CLASS 10TH SOCIAL SCIENCE (GEOGRAPHY ) UNIT – 11 INDIAN NATURAL DISASTERS NOTES 2021 -22

UNIT – 11 INDIAN NATURAL DISASTERS

I. Fill in the blanks with suitable answers.

1. The most destructive atmospheric disaster is ____________ (Earthquakes)

2. In India the eastern coast is more prone to ___________ (Cyclones)

3. In peninsular India ___________ occur occasionally. (Floods)

4. In India ___________ occur very aften in hilly states. (Landslides)

5. Coastal erosion is mostly caused by ___________ action. (sea waves)

II. Answer the following questions in one sentence each:

1. What is natural disasters?

 The natural hazards which create widespread destruction are known as natural disasters.

2. What is Flood?

 Flood refer to the inundation of land by river water

3. What is landslides?

 The sliding of land mass along steep slopes of hills or mountains is called landslides

4. What is earthquake?

 An earthquake is a violent vibration in the Earth‟s crust

5. Which zone is called "The zone of moderative intensity"?

 The Indo - Gangetic Zone is called "The zone of moderative intensity”

6. Which zone is called “Zone of minimum intensity”?

 The peninsular zone is called “Zone of minimum intensity.”

7. The peninsular zone is called “Zone of minimum intensity”.Why?

 Only a few earthquakes have been occured in this zone mostly in recent years. Therefore it is known as “Zone of minimum intensity”.

8. What was the main reason for the earthquake that occurs in India?  In India most of the earthquakes that have occured earlier were due to plate movement

III. Answer the following questions:

1. What are natual disarters? Give example.

 The natural hazards which create widespread destruction are known as natural disasters

 Examples: earthquakes, volcanoes, tsunamis, landslides and avalanches.

2. What are floods? Mention the natural causes of floods?

 Flood refer to the inundation of land by river water. Causes:

 Floods are caused by both natural and man made factors.

 The natural factors include heavy rainfall, melting of snow, tropical cyclones, cloud burst, blockage of the free flow of river water and silting river beds etc.

 The man made causes are deforestation, faulty irrigation and agricultural practices, breaching of barrages and rapid urbanization.

3. What is a cyclone? Mention their major effects.

 In a cyclone the wind blows spirally inwards towards the centre of low presseure Effects:

 loss of life and property

 damage to buildings

 transports and communication system

 disrupt power supply

 destroy crops, vegetation, animals

4. Explain the causes and effects of landslides. Causes:

 Under cutting of the slope as in sea wave erosion of a sea cliff, earthquakes and heavy rainfall

 Deforestation, construction of roads, railway lines, dams and reservoirs, hydel power projects, mining, quarrying Effects:

 blocking of roads,

 railway lines,

 burrying of human settlements and vegetation,

 loss of life and property etc.

5. Write about causes and distribution of coastal erosion in India. Causes:

 Monsoon winds

 Tropical cyclones

 Tsunamis. Distribution:

 During The South West Monsoon season the coasts of Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu are largely affected by coastal erosion.

 Andaman - Nicobar Islands and east coast of India have been affected by Tsunamis

6. Mention the precautionary measures to be taken to reduce the effects of earthquakes .

 Avoid the human settlements in the earthquake prone zones.

 Follow earthquake resistant designs for the construction of buildings.

 Use building materials of high quality and avoid high rise buildings.

 Restrict the over groundwater mining.

 Restrict urban growth in the hilly areas with high seismic vulnerability.

 Avoid the construction of large dams and reservoires.

 Stop deforestration and heavy quarrying activities

7. What are the causes for Cyclones?

 high temperature

 calm air and

 highly saturated air

 These conditions result in the development of low pressure centre

8. What are the effects of Cyclones?

 Tropical cyclones are very destrutive to causes loss of life and property

 damage to buildings

 damage to transports and communication system

 disrupt power supply

 destroy crops, vegetation, animals etc.

9. What are the Preventive Measures of Cyclones?

 Cyclones are natural phenomenon. We cannot prevent them.

 But people can pay heed to the warnings.

 They should keep in touch with radio, television and other communicative lines.

 Temporary shelters should be provided during cyclones.

 Cyclone proof structures can be constructed.

 Mangrove forests and other deep rooted trees can be grown along the coastline to check the impact of cyclonic winds and the soil erosion

10. What are the effects of floods?

 Floods causes loss of life and property

 Damage to crops, vegetation

 Breakdown of communication and power system.

 Dislocation of transport system.

 Soil erosion

 disruption of essential services

11. Explain Flood control measuares.

 Afforerstation in the catchment area which helps in the reduction of run off.

 Construction of dams across the rivers and storing of water in reservoirs.

 It reduce the volume of water and helps to provide water for irrigation etc.

 Construction of embankments for protection against inundation of the inhabited areas and agricultural land.

 Flood forecasting and early warnings. This is essential for taking timely action to prevent loss of human life, livestocks and property.

12. Explain the effects of coastal erosion.

 Coastal areas including trees and building can be washed away.

 The roads, railway lines, bridges etc., along the coast can be damaged.

 Coastal areas can remain flooded over a long period of time requiring resettlement of people

13. What are the Preventive Measures of Coastal Erosion?

 Constructing Sea Walls, Groins and Break waters to protect the coastal areas from wave erosion.

 Restrict sand mining in coastal areas.

 Planting of trees to stabilise the beaches and coastal dunes

14. What are the reasons for earthquakes?

 plate movements

 volcanic eruption

 faulting and folding

 landslides

 collapse of underground cave roofs

 hydrostatic pressure of man made water bodies like reservoirs

15. Explain the effects of earthquakes.

 cracking of ground surface,

 damage and destruction of buildings, rails, roads, power lines,telecom lines, bridges, dams, factories,

 loss of human and animal lives and property.

 fires

 landslides

 disturbance in ground water level

 blockage and diversion of river course  destruction of forests due to fires

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