Natural Hazards & Disasters Class 11 geography MCQ & SAQ

Natural Hazards & Disasters Class 11 geography NCERT SOLUTION:

1. Choose the right answer from the four alternatives given below

(i) Which one of the following states of India experiences floods frequently?

(a) Bihar

(b) West Bengal

(c) Assam

(d) Uttar Pradesh

Answer: (c) Assam

Note: Assam, West Bengal and Bihar are among the high flood-prone states of India and floods are almost annual features of these states.

(ii) In which one of the following districts of Uttarakhand did the Malpa Landslide disaster take place?

(a) Bageshwar

(b) Champawat

(c) Almora

(d) Pithoragarh

Answer: (d) Pithoragarh

(iii) Which one of the following states receives floods in the winter months?

(a) Assam

(b) West Bengal

(c) Kerala

(d) Tamil Nadu

Answer: (d) Tamil Nadu

(iv) In which of the following rivers is the Majuli River Island situated?

(a) Ganga

(b) Brahmaputra

(c) Godavari

(d) Indus

 

Answer: (b) Brahmaputra

(v) Under which type of natural hazards do blizzards come?

(a) Atmospheric

(b) Aquatic

(c) Terrestrial

(d) Biological

 

Answer: (a) Atmospheric

(i) When can a hazard become a disaster?

Answer: Natural hazards are elements of circumstances in the natural environment that have the potential to cause harm to the people or property or both. As compared to natural hazards, natural disasters are relatively sudden and cause large scale, widespread death, loss of property and disturbance to social systems and life over which people have a little or no control.

(ii) Why are there more earthquakes in the Himalayas and in the north-eastern region of India?

Answer: The Himalayas comprise young fold mountain ranges. The Indian plate is moving towards the north and this movement of plates is being constantly obstructed by the Eurasian plate from the north. As a result of this, Indian and Eurasian plates are said to be locked with each other, resulting in accumulation of energy at different points of time. Excessive accumulation of energy results in building up of stress and the sudden release of energy causes earthquakes along the Himalayan arch.

(iii) What are the basic requirements for the formation of a cyclone?

Answer: There are differences of opinion among scientists about the exact mechanism of a tropical cyclone. However, some initial conditions for the emergence of a tropical cyclone are:

Large and continuous supply of warm and moist air

Strong Coriolis force that can prevent filling of low pressure at the center

Unstable condition through the troposphere

Absence of strong vertical wind wedge

(iv) How are the floods in Eastern India different from the ones in Western India?

Answer: Eastern states like Assam, West Bengal and Bihar are among the high flood-prone states of India due to the extreme precipitation. But the northern states like Punjab and Uttar Pradesh are also vulnerable to occasional floods because of blocking of most of the streams and river channels of western India by human activities.

(v) Why are there more droughts in Central and

Western India?

Answer: Most parts of Rajasthan, Gujarat, Madhya Pradesh, eastern parts of Maharashtra, interior parts of Telangana and Karnataka Plateau, northern parts of interior Tamil Nadu and southern parts of Jharkhand and interior Odisha are drought prone areas of India. These areas receive scanty rainfall and rainfall variability is very high. As a result the tanks, wells and similar underground water reserves remain unchanged.

3. Answer the following questions in not more than 125 words.

(i) Identify the Landslide-prone regions of India and suggest some measures to mitigate the disasters caused by these.

Answer: A landslide is a geological phenomenon that includes a wide range of ground movements. India has been divided into a number of zones.

 Very High Vulnerability Zone: This zone includes the areas in Himalayas, Andaman and Nicobar, steep and rainy slopes of the Western Ghats and Nilgiris, the northeastern states of India.

 High Vulnerability Zone: These areas have geographical conditions similar to those areas which have very high vulnerability. This zone includes all the Himalayan states and hilly areas of northeastern states. The intensity and frequency of landslides in these areas is less as compared to areas of very high vulnerability.

 Moderate to Low Vulnerability Zone: Landslides due to mining and subsidence are most common in states like Jharkhand, Odisha, Chhattisgarh, Madhya Pradesh, Maharashtra, Telangana, Andhra Pradesh, Karnataka, Tamil Nadu, Goa and Kerala.

