Classification of Disasters

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Disaster 101 - Defining & Dividing

A disaster is a serious disruption of community functioning, causing widespread losses (human, material, economic, environmental) that exceed its ability to cope using its own resources.

  • Key Criteria: Overwhelms local capacity. Often >10 deaths, >100 affected.

    ⭐ A disaster is an event that overwhelms local capacity to respond without external assistance. (WHO)

  • Primary Classification:
    • Natural: Geophysical (earthquake, tsunami), Hydrological (flood), Biological (epidemic).
    • Man-made (Anthropogenic): Technological (industrial spill), Intentional (conflict, terror). Icons of various natural disasters

Nature's Wrath - Cataloguing Calamities

📌 Mnemonic for Natural Disaster Categories: Good Heavens, My Cat Bit! (Geophysical, Hydrological, Meteorological, Climatological, Biological)

CategorySub-typeKey Examples/Characteristics
GeophysicalEarthquakesRichter (magnitude), Mercalli (intensity); ground shaking
TsunamisGiant sea waves from underwater seismic activity
Volcanic EruptionsMolten rock (lava), ash, gas expulsion
LandslidesDownslope movement of soil, rock, debris
HydrologicalFloodsInundation: flash, riverine, coastal
AvalanchesRapid flow of snow, ice, or debris down a slope
Storm SurgesAbnormal sea level rise with storms
Limnic EruptionsSudden CO2 gas release from deep lakes
MeteorologicalCyclones/Hurricanes/TyphoonsIntense tropical storms; Saffir-Simpson (Cat 1-5)
TornadoesViolent rotating air columns (land); Fujita (F0-F5)
Heat Waves/Cold WavesProlonged extreme hot/cold temperatures
Blizzards/HailstormsSevere snowstorms / Solid ice precipitation
ClimatologicalDroughtsExtended lack of rainfall, water shortage
WildfiresUncontrolled fires in forests/wildlands (forest fires)
GLOFsSudden water release: Glacial Lake Outburst Floods
BiologicalEpidemics/PandemicsWidespread disease (e.g., Cholera, COVID-19)
Pest InfestationsDestructive insects/animals (e.g., locust swarms)

⭐ India is one of the most flood-prone countries in the world, with riverine floods being particularly common during monsoon season.

Human Errors - Unveiling Man-Made Crises

Man-made disasters arise from human actions: intent, negligence, or technological failure. Key types:

CategorySub-typeKey Examples/Characteristics
TechnologicalIndustrial accidentsChemical spills (Bhopal - MIC), gas leaks, explosions, fires.
Nuclear accidentsMeltdowns, radiation release (Chernobyl, Fukushima).
Radiological emergenciesLost sources, improper disposal, contamination.
Transport accidentsMajor road, rail, air, sea incidents; mass casualties.
Structural collapsesBuildings, bridges, dams, tunnels; design flaws.
OthersMine disasters, large oil spills, major power outages.
Intentional/SociologicalTerrorismPolitically motivated violence; CBRN-T. 📌 CBRN: Can Be Really Nasty!
War & Civil StrifeArmed conflicts, insurgencies, displacement.
Riots & Civil UnrestMass public disturbances, looting.
StampedesCrowd surges at mass gatherings (religious, sports).
OthersDeliberate arson, sabotage.
Complex EmergenciesCombinationNatural + man-made factors (e.g., drought + conflict → famine).

⭐ The Bhopal Gas Tragedy in 1984, involving the release of Methyl Isocyanate (MIC) gas, is a stark example of a catastrophic industrial disaster.

Pace & Punch - Onset, Severity & India Focus

  • Onset Speed:
    • Rapid/Sudden: Earthquake, Cyclone, Flash Flood. 📌 Every Child Falls.
    • Slow/Creeping: Drought, Famine, Climate Change.
  • Severity: Minor, Moderate, Major/Catastrophic (impact on life, property, environment; overwhelms local capacity).
  • India Focus:
    • NDMA leads. High vulnerability: hydro-meteorological (floods, cyclones), seismic zones.

    ⭐ Drought is a slow-onset disaster that affects more people in India than any other single disaster type.

High‑Yield Points - ⚡ Biggest Takeaways

  • Key types: Natural (earthquakes, floods) and Man-made (industrial accidents, CBRN events).
  • Onset: Rapid (cyclones, tsunamis) versus Slow (droughts, environmental degradation).
  • Biological disasters: Include epidemics (e.g., cholera) and pandemics (e.g., COVID-19).
  • Complex emergencies: Often involve conflict, large-scale displacement, and food insecurity.
  • Severity is assessed by human casualties, economic losses, and geographical scope.
  • India's Disaster Management Act, 2005 provides the crucial legal framework for management activities.
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Practice Questions: Classification of Disasters

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What is the most critical priority in reducing mortality in the immediate aftermath of natural disasters?

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_____ will be the choice of insecticide for floods.

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_____ will be the choice of insecticide for floods.

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