This MCQ module is based on: Chapter 6 Summary, Map Work & Exercises
TOPIC 17 OF 17
Chapter 6 Summary, Map Work & Exercises
🎓 Class 11
Social Science
CBSE
Theory
Ch 6 — Natural Hazards and Disasters
⏱ ~22 min
🌐 Language: [gtranslate]
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Chapter 6 · Summary, Key Terms & NCERT Exercises
A revision pack of the entire chapter on Natural Hazards and Disasters. Find a one-page summary, the chapter glossary, all NCERT exercises with model answers, the project-work options, and a final round of CBQ + Assertion–Reason questions to consolidate everything you have learned about floods, droughts, earthquakes, tsunami, cyclones, landslides and India's disaster management framework.
6.11 Chapter Summary
📝 The Whole Chapter in One Page
(a) Hazard vs Disaster: A natural hazard is an element of the environment with potential to cause harm; a disaster is the actual event of large-scale destruction. Every disaster is rooted in a hazard, but only some hazards become disasters — usually because of high population density or low coping capacity.
(b) Classification: NCERT recognises four categories — atmospheric (cyclones, droughts, blizzards), terrestrial (earthquakes, landslides, volcanoes), aquatic (floods, tsunami, storm surge) and biological (locust swarms, viral diseases).
(c) Earthquakes: The Indian plate moves north at ~1 cm/yr, locking against the Eurasian plate and causing earthquakes along the Himalayan arc. India is divided into five seismic zones; major events include 1819 Kachchh, 1993 Latur, 2001 Bhuj, 2005 Kashmir, 2011 Sikkim, 2015 Nepal.
(d) Tsunami: Sea-floor displacement creates long-wavelength waves that grow in height as they hit shallow water. The 26 December 2004 Indian Ocean tsunami killed more than 3,00,000 people and triggered India's joining of the International Tsunami Warning System.
(e) Floods: Rashtriya Barh Ayog identifies 40 million hectares as flood-prone. Assam, West Bengal and Bihar lead the list; Rajasthan and Punjab now face flash floods. Tamil Nadu floods in November–January from the retreating monsoon.
(f) Droughts: Four types — meteorological, agricultural, hydrological, ecological. About 30 % of India is drought-prone; Marusthali (Rajasthan) and Kachchh are extreme zones.
(g) Cyclones: Form between 30° N–30° S; have eye, eye-wall and spiral bands; Bay of Bengal hosts more cyclones than the Arabian Sea. Recent storms: Phailin (2013), Hudhud (2014), Vardah (2016), Fani (2019), Amphan (2020).
(h) Landslides: Highly localised; very-high vulnerability in the Himalayas, NE India and the Western Ghats. Malpa (1998) and Kedarnath (2013) stand as landmark events.
(i) Disaster Management: The Disaster Management Act, 2005 created the NDMA (policy) and NDRF (response). Three stages — pre-disaster (mitigation, preparedness), during (rescue, relief), post-disaster (recovery, capacity-building) — together form the disaster management cycle.
6.12 Key Terms & Glossary
| Term | Definition |
|---|---|
| Hazard | An element of the natural environment with the potential to harm people or property. |
| Disaster | An undesirable occurrence beyond human control that causes large-scale loss of life and property. |
| Mitigation | Long-term measures (structural and non-structural) to reduce the impact of disasters. |
| Preparedness | Plans, drills, awareness, and capacity-building to face an imminent disaster. |
| Vulnerability | The degree to which people, property and systems are exposed to and unable to cope with disasters. |
| Earthquake | Sudden release of energy in the Earth's crust producing seismic waves. |
| Seismic Zone | A region classified by expected earthquake intensity (Zones I to V in India, where V is highest risk). |
| Tsunami | A long-wavelength sea wave caused by sub-marine earthquakes or volcanic eruptions; can rise to 15 m on coast. |
| Flood | Inundation of land due to overflow of water from rivers, channels or seas. |
| Drought | An extended period of water shortage caused by inadequate rain and excessive evaporation. |
| Tropical Cyclone | An intense low-pressure system between 30° N–30° S powered by latent heat from warm seas. |
| Storm Surge | Abnormal rise of sea level caused by cyclonic winds and pressure gradient. |
| Landslide | Rapid downslope movement of rock and soil under gravity. |
| NDMA | National Disaster Management Authority — the apex policy body, chaired by the PM. |
| NDRF | National Disaster Response Force — the specialist search-and-rescue force. |
| NIDM | National Institute of Disaster Management — capacity-building and research. |
| IDNDR | International Decade for Natural Disaster Reduction (1990–2000), declared by the UN. |
| Yokohama Strategy | Plan of Action for a Safer World (1994); priority to vulnerable countries; emphasis on cooperation. |
