Optional themes: Extreme environments and/or Geophysical hazards
Extreme environments and geophysical hazards
This optional theme examines harsh environments and tectonic hazards. For hazards, the key idea is that a hazard becomes a disaster only when it intersects vulnerability and exposure.
Core rules
- Extreme environments include polar, high-altitude and hot-arid regions. They have low biodiversity, slow soil formation and high adaptation costs; resource extraction and tourism increase pressure.
- Plate boundaries: divergent (constructive), convergent (destructive) and transform (conservative). Earthquakes occur at all three; volcanoes mainly at divergent and convergent boundaries.
- Hazard profile: magnitude, frequency, duration, speed of onset and spatial extent. These shape preparation and response.
- Risk is often modelled as hazard × vulnerability, divided by capacity. The Pressure and Release (PAR) model links root causes, dynamic pressures and unsafe conditions.
- Vulnerability includes poverty, building quality, age, gender and governance. Capacity includes search and rescue, hospitals, insurance and early warning.
- Management follows prediction, protection, planning and insurance, plus post-disaster recovery.
Worked example
Two earthquakes have similar magnitudes but very different death tolls. Reasoning: the higher toll is likely where exposure is high (dense housing), vulnerability is high (poorly reinforced buildings) and capacity is low (limited rescue equipment). Secondary hazards such as landslides, liquefaction and fires may cause more damage than shaking. The hazard profile matters: a shallow, midnight earthquake in a city is more lethal than a deep, offshore one. A strong answer compares all three sides of the risk equation.
Traps
- Treating a hazard as the same thing as a disaster.
- Assuming the largest magnitude always causes the most deaths.
- Ignoring capacity and governance.
- Forgetting secondary hazards such as liquefaction and landslides.