Chapter 3: Natural Disaster

Fill in the blanks

1. Disasters that are caused by nature are called as…………………………………… 

2. The earthquake zoning map divides India into …………………...seismic zones. 

3. The state of Jammu and Kashmir falls in seismic zone ………….. and ………….. 

4. ……………………… is a large mass of snow that moves rapidly down a mountain slope. 

5. ……………………….. can be defined as a lack or shortage of water for an unusually long period. 

6. A …………………………. is a widespread scarcity of food in an area. 

7. Storing rain water on the roofs of the houses is called as ………………………….. 

8. ………………….. is a disastrous weather event in which, the heavy rainfall occurs over a localized area. 

9. An …………………….. is a natural disaster in which the sudden shaking of earth’s surface is involved.

10. Instrument used to measure the magnitude of an earthquake is called as ……………….. 

Answers:

1. Disasters that are caused by nature are called as Natural Disasters.

2. The earthquake zoning map divides India into four (Zone  II,  III,  IV  and  V) seismic  zones  

3. The state of Jammu and Kashmir falls in seismic zone IV and V

4. Snow Avalanche is a large mass of snow that moves rapidly down a mountain slope. 

5. Drought can be defined as a lack or shortage of water for an unusually long period. 

6. A famine is a widespread scarcity of food in an area. 

7. Storing rain water on the roofs of the houses is called as Roof top rain water harvesting

8. Cloud burst is a disastrous weather event in which, the heavy rainfall occurs over a localized area. 

9. An earthquake is a natural disaster in which the sudden shaking of earth’s surface is involved.

10. Instrument used to measure the magnitude of an earthquake is called as seismograph

One word Answers

1. Which disaster hit Muzaffarabad region in year 2005?

Answer: Earthquake. (with magnitude of 7.6 on Richter scale  on 8th  October,  2005  at  9.20  a.m.)

2. Which disaster involves the movement of a mass of soil, rock or debris down the slope?

Answer: Landslide.

3. Which disaster hit the famous Kedarnath Shrine area at Uttrakhand in June, 2013?

Answer: Flash Flood.

4. Which disaster devastated the normal life in Leh on 6th August, 2010?

Answer: Cloud Burst

5. Which disaster hit the Bhaderwah area in year 2013

Answer: Earthquake.

Very short/ short answers

1. What is the difference between hazard and disaster?

Answer: HAZARD:  is  a  situation  that  poses  a  level  of threat  to  life,  health,  property  or  environment. 

DISASTER: Disasters  occur  when  hazards  meet  vulnerable situations.  A  disaster  is  a  natural,  man-madetechnological  event  that  causes  significant physical  damage  or  destruction,  widespread loss  of  life  or  drastic  change  to  the  environment.

2.What do you understand by a natural disaster? Enlist few.

Answer: A Natural Disaster is an event that is caused by  natural hazards and leads to loss of life and damage to  physical infrastructure and environment. Examples    of  natural disasters are: 

• Tsunami, 
• Earthquake, 
• Snow  Avalanche, 
• Cloudburst 
• Landslides

3. Write down some events of earthquakes in India?

Answer: Some important Earthquakes in India are;

Area	Year	Magnitude
Rann of Kutch	1819	8.0
Assam	1897	8.7
Kangra	1905	8.0
Arunachal Pradesh	1950	8.5
Uttrakashi	1991	7.0
Kutch	2001	7.7
Sikkim	2011	6.9
Uri Muzaffarabad	2005	7.6

    

4. What is the difference between drought and famine?

Answer: Drought  can  be  defined  as  a  lack  or  shortage  of water  for  an  unusually  long  period.  A  drought is  an  extended  period  of  months  or  years  when a  region  notes  a  deficiency  in  its  water  supply whether  surface  or  underground. 

Famine is a widespread scarcity of food, caused by several factors including crop failure, population unbalance or government policies. Drought results in shortage in the agricultural production thereby causing food shortages that can lead to famine.

5. Illustrate briefly how an earthquake occurs. 

Answer: An earthquake is a sudden shaking of earth’s surface due to release of energy in the Earth's crust. 

