IB Geography HL — Hazard risk and vulnerability

Key Idea: Topic 10.3 asks why two natural events of similar size can cause wildly different human disasters. Its one micro pulls the whole idea together: 10.3.1 — hazard risk and vulnerability: the risk a hazard poses is not just its magnitude. Geographers use Risk = Hazard x Vulnerability / Capacity to cope — so impact depends on who is exposed and how well they can cope, driven by economic (wealth vs poverty), social (education, risk perception), demographic (age, density) and political (governance) factors. This is an option topic, examined on Paper 1 (you answer 2 options at SL, 3 at HL — same questions at both levels). Each option ends in a [10] markband essay, so most marks here come from weighing those factors with named events (Haiti 2010, Christchurch 2011, Nevado del Ruiz 1985) and reaching a clear judgement.

⚠️ 10.3.1 — Risk, vulnerability and capacity to cope

A hazard is a natural event that could harm people; the risk it poses depends on vulnerability (how susceptible people are to harm) and their capacity to cope (the wealth, governance and planning to prepare and recover). The core idea is the risk equation: Risk = Hazard x Vulnerability / Capacity to cope. The same earthquake hits a rich, prepared city far more gently than a poor, unprepared one — so the marks come from explaining vulnerability, not the geology.

Two earthquakes of the same magnitude can cause wildly different damage. The difference is vulnerability and capacity to cope — wealth, building codes, governance, density and preparedness — not the size of the shake.

🏚️ Why similar events cause different impacts

Vulnerability is driven by four groups of factors — economic, social, demographic and political — and the same hazard can devastate one community while barely touching another. The skill examiners test is reading a comparison chart or table of two named events (deaths, building damage or a vulnerability index side by side), identifying the more vulnerable place and estimating a value, then explaining the gap with a factor — always name the factor and develop how it raises or lowers vulnerability.

Tip: When a figure compares two events, the marks come from the comparison: a similar magnitude but a huge gap in deaths points straight to vulnerability (wealth, building codes, governance) rather than the hazard itself. Identify the more vulnerable place and estimate a value off the axis before you explain.

🌍 The factors in real events

Top marks need named events with data — the same magnitude can devastate one community while barely touching another, and the contrast is your evidence. Tie each factor to a real place and a number.

Example: The 2010 Eyjafjallajokull eruption in Iceland caused no local deaths — a wealthy, prepared state with monitoring and good planning. By contrast the 1985 Nevado del Ruiz eruption in Colombia killed about 23,000 in the town of Armero: warnings were poor and ignored, so a lahar buried a community that could have been evacuated. Low capacity to cope — not eruption size — drove the disaster.

Do not just name a factor — explain how it changes vulnerability. Poverty → flimsy housing + no insurance → buildings collapse + slow recovery → higher death toll. That chain from cause to consequence is what earns the development mark.

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