Unit 5: Disaster management

CHE110 — Environmental Studies 11 min read

I. Orientation

Disaster management is the organized process of preventing, reducing, preparing for, responding to, and recovering from events that seriously disrupt communities. A disaster occurs when a hazard interacts with exposed and vulnerable people, infrastructure, or ecosystems beyond their capacity to cope.

Risk: The possibility of harmful consequences from a hazard; it increases with hazard intensity, exposure, and vulnerability.
Hazard: A potentially damaging event, such as an earthquake, flood, epidemic, or industrial explosion.
Vulnerability: Physical, social, economic, or environmental conditions that increase susceptibility to harm.
Capacity: Skills, institutions, resources, and infrastructure available to anticipate and manage disasters.
Disaster-management cycle: Mitigation and prevention precede preparedness; response is followed by recovery, rehabilitation, and reconstruction.
Core principle: Disaster losses are reduced most effectively before an event through risk assessment, resilient planning, early warning, and community preparedness.

II. Natural Disasters — Hazard-Based Classification

A. Natural disasters

Natural disasters arise from natural Earth or atmospheric processes, although human settlement and environmental degradation often increase their impacts.

Major categories: Hydrological events include floods and droughts; meteorological events include cyclones and storms; geological events include earthquakes, landslides, avalanches, and volcanic eruptions.
Disaster intensity: Magnitude, duration, speed of onset, affected area, and population exposure determine consequences.
Risk reduction: Hazard mapping, land-use regulation, resilient buildings, early-warning systems, evacuation plans, and public education reduce vulnerability.
Human influence: Deforestation can intensify floods and landslides, while unplanned urbanization increases exposure in floodplains and unstable slopes.

B. Water-related disasters

Water-related disasters result from excessive, deficient, or contaminated water and are closely connected with climate, drainage, and land use.

Excess water: Floods, storm surges, and dam failures can damage homes, roads, crops, and water-supply systems.
Insufficient water: Droughts reduce agricultural production, drinking-water availability, livestock health, and hydropower generation.
Contamination: Sewage, chemicals, or pathogens entering water after floods may produce cholera, diarrhoea, and other diseases.
Management: Watershed protection, drainage maintenance, rainwater harvesting, water-quality monitoring, and safe sanitation reduce impacts.

C. Floods and drought

Floods involve the temporary submergence of normally dry land; drought is a prolonged period of unusually low water availability.

Flood causes: Intense rainfall, river overflow, cloudbursts, storm surges, glacial-lake outbursts, blocked drainage, and dam failure.
Flood effects: Fast-moving water causes drowning and structural collapse; stagnant water damages crops and increases vector-borne disease.
Drought types: Meteorological drought concerns rainfall deficiency; agricultural drought affects soil moisture and crops; hydrological drought affects rivers, reservoirs, and groundwater.
Preparedness: Flood forecasting, raised shelters, zoning, embankment maintenance, drought-resistant crops, efficient irrigation, and groundwater recharge are practical measures.
Example: A flood warning becomes useful only when it is linked to clear instructions, transport, shelters, and assistance for people unable to evacuate independently.

D. Air-related disasters

Air-related disasters are atmospheric events that threaten health, visibility, infrastructure, or transport.

Examples: Severe air pollution episodes, dust storms, heat waves, cold waves, lightning, and smoke from wildfires.
Health effects: Fine particulate matter can enter the lungs and bloodstream; heat waves cause dehydration, heat exhaustion, and heatstroke.
Warning measures: Air-quality indices, temperature alerts, public advisories, cooling centres, masks, and restrictions on outdoor activity reduce exposure.
Urban vulnerability: Concrete surfaces, limited vegetation, and trapped pollutants can create urban heat islands and intensify respiratory stress.

E. Cyclones and storms

Cyclones are large rotating low-pressure systems; storms include intense wind, rain, thunder, lightning, hail, or storm surges.

Cyclone hazards: Strong winds, torrential rain, coastal flooding, storm surges, erosion, and landslides can occur together.
Early warning: Meteorological satellites, radar, ocean buoys, and numerical forecasts track movement and intensity.
Preparedness: Coastal shelters, evacuation routes, trimmed trees, secured roofs, emergency kits, and protection of communication systems are essential.
Response rule: Evacuation should occur before dangerous winds arrive; people should remain indoors away from windows during the peak.

III. Earth-Related Disasters — Geological Processes

A. Earth-related disasters

Earth-related disasters result from movements and processes within the Earth’s crust or from gravity acting on unstable terrain.

