Tectonic hazards: explain the different impacts
Connect plate movement to a hazard, then explain why similar events can produce different impacts.
From plate motion to shaking
Plates move across Earth’s surface. Where movement is resisted along a fault, elastic strain can build. Sudden slip releases energy as seismic waves. The focus lies within Earth; the epicentre is directly above it.
Subduction can produce earthquakes and volcanic activity. Conservative boundaries involve lateral motion and earthquakes; they do not normally generate magma. A boundary label needs a mechanism.
Worked example
In a fictional cross section the focus is 15 km deep and the epicentre is 40 km from a town horizontally. These distances describe different dimensions; neither is the earthquake magnitude.
Common mistake: Magnitude measures the event; experienced shaking varies by location.
Explain an impact chain
Damage depends on the hazard reaching exposed people and buildings, and on their vulnerability. Building strength, slope stability, access and emergency capacity influence outcomes.
Primary effects arise directly from shaking. Landslides, interrupted supplies and disease risks can follow, though the classification needs the event’s evidence.
Worked example
In a fictional town 800 buildings are exposed; 120 become unusable. The proportion is 120 ÷ 800 × 100 = 15%. This measures affected buildings, not the proportion of residents injured.
Common mistake: A lower death toll does not prove the earthquake was weaker.
Compare responses fairly
Immediate rescue, shelter and supplies address urgent needs. Rebuilding infrastructure, restoring livelihoods and improving building standards extend over longer periods.
Compare contrasting events using the same outcome and timescale. Wealth can influence resources, but governance, isolation and the particular event also matter.
Worked example
Fictional response teams reach 70 of 100 villages in one area and 45 of 50 in another: 70% and 90%. The second coverage rate is higher even though fewer villages were reached.
Common mistake: Counts alone can reverse a comparison when denominators differ.
Try a different resource
Hazard and exposure overlays
The occupied-home count represents exposure. Hazard and vulnerability categories are ordinal labels; multiplying them does not produce a probability of loss. A screening rule is supplied for this fictional exercise.
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.
Write an explanation
Check your answer
- Name both events and establish comparable evidence.
- Link a physical process to exposure and vulnerability.
- Explain differences in immediate and longer-term responses.
- Consider another cause alongside wealth.
Practise and review a written answer
Case studies
Nepal earthquake, 2015 · Tōhoku earthquake and tsunami, 2011 · Haiti earthquake, 2010
These pages provide selected evidence. Check the whole case requirement with your teacher.
Read further
- www.aqa.org.uk — source or course reference
- www.aqa.org.uk — source or course reference
- qualifications.pearson.com — source or course reference
- www.sqa.org.uk — source or course reference
- www.ocr.org.uk — source or course reference
- www.eduqas.co.uk — source or course reference
Plate motion and tectonic hazards · Hazard, exposure and vulnerability
Course links
AQA GCSE Geography · Pearson Edexcel GCSE Geography B · National 5 Geography · OCR GCSE Geography B · Eduqas GCSE Geography A
Next topics
Weather hazards and atmospheric circulation · Hazard systems: cascades, probability and resilience
Selected teaching sequence with fictional worked data. The linked case records supply bounded evidence; they do not satisfy every course case requirement.
Scottish links identify reusable parts of the topic. Scottish landforms, soil, weather and disease requirements need additional course-specific teaching.