6.13 NCERT Exercises — Choose the Right Answer (Q1)
1. Choose the right answer from the four alternatives given below.
1(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. Although Bihar, West Bengal and parts of UP do flood, Assam — through which the unstable Brahmaputra braids in a vast valley — sees the most frequent and widespread floods every monsoon. NCERT identifies Assam, West Bengal and Bihar as the most flood-prone states; among these, Assam tops the list in frequency.
1(ii). In which one of the following districts of Uttaranchal did Malpa Landslide disaster take place?
(a) Bageshwar (b) Champawat (c) Almora (d) Pithoragarh
Answer: (d) Pithoragarh. The Malpa landslide of 1998 occurred in Malpa village of Pithoragarh district (then in Uttaranchal, now Uttarakhand). It buried more than 200 pilgrims of the Kailash-Mansarovar Yatra under thousands of tonnes of debris.
1(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. Tamil Nadu experiences floods during November–January due to the retreating monsoon, which delivers most of its rainfall in those months. The other states receive most of their rain (and floods) during the south-west monsoon (June–September).
1(iv). In which of the following rivers is the Majuli River Island situated?
(a) Ganga (b) Brahmaputra (c) Godavari (d) Indus
Answer: (b) Brahmaputra. Majuli, in Assam, is the world's largest riverine island and lies between the main channel of the Brahmaputra and the Subansiri-Kherkutia Suti braid. Its annual paddy crop is famously revived by the silt deposited during Brahmaputra floods.
1(v). Under which type of natural hazards do blizzards come?
(a) Atmospheric (b) Aquatic (c) Terrestrial (d) Biological
Answer: (a) Atmospheric. Blizzards — intense snowstorms with strong winds and very low temperatures — are weather phenomena and therefore atmospheric hazards, alongside thunderstorms, lightning, tornadoes, tropical cyclones, droughts, hailstorms, frost, heatwaves (loo) and cold waves.
6.14 Short-Answer Questions (Q2 — in less than 30 words)
2. Answer the following questions in less than 30 words.
2(i). When can a hazard become a disaster?
Model Answer: A natural hazard becomes a disaster when its scale of destruction is very high — that is, when it strikes an area of high population density or low coping capacity, causing widespread death, damage and disruption beyond local relief services.
2(ii). Why are there more earthquakes in the Himalayas and in the north-eastern region of India?
Model Answer: The Indian plate moves about 1 cm/yr northward and is constantly obstructed by the Eurasian plate. The two plates lock together, energy accumulates, and its sudden release along the Himalayan arc and NE faults causes frequent earthquakes.
2(iii). What are the basic requirements for the formation of a cyclone?
Model Answer: (1) A continuous supply of warm, moist air to release latent heat; (2) a strong Coriolis force (so absent within 0°–5°); (3) tropospheric instability creating local disturbances; (4) absence of strong vertical wind shear that would disturb upward latent-heat transport.
2(iv). How are the floods in Eastern India different from the ones in Western India?
Model Answer: Eastern Indian floods (Assam, West Bengal, Bihar, eastern UP) are slow-onset river floods caused by heavy south-west monsoon rain in large catchments; western Indian flash floods (Rajasthan, Gujarat, Haryana, Punjab) are sudden, short, cloudburst-driven floods amplified by blocked drainage channels.
2(v). Why are there more droughts in Central and Western India?
Model Answer: Central and western India lie in the rain-shadow / interior tracts where the south-west monsoon is weakest and most erratic. High evaporation, sparse rainfall (e.g. less than 90 mm in Jaisalmer / Barmer), poor soil moisture and limited surface water cause recurrent droughts.
6.15 Long-Answer Questions (Q3 — in not more than 125 words)
3. Answer the following questions in not more than 125 words.
3(i). Identify the landslide-prone regions of India and suggest some measures to mitigate the disasters caused by these.
