Natural Hazards, Disasters & Disaster Management

• Hazard — आपदा जोखिम/खतरा: A potential threat or event that could cause harm. (e.g., an earthquake fault line)
• Disaster — आपदा: An actual event that causes widespread damage, loss, and disruption. (e.g., an earthquake that destroys a city)

Disaster Risk = Hazard × Vulnerability × Exposure

• Hazard — आपदा जोखिम/खतरा: Natural event (earthquake, flood, cyclone)
• Vulnerability — संवेदनशीलता/भेद्यता: How susceptible a community is to damage (poverty, poor infrastructure, lack of awareness)
• Exposure — जोखिम/एक्सपोजर: How many people/properties are in the hazard zone

Key Point: Reducing vulnerability and exposure can reduce disaster risk even if the hazard cannot be prevented.

Geological Hazards Earth's geological processes से उत्पन्न होने वाले hazards हैं — tectonic, volcanic, mass movement.

• Earthquake — भूकंप: Sudden shaking of the ground due to tectonic plate movement
• Tsunami — सुनामी: Large ocean waves caused by underwater earthquakes
• Volcano — ज्वालामुखी: Eruption of magma, ash, and gases
• Landslide — भूस्खलन: Downward movement of rock/soil on slopes
• Avalanche — हिमस्खलन: Rapid flow of snow/ice down a slope

• Flood — बाढ़: Overflow of water onto normally dry land — caused by heavy rain, river overflow, coastal storm surges.
• Cyclone — चक्रवात: Rotating storm system with low pressure — also called hurricanes/typhoons. Causes strong winds, heavy rain, storm surges.
• Drought — सूखा: Prolonged period of abnormally low rainfall — leading to water shortage, crop failure, food insecurity.

• Earthquake — भूकंप: Caused by tectonic plate movement (fault lines). Measured on Richter Scale (magnitude). Effects: ground shaking, building collapse, landslides, fires, tsunamis.
• Tsunami — सुनामी: Series of large ocean waves caused by underwater earthquakes, volcanic eruptions, or landslides. Travel at high speed across oceans; cause massive coastal destruction.

Key Points:

• Richter Scale measures earthquake magnitude (logarithmic: each unit = 10x increase in amplitude)
• Earthquake early warning systems can provide precious seconds/minutes of warning
• Tsunami warning systems monitor seismic activity and ocean buoys

• Landslide — भूस्खलन: Movement of rock, earth, or debris down a slope. Causes: heavy rain, earthquakes, deforestation, construction on slopes. Effects: damage to infrastructure, loss of life, road blockages.
• Heatwave — लू/ताप लहर: Prolonged period of excessively hot weather (temperatures above normal). Effects: heat exhaustion, heatstroke, increased mortality, crop damage, increased energy demand.

Disaster Management Cycle disaster management के phases का continuous cycle है — from pre-disaster to during-disaster to post-disaster.

Three Phases:

• Pre-Disaster: Prevention, Mitigation, Preparedness (before the disaster)
• During-Disaster: Response (during the disaster)
• Post-Disaster: Recovery, Rehabilitation (after the disaster)

Prevention disasters को completely avoid करने की कोशिश है — eliminating the hazard or stopping it from occurring.

Examples:

• Building dams to prevent floods
• Stopping construction in high-risk zones
• Enforcing building codes in seismic zones
• Protecting forests to prevent landslides

Note: Complete prevention is not always possible for natural hazards (earthquakes, cyclones).

Mitigation disaster के impacts को reduce करना है — even if the hazard cannot be prevented.

Examples:

• Earthquake-resistant building design
• Flood shelters and embankments
• Cyclone-resistant housing
• Drought-resistant crops
• Afforestation to prevent landslides
• Building codes and land-use planning

Preparedness disaster से पहले pre-planning and preparation है — to ensure effective response when a disaster strikes.

Examples:

• Early warning systems
• Emergency evacuation plans and drills
• Stockpiling emergency supplies (food, water, medicine)
• Training for first responders (police, fire, medical)
• Public awareness campaigns
• Emergency communication systems

Response disaster के during and immediately after की actions हैं — saving lives, providing emergency assistance.

