The Challenge of Natural HazardsTopic Summary
Topic Summary: Tectonic Hazards
Part of Tectonic Hazards — GCSE Geography
This topic summary covers Topic Summary: Tectonic Hazards within Tectonic Hazards for GCSE Geography. Revise Tectonic Hazards in The Challenge of Natural Hazards for GCSE Geography with 14 exam-style questions and 24 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 12 of 12 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 12 of 12
Practice
14 questions
Recall
24 flashcards
Topic Summary: Tectonic Hazards
Key Terms
- Lithosphere — Earth's rigid outer layer, divided into tectonic plates
- Subduction — oceanic plate forced beneath continental plate at destructive margin
- Focus — underground origin point of earthquake energy release
- Epicentre — surface point above the focus
- Vulnerability — susceptibility to harm (poverty, building quality, terrain, governance)
- Preparedness — actions taken before a hazard to reduce impact
- Pyroclastic flow — fast-moving superheated gas, ash and rock (up to 700 km/h)
- Lahar — volcanic mudflow; continues years after eruption
Chile 2010 Key Facts
- Magnitude 8.8 Mw — one of the largest ever recorded
- Destructive margin: Nazca Plate subducting under South American Plate
- ~550 deaths; $30 billion damage; 2 million displaced
- Tsunami hit coastal towns (Constitución, Dichato)
- Low deaths due to: strict building codes since 1960, GDP ~$10,000, effective governance
- $8.4 billion reconstruction plan; largely complete within 3–4 years
Nepal 2015 Key Facts
- Magnitude 7.8 Mw — 32× less energy than Chile
- Collision margin: Indian Plate colliding with Eurasian Plate
- ~9,000 deaths; $10 billion damage (~50% of GDP); 2.8 million displaced
- 600,000+ houses completely destroyed; UNESCO heritage sites collapsed
- High deaths due to: unreinforced brick/stone buildings, GDP ~$700, remote terrain, limited services
- Recovery extremely slow; families still in temporary shelters 3 years on
Exam Must-Know Points
- Bigger magnitude ≠ more deaths — vulnerability is the key variable
- Always compare Chile (HIC) and Nepal (LIC) with specific statistics
- Three margin types: Destructive (earthquakes + volcanoes), Collision (earthquakes only), Conservative (earthquakes only)
- Volcanoes also form at hotspots (Hawaii) and constructive margins (Iceland)
- Level 3 answers need: named case study + specific evidence + supported judgement about WHY
- CLEVER framework: Context → Location → Effects → Vulnerability → Emergency response → Rebuilding