Hazard, exposure and vulnerability
Separate physical intensity from exposure and support needs, then compare preparedness choices.
Hazard, exposure and vulnerability
Original fictional unfamiliar-resource pack. Work across the resources; each describes the same teaching scenario. This is not an official examination paper or a real project forecast.
Hazard and occupied-home layers
Scroll the diagram sideways to see the full resource.
| District | Hazard category | Occupied homes | Vulnerability index (ordinal 1–3) |
|---|---|---|---|
| A | High | 180 | 1 |
| B | Medium | 70 | 1 |
| C | High | 90 | 2 |
| D | Low | 180 | 3 |
Resource description
A: High hazard, 180 occupied homes, vulnerability index 1; B: Medium hazard, 70 occupied homes, vulnerability index 1; C: High hazard, 90 occupied homes, vulnerability index 2; D: Low hazard, 180 occupied homes, vulnerability index 3. The vulnerability index is ordinal, not a probability.
Scenario exposure and support assumptions
| District | Scenario-exposed homes (%) | Share needing support among exposed homes (%) | Modelled homes needing assistance |
|---|---|---|---|
| District A | 30 | 75 | 40.5 |
| District B | 50 | 25 | 8.75 |
| District C | 60 | 25 | 13.5 |
| District D | 60 | 25 | 27 |
Resource description
Teaching assumption: assistance = occupied homes × scenario-exposed share × support-needing share. The ordinal vulnerability index is not multiplied into this calculation. Shares are supplied fictional assumptions, not probabilities inferred from map categories.
Management alternatives
| Option | Capital cost (£ million) | Benefit | Limitation |
|---|---|---|---|
| Warning and evacuation support | 1.8 | Can improve access to warnings and assistance | Does not reduce the physical hazard; response and accessibility matter |
| Strengthen vulnerable buildings | 5.8 | Can reduce structural vulnerability in priority areas | Coverage is limited by the budget and implementation time |
| Protect emergency access routes | 3.2 | Supports rescue and supply movement | Homes may remain exposed and vulnerable |
Resource description
Available capital budget: £6 million. Options are alternatives; their benefits cannot simply be added. Operating costs are separate.
Options
Warning and evacuation support
Capital cost: £1.8 million
Can improve access to warnings and assistance
Does not reduce the physical hazard; response and accessibility matter
Strengthen vulnerable buildings
Capital cost: £5.8 million
Can reduce structural vulnerability in priority areas
Coverage is limited by the budget and implementation time
Protect emergency access routes
Capital cost: £3.2 million
Supports rescue and supply movement
Homes may remain exposed and vulnerable
Stakeholder statements
Residents of the most exposed district: We need warnings we can act on and help for people unable to leave.
Emergency coordinator: The teaching estimate totals 89.75 households; emergency routes must remain usable.
Building engineer: Reducing vulnerability takes time and cannot promise zero damage.
Limits of this resource model
- Hazard and vulnerability categories are ordinal; multiplying them does not give a loss probability.
- The assistance formula is an explicit teaching assumption, not a real loss model.