Mitigation: Landslide mitigation refers to construction and other man-made activities on slopes with the goal of lessening the effect of landslides. It is always advisable to adopt area-specific measures to deal with landslides.

Restriction on the construction of roads and dams, and agricultural activities in the areas of moderate slopes.

Preventing water entering the hillside through open or discontinuous traction cracks.

Large-scale afforestation programmes and construction of bunds to reduce the flow of water in the hilly areas.

Terrace farming should be encouraged in the areas of Jhumming.

(ii) What is vulnerability? Divide India into natural disaster vulnerability zones based on droughts and suggest some mitigation measures.

Answer: Vulnerability is a concept that links the relationship that people have with their environment to social forces and institutions and the cultural values that sustain and contest them during hazards and disasters. On the basis of severity of droughts, India can be divided into the following regions:

Extreme Drought Affected Areas: most parts of western Rajasthan and Rann of Kachchh region of Gujarat are areas of extreme drought.

Severe Drought Prone Area: This category of drought prone areas include parts of eastern Rajasthan, most parts of Madhya Pradesh, eastern parts of Maharashtra, interior parts of Telangana and Andhra Pradesh and Karnataka Plateau, northern parts of interior Tamil Nadu and southern parts of Jharkhand and interior Odisha.

Moderate Drought Affected Area: Northern parts of Rajasthan, Haryana, southern districts of Uttar Pradesh, the remaining parts of Gujarat, Maharashtra except Konkan, Jharkhand and Coimbatore plateau of Tamil Nadu and interior Karnataka are included in this category.

Drought mitigation measures:

Immediate steps should be taken to provide safe drinking water, medicines, and fodder for the people and their livestock.

Rain water harvesting should be encouraged as far as possible.

Various devices of remote sensing, satellite mapping and GIS may be used for identifying water aquifers.

Afforestation retains water and helps in reducing the frequency and intensity of droughts.

Drought resistant or rain fed crops should be grown in areas of deficient rainfall.

(v) When can developmental activities become the cause of disasters?

Answer: Developmental activities become the cause of disasters when such activities are carried on in the disaster prone areas without carrying the environmental conditions and severe consequences of such activities. For example development of large cities and port-towns like – Mumbai and Chennai along the coast, and touching the shore due to high land values, make them vulnerable to the occurrence of cyclones, hurricanes and tsunamis. The development activities in the landslide prone areas like the Himalayas and the Western Ghats can be harmful. The construction activities in the river valley can lead to soil disturbance and flood. Sometimes, rivers also change their course causing floods and other calamities in the affected areas.

Natural Hazards & Disasters Class 11 geography MCQ 

Question. When the situation of hazard arises?

(a) When there is the threat of natural calamity

(b) When there is a threat to the consequences of the disaster

(c) When there is a threat to property and lives from calamities

(d) All of the above

Answer : B

Question. How many different activities are defined under disaster management?

(a) 4

(b) 7

(c) 5

(d) 6

Answer : D

Question. Who among these govern/ head the National Crisis Management Committee?

(a) Cabinet Secretary

(b) Ministry of Home Affairs

(c) Prime Minister

(d) Ministry of Environment

Answer : A

Question.  Which of the following is an example of a terrestrial natural disaster?

(a) Blizzard

(b) Tornado

(c) Thunderstorm

(d) Landslide

Answer : D

Question.  According to WHO, the number of countries and territories affected by

(a) 255

(b) 195

(c) 218

(d) 220

Answer : C

Question. National Disaster Management Authority is headed by

(a) the Prime Minister.

(b) the Home Minister

(c) the President.

(d) the Health Minister.

Answer : A

Question. Zika virus is spread by which of the following:-

(a) Pig

(b) Fly

(c) Mosquito

(d) Rat

Answer : C

 

 

Question. The mass movement of rock, debris or earth down a slope is referred to as:

(a) Volcano

(b) earthquake

(c) flood

(d) landslide

Answer : D

Question. Where is the International Tsunami information center located?

(a) Honolulu

(b) Hyderabad

(c) Goa

(d) Pondicherry

Answer : A

Question. Where is the Tsunami Warning Center located in India?

(a) New Delhi

(b) Hyderabad

(c) Gujarat

(d) Kolkata

Answer : B

Question. Which option is referred to as the Ring of Fire?

