Distinguish hazard from risk and explain how exposure and vulnerability shape disaster impact

What this dot point is asking

SCSA wants you to distinguish hazard from risk and explain how exposure and vulnerability shape the impact of Earth hazards. This conceptual distinction is what lets you evaluate why mitigation works: we cannot stop earthquakes, but we can reduce the risk they pose.

Hazard versus risk

The terms are often confused but mean different things.

• A hazard is the potentially damaging natural process itself, such as an earthquake, eruption or tsunami. It exists whether or not anyone is affected.
• Risk is the expected harm, combining how likely the hazard is with how severe its consequences would be. A hazard in an empty desert poses little risk; the same hazard in a city poses high risk.

Exposure and vulnerability

Risk has two human dimensions that the hazard alone does not capture.

• Exposure is the people, property, infrastructure and ecosystems located where the hazard can reach them. A growing coastal city increases exposure to tsunamis.
• Vulnerability is how susceptible those exposed elements are to harm. Poorly built housing, weak warning systems, limited emergency services and poverty all raise vulnerability; strong building codes, education and preparedness lower it.

Risk can be thought of as combining the hazard with exposure and vulnerability: a large hazard affecting many highly vulnerable people produces a high-risk, high-impact disaster.

Why the distinction matters for management

Because we usually cannot change the hazard, risk reduction targets exposure and vulnerability.

• Reducing exposure: land-use planning that keeps people away from fault lines, lahar valleys and tsunami inundation zones.
• Reducing vulnerability: building codes for earthquakes, warning systems, education and emergency planning.

A wealthy country with strong codes and warnings may suffer few deaths from a large hazard, while a poorer country with high vulnerability suffers a catastrophe from a similar event. Comparing such cases is a common exam task, and the explanation always comes back to exposure and vulnerability rather than the hazard alone.

Vulnerability has social as well as physical dimensions

A sophisticated answer recognises that vulnerability is not only about how strongly a building is engineered; it has social and economic dimensions that examiners increasingly reward. Poverty raises vulnerability because people cannot afford safe housing, insurance or rapid recovery. Age, disability and isolation affect who can evacuate in time. Weak governance, poor communication and limited emergency services mean warnings may not reach people or be acted on. Recovery capacity matters too: a wealthy community rebuilds quickly, while a poorer one may suffer long-term displacement and economic loss long after the shaking stops. This is why two communities facing the same hazard and similar physical exposure can still differ in risk, and why disaster risk reduction includes social measures (education, equitable planning, resilient services) alongside engineering. Framing vulnerability this broadly connects Earth hazards to human geography and is the kind of synthesis SCSA values in top-band responses.