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Welcome to GCSE A Q A Geography revision.

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Topic G 1: Natural hazards.

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Use your school’s selected case studies if they differ from these revision examples.

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A natural hazard is a natural event or process that could harm people, property or the environment.

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An earthquake in an uninhabited area is a natural event; it becomes a hazard where people or their assets are exposed.

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Tectonic hazards include earthquakes and volcanic eruptions.

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Weather hazards include tropical storms, droughts and heatwaves.

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Floods can result from weather and can be made worse by human changes to drainage.

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Hazard risk means the chance of harm and how serious that harm could be.

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It depends on the hazard's likelihood and strength, the people and assets exposed, and their vulnerability (how easily they can be harmed).

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Why hazard risk differs.

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Risk depends on these factors together; this is not a numerical risk equation.

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Exposure increases where more people live in a hazard zone.

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A densely populated coastal city can have more people and buildings in the path of a storm surge than a sparsely populated coastline.

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Vulnerability increases where buildings are weak, clean water is limited or people cannot afford transport to evacuate.

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Age, disability and access to warnings can also affect someone's ability to respond.

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Wealth can pay for stronger buildings, emergency services and flood defences.

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However, wealthy places can still suffer severe losses, especially where expensive infrastructure is exposed.

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Urbanisation can increase risk if rapid growth leads to crowded informal settlements on steep slopes, floodplains or unstable ground.

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Planning can reduce exposure by limiting building in dangerous locations.

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Climate change can alter the likelihood or severity of some weather hazards.

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It does not cause plate movement or make earthquakes more frequent.

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Risk changes with location: proximity to a plate margin, height above sea level, slope steepness and local climate all affect which hazards are likely.

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Preparation can reduce vulnerability.

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Education, drills, evacuation routes, building rules and emergency supplies help people act before and after an event.

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People may accept risk because a place offers jobs, fertile soils, family ties or affordable housing.

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Some cannot afford to move; others judge that the benefits outweigh the danger.

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A disaster occurs when a hazardous event causes serious disruption beyond a community's ability to cope using its own resources.

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The same physical event can have very different outcomes in different places.

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When explaining hazard risk, build a chain of reasoning: weak buildings are more likely to collapse, which increases injuries and makes rescue harder.

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Naming a factor alone does not explain its effect.

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That completes Natural hazards.

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Revisit the notes and test yourself on the revision website.