Unit 6: Disaster Causes and Hazards

Unit 6: Topic Wise Notes

Topic Wise Notes

  • 1. Introduction to Disasters
    Definition: A disaster is a sudden, catastrophic event causing significant disruption, destruction, and loss of life, property, and environment.
    Causes: Can result from both natural processes and human activities.
    Impact: Leads to both direct and indirect economic losses, infrastructure damage, and livelihood disruption.
    Preparedness: Strategies like preparedness, mitigation, and response help reduce disaster impacts.
    Collaboration: Disaster management involves governments, communities, and international organizations.
  • 2. Classification of Natural Disasters
    Geophysical: Earthquakes, tsunamis, volcanic eruptions, and landslides.
    Hydrological: Floods, coastal erosion, and tsunamis.
    Meteorological: Cyclones, thunderstorms, lightning, and heatwaves.
    Climatological: Droughts, forest fires, and extreme temperatures.
    Biological: Epidemics, pandemics, and insect infestations.
    Purpose: Classification helps in disaster understanding and preparing appropriate response plans.
  • 3. Classification of Natural Disasters in India
    Types in India: Major natural disasters include earthquakes, tsunamis, floods, droughts, landslides, and thunderstorms.
    Regional Vulnerability: Regions like the Himalayan belt and coastal areas are more prone to specific disasters.
    National Disaster Management Authority (NDMA): Coordinates response and recovery efforts during disasters.
  • 4. Earthquake
    Definition: A sudden shaking or movement of the ground caused by tectonic plate shifts.
    Cause: Tectonic movements, volcanic activity, or artificial causes like mining.
    Impact/Effect: Destruction of infrastructure, loss of life, landslides, and ground fractures.
    Mitigation: Constructing earthquake-resistant buildings and enforcing land-use policies in high-risk areas.
    Preparedness: Drills, public awareness, and emergency supply kits.
    Response: Rescue operations, medical aid, shelter provision, and infrastructure assessment.
  • 5. Tsunami
    Definition: A series of ocean waves triggered by large underwater earthquakes or volcanic eruptions.
    Cause: Submarine earthquakes, volcanic eruptions, or underwater landslides.
    Impact/Effect: Coastal flooding, destruction of infrastructure, and loss of marine life.
    Mitigation: Coastal green belts, early warning systems, and safe zones.
    Preparedness: Evacuation plans, warning systems, and public education in coastal areas.
    Response: Immediate evacuation, provision of medical aid, and restoration of essential services.
  • 6. Flood
    Definition: Overflow of water onto land that is normally dry, often due to heavy rains or river overflow.
    Cause: Heavy rainfall, river overflow, dam failure, or storm surges.
    Impact/Effect: Damage to agriculture, loss of property and life, spread of waterborne diseases.
    Mitigation: Construction of levees, dams, and better drainage systems.
    Preparedness: Early warning systems, evacuation plans, and community awareness.
    Response: Evacuation, emergency supplies, and provision of clean drinking water.
  • 7. Drought
    Definition: A prolonged period of deficient rainfall resulting in water scarcity.
    Cause: Lack of precipitation, high temperatures, deforestation, and overuse of water resources.
    Impact/Effect: Crop failure, famine, economic loss, and water scarcity.
    Mitigation: Rainwater harvesting, efficient irrigation techniques, and afforestation.
    Preparedness: Water conservation education, planning, and storage.
    Response: Distribution of water, food aid, and agricultural support.
  • 8. Landslide
    Definition: The movement of rock, debris, or soil down a slope due to gravity.
    Cause: Heavy rainfall, earthquakes, volcanic activity, and human construction activities.
    Impact/Effect: Road blockages, loss of life, and destruction of property.
    Mitigation: Slope stabilization, retaining walls, and proper land use.
    Preparedness: Public awareness, early warnings, and restricting construction in vulnerable areas.
    Response: Rescue operations, debris clearing, and relocation of affected communities.
  • 9. Thunderstorm and Lightning
    Definition: Severe weather involving lightning, strong winds, and sometimes hail or heavy rain.
    Cause: Moisture, warm air, and lifting mechanisms such as hills or fronts.
    Impact/Effect: Fire hazards, injury or death from lightning strikes, property damage.
    Mitigation: Lightning rods, weather monitoring, and avoiding metal objects during storms.
    Preparedness: Public advisories, safety drills, and education on staying safe indoors.
    Response: Medical assistance, fire services, and restoring power where needed.
  • 10. Cyclone
    1. Definition: A cyclone is a large-scale air mass that rotates around a strong center of low atmospheric pressure. Cyclones typically bring heavy rainfall, high winds, and coastal flooding.

    2. Cause: Cyclones form over warm ocean waters near the equator, where the warm, moist air rises, creating a low-pressure area. The rotation of the Earth and the Coriolis effect cause the air to spin, leading to the formation of cyclonic storms.

    3. Impact/Effect: - **Human Life:** Cyclones can lead to loss of life due to strong winds, flooding, and building collapses.
    - **Infrastructure:** Damage to homes, roads, bridges, and power lines, causing disruptions in daily life.
    - **Agriculture:** High winds and flooding can destroy crops, leading to food shortages and economic loss.
    - **Environment:** Coastal erosion, loss of habitat, and water pollution due to storm surges and flooding.

    4. Mitigation: - Constructing cyclone shelters and strengthening coastal structures to withstand high winds and flooding.
    - Coastal afforestation projects, such as planting mangroves, which can act as natural barriers against storm surges.
    - Enforcing building codes in cyclone-prone areas to ensure structures are resilient.

    5. Preparedness: - Setting up early warning systems to provide timely information to communities.
    - Conducting regular community drills and public awareness programs on cyclone safety.
    - Ensuring that emergency supplies, such as food, water, and medical supplies, are readily available in cyclone-prone areas.

    6. Response: - **Evacuation:** Moving people to safer locations or cyclone shelters when warnings are issued.
    - **Medical Aid:** Providing immediate healthcare to those injured or affected.
    - **Relief and Recovery:** Supplying food, water, and shelter; restoring power and transportation services; and assessing damages for long-term rebuilding efforts.