(a) Area encircling the pacific ocean named as Circum-Pacific Belt

(b) Area encircling by a belt of volcanoes of mid-Atlantic ocean

(c) Area encircling by the belt of volcanoes of the mid-continental region.

(d) None of these

Answer : A

Question. The two atom bombs in World war II has been dropped on which of the following:-

(a) Hiroshima and Nagasaki in Japan

(b) Germany

(c) Italy

(d) Great Britain

Answer : A

Question. Which of the following is the most damaged MSK IX risk zone in the context of an earthquake?

(a) Tamil Nadu

(b) Rajasthan

(c) North eastern states

(d) Karnataka

Answer : C

Question. In which year the largest cyclone-hit Andhra Pradesh displaced 63,40,000 people?

(a) 1992

(b) 1989

(c) 1990

(d) 1991

Answer : C

Question. The extreme risk zone during a volcanic eruption is…………….

(a) At a distance Upto 100 Meters

(b) At a distance of 100-300 mtrs

(c) At a distance of 300mtrs- 3 km

(d) None of these

Answer : A

Question. What is the range of the intensity scale used in measuring earthquakes?

(a)1 to 12

(b)1 to 7

(c)1 to 15

(d)1 to 5

 

Answer : A 

Question. Far less dramatic disaster is

(a) Volcano.

(b) Landslide.

(c) Earthquake.

(d) Tsunami.

 

Answer : B

 

 

 

 

Question. What causes a Tsunami?

(a) Sudden vertical movement of the Earth

(b) Convergence of destructive plates in the ocean floor

(c) Explosive volcanic eruptions in the seas/oceans.

(d) All of the above

 

Answer : D

 

Question. Debris flow that originates on the slope of a volcano is known as

(a) Creep.

(b) Fall.

(c) Lahar.

(d) Lateral spreads.

 

Answer : D

 

Question. What was the cause of the Koyna Earthquake?

(a) Current Pressure in Koyna reservoir.

(b) Hydraulic Pressure in Koyna reservoir.

(d) Cyclone in Koyna reservoir.

(d) None of the above

 

Answer : B

 

Question. What is the rank of India in the world for natural disasters after China as per UNISDR?

(a) Third

(b) Second

(c) Seventh

(d) Eighth

 

Answer : B

 

Question. Landslides and floods occur due to

(a) Deforestation

(b) Global warming

(c) Environmental pollution

(d) None of them

 

Answer : A

 

Question. Anthropogenic causes:

(a) Emission of greenhouse gasses

(b) Pollution of soil

(c) Deforestation

(d) All of them

 

Answer : D

 

Question. Out of these, which is the aquatic type of disaster?

(a) Tidal waves

(b) Bacterial and viral diseases

(c) Landslides

(d) Thunderstorms

 

Answer : A

 

Question. Under which type of natural hazards do blizzards come?

(a) Atmospheric

(b) Aquatic

(c) Terrestrial

(d) Biological.

 

Answer : A

 

Question. Proportion of the country’s total area identified as drought prone is

(a) 50%

(b) 70%

(c) 30%

(d) 40%

 

Answer : C

 

Question. Which river is called the sorrow of Bengal?

(a) Ganga

(b) Damodar

(c) Brahmaputra

(d) Kosi

 

Answer : B

 

Question. Which one of the following states of India experiences floods frequently?

(a) Bihar

(b) West Bengal

(c) Assam

(d) Uttar Pradesh.

 

Answer : C

 

Question. Which of the following types of volcanic eruptions associated with Lacroix?

(a) Hawaii Eruption

(b) Strombolian Eruption

(c) Vulcanian

(d) All of the above

 

Answer : D

1. Which one of the following states receives floods in the winter?

(a) Assam

(b) West Bengal

(c) Kerala

(d) Tamil Nadu

► (d) Tamil Nadu

 

2. Far less dramatic disaster is

(a) Volcano.

(b) Landslide.

(c) Earthquake.

(d) Tsunami.

► (b) Landslide.

 

3. Natural disasters are

(a) Relatively slow movements in comparison to hazard.

(b) Relatively sudden and cause large scale disaster in comparison to hazard.

(c) Relatively small scale disaster.

