Tsunami: Meaning, Nature and Effects

What is Tsunami ? 

Tsunami is a Japanese word meaning “harbor wave,” used for a class of abnormal sea waves (or tidal waves) that can cause catastrophic damage when it hits a coastline. Tsunami is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake causing damage to life and property. It is caused by an undersea earthquake, an undersea landslide, the eruption of an undersea volcano, or by the force of an asteroid dashing into the ocean. The most frequent cause of Tsunami is an undersea earthquake. Therefore, tsunami is most popularly understood as the earthquake under the sea/ocean. The Ring of Fire, a zone of volcanoes and seismic activity, 32,500 km (24,000 mi) which encircles the Pacific Ocean experiences most number of tsunamis is the world. Tsunami is not a wave but a series of waves. Tsunamis should not be mistaken for storm surges, which are caused by hurricanes or cyclones and bring extensive coastal flooding when the storms reach land-coast. For example, super storm sandy hit the east coast of the USA in North Atlantic Ocean on October 29, 2012 when much New York was plunged into darkness by this super storm that overflowed the city’s historic waterfront, flooded the financial district and subway tunnels and cut power to nearly a million people. This was not a tsunami

Most tsunamis are not very destructive for humans but few of them are devastating in nature. On December 2004, the Indian Coastline experienced the most devastating tsunami in recorded history. An earthquake having a magnitude of 9 off the coast of Sumatra in the Indonesian Archipelago triggered the tsunamis. In another example, a ferocious tsunami spawned by one of the largest earthquakes slammed Japans eastern coast on March 11, 2011 killing hundreds of people as it swept away boats, cars and homes while widespread fires burned out of control. The magnitude of 8.9 offshore quake unleashed a seven-meter tsunami and was followed by more than 50 aftershocks for hours, many of them of more than magnitude 6.0. Dozens of citizens and villages along a 2100-km stretch of coastline were shaken by violent tremors that reached as far away as Tokyo, hundreds of kilometers away from the epicenter.

Effects of tsunami: 

A tsunami causes loss of human and animal life, devastates property, bring flooding and spreads disease. It causes environmental effects such as contamination of soil and water, unmanaged toxic substances in them, permanent change to the landscape, scattered solid waste and disaster debris. Like earthquakes, small and undetectable tsunamis occur almost every day but only larger tsunamis have devastating effects on life, property and land. Tsunami strikes suddenly giving no time to escape causing near instant death, usually by drowning, and also by collapsing buildings, electrocution and more. Since 1850, tsunamis have killed more than 430,000 people. The March 2011 tsunami in Japan left a total of 15,894 people dead, 6,152 people injured and 2,562 people missing.

The excessive flooding caused by the tsunami waves also damages sewer systems, water supplies and worst the quality of soil. Standing dirty water in this way becomes the source of spreading malaria and other diseases along with illness, infection and even death. The inflow of sea water on the coastal and mainly areas make the soil saline lowering the fertility of land which in turn affects the long-term yields of crops.; The high intensity impact of tsunami waves destroys the architecture, building and property permanent path and destroy everything including buildings, trees, power lines, bridges, factories, nuclear plants, cars, boats and more. A huge mound (mass) of solid waste and debris that is almost impossible to clean up is left behind after a tsunami attack. Tsunami attack damages the entire ecological system consisting of flora and fauna and other natural resources on its way. Hazardous materials and toxic substances released by the leakage and bursting of the physical infrastructures and the factories release toxic gases and chemicals spreading environmental pollution which causes death by inhalation and consumption of toxic goods.

Ways to remain safe from tsunami

The tsunami is very unpredictable natural disasters leaving very less time to minimize the loss of life and property. However, modern science and technology have made it possible to catch some early signs of impending natural disasters to take precautionary steps for evacuating or rescuing the people from the danger zone.

The following are some of the ways to remain safe from tsunamis:

a) To be always in the reachable zone to access information from radio, television or others

b) To be prepared in advance for the mitigation of the impacts when the tsunamis strike

c) To install tsunami resistance physical structures in building architectures

d) To make emergency kit and disaster bag ready to deal with sudden strike of natural disasters like tsunami.