NCERT Solutions for class 10th Social Science Chapter 30 Tsunami –The Killer Sea Waves


Question 1. Name three causes of Tsunami and explain its impact.

Answer : Three causes of Tsunami are
(i) Earthquakes
(ii) Volcaniceruptions
(iii) Underwater landslides

Impact Tsunamis are waves which can reach upto 15 meters or more in height, devastating coastal communities. In recorded history, tsunamis worldwide have killed hundreds of thousands of people. Tsunamis caused by nearby earthquakes may reach the coast within minutes. When the waves enter shallow water, they may rise to several meters, striking the coast with devastating force. The tsunami danger period can continue for many hours after a major earthquake.

Question 2. Explain two different ways of detecting Tsunami.

Answer : Two ways of detecting Tsunamis nowadays are

  • With the use of satellite technology it is possible to provide nearly immediate warning of potentially tsunamigenic earthquake s. ‘Tsunameters’ transmit warnings to buoys on the sea surface , which relay it to satellites. Warning time depends upon the distance of the epicenter from the coastline. The warning includes predicted times at selected coastal communities where the tsunami could travel within a few hours.
  • Tsunami detectors, linked to land by submarine cables, are deployed at about 50 kms out at sea.

Question 3. State two preparedness measures each in pre, during and post tsunami scenario.

Answer :
Pre Tsunami

  • Know the height of your home/road above sea level and the distance of your home from the coast or other water sources in which tsunami water can flow.
  • Plan evacuation routes from your home, school, workplace or any other place you could be where tsunamis present a risk.

During Tsunami

  • (i) Your family should evacuate the house if you live in a tsunami prone area. Evacuate to a safe elevated area and move in an orderly, calm and safe manner to the evacuation site.
  • (ii) Take your Disaster Supplies Kit. Having supplies will m ake you more comfortable during the evacuation.

Post Tsunami

  • Continue using a battery operated radio for updated emergency information. The tsunami may have damaged roads, bridges, or other places that may be unsafe.
  • Avoid disaster areas. Your presence might hamper rescue and other emergency operations and put you at further risk from the residual effects of floods, such as contaminated water, crumbled roads, landslides, mudflows, and other hazards.
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