Tsunami - Class 10 MCQ

A tsunami is a sequence of waves in a body of water caused by a large amount of water being displaced, usually in an ocean or a large lake.

People living in tsunami prone areas should ensure that they live at a safe distance from the coast line. They should elevate their houses so that only a minimum damage is caused to property in the event of a tsunami.
They should live in houses that can with stand the onslaught of the killer waves.
A proper drainage system should be provided to ensure that there is no flooding of the surrounding areas.
People should have access to radio and TV, so that can be informed about impending danger. The most important thing is to follow the instructions given during emergency.

When a tsunami warning is sounded, the whole family should immediately shift to a safer place. People should move to the upper floors of a multi-storied building. They should have disaster supplies kit with them.
People who have cattle should take them along. People should stay away from rivers that flow into the sea as the sea water will rush inland through these rivers.
They should leave low-lying coastal areas and head towards the interior.
They should listen to the radio or TV for the latest up date on the situation

As tsunamis are natural disasters and cannot be prevented, the next best thing one can do is be prepared for the eventuality and ensure the safety all the people.
Tsunami prone areas can be identified by the government. People living in these areas should be educated about tsunamis. They should be informed about the evacuation routes in case a tsunami hits the coast.
Mock evacuation drills should be conducted periodically so that the people are aware of it.
The government should make arrangements for sufficient provision during emergency.
The people in these tsunami prone areas should know how to contact their friends or relatives who live in risk-free zones, in the event of a tsunami.

Characteristics of Tsunami

• Tsunamis are among Earth’s most infrequent hazards and most of them are small and nondestructive. 
• Over deep water, the tsunami has very long wavelengths (often hundreds of kilometres long) when a tsunami enters shallow water, its wavelength gets reduced and the period remains unchanged, which increases the wave height.
• Tsunamis have a small amplitude (wave height) offshore. This can range from a few centimetres to over 30 m in height. However, most tsunamis have less than 3 m wave height.
• It radiates in all directions from the point of origin and covers the entire ocean.
• It generally consists of a series of waves, with periods ranging from minutes to hours.
• These are the waves generated by tremors and not by earthquakes themselves.
• There is no season for tsunamis and not all tsunamis act the same. It cannot be predicted where, when and how destructive it will be. A small tsunami in one place may be very large a few miles away.
• An individual tsunami may impact coasts differently. A tsunami can strike any ocean coast at any time. They pose a major threat to coastal communities. The effect of Tsunami would occur only if the epicentre of the tremor is below oceanic waters and the magnitude is sufficiently high.
• The speed of the wave in the ocean depends upon the depth of water. It is more in the shallow water than in the ocean deep. As a result of this, the impact of a tsunami is more near the coast and less over the ocean