The epicentre is the point on the Earth's surface that is  directly above the focus, the point where an earthquake  originates. 

Earthquakes generate seismic waves which can be  detected with seismograph.

Long answers 

1. What do we understand by Mitigation? Give some examples. 

Answer: Mitigation is an effort to reduce loss of life and  property by reducing the impact of disasters. Mitigation  is taking preventive actions before the next disaster  happens in order to reduce human and financial consequences.

MITIGATION MEASURES TO REDUCE THE EFFECTS OF  LANDSLIDES

Drainage Management: Landslides occur mostly when water infiltrates into the land during heavy rains. In  order to prevent or minimize this infiltration, natural  drains should be strengthened to allow the smooth flow of water.    

Retaining walls: Construction of concrete retaining  walls prevents the slippage from slopes. 

Plantation: Growing more and more plants along the  landslide zones helps in total or maximum arrest of the slippage.

Mapping: Mapping helps to identify the landslide risk  areas. This data can help to avoid such areas to use for settlements. 

Awareness  programmes: People should be educated  about various signs and caution boards installed at various landslide risk zones. 

2. List some of the major natural disasters that are likely to occur in hilly regions. Elaborate any one of them. 

Answer: Some of the major natural disasters that are likely to occur in hilly regions are;

• Landslide
• Cloud Burst
• Snow Avalanches
• Flash Floods

Cloud Burst: The cloud burst is a disastrous weather event in which,  the heavy rainfall occurs over a localized area at a faster rate. The rate of rainfall may be of the order of 100mm per hour. It is sometimes associated with hail and thunder and is capable of creating flood  conditions. The cloud bursts in India occur during  monsoon season in Himalayan region, Northeastern  states and the Western Ghats. Cloudbursts lead to  flooding, landsliding, ponding of  rivers due to huge  landslides, mudflows. Cloudbursts cause huge damage to buildings, infrastructure, communication  links etc. The cloud bursts lead to sudden flash  floods, mudslides and debris slides. It is therefore necessary to follow the same mitigation measures as are to be followed in case of floods.

3. What is a drought? Describe how it can be prevented? 

Answer: Drought can be defined as a lack or shortage  of water for an unusually long period. A drought is an  extended period of months or years when a region  notes a deficiency in its water supply whether surface  or underground. A situation of drought occurs  generally when a region receives consistently below  average precipitation. It can have a substantial impact  on the ecosystem and agriculture of the affected  region. 

The Drought can be prevented by adopting below mentioned measures:

• Construction of dams/check dams to store water 
• Watershed management 
• Proper selection of drought resistant crop for drought affected areas 
• Soil conservation techniques 
• Reducing deforestation and cutting of firewood in affected areas 
• Education and awareness to people

4. What are the relief steps that need to be taken in the aftermath of landslides or snow avalanches? 

Answer: The relief steps that need to be taken aftermath of landslide or snow avalanches include shifting people and property from the areas which are prone to avalanches, or by protecting the people and property by using engineered sheds, walls, berms and deflectors to absorb, dissipate or redirect moving  avalanches. In addition the following mitigation measures can be adopted: 

• Stopping indiscriminate mining and quarrying in  mountain areas which may lead to avalanches during winter. 
• Afforestation of zones prone to snow avalanches. 
• Modifying the slopes removing unstable material through engineering measures.

5. Describe some of the safety measures that should be adopted during an earthquake.

Answer: The safety measures that should be adopted during an earthquake are:

• Remain calm, try to be calm and reassure others to derive an action plan. 
• If you are inside a building, watch for falling  plaster/bricks/stones, light fixtures and other objects. 
• Watch for high book cases, shelves and other  cabinets which might slide or topple.
• Stay away from glass, windows, mirrors and chimneys. 
• If in danger get under a table, desk or bed in a  corner away  from the window with your head covered by your arms. 
• Encourage others to follow your example and  don't run and create panic, instead walk calmly outside to an open area 
• If outside avoid high building walls, power poles  and other objects that could fall. 
• Do not run through streets. If surrounded by  buildings take shelter in the nearest strongest one.
• If in an automobile, stop in a safe place available, preferably an open area 
• Don’t use elevators while coming out of a building instead use stair cases.