(d) Disaster with no damage.

► (b) relatively sudden and cause large scale disaster in comparison to hazard.

 

4. The cause for floods in India is due to

(a) Deforestation.

(b) Overpopulation.

(c) High temperature.

(d) Increasing transportation.

► (a) deforestation.

 

5. Tsunamis are caused when

(a) An earthquake occurs.

(b) Wind is strong.

(c) Ocean currents become warm.

(d) Sea level rises.

► (a) An earthquake occurs.

 

6. The most disastrous giant waves are

(a) body waves.

(b) ocean currents.

(c) tsunamis.

(d) surface waves.

► (c) tsunamis.

7. The river valley project has been constructed to check floods in india is

(a) Bhakra and Nangal Dam.

(b) Damodar Valley Corporation.

(c) Annasagar project.

(d) Narmada dam.

► (b) Damodar Valley Corporation.

 

8. Debris flow that originates on the slope of a volcano is known as

(a) Creep.

(b) Fall.

(d) Lahar.

(d) Lateral spreads.

► (d) lahar.

 

9. Which instrument measures the seismic waves?

(a) Earthometer

(b) Seismograph

(d) Quake Graph

(d) None of the above

► (b) Seismograph

 

10. How many divisions are there on the Richter Scale?

(a) From 1 to 7.

(b) From 1 to 8.

(d) From 1 to 9.

(d) From 1 to 10.

► (d) From 1 to 9.

 

11. On which scale, is the intensity of Earthquakes measured?

(a) Seismograph

(b) Quake Scale

(d) Richter Scale.

(d) Earthometer

► (d) Richter Scale.

 

12. When a mass of earth saturated with water slides down a hill slope it is called:

(a) Ocean current

(b) Landslide

(d) Floods

(d) Cyclones

► (b) Landslide

 

13. What was the main cause of latur Earthquakes?

(a) Southward drifting of the Indian Plate.

(b) Northward drifting of the Indian Plate.

(d) Eastward drifting of the Indian Plate.

(d) Westward drifting of the Indian Plate.

► (b) Northward drifting of the Indian Plate.

 

14. What was the cause of the Koyna Earthquake?

(a) Current Pressure in Koyna reservoir.

(b) Hydraulic Pressure in Koyna reservoir.

(d) Cyclone in Koyna reservoir.

(d) None of the above

► (b) Hydraulic Pressure in Koyna reservoir.

Natural Hazards & Disasters Class 11 geography SAQ

 

What is an earthquake and what is its intensity?

An earthquake is the sudden movement of the crust of the earth resulting in tremors and vibrations. Like magnitude, the intensity is also one of the ways to measure the strength of an earthquake. Intensity relates to the force of an earthquake. It is the measure of the damage caused by the earthquake.

 

Name a high and very high-risk seismic area of India.

From the earthquake point of view, the high-risk areas are the Ganga plains and western Rajasthan, whereas the very high-risk areas are the Himalayan mountain, north-eastern India, Kachchh, west coast around Ratnagiri and Andaman and Nicobar islands.

 

What are the basic requirements for the formation of a cyclone?

The following are the basic requirements for the formation of a cyclone:

1. The temperature of the oceanic surface is over 26°C.

2. The appearance of a closed isobar.

3. Pressure dropping below 1000 Mb.

4. Areas of circular movement, first spreading to a radius of 30-50km., then increasing gradually to 100-200 km. and even to 1000 km.

5. Vertically Thewindspeedfirstrisingtoaheightof6km., then much higher.

 

What is the velocity of a cyclone and its normal duration?

The speed of movement of a cyclone per unit of time is called its velocity. The cyclones move at an average velocity of about 20 km. per hour. Its normal duration is five to seven days.

 

Mention the flood-prone areas of India.

The flood-prone areas of India include the Ganga basin covering Uttar Pradesh, Bihar, and West Bengal, the Brahmaputra basin in Assam, and the Baitarani, the Brahmani and Subarnarekha basins of Orissa.

 

 

Name two human activities that cause a flood in India.

These are the two factors that increase the incidence of a flood.

1. Deforestation,

2. Drainage congestion (caused by the badly planned construction of bridges, roads, railway tracks, and other developmental activities).

 

What are the consequences of landslides on humans?

