Understanding Disaster

Class 6 | Social Science — Geography | Unit 3

Class 6 Unit 3 Geography

Unit 3 Understanding Disaster

Learning Objectives

• To understand the meaning of disaster.

• To know about the types of disasters.

• To know a few key concepts in Disaster Management and orient them to the words used in the media.

• To understand Tsunami and flood.

• To understand about Forecasting, Emergency Operation Centre etc.

This lesson explains about the various natural disasters and man-made disasters. It also deals with the precautionary and mitigation measures taken to avoid the loss of lives and materials. Disaster is a very common phenomenon in human society. It has been experienced by people since time immemorial. Though its form may be varied, it has been a challenge for society. The latest development which has been discovered in the World Disaster Reports recently is that the disasters have increased in frequency and intensity. India is one of the most disaster-prone countries in the world. It has some of the world's most severe droughts, famines, cyclones, earthquakes, chemical disasters, rail accidents and road accidents. The high density of population in the developing countries, especially in the high-risk coastal areas, results in millions of people getting affected by natural disasters, especially in recurring disasters like floods, cyclones, storm surges, etc.

Disaster

'A disaster is a serious disruption of the functioning of a society involving human and material loss. Disaster is broadly classified into natural and manmade disasters.

Disasters

Natural Disasters	Man Made Disasters
Earthquakes	Fire
Volcanoes	Destruction of buildings
Tsunamis	Accidents in Industries
Cyclones	Accidents in transport
Floods	Terrorism
Landslides	Stampede
Avalanches
Thunder and Lightning

Natural Disasters

Earthquake

The sudden shaking of the earth at a place for a short spell of time is called an earthquake. The duration of the earthquake may be a few seconds to some minutes. The point where an earthquake originates is called its 'focus'. The vertical point at the surface from the focus is called 'epicentre'.

Volcanoes

Volcanoes are openings or vents where lava, small rocks and steam erupt onto the earth's surface.

Tsunami

Tsunami are waves generated by earthquake, volcanic eruptions and underwater landslides.

Cyclones

A low-pressure area which is encircled by high-pressure wind is called a cyclone.

Floods

An overflow of a large amount of water, beyond its normal limits, especially on the rainfed areas is called a flood.

Landslide

The movement of a mass of rocks, debris, soil etc. Downslope is called a landslide.

Avalanche

A large amount of ice, snow and rock falling quickly down the side of a mountain is called an Avalanche.

Thunder and lightning

Thunder is a series of sudden electrical discharge resulting from atmospheric conditions. This discharge results in sudden flashes of light and trembling sound waves which are commonly known as thunder and lightning.

Man-made disasters

Fire

Massive forest fires may start in hot and dry weather as a result of lightning, and human carelessness or from other causal factors.

Destruction of buildings

Demolition of buildings by human activities.

Accidents in industries

Chemical, biological accidents that occur due to human error. (Example: Bhopal gas tragedy)

Accidents in Transport

Violation of road rules, carelessness causes accidents.

Terrorism

The social unrest or differences in principles leads to terrorism.

Stampede

The term stampede is a sudden rush of a crowd of people, usually resulting in injuries and death from suffocation and trampling.

Tsunami and floods

A killer Tsunami hit the southeast Asian countries on the 26th of December, 2004. A massive earthquake with a magnitude of 9.1 to 9.3 in the Richter scale in the Indonesian island of Sumatra. It triggered one of the biggest Tsunamis the world had ever witnessed. The massive waves measuring up to 30 metres that killed more than 2,00,000 (2 LAKHS) people in Asia. In India, over 10,000 people were killed by this disaster. Tamil Nadu alone accounted for 1,705 deaths. All the coastal districts were affected, Nagapattinam was the worst hit in the state of Tamil Nadu. Fishermen, tourists, morning walkers, children playing on the beach and people living on the coast were unprepared for the waves. So they lost their life and most of the loss of lives and damage to property was within 500 metres of the shore. After that the Indian government set up a Tsunami Early Warning System at Indian National Centre for Ocean Information Services (I N C O I S), Hyderabad in 2007.

Tsunami - Do's and Don'ts

You should:

• Find out if your home, school etc., are in vulnerable areas along the seashore.

• Know the height of your street above sea level.

• Plan evacuation routes and practise your evacuation routes.

