📌 Chapter Snapshot
4
Earthquake Zones in India
2005
Disaster Management Act
2007
Indian Tsunami Early Warning System
1984
Bhopal Gas Tragedy
- This chapter covers major natural & man-made disasters — Earthquake, Tsunami, Landslide, Flood, Drought, Cyclone — along with India's institutional disaster management framework.
- Also includes other notable disaster events: Cloudburst, Bhopal Gas Tragedy, and Chernobyl Disaster.
⚡ QUICK RECALL
Disaster Management Act, 2005 established the three-tier structure: National, State, and District Disaster Management Authorities.
🌍 Earthquake
- Sudden ground shaking caused by rapid release of stored elastic energy, most commonly when rocks slip along a fault.
Causes
- Movement of plate tectonics
- Mining or fluid injection can induce seismicity
- Volcanic activity
- Reservoir loading can trigger seismicity
Earthquake Zones of India
| Zone | Risk Level | States / Regions |
|---|---|---|
| Zone-2 | Minimum impact (Intensity 6 or less) | Northern & eastern Rajasthan, Tamil Nadu, Northern Andhra Pradesh, Chhattisgarh, etc. |
| Zone-3 | Moderate impact (Intensity VII) | Kerala, Goa, Gujarat, Uttar Pradesh, West Bengal, Odisha, etc. |
| Zone-4 | High impact (Intensity VIII) | Jammu & Kashmir, Himachal Pradesh, Delhi, Sikkim, etc. |
| Zone-5 | Very high impact (Intensity IX and above) | North-Eastern India, Uttarakhand, Western Himachal Pradesh, Andaman Islands, etc. |
⚠ EXAM TRAP
Delhi falls in Zone-4 (High impact) despite being a plains capital city — often wrongly assumed to be in a lower-risk zone.
🌊 Tsunami
- Tsunami is a Japanese word.
| Causes | Effects |
|---|---|
| Earthquake, volcanic eruption, submarine landslide | Coastal ecosystem affected, spread of toxic waste in coastal areas, migration of exotic species, damage to infrastructure, etc. |
Tsunami Management
- Early warning, rapid alerts, evacuation routes/drills, hazard mapping and suitable natural/engineered buffers.
- Coastal plantation of mangrove vegetation, etc.
- ITEWS at INCOIS: fully operational in October 2007; round-the-clock monitoring and tsunami warning.
⛰ Landslide
- Downslope movement of rock, soil or debris under gravity.
- Common occurrence in Himalayan regions/states of India.
| Causes | Effects | Management |
|---|---|---|
| Rainfall and snowfall, mining and excavation, deforestation, infrastructure development | Damage to infrastructure, obstruction in river flow, hindrance in grazing, etc. | Afforestation, ban on mining, control over construction, contour farming, etc. |
🌊 Flood
- Overflow or accumulation of water inundating normally dry land.
| Causes | Effects | Management |
|---|---|---|
| Heavy rainfall, change in river course, increase in siltation, faulty agricultural practices, faulty agriculture irrigation, etc. | Destruction of basic infrastructure, spread of water-borne diseases, soil erosion, soil salinisation, etc. | Construction of embankments, cleaning of river beds, development of flood warning systems, etc. |
☀ Drought: Meteorological, Hydrological, Agricultural
| Causes | Effects |
|---|---|
| Low rainfall for a long time, decrease in reservoir and groundwater level, water scarcity | Agriculture and animal husbandry affected, human & animal migration, famine, etc. |
Major Programmes for Drought Management
- Desert Development Programme — 1977–78
- National Watershed Development Project — 1990–91, etc.
⚠ EXAM TRAP
Desert Development Programme (1977–78) predates the National Watershed Development Project (1990–91) by over a decade — don't swap the order.
🌀 Cyclone
- Large-scale low-pressure system with winds rotating around its centre; includes tropical and extratropical cyclones.
- Effects → Floods, coastal areas affected, etc.
- Protection → Early warning and evacuation, cyclone shelters, resilient construction, coastal planning and mangrove protection/restoration.
🏛 Disaster Management
- Formation of National, State and District Disaster (Management) Authorities.
- Disaster Management Act, 2005; substantially amended in 2025. The framework includes NIDM/NDRF; amendment provisions include UDMA, NCMC, HLC, SDRF and a National Disaster Database.
⚠ Other Disasters
| Disaster | Details |
|---|---|
| Cloudburst | Extreme localised rainfall, commonly 100 mm or more in one hour | Flash-flood/landslide risk |
| Bhopal Gas Tragedy | Bhopal, night of 2-3 December 1984 | Principal toxic chemical: methyl isocyanate (MIC) |
| Chernobyl Disaster (Ukraine) | Industrial nuclear incident, 26th April 1986 |
⚡ QUICK RECALL
Bhopal Gas Tragedy (1984, India) and Chernobyl Disaster (1986, Ukraine) were 509 days apart (3 December 1984 to 26 April 1986), about 1 year 4 months 23 days — both are landmark man-made industrial disasters in world history.
📋 Master Quick-Revision Table
| Topic | Key Fact |
|---|---|
| Earthquake | Tectonic vibrations of Earth's crust | Causes: plate tectonics, volcanic activity |
| Zone-2 | Minimum impact | Intensity 6 or less | Rajasthan, TN, N. AP, Chhattisgarh |
| Zone-3 | Moderate | Intensity VII | Kerala, Goa, Gujarat, UP, West Bengal, Odisha |
| Zone-4 | High | Intensity VIII | J&K, HP, Delhi, Sikkim |
| Zone-5 | Very High | Intensity IX+ | North-East India, Uttarakhand, W. HP, Andaman Islands |
| Tsunami | Japanese word | Causes: Earthquake, volcanic eruption, submarine landslide |
| Indian Tsunami Early Warning System | Established 2007 | Warning about tsunami effects |
| Landslide | Downslope movement of rock, soil or debris due to gravity | Common in Himalayan states |
| Flood | Sudden rise in water | Causes: heavy rainfall, river course change, siltation |
| Drought | Meteorological, hydrological and agricultural; socio-economic drought also recognised |
| Desert Development Programme | 1977–78 |
| National Watershed Development Project | 1990–91 |
| Cyclone Protection | Early warning/evacuation, shelters, resilient infrastructure, coastal planning, mangrove buffers |
| Disaster Management Act | 2005, amended 2025 | NDMA, SDMAs, DDMAs; NIDM/NDRF and additional 2025 provisions |
| Cloudburst | Extreme localised rainfall, commonly 100 mm or more in one hour | Flash-flood/landslide risk |
| Bhopal Gas Tragedy | Night of 2-3 December 1984 | Methyl isocyanate (MIC) release |
| Chernobyl Disaster | Ukraine | 26 April 1986 | Industrial nuclear incident |