There are the following consequences of landslides:

1. Damage to planted vegetation and crops.

2. Disruption of communication due to the blocking of roads and rivers.

3. Destruction of human settlements over slopes and loss of human life.

 

What is disaster management?

The term disaster management includes all aspects of prevention and protection measures, preparedness, and organization of relief operations for mitigating the impact of disasters on human beings and socio-economic aspects of the disaster-prone area.

 

How do embankments worsen the problem of a flood?

The construction of embankments, the river water spreads out the stream and flows over it, it worsens the problem of a flood. The width of the river stream becomes narrow and a flood occurs.

 

What are the major hazards that occur in India?

Drought, floods, cyclones, landslides, and earthquakes are some of the major hazards which occur in India. These natural hazards or disasters are the results of sudden earth movements that change the face of the earth in a short period causing heavy loss of life 

What do you understand by ‘tsunami’?

‘Tsunami’ is a series of waves generated under the body of water by an impulsive disturbance that vertically displaces the water column. Earthquakes, landslides, volcanic eruptions, and the impact of cosmic bodies like asteroids can generate a tsunami.

 

Define solifluction.

Solifluction is the slow movement of rock debris, saturated with water and not confined to definite demands, down a slope under the force of gravity. It occurs particularly when thawing releases such surface deposits while the underlying layers are still frozen. The term is usually applied to saturated deposits.

 

Define the pressure gradient.

The amount of change in atmospheric pressure between two points is called the pressure gradient. It is indicated by the distance apart on a level surface of the isobar. Closely spaced isobars indicate a steep gradient and those widely spread represent gentle gradients.

 

Why do the north bank tributaries of the Brahmaputra river create more floods than those of the south bank?

It is because the northern tributaries have steep slopes, shallow and braided channels, and coarse sandy beds; they carry a heavy silt charge and have a tendency to bring fresh floods. The south bank tributaries, on the other hand, have comparatively flatter gradients and deeper channels, they are clayey and have more stable banks and beds.

Natural Hazards & Disasters Class 11 geography long question

Discuss the three components of the impact phase of disaster management.

The term disaster management includes all aspects of preventive and perspective measures, preparedness, and organization of relief operations for mitigation of the impact of the disaster on human beings and socio-economic aspects of the disaster-prone areas.-The whole process of disaster management can be divided into three phases, impact phase, rehabilitation and reconstruction phase, and integrated large term development and preparative phase.

The impact phase contains three components – forecasting of disaster, close monitoring of agents causing disasters, and management activities after the disaster has occurred. As far as forecasting of disaster is concerned, flood forecasting can be done by studying rainfall in the catchment area. The approach of cyclones can be tracked and monitored by satellites. Based on these details, early warning and evacuation efforts may be made.

Close monitoring of agents responsible for disaster can help the deployment of terms to help evacuation and supply of food, clothing and drinking water. Disaster leaves a trail of death and destruction. This will require medical care and the help of the affected people. Under the long-term development phase, preventive and precautionary measures of various kinds should be chalked out.

 

What should people do and don’t do in an area going to be hit by a cyclone?

In order to draw the attention of the people of the world, the UNESCO observed the International Decade for natural disaster Reduction during 1990-2000. Along with other nations of the world, India observed World Disaster Reduction Day in October during the decade. Do’s and Don’ts for the people in cyclone-hit areas, which were issued by the Government of India are as follows:

1. Listen to the radio for advance information and advice. Allow a considerable margin for safety.

2. When the storm force winds or severe gales are forecast for your area: store or secure loose boards, corrugated iron, rubbish lines, or anything else that could become dangerous; tape up large windows to prevent them from shattering; and move to the nearest shelter or evacuate the area if this is ordered by the ‘ appropriate government agency.

3. When the storm hits it is advisable: to stay indoors and take shelter in the strongest part of your house; listen to the radio and follow instructions; open windows on the sheltered side of the house if the roof begins to lift; find shelter if you are caught out in the open, and do not go outside during a lull in the storm.

 

Describe the flood in India as a disaster. Write an essay on floods as a disaster.

 

Floods are a major cause of human misery in India every year. Out of a number of natural disasters that the country has experienced, floods are the most important ones. India is the most flood-affected country in the world next to Bangladesh. Twenty percent of the global deaths caused by floods in the world are in India.