• Discuss tsunamis with your family.

• Review safety and preparedness measures with your family.

• If you see the sea water receding, you must immediately leave the beach and go to higher ground far away from the beach.

Don't:

• Don't go to the coast to watch the Tsunami.

• Don't try to surf the tsunami waves.

• Be aware of facts about tsunamis.

Floods

Floods are high stream flows, which overlap natural or artificial banks of a river or a stream and are markedly higher than the usual flow as well as inundation of low land.

Types of floods

Flash floods: Such floods that occur within six hours during heavy rainfall.

River floods: Such floods are caused by Precipitation over large catchment areas or by melting of snow or sometimes both.

Coastal floods: Sometimes floods are associated with cyclone high tides and tsunami.

Causes of floods

• Torrential Rainfall.

• Encroachment of rivers bank.

• Excessive rainfall in catchment.

• Inefficient engineering design in the construction of embankments, dams and canals.

Effects of floods

• Destruction of drainage system

• Water pollution

• Soil erosion

• Stagnation of water

• Loss of agricultural land and cattle

• Loss of life and spread of contagious diseases.

Do's

• To find out if the settlement area is to be affected by flood or not.

• Keeping radio, torch, and additional batteries, storing drinking water, dry foods items, salt and sugar.

• Safeguarding materials like kerosene, candle, match box, clothes and valuable things.

• Keeping umbrella and bamboo poles.

• Keeping a first aid box and strong ropes to bind things.

• To dig canals from the farmland, to drain the excessive water keeping sand bags etc.

Don'ts

• Try to connect electricity once it is cut.

• Operate vehicles

• Swim against floods

• Avoid going on excursions.

• Neglect flood warning messages

During floods

• Cut off gas connection and electricity.

• Keep sandbags on drainage holes and bathroom holes.

• Leave immediately through the known passage or prescribed passage

• Drink hot water.

• Use bleaching powder to keep your environment hygienic.

• Before using match sticks and candles, ensure that there is no gas leakage.

• Don't eat more food when you are affected by diarrhoea.

• Don't try to take anything that floats in flood.

Disaster Risk Reduction (DRR)

Disaster Risk Reduction: The practice of reducing disaster risks through systematic efforts to analyse and manage the causal factors of disasters. There are four key approaches to public awareness for disaster risk reduction. Campaigns, participatory learning, informal education, and formal school based interventions.

Case Study: Chennai Flood 2015

Chennai is one of the largest metropolitan cities in India, which lies on the south eastern coast. The north east monsoon along with tropical cyclones hits Chennai every year and gives heavy cyclonic rainfall. In 2015, November and December due to heavy rain, the devastating floods that hit Chennai and other parts of Tamil Nadu claimed more than 400 lives and caused enormous economic damage. The Government of India and Tamil Nadu have taken a lot of action to reduce loss of life and minimize human sufferings.

Forecasting and Early Warning

Weather forecasting, Tsunami early warning system, cyclonic forecasting and warning provide necessary information which help in reducing risks during disasters. School Disaster Management Committee, Village Disaster Management Committee, State and Central government institutions take mitigation measures together during disaster. Newspaper, Radio, Television and social media bring updated information and give alerts on the vulnerable area, risk, preparatory measures and relief measures including medicine.

Glossary

Mitigation The lessening of the adverse impacts of hazards and related disasters. Forecast Definite statement or statistical estimate of the likely occurrence of a future event or conditions for a specific area. Magnitude A measure of the amount of energy released by an earthquake. Contagious Transmissible by direct or indirect contact. Catchment The action of collecting water, especially the collection of rainfall over a natural drainage area.

Exercise

Exercise 1. Answer in brief

1. Define Disaster

2. What are the two types of disasters? Give examples.

3. Write a short note on 'Thunder and lightning'

4. Chennai, Cuddalore and Cauvery delta are frequently affected by floods. Give reason.

5. Differentiate: Landslide – Avalanche

Exercise 2. Answer in a paragraph

1. What is flood? Explain the do's and don'ts during floods.

Exercise 3. Activity

Make a flood plan

On a piece of paper, draw your village or town map roughly. Locate your home, school and playground on the map. Then draw the rivers or stream or lake and road, located nearest to your village or town. Answer the questions listed below.

