Natural Disasters in India: Earthquakes, Floods, Cyclones, Tsunamis

India is highly vulnerable to natural disasters due to its geographical diversity. About 58.6% of India’s landmass is prone to earthquakes, 12% to floods, and 8% of the coastline is cyclone-prone. Kerala PSC frequently asks 2-4 questions on disaster management.

1. Earthquakes in India

Seismic Zones of India

India is divided into 4 seismic zones (Zone I was merged into Zone II in 2002):

Zone	Intensity (MSK Scale)	Risk Level	Areas Covered
Zone V	IX and above	Very High	Entire NE India, J&K (Kashmir Valley), Uttarakhand, Kutch (Gujarat), North Bihar, Andaman and Nicobar
Zone IV	VIII	High	Remaining J&K, Himachal Pradesh, Delhi, parts of UP, Bihar, West Bengal, parts of Gujarat, Maharashtra coast
Zone III	VII	Moderate	Kerala, Goa, remaining Maharashtra, Madhya Pradesh, Rajasthan, parts of UP, Punjab, Haryana
Zone II	VI and below	Low	Remaining parts of peninsular India

Major Earthquakes in India

Year	Location	Magnitude	Key Fact
1819	Kutch, Gujarat	8.0	Created “Allah Bund” (dam)
1897	Shillong, Assam	8.1	One of the most powerful in recorded history
1905	Kangra, HP	7.8	Over 20,000 deaths
1934	Bihar-Nepal	8.1	Destroyed Munger, Muzaffarpur
1950	Assam	8.6	One of the largest earthquakes of 20th century
1993	Latur, Maharashtra	6.2	Over 7,600 deaths; peninsular India proved vulnerable
2001	Bhuj, Gujarat	7.7	Over 20,000 deaths; Republic Day earthquake
2005	Kashmir (PoK/J&K)	7.6	Over 80,000 deaths (combined India-Pakistan)
2015	Nepal (affected Bihar, UP)	7.8	Widespread damage in Nepal and North India

Key Terms

Term	Meaning
Epicentre	Point on surface directly above earthquake origin
Hypocentre/Focus	Actual point of origin underground
Richter Scale	Measures magnitude (energy released) — logarithmic
Mercalli Scale	Measures intensity (damage caused) — I to XII
Seismograph	Instrument to record seismic waves

2. Floods in India

Flood-Prone Areas

River System	States Affected
Brahmaputra	Assam, Arunachal Pradesh, Meghalaya
Ganga	Bihar, UP, West Bengal
Kosi (“Sorrow of Bihar”)	Bihar
Damodar (“Sorrow of Bengal”)	West Bengal, Jharkhand
Mahanadi	Odisha
Godavari	Andhra Pradesh, Telangana
Narmada, Tapi	Gujarat, Maharashtra
Periyar, Pamba	Kerala

Types of Floods

Type	Cause	Example Region
Riverine floods	Heavy rainfall, dam overflow	Bihar, Assam
Flash floods	Sudden heavy rain in hilly areas	Uttarakhand, Himachal Pradesh
Coastal floods	Storm surge from cyclones	Odisha, Andhra Pradesh
Urban floods	Poor drainage + heavy rain	Mumbai, Chennai, Hyderabad
Glacial Lake Outburst (GLOF)	Glacial lake breach	Uttarakhand, Sikkim

Kerala Floods

Year	Key Details
2018	Worst in nearly 100 years; 483 deaths; all 14 districts affected; 35 of 54 dams opened
2019	Severe flooding again; Wayanad, Malappuram worst hit; Kavalappara landslide
2024	Wayanad landslide disaster

3. Cyclones

Cyclone-Prone Areas in India

Coast	States	Peak Season
East Coast (Bay of Bengal)	West Bengal, Odisha, Andhra Pradesh, Tamil Nadu	October–December
West Coast (Arabian Sea)	Gujarat, Maharashtra, Kerala, Karnataka	May–June, October–November

The Bay of Bengal generates approximately 5 times more cyclones than the Arabian Sea.

Cyclone Naming System

Region	Naming Authority
North Indian Ocean (Bay of Bengal + Arabian Sea)	IMD (India Meteorological Department)
Names contributed by	13 member countries of WMO/ESCAP Panel

The 13 countries: Bangladesh, India, Iran, Maldives, Myanmar, Oman, Pakistan, Qatar, Saudi Arabia, Sri Lanka, Thailand, UAE, Yemen.

Recent Named Cyclones (India’s contributions)

Name Given by India	Year	Notes
Agni	—	(from earlier list)
Gati	2020	Hit Somalia
Tej	2023	Arabian Sea
Murasu	(upcoming list)	—
Aag, Jal, Lehar, Megh, Sagar, Vayu	Various	Indian-named cyclones

Classification of Cyclones (IMD)

Category	Wind Speed (km/h)
Depression	31–49
Deep Depression	50–61
Cyclonic Storm	62–87
Severe Cyclonic Storm	88–117
Very Severe Cyclonic Storm	118–166
Extremely Severe Cyclonic Storm	167–221
Super Cyclonic Storm	222 and above

