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.
The risk equation — what each part means
| Term | What it means | What raises it / lowers it |
|---|---|---|
| Hazard | The natural event itself (earthquake, eruption, landslide) | Set by physics — magnitude, depth, secondary hazards |
| Vulnerability | How susceptible a community is to harm | Raised by poverty, weak codes, density; lowered by wealth and planning |
| Capacity to cope | Ability to prepare for, withstand and recover | Raised by wealth, strong governance, warnings, insurance |
| Exposure | The people and property where the hazard strikes | Raised by dense settlement on risky land |
| Risk perception | How seriously people judge the threat | Low after no recent event — so people fail to prepare |
Key terms for hazard risk
- Hazard — a natural event (earthquake, eruption, landslide) that threatens people.
- Risk — the probability of harmful consequences from a hazard.
- Vulnerability — how susceptible a community is to harm from a hazard.
- Capacity to cope — the ability to prepare for, withstand and recover (wealth, governance, planning, warnings).
- Exposure — the people and property in the place where the hazard strikes.
- Risk perception — how seriously people judge the threat, which shapes whether they prepare.
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.
Vulnerability factors and how they change risk
| Factor | Raises vulnerability | Lowers vulnerability |
|---|---|---|
| Economic (wealth) | Poverty — flimsy homes, no insurance, slow recovery | Wealth — strong buildings, insurance, recovery funds |
| Political (governance) | Weak state — no enforced codes or warnings | Strong state — enforced codes, warning systems, planning |
| Demographic (age structure) | Many elderly / very young — hard to flee or recover | Working-age, mobile population |
| Social (awareness) | Low risk perception — hazard seen as fate | Drills, education, high risk perception |
| Demographic (density) | Crowded settlement — high exposure | Lower density, planned land use |
Read the key first — a higher score means more vulnerable. Event P sits higher on every bar despite a similar magnitude: that gap is vulnerability, not the hazard.
🔒 Interactive diagram
Explore the labelled diagram, charts and maps for this topic in study mode.
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.
Same magnitude, very different impacts — why vulnerability matters
| Factor | Haiti 2010 (Mw 7.0) | Christchurch 2011 (Mw 6.3) |
|---|---|---|
| Deaths | ~220,000 | 185 |
| Wealth (development) | Low-income, very poor | High-income, wealthy |
| Buildings | Unreinforced, no enforced codes | Strict, enforced building codes |
| Governance / preparedness | Weak government, little planning | Strong response, drills, insurance |
| Population & density | Dense, fast-growing capital | Lower density, planned city |
| Outcome | Catastrophic — high vulnerability | Serious but survivable — low vulnerability |
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.
✍️ IB-style questions
Explain how economic conditions can change the impact of two earthquakes of a similar magnitude.
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
Examine why two earthquakes of similar magnitude can produce very different human impacts.
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
✅ Quick self-check
Tap each card to reveal the answer.
State the hazard risk equation. Risk = Hazard x Vulnerability / Capacity to cope — impact depends on exposure and coping ability, not just the size of the event.
What is vulnerability, and what drives it? How susceptible a community is to harm. Driven by economic, social, demographic and political factors — wealth, education, age structure and governance — not the hazard's size.
Why did Haiti 2010 kill far more than Christchurch 2011? Similar magnitude, but Haiti's poverty, weak governance, no enforced codes and dense housing meant high vulnerability; wealthy, well-governed Christchurch had enforced codes, insurance and preparedness — only 185 died vs ~220,000.
How does age structure change earthquake risk? Many elderly or very young people struggle to flee and recover (limited mobility, reliance on care), raising a community's vulnerability.
What does a top [10] Examine answer need? A range of developed factors (economic / social / demographic / political), named case studies with data, a weighing of relative importance, and a clear judgement.
🎯 Highest-yield exam reminders
Exam Tips
- Risk = Hazard x Vulnerability / Capacity to cope — size alone does not decide the impact.
- For a comparison figure: IDENTIFY the more vulnerable place and ESTIMATE a value off the axis, THEN explain the gap with a factor.
- Explain = name the factor + develop HOW it raises or lowers vulnerability (poverty → flimsy homes → collapse → high death toll).
- Use named events with data: Haiti 2010 (~220,000), Christchurch 2011 (185), Nevado del Ruiz 1985 (~23,000).
- Economic, social, demographic and political factors all shape vulnerability — show a range, not just one.
- On the [10] Examine/Evaluate/Discuss: weigh a range of developed factors + named data, then finish with a clear judgement (one factor or no judgement caps mid-band).