1. Which areas and roads would be mostly affected by flood?

2. Can you find an evacuation route?

3. If you live in a flood-prone area, what are the precautionary measures you have to take during heavy rains?

4. What are things that you should have in your 'Go- Kit ' or 'Drive -away kit'?

5. Make a list of emergency numbers.

('Go-Kit' - A kit prepared by and for an individual or group who expects to develop it in alternative locations during emergency)

ICT CORNER

Understanding Disaster

Through this activity you will know about prevention activities before cyclone through a game.

Steps:

Step 1 Use the URL or scan the QR code to open the "storm safe" game page.

Step 2 Click the "play" icon to enter the game page

Step 3 Click the "continue" button start the game.

Step 4 Drag and put weightless things in the house

Browse in the link

Web: http://www.vicses.com.au/stormsafe-game/ (or scan the Quick Response Code)

Book-back Exercises — Questions & Answers

Answers generated strictly from the Samacheer Kalvi textbook content. Attempt each question first, then click "Show Answer" to check.

1. Answer in brief

1. Define Disaster

Answer: A disaster is a serious disruption of the functioning of a society involving human and material loss. Disasters are broadly classified into natural and man-made disasters.

2. What are the two types of disasters? Give examples.

Answer: The two types of disasters are Natural Disasters and Man Made Disasters. Examples of Natural Disasters: Earthquakes, Volcanoes, Tsunamis, Cyclones, Floods, Landslides, Avalanches, Thunder and Lightning. Examples of Man Made Disasters: Fire, Destruction of buildings, Accidents in Industries, Accidents in transport, Terrorism, Stampede.

3. Write a short note on 'Thunder and lightning'

Answer: Thunder is a series of sudden electrical discharge resulting from atmospheric conditions. This discharge results in sudden flashes of light and trembling sound waves which are commonly known as thunder and lightning.

4. Chennai, Cuddalore and Cauvery delta are frequently affected by floods. Give reason.

Answer: Chennai lies on the southeastern coast and the northeast monsoon along with tropical cyclones hits Chennai every year giving heavy cyclonic rainfall. These coastal areas are high-risk zones where millions of people get affected by natural disasters, especially recurring disasters like floods and cyclones.

5. Differentiate: Landslide – Avalanche

Answer: Landslide: The movement of a mass of rocks, debris, soil etc. downslope is called a landslide. Avalanche: A large amount of ice, snow and rock falling quickly down the side of a mountain is called an Avalanche.

2. Answer in a paragraph

1. What is flood? Explain the do's and don'ts during floods.

Answer: An overflow of a large amount of water, beyond its normal limits, especially on the rainfed areas is called a flood. Do's during floods: Find out if the settlement area is to be affected by flood, keep radio, torch, and additional batteries, store drinking water and dry food items, safeguard materials like kerosene, candle, match box, clothes and valuable things, keep umbrella and bamboo poles, keep a first aid box and strong ropes to bind things. Don'ts during floods: Don't try to connect electricity once it is cut, don't operate vehicles, don't swim against floods, avoid going on excursions, don't neglect flood warning messages.

📝 Summary

1. A disaster is a serious disruption of the functioning of a society involving human and material loss, and India is one of the most disaster-prone countries in the world with severe droughts, famines, cyclones, earthquakes, and various accidents.
2. Disasters are broadly classified into natural disasters (earthquakes, volcanoes, tsunamis, cyclones, floods, landslides, avalanches, thunder and lightning) and man-made disasters (fire, building destruction, industrial accidents, transport accidents, terrorism, stampede).
3. Natural disasters include earthquakes (sudden shaking of earth originating from a 'focus' with 'epicentre' being the vertical point at surface), volcanoes (openings where lava and rocks erupt), and tsunamis (waves generated by earthquakes, volcanic eruptions and underwater landslides).
4. Other natural disasters are cyclones (low-pressure areas encircled by high-pressure wind), floods (overflow of water beyond normal limits), landslides (movement of rocks and debris downslope), avalanches (ice, snow and rock falling down mountains), and thunder and lightning (electrical discharges creating flashes and sound waves).
5. Man-made disasters include massive forest fires from human carelessness, building destruction, industrial accidents like the Bhopal gas tragedy, transport accidents from rule violations, terrorism from social unrest, and stampedes causing injuries and death from suffocation and trampling.