In spite of the fact that floods are a natural disaster, it often turns out to be a social disaster as the people who are severely affected are generally the poor because they live on the periphery of the human habitat. The annual flood-affected population has risen faster than the growth of India’s population. The flood-affected area and damages have also increased recently; the reason for this increase is the encroachment of floodplains by the people.

The most flood-prone basins in the country are those of the Ganga-in Uttar Pradesh, Bihar, and West Bengal, the Brahmaputra in Assam, and the Batumi, the Brahmani, and the Subarnarekha basins in Orissa. Sometimes floods occur also in Andhra Pradesh, Rajasthan, Haryana, and Gujarat.

Flood Control – Floods are not new in India. The practice of building flood protection embankments along rivers is an ancient one. We had flood protection embankments on the Godavari, Krishna, and the Kaveri deltas and in the Indo-Ganges plain.

The nationwide flood protection programs, however, began only after independence. At the time of independence in 1947, India had some 5280 km. of embankments along different rivers. Of this 3500 km. were in the Sundarbans in West Bengal and 1209 km. along the Mahanadi in Orissa. This provided protection to about 3 million hectares of land.

In 1954 a spate of severe floods came. Enormous devastation was caused in Uttar Pradesh, Bihar, West Bengal, and Assam. Long term programs for the construction of dams and embankments were drawn. Central and state flood control boards were set up. In spite of various measures taken up to minimize the fury of floods, they are still a regular feature in the Ganga and the Brahmaputra basin.

Reducing Impact of Flood-The building of embankments was the only way floods could be controlled in the 1940s.

 

Fig.7.3: “Heavily embankment areas of India’

The dams and reservoirs were considered useful to control runoff water and reduce flooding. Now there are several other measures to reduce the severity of the flood. The felling of trees and deforestation on mountain slopes and in catchment areas need control. Weather forecast and flood warning feature is a regular feature.

 

What is a tsunami? How it occurs and what are its consequences? Describe in detail.

A tsunami is a series of waves generated in the body of water by an impulsive disturbance that vertically displaces the water column. Earthquakes, landslides, volcanic eruptions, and even the impact of cosmic bodies such as asteroids can generate a tsunami. When the Indian plate in the north-east gets locked with the Eurasian plate, it creates high stress, and the accumulation of high energy causes an earthquake.

Cause – Nomially the seismic waves cause only one instantaneous vertical wave but after the initial disturbance, a series of after waves are created in the water that oscillates between the high crest and low trough in order to restore the water level. The speed of waves in the ocean depends upon the depth of water. It is more in shallow water than at the ocean depth.

Consequences – The impact of the tsunami is less over the ocean and more near the coast where they cause large scale devastation. Therefore, a ship at sea is not much affected by tsunamis. The tsunami wave raises the ship only one meter because over deep water tsunami has a very long wavelength and limited wave height. Over shallow water, a tsunami causes large-scale destruction along the shores, where wavelength gets reduced and height can be up to 15 meters.

• After reaching the coast they release enormous amounts of energy and destroy the port cities and towns, structures, buildings, and other settlements.

• The loss of property and life by the tsunami is much higher as compared to other natural hazards in the coastal areas.

Mitigation steps – It is difficult to mitigate the hazards caused by the tsunami because of the fact that losses are on a much larger scale.

 

What is an earthquake? Discuss the causes and consequences of an earthquake.

An earthquake is a sudden movement of the crust of the earth. When an earthquake occurs when the Indian plate gets locked up with a Eurasian plate, high stress is developed which results in the release of high energy. It is a sudden shaking of the crust which results in tremors and vibrations.

Causes – The following are the causes of earthquakes:

1. Volcanic eruption

2. Tectonic causes

3. Elasticity of rocks

4. Local causes

Consequences –

1. If the intensity of an earthquake is more than 6 on the Richter scale, there is a loss of life and property on a large scale.

2. In the young fold mountains, the earthquake leads to cracks in the rocks and causes landslides.

3. Due to earthquakes, there are short circuits of electrical wires which damage and blast the equipment.

4. Usually, earthquakes lead to distortion and displacement of the surface rocks which block the flow of the river coming in the way.