Model Answer: The very-high vulnerability zone covers the young Himalayan ranges, the Andaman & Nicobar Islands, the high-rainfall Western Ghats and Nilgiris, and the entire north-eastern region; the high-vulnerability zone covers all Himalayan and NE states (except plains of Assam). Mining-induced subsidence and slope failures occur in Jharkhand, Odisha, Chhattisgarh, MP, Maharashtra, AP, Karnataka, Tamil Nadu, Goa and Kerala. Mitigation measures recommended by NCERT: (i) restrict construction of roads and dams in high-risk zones; (ii) limit agriculture to valleys and gentle slopes; (iii) regulate large settlements in vulnerable belts; (iv) launch large-scale afforestation and bunding to slow run-off; and (v) replace slash-and-burn (jhumming) with terrace farming in NE hill states.
3(ii). What is vulnerability? Divide India into natural-disaster vulnerability zones based on droughts and suggest some mitigation measures.
Model Answer: Vulnerability is the degree to which a community, area or system is exposed to a hazard and is unable to cope with its impact — it depends on physical, social and economic factors. On the basis of drought severity, India is divided into four zones: extreme (Marusthali west of the Aravalis, Kachchh, Jaisalmer, Barmer — less than 90 mm rainfall); severe (eastern Rajasthan, MP, eastern Maharashtra, interior AP, Karnataka plateau, northern interior Tamil Nadu, southern Jharkhand, interior Odisha); moderate (northern Rajasthan, Haryana, southern UP, rest of Gujarat & Maharashtra, Coimbatore plateau); and safe / less prone (NE foothills, Konkan, Kerala, deltaic east coast). Mitigation: drought-resistant crops, rainwater harvesting, river inter-linking, watershed development, identification of aquifers, and short-term distribution of safe drinking water and fodder.
3(iii). When can developmental activities become the cause of disasters?
Model Answer: Developmental activities turn into the cause of disasters when they are pursued without ecological sensitivity. Indiscriminate deforestation in fragile catchments accelerates floods and landslides. Reckless construction of roads, tunnels and dams in unstable Himalayan or Western Ghat slopes triggers slope failures. Colonisation of flood plains and river beds raises both flood frequency and damage. Unscientific agriculture and over-extraction of groundwater cause hydrological drought. Mining-induced subsidence destabilises peninsular landscapes. Industrial accidents like Bhopal (1984) and the release of CFCs and greenhouse gases lead to anthropogenic disasters at every scale. Whenever development ignores vulnerability mapping, building codes and environmental impact assessments, the very projects intended to improve life become sources of large-scale destruction.
6.16 Project / Activity (NCERT)
📚 Project Topics — Choose Any One
- Malpa Landslide
- Tsunami (e.g. 2004 Indian Ocean event)
- Odisha and Gujarat Cyclones
- Inter-linking of Rivers
- Tehri Dam / Sardar Sarovar
- Bhuj / Latur Earthquakes
- Life in a Delta / Riverine Island
- Prepare a Model of Rooftop Rainwater Harvesting
Suggested Project Outline (any topic)
- Introduction — What is the disaster? Where and when did it happen?
- Causes — Combine natural and human factors; cite at least three primary sources.
- Consequences — Lives lost, property damaged, economic and social aftermath.
- Response & Recovery — Government, NGOs, international community.
- Lessons & Mitigation — What changed in India's policies after the event? What further steps are needed?
- Conclusion & References — Personal reflection plus a reading list.
6.17 Map Work
Map Skills — Hazards on India's Outline
- On an outline map of India, mark and shade the five earthquake hazard zones: highlight Zone V along the Himalayan arc, NE states, and Kachchh.
- Mark the locations of major Indian earthquakes: Kachchh (1819, 2001), Latur (1993), Kashmir (2005), Sikkim (2011), Nepal (2015).
- Shade flood-prone areas: Brahmaputra Valley (Assam), Ganga plains (Bihar, eastern UP, West Bengal), Indus and tributaries (Punjab), and the eastern coast affected by cyclonic floods.
- Mark drought-prone zones: extreme — Marusthali; severe — eastern Rajasthan, MP, interior Maharashtra, AP, Karnataka.