Examples:

• Search and rescue operations
• Medical assistance (first aid, hospitals)
• Evacuation and shelter provision
• Food, water, and supply distribution
• Emergency communication
• Damage assessment (initial)
• Coordination of relief efforts

• Recovery — पुनर्प्राप्ति: Affected communities को return to normalcy लाना — restoring essential services, infrastructure, economy.
• Rehabilitation — पुनर्वास: Long-term rebuilding — houses, infrastructure, livelihoods, psychological support.

Examples:

• Rebuilding damaged houses, schools, hospitals
• Restoring roads, bridges, power, water supply
• Economic recovery (jobs, agriculture)
• Psychological counselling
• Building back better (using mitigation measures)
• Community rebuilding and social support

• Trap 1: Hazard and disaster are the same → ❌ Hazard = potential; Disaster = actual event.
• Trap 2: Disaster Risk = Hazard only → ❌ Risk = Hazard × Vulnerability × Exposure.
• Trap 3: Prevention = Mitigation → ❌ Prevention = avoid; Mitigation = reduce impact.
• Trap 4: Preparedness = Response → ❌ Preparedness is before; Response is during/after.
• Trap 5: Recovery = Rehabilitation → ❌ Recovery = return to normal; Rehabilitation = long-term rebuild.
• Trap 6: Mitigation happens after the disaster → ❌ Mitigation is pre-disaster (reducing future impact).
• Trap 7: Response happens after recovery → ❌ Response is during/immediately after; Recovery comes after response.

An earthquake fault line is an example of:

• A. Disaster
• B. Hazard
• C. Response
• D. Recovery

Explanation: An earthquake fault line is a potential threat (hazard), not an actual event (disaster).

Disaster Risk = Hazard × _____ × Exposure

• A. Vulnerability
• B. Response
• C. Recovery
• D. Preparedness

Explanation: Disaster Risk = Hazard × Vulnerability × Exposure.

Building earthquake-resistant buildings is an example of:

• A. Prevention
• B. Mitigation
• C. Response
• D. Recovery

Explanation: Earthquake-resistant buildings reduce the impact of earthquakes — this is mitigation (pre-disaster).

Search and rescue operations during a disaster are part of:

• A. Preparedness
• B. Mitigation
• C. Response
• D. Rehabilitation

Explanation: Search and rescue is an immediate action taken during/after a disaster — response phase.

Which phase involves rebuilding houses and restoring livelihoods after a disaster?

• A. Prevention
• B. Preparedness
• C. Response
• D. Rehabilitation

Explanation: Rehabilitation is the long-term rebuilding phase after a disaster — houses, livelihoods, infrastructure.

An early warning system for cyclones is part of:

• A. Prevention
• B. Preparedness
• C. Mitigation
• D. Recovery

Explanation: Early warning systems help communities prepare for an impending disaster — preparedness phase.

Types of Hazards:

• Geological: Earthquake, Tsunami, Volcano, Landslide
• Hydrological: Flood, Cyclone, Storm surge
• Climatic: Drought, Heatwave, Cold wave

Disaster Management Cycle:

• Prevention → Mitigation → Preparedness → Response → Recovery → Rehabilitation

Pre-Disaster:

• Prevention (avoid), Mitigation (reduce impact), Preparedness (plan/train)

During-Disaster:

• Response (save lives, emergency assistance)

Post-Disaster:

• Recovery (restore normalcy), Rehabilitation (long-term rebuild)

Key Measures:

• Earthquake: Seismic-resistant buildings, early warning
• Flood: Dams, embankments, early warning
• Cyclone: Shelters, early warning, evacuation
• Drought: Water conservation, drought-resistant crops
• Landslide: Afforestation, slope stabilisation
• Heatwave: Early warning, cooling centres

Exam Formula:

UGC NET में Natural Hazards, Disasters & Disaster Management के questions hazard/disaster distinction, risk formula, and management cycle phases पर based होते हैं।