NATURAL HAZARDS AND DISASTERS: CAUSES, CONSEQUENCES AND MANAGEMENT | Class 11 Geography Notes

Geological Hazards

Geological hazards are natural events caused by movements and processes within the Earth's crust. The primary geological hazards include earthquakes, volcanic eruptions, landslides, and avalanches. Earthquakes occur due to sudden release of energy in the Earth's lithosphere, resulting in seismic waves. They are caused by tectonic plate movements along faults. The Richter scale measures earthquake magnitude, while the Mercalli scale assesses intensity based on observed effects. Volcanic eruptions happen when magma from the mantle reaches the surface, releasing lava, ash, and gases. Active volcanoes are often located along plate boundaries. Landslides involve the downward movement of rock and soil on slopes, triggered by factors like heavy rainfall, earthquakes, or human activities. Avalanches are rapid flows of snow down mountain slopes, often triggered by snowfall or vibrations. Geological hazards can cause massive destruction to life, infrastructure, and the environment. Understanding their causes helps in risk assessment and disaster preparedness.

📊 Diagram: Diagrams illustrating earthquake waves, volcanic eruption structure, and landslide movement on slopes.

🧪 Activity: Activity: Mapping earthquake-prone zones in India using seismic zone maps.

🔗 Connection: Leads to the next section on hydrological hazards, focusing on water-related disasters.