Major Cyclones in India

Cyclone	Year	Area	Impact
Bhola Cyclone	1970	East Pakistan (Bangladesh)	Deadliest — 300,000+ deaths
Super Cyclone	1999	Odisha	10,000+ deaths; wind speed over 260 km/h
Hudhud	2014	Visakhapatnam	Severe damage to city
Fani	2019	Odisha	Category 5 equivalent; effective evacuation saved lives
Amphan	2020	West Bengal	Super cyclone; massive economic damage
Tauktae	2021	Gujarat (Arabian Sea)	Extremely severe; affected Kerala to Gujarat
Biparjoy	2023	Gujarat (Arabian Sea)	Very severe cyclonic storm

4. Droughts

Types of Drought

Type	Definition
Meteorological	Rainfall deficiency of more than 25% of normal
Hydrological	Depletion of surface and sub-surface water
Agricultural	Soil moisture insufficient for crop growth

Drought-Prone Areas in India

Region	States
Western Rajasthan	Thar Desert region
Deccan Plateau	Maharashtra (Marathwada, Vidarbha), Karnataka, Telangana
Gujarat	Kutch, Saurashtra
Interior Tamil Nadu	Ramanathapuram, parts of Coimbatore
Rayalaseema	Andhra Pradesh

Key Points on Drought

• IMD declares drought when rainfall is below 75% of normal (25% deficiency)
• Severe drought: below 50% of normal rainfall
• India receives 75% of rainfall from Southwest Monsoon (June-September)
• El Nino often correlates with weak monsoon and drought in India
• The Drought Management Division is under the Department of Agriculture

5. Tsunamis

Indian Ocean Tsunami (26 December 2004)

Aspect	Details
Origin	Undersea earthquake off Sumatra, Indonesia (M 9.1)
Deaths (total)	Over 2,30,000 across 14 countries
Deaths in India	About 10,749 (Tamil Nadu, Andaman and Nicobar, Andhra Pradesh, Kerala, Puducherry)
Most affected in India	Andaman and Nicobar Islands, Nagapattinam (Tamil Nadu)
Wave height	Up to 30 metres at some locations
Warning time	None (no warning system existed for Indian Ocean)

Post-Tsunami Measures

Measure	Details
INCOIS	Indian National Centre for Ocean Information Services — now issues tsunami warnings
ITEWC	Indian Tsunami Early Warning Centre at Hyderabad (est. 2007)
Deep ocean sensors	Bottom Pressure Recorders deployed in Bay of Bengal and Arabian Sea
Coastal vulnerability mapping	Undertaken by multiple agencies

6. Disaster Management Framework in India

National Level

Body	Full Form	Role
NDMA	National Disaster Management Authority	Apex body; chaired by Prime Minister
NDRF	National Disaster Response Force	Specialised response force; 16 battalions
NIDM	National Institute of Disaster Management	Training, research, policy
NEC	National Executive Committee	Chaired by Union Home Secretary; implementation

State Level

Body	Role
SDMA	State Disaster Management Authority; chaired by Chief Minister
SEC	State Executive Committee; chaired by Chief Secretary
SDRF	State Disaster Response Fund

District Level

Body	Role
DDMA	District Disaster Management Authority; chaired by District Collector/Magistrate

Key Legislation

Law	Year	Key Provision
Disaster Management Act	2005	Established NDMA, SDMA, DDMA, NDRF
Amended	2024	Strengthened urban disaster management provisions

NDRF Details

Feature	Details
Established	2006 (under DM Act 2005)
Headquarters	New Delhi
Strength	16 battalions (each about 1,149 personnel)
Parent forces	Drawn from BSF, CRPF, CISF, ITBP, SSB, and Assam Rifles
Specialisation	Nuclear, Biological, Chemical disasters + natural disasters
Director General	IPS officer

7. Kerala-Specific Disaster Information

Disaster Type	Kerala’s Vulnerability
Floods	Very high — Western Ghats rainfall, dam overflow
Landslides	High — hilly terrain of Wayanad, Idukki, Pathanamthitta
Cyclones	Moderate — occasionally affected by Arabian Sea cyclones
Earthquakes	Zone III (moderate risk)
Coastal erosion	Severe — affects entire 590 km coastline
Lightning	Major cause of weather-related deaths

Kerala SDMA

Aspect	Details
Chaired by	Chief Minister
Key agency	KSDMA (Kerala State Disaster Management Authority)
Disaster response	Kerala Fire and Rescue Services, Police, Navy assistance
Notable response	2018 floods — “Kerala’s worst flood in a century”

8. Key Points for PSC

• India has 4 seismic zones (not 5 — Zone I was merged into Zone II)
• Zone V is the most dangerous seismic zone
• Kerala falls in Seismic Zone III
• Bay of Bengal produces more cyclones than Arabian Sea (ratio approximately 5:1)
• NDMA is chaired by the Prime Minister
• SDMA is chaired by the Chief Minister
• DDMA is chaired by the District Collector
• NDRF was established under the Disaster Management Act, 2005
• The Indian Ocean Tsunami Warning System was set up after the 2004 tsunami
• Kosi river is called the “Sorrow of Bihar”
• Damodar river is called the “Sorrow of Bengal”
• El Nino = warm Pacific = weak Indian monsoon = drought risk
• La Nina = cool Pacific = strong Indian monsoon = flood risk