Global hazard distribution: physical patterns and human factors

Physical patterns

• Earthquakes and volcanoes cluster along plate boundaries, especially the Pacific Ring of Fire, with some at hotspots.
• Tropical cyclones form over warm tropical oceans, away from the equator itself (the Coriolis effect is too weak there to start rotation), and track west and then poleward.
• Floods are concentrated on floodplains, deltas and low coasts, and in monsoon regions.
• Drought affects subtropical and semi-arid areas such as the Sahel, and areas affected by ENSO.

Skill (2): when you analyse a hazard distribution map, describe the overall pattern, name regions or latitudes, give data and note anomalies.

Human factors shape disaster impacts

• Level of development: poorer countries have weaker buildings and fewer warning systems, so more deaths but often lower absolute economic losses.
• Population density: more people exposed per square kilometre.
• Accessibility: remote mountain or island communities are hard to reach with aid.
• Governance: corruption and weak enforcement of building codes raise vulnerability; good governance supports planning and response.

The Philippines ranked first of 193 countries on the WorldRiskIndex 2024 (score 46.91), which multiplies exposure by vulnerability (susceptibility, lack of coping capacity and lack of adaptive capacity) (WorldRiskReport 2024).

Skill (3): mapping impacts

• Choropleth map: areas shaded by value. Use rates (deaths per 100,000) rather than totals, because larger areas or populations would otherwise dominate.
• Dot (dot density) map: each dot represents a set number of events or people; shows clustering.
• Proportional symbols: circles sized by value at a location.
• Cartogram: countries resized in proportion to a variable (such as deaths), so the most affected countries look largest.

At local and regional scales these maps can show which districts suffered most.

Worked example

Typhoon Haiyan (2013) killed 6,300 people and affected over 16 million people (NDRRMC, reported April 2014). Express the deaths per 100,000 people affected.

1. Deaths per person affected = 6,300 / 16,000,000
2. Multiply by 100,000

Answer: About 39.4 deaths per 100,000 people affected.

Check yourself

1. Typhoon Haiyan killed 6,300 people and affected over 16 million. Calculate deaths per 100,000 people affected, to 1 decimal place.
   Show answer

   39.4. 6,300 / 16,000,000 x 100,000 = 39.4.

2. Which map is most suitable for showing disaster deaths per 100,000 people for each country?
   • Choropleth
   • Proportional flow lines
   • Isoline map of rainfall
   • Network map
   Show answer

   Choropleth. Rates for areas are shaded on a choropleth.

3. In a cartogram of disaster deaths, a country appears much larger than its true area because
   • it has a high population density
   • it is closer to the equator
   • the map resizes countries in proportion to deaths
   • the map uses a choropleth key
   Show answer

   the map resizes countries in proportion to deaths. Area represents the variable, not land area.

4. Why do tropical cyclones not form right on the equator?
   • The sea is too cold at the equator
   • The Coriolis effect is too weak there to start the storm rotating
   • There is no evaporation at the equator
   • Plate boundaries block them
   Show answer

   The Coriolis effect is too weak there to start the storm rotating. Rotation needs Coriolis force, which is near zero at the equator.

5. The greatest concentration of earthquakes and volcanoes is found
   • in the centre of continents
   • only at hotspots
   • along the equator
   • around the edges of the Pacific Ocean
   Show answer

   around the edges of the Pacific Ocean. The Pacific Ring of Fire is dominated by subduction zones.

6. Explain how poor governance can increase the impact of a natural hazard.
   Show answer

   Corruption and weak enforcement of building codes mean buildings are poorly built, so more collapse and more people die; slow emergency response also increases losses.. Corruption or weak regulation means unsafe buildings and slow response, raising deaths and losses.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Geography specification (Issue 3, September 2025)
• Bundnis Entwicklung Hilft and IFHV Ruhr University Bochum: WorldRiskReport 2024 (September 2024)
• Philstar.com: NDRRMC, Yolanda deaths rise to 6,300 (17 April 2014)

Last updated 8 November 2026. Spotted a mistake? Tell us.