Natural Hazards: Complete Classification with Examples

Natural hazards = natural processes threatening life/property. Four categories:

1. Geological

• Earthquakes (tectonic stress release)
• Volcanic eruptions (lava, ash, pyroclastic flows, lahars)
• Landslides / debris flows / rockfalls
• Tsunamis (seismic/landslide displacement)
• Avalanches (snow/ice/rock)
• Land subsidence / sinkholes

2. Hydrological

• Floods (river, flash, coastal, urban)
• Dam/levee failure
• Drought (meteorological, agricultural, hydrological)
• Water pollution (natural: arsenic, fluoride; exacerbated by humans)
• Saltwater intrusion

3. Meteorological / Climatological

• Tropical cyclones (hurricanes, typhoons, cyclones)
• Tornadoes / waterspouts
• Severe storms (hail, derecho, lightning)
• Heat waves / cold waves
• Wildfires (weather-driven)
• Blizzards / ice storms
• Fog / dust storms

4. Biological

• Pandemics / epidemics (zoonotic spillover)
• Epizootics (animal disease outbreaks)
• Locust / insect swarms
• Harmful algal blooms (red tide, cyanobacteria)
• Invasive species (natural range expansion)

Human Amplification

Deforestation → landslides/floods. Urbanization → flash floods/heat islands. Climate change → intensity/frequency ↑. Risk = Hazard × Exposure × Vulnerability.