- Mark the cyclone landfalls: Phailin (Gopalpur, 2013), Hudhud (Visakhapatnam, 2014), Vardah (Chennai, 2016), Fani (Puri, 2019), Amphan (Sundarbans, 2020).
- Mark the landslide events: Malpa (Pithoragarh, 1998); Kedarnath (Rudraprayag, 2013).
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Final Round — Competency-Based Questions (All Themes)
Case Study: A school's quiz team is assembling a bank of higher-order questions covering the full chapter. They want at least one question on each disaster type, plus one synthesis question on the disaster-management cycle. Use the questions below to test integrated understanding.
Q1. Which conference produced the “Plan of Action for a Safer World”?
L1 RememberAnswer: (B) — The Yokohama (Japan) conference of May 1994 adopted the “Yokohama Strategy and Plan of Action for a Safer World” and reaffirmed 1990–2000 as the International Decade for Natural Disaster Reduction.
Q2. Approximately how much of India's geographical area is identified as drought-prone?
L2 UnderstandAnswer: (C) — About 30 % of India's geographical area is officially identified as drought-prone, affecting roughly 50 million people. NCERT cites that nearly 19 % of total area and 12 % of total population suffer from drought every year.
Q3. The Disaster Management Act came into force in:
L1 RememberAnswer: (C) — The Disaster Management Act, 2005 set up the NDMA, the SDMAs, the DDMAs and the NDRF, transforming India's disaster response architecture.
Q4. Compare two disasters that have struck Gujarat: Bhuj earthquake (2001) and Kachchh drought zone. Which statement best contrasts them?
L5 EvaluateAnswer: (A) — Kachchh sits at the intersection of two very different hazards: it is in seismic Zone V (very high earthquake risk) and is also in the extreme drought zone (less than 90 mm annual rainfall in places). Mitigation must therefore combine seismic-resistant buildings and water-harvesting infrastructure simultaneously.
HOT Q. India faces almost every disaster category. Imagine you are heading the NDMA for a year. Sketch a one-page integrated “Mission Resilient India 2030” covering: (i) early-warning network, (ii) building-code reform, (iii) school-curriculum integration, (iv) inter-state cooperation, and (v) international partnerships post-Yokohama.
L6 CreateHint: (i) IMD doppler radars + Indian Tsunami Warning System + GPS plate-monitoring; common SMS / Cell-Broadcast alerts. (ii) Mandatory IS-1893 seismic codes; cyclone-resistant rural housing; flood-zoning maps tied to building permits. (iii) Mock-drill calendar; class-wise modules from Std 6–12; teacher-training certificates from NIDM. (iv) Memoranda between bordering states for shared embankments and reservoirs; joint NDRF deployments. (v) Continued partnership with UNISDR, the Sendai Framework (successor to Yokohama), bilateral exchanges with Japan, Bangladesh and ASEAN; technology and finance support to small-island and least-developed neighbours.
⚖ Final Round — Assertion–Reason Questions
Options:
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is NOT the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is NOT the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Assertion (A): About two-thirds of India's geographical area and population are vulnerable to disasters.
Reason (R): India straddles a tectonically active plate margin, a monsoon climate with extreme variability, two cyclone-prone seas, and the world's youngest mountain belt — all within a single political boundary.
Answer: (A) — Both A and R are true; R is the correct explanation of A. The geographical reasons listed in R are precisely why such a large share of India's territory and population face one or more hazards.
Assertion (A): Tamil Nadu can experience floods in the winter months.
Reason (R): The retreating monsoon delivers the bulk of Tamil Nadu's rainfall during October–January, occasionally producing intense storms and flash floods.
Answer: (A) — Both A and R are true; R correctly explains A. The 2015 Chennai floods, for instance, occurred during the November-December retreating-monsoon season.
Assertion (A): Disaster preparedness and mitigation are more important than curative measures for earthquakes.
Reason (R): Earthquakes cannot be prevented and they damage transport and communication networks first — making post-event relief difficult to deliver in time.
Answer: (A) — Both A and R are true and R correctly explains A. Because we cannot prevent quakes and we cannot reach victims fast enough afterwards, the only effective lever is to invest in earthquake-resistant buildings and well-rehearsed preparedness drills before the next event arrives.
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Class 11 Geography — India: Physical Environment
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