By studying the past, we can open a new avenue for a hazardless environment for us and for our future generations. The lessons learned in this decade from a rash disaster, have yielded new ways to track these killer ways- will help save lives and infrastructures in futures.

In this article main emphasis is given to vegetation. If any one analyses, hundreds of photographs published by media one would identify wonderful nature's gifts - palm trees especially coconut trees and palmyrah trees. All palm trees belong to palmaea family and they are monocots. They have fibrous root system. This root system facilitate palm tree to fetch groundwater from soil as deep as 3-4 meters. Thus this root system holds together tons of soil mass that provides strength to palm trees to withstand tsunamis' wave power.

Other than this, palm trees have dissected leafs which provide less friction to fluids such as wind and water. Stems of palm trees are cylindrical which is also has less friction. These are the main reasons for their survival even after the super-mega-tsunami. Many palm trees are coastal plants and their seeds are disposed by water. Also they can thrive well under saline conditions too.

Conclusion

Based on the above-mentioned facts it is obvious that palm trees such coconut and palmyrah are most suitable trees for bio-dams. They are not only capable of resisting tsunamis but also can yield useful products for humans and cattle.

V Dhuruvasangary