Natural Hazard Risk – Impacts and Responses
GeographyEarth's Structure & LandformsAges 15–16
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Sign in to playChoose a hazard (earthquake, volcanic eruption, tropical cyclone or river flood) and set its size, its distance from a city, population density, level of development (low, middle or high income) and the share of buildings built to hazard-resistant codes. Switch on monitoring and prediction, protection, planning, and aid and insurance to see how deaths, injuries, homelessness, economic losses and recovery time change. Risk is shown as Hazard × Vulnerability ÷ Capacity, with primary and secondary effects, immediate and long-term responses, and knock-on effects.
Lesson: Natural hazards: risk, impacts and management
What it shows
A natural hazard becomes a disaster when it strikes people who are vulnerable and lack the capacity to cope. This model places a city at a chosen distance from an earthquake, eruption, cyclone or flood. Shaking intensity, ash fall, wind, storm surge and flood depth all fall with distance. Weak buildings, poverty and missing plans raise vulnerability; health care, warnings, drills, aid and insurance raise capacity. The same event usually kills far more people in a low-income country, while a high-income country loses more money but recovers faster.
How to use
Pick a Hazard and a Development setting, then set the size, distance, Population density and Codes. Watch the event on the map and read the intensity graph. Tick Monitoring & prediction, Protection, Planning & drills or Aid & insurance and compare the results table. Press Keep for comparison, change one setting, and the two columns show the difference. Replay event runs the animation again.
Parameters you can change
- Hazard type Earthquake, Volcanic eruption, Tropical cyclone, River flood
- Earthquake magnitude (moment magnitude scale) 5–9.5 Mw
- Focus (hypocentre) depth 5–300 km
- Volcanic Explosivity Index 1–7 VEI
- Saffir-Simpson category 1–5 category
- Flood depth on the floodplain next to the river 0.5–6 m
- Distance from the hazard source to the city 0–150 km
- Population density of the city (area 100 km²) 100–10000 people/km²
- Level of development Low-income country (LIC), Middle-income country, High-income country (HIC)
- Share of buildings built to hazard-resistant codes 0–100 %
- Monitoring and prediction (early warning)
- Protection (retrofitting, levees, sea walls, shelters)
- Planning: hazard maps, land-use zoning, evacuation drills
- International aid and insurance
Questions to explore
- Why does the same magnitude 7.0 earthquake cause far more deaths in a low-income country?
- How is moment magnitude different from Mercalli intensity, and why is a deep earthquake less damaging?
- Why do warnings save many lives only when people also have an evacuation plan?