Principal forms: Earthquakes arise from sudden fault movement; landslides and avalanches involve mass movement; volcanic eruptions release magma, ash, and gases.
Common feature: They may occur with little warning, so structural safety, land-use planning, and drills are more reliable than last-minute action.
Secondary hazards: Earthquakes can cause tsunamis, fires, liquefaction, and dam failure; volcanoes can produce lahars and ash-related aviation hazards.
Risk mapping: Geological surveys identify faults, unstable slopes, volcanic zones, and areas requiring building restrictions.

B. Earthquakes

An earthquake is the sudden release of accumulated strain along a fault, producing seismic waves that shake the ground.

Measurement: Magnitude describes released energy; intensity describes observed effects at a particular location. Seismographs record ground motion.
Damage factors: Destruction depends on magnitude, depth, distance from the epicentre, soil conditions, building quality, and duration of shaking.
Building safety: Reinforced frames, ductile construction, shear walls, foundation design, and securing heavy equipment reduce collapse risk.
Immediate action: “Drop, Cover, and Hold On” protects people from falling objects; elevators, damaged buildings, and coastal areas should be avoided after shaking.
Secondary hazards: Fires, ruptured pipelines, landslides, liquefaction, and tsunamis may continue after the main shock.

C. Landslides

A landslide is the downslope movement of soil, rock, or debris under gravity, commonly triggered by water, earthquakes, or human disturbance.

Triggers: Prolonged rainfall, cloudbursts, slope cutting, deforestation, mining, road construction, and seismic shaking weaken slopes.
Warning signs: New cracks, tilted trees or poles, bulging ground, blocked drainage, unusual sounds, and doors or windows sticking.
Control measures: Drainage channels, retaining walls, terracing, vegetation, rock bolting, and restrictions on construction reduce slope failure.
Response: Evacuation should move people away from the slide path; roads and valleys may remain dangerous because of secondary slides.

D. Avalanches

An avalanche is the rapid downslope movement of snow, ice, and debris, usually on steep mountain slopes.

Causes: Heavy snowfall, wind-loaded snow, rapid warming, rain, vibrations, or weak layers within the snowpack.
Risk indicators: Recent snowfall, cracking or “whumpfing” sounds, unstable snow slabs, and rising temperatures.
Protection: Hazard zoning, controlled snow release, observation, avalanche barriers, transceivers, probes, and trained rescue teams limit casualties.
Survival response: Travellers should avoid unstable slopes; buried victims require rapid location, airway clearance, and coordinated rescue.

E. Volcanic eruptions

A volcanic eruption occurs when magma, ash, gases, or rock fragments reach the surface through a vent or fissure.

Hazards: Lava flows, ash fall, pyroclastic flows, toxic gases, volcanic bombs, lahars, and short-term climate effects.
Monitoring: Seismic activity, ground deformation, gas emissions, thermal changes, and crater observations can indicate rising magma.
Preparedness: Exclusion zones, evacuation routes, masks or respirators, ash-resistant infrastructure, and protection of water supplies are important.
Response: People should follow official evacuation orders and avoid valleys during eruptions because lahars can travel far along river channels.

IV. Human-Caused and Technological Disasters

A. Manmade disasters

Manmade disasters result from human error, negligence, unsafe technology, conflict, poor regulation, or deliberate action.

Examples: Industrial explosions, fires, pollution, dam failures, building collapse, terrorism, war, transport accidents, and infrastructure failure.
Preventability: Safety standards, inspections, environmental impact assessment, emergency drills, maintenance, and accountability reduce risk.
Compound effects: A technological accident during a flood, earthquake, or conflict can create a cascading disaster.
Management focus: Prevention and strict regulation are generally more effective and less costly than emergency rescue alone.

B. Nuclear disasters

Nuclear disasters involve uncontrolled radiation release from nuclear power plants, research facilities, weapons, transport, or radioactive sources.

Exposure pathways: External irradiation, inhalation, ingestion, and contamination of surfaces or food can affect people.
Health effects: High doses may cause acute radiation syndrome; lower or prolonged exposure can increase cancer risk.
Protective actions: Time, distance, and shielding reduce exposure; sheltering indoors, evacuation, contamination monitoring, and controlled iodine administration may be directed by authorities.
Preparedness: Plant safety systems, exclusion zones, radiation detectors, specialized medical teams, and transparent communication are essential.

C. Chemical disasters

Chemical disasters involve accidental or intentional release of toxic, corrosive, flammable, or reactive substances.

Sources: Factories, storage tanks, pipelines, laboratories, warehouses, and transport vehicles.
Hazards: Inhalation, skin contact, fire, explosion, toxic clouds, and contamination of soil and water.
Response: Identify the substance, isolate the area, approach from upwind, use appropriate protective equipment, and decontaminate exposed persons.
Preparedness: Safety Data Sheets, hazard labels, on-site emergency plans, leak detection, community warning systems, and hospital preparedness are necessary.

D. Biological disasters

Biological disasters are large-scale disease events caused by pathogens, toxins, or biological agents affecting humans, animals, or plants.

Examples: Epidemics, pandemics, zoonotic spillovers, food-borne outbreaks, and deliberate biological attacks.
Control chain: Surveillance, laboratory confirmation, case isolation, contact tracing, vaccination, treatment, sanitation, and risk communication interrupt transmission.
Preparedness: Personal protective equipment, infection-control procedures, stockpiled medicines, laboratories, and trained health workers are critical.
Public conduct: Accurate reporting, hygiene, respiratory etiquette, and compliance with scientifically justified public-health measures reduce spread.

E. Transport accidents

Transport accidents include collisions, derailments, shipwrecks, aircraft crashes, and hazardous-material incidents on roads or railways.

Risk factors: Speed, fatigue, poor maintenance, weather, inadequate signalling, unsafe loading, and driver or operator error.
Immediate priorities: Establish incident command, secure the scene, rescue survivors, provide triage, control fire or leaks, and maintain access for emergency vehicles.
Hazardous cargo: Placards and cargo manifests help responders identify flammable, toxic, corrosive, or radioactive materials.
Prevention: Licensing, vehicle inspection, seat belts, helmets, signalling systems, route planning, and enforcement of transport rules reduce accidents.

V. Disaster Governance and Public Response

A. National disaster management framework

A national disaster-management framework assigns legal authority, institutions, resources, and procedures across prevention, preparedness, response, and recovery.

Institutional structure: In India, the Disaster Management Act, 2005 established the National Disaster Management Authority, State Authorities, District Authorities, and national response mechanisms.
Planning: National, state, and district plans identify hazards, vulnerable groups, evacuation routes, shelters, critical facilities, and responsibilities.
Response system: Incident-response arrangements coordinate command, search and rescue, medical aid, logistics, shelter, communications, and public information.
Recovery principle: Reconstruction should “build back better” by restoring services with greater resilience rather than reproducing previous vulnerabilities.

B. Role of governmental agencies in disaster response

Government agencies provide authority, specialized resources, coordination, and public services before, during, and after disasters.

Forecasting agencies: Meteorological, geological, hydrological, and health departments issue warnings and technical assessments.
Emergency forces: Police, fire services, armed forces, civil defence, and specialized response teams conduct rescue, evacuation, security, and emergency engineering.
Local administration: District officials manage shelters, food, water, sanitation, medical services, relief registration, and restoration of roads and power.
Accountability: Governments must ensure inclusive relief, transparent damage assessment, compensation, and protection of children, older persons, and persons with disabilities.

C. Role of NGOs in disaster response

Non-governmental organizations supplement official capacity through specialized, flexible, and locally informed assistance.

Relief services: NGOs may provide food, water, temporary shelter, sanitation, healthcare, counselling, and protection services.
Local access: Established relationships help reach remote or marginalized groups and identify needs overlooked by centralized assessments.
Coordination: Effective NGOs share beneficiary data, follow humanitarian standards, avoid duplication, and coordinate with government and other agencies.
Recovery: They support livelihood restoration, psychosocial care, education continuity, and community training after immediate relief ends.

D. Role of community-based organizations in disaster response

Community-based organizations are local groups such as self-help groups, resident associations, youth clubs, faith groups, and village committees.

Local knowledge: Residents know vulnerable households, safe routes, water points, shelter locations, and recurring hazards.
Preparedness: They organize drills, first-aid training, volunteer teams, emergency stores, and neighbourhood warning networks.
Inclusive response: Local groups can check on isolated older people, persons with disabilities, children, and households lacking transport.
Trust: Familiar leaders improve compliance with evacuation and reduce rumours, while community participation makes recovery more culturally suitable.

E. Role of media in disaster response

Media communicates warnings, explains risks, reports needs, and scrutinizes relief operations through television, radio, newspapers, and digital platforms.

Early warning: Clear messages should state the hazard, location, timing, expected impact, and specific action required.
Public information: Radio and mobile platforms remain valuable when electricity or internet access is disrupted.
Ethical reporting: Journalists should verify information, protect victims’ dignity, avoid graphic imagery, and distinguish confirmed facts from rumours.
Two-way communication: Media can relay missing-person information and public needs, but unverified social-media posts may create panic or obstruct rescue operations.
Accountability: Investigative reporting can reveal failures in safety standards and ensure that relief distribution reaches affected communities.