Hazardous Earth: Revision and Exam Practice

This final lesson brings together everything you have learned across the Hazardous Earth topic. It provides a comprehensive glossary of key terms, revision checklists for each sub-topic, guidance on Edexcel B exam technique, and practice questions with model answer structures. Use this lesson as your go-to revision resource in the weeks and days before your exam.

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Key Terms Glossary

The following table contains all the essential terms you need to know for the Hazardous Earth topic. Being able to define these precisely will earn you marks across all question types.

Term	Definition
Atmospheric circulation	The large-scale movement of air across the Earth's surface, driven by differential heating and the Coriolis effect
Hadley Cell	The largest atmospheric circulation cell, operating between the equator and approximately 30° latitude
Ferrel Cell	The mid-latitude circulation cell, operating between approximately 30° and 60° latitude
Polar Cell	The smallest atmospheric circulation cell, operating between approximately 60° and 90° latitude
Coriolis effect	The deflection of moving objects (including air and water) caused by the Earth's rotation — to the right in the Northern Hemisphere, to the left in the Southern Hemisphere
ITCZ	Inter-Tropical Convergence Zone — a belt of low pressure near the equator where trade winds converge and air rises
Trade winds	Surface winds blowing from the subtropical highs towards the equator (NE in NH, SE in SH)
Thermohaline circulation	The global ocean conveyor belt, driven by differences in water temperature and salinity
Milankovitch cycles	Long-term variations in Earth's orbit (eccentricity, axial tilt, precession) that cause glacial-interglacial cycles
Enhanced greenhouse effect	The additional warming caused by human-produced greenhouse gases trapping more heat in the atmosphere
Mitigation	Actions taken to reduce the causes of climate change (e.g., reducing greenhouse gas emissions)
Adaptation	Actions taken to adjust to the effects of climate change (e.g., building flood defences)
Tropical cyclone	A large, rotating low-pressure weather system with sustained winds ≥119 km/h, fuelled by warm ocean water
Storm surge	A temporary rise in sea level caused by low pressure and onshore winds during a tropical cyclone
Saffir-Simpson scale	A scale classifying tropical cyclones into Categories 1–5 based on sustained wind speed
Tectonic plate	A large, rigid section of the Earth's lithosphere that floats on the semi-molten asthenosphere
Subduction	The process by which a denser oceanic plate is forced beneath a less dense plate at a destructive boundary
Convection currents	Circular flows of semi-molten rock in the mantle, driven by heat from the core, that move tectonic plates
Focus (hypocentre)	The point underground where an earthquake originates
Epicentre	The point on the Earth's surface directly above the focus
Seismic waves	Vibrations of energy released during an earthquake (P-waves, S-waves, surface waves)
Moment magnitude scale	The scale used to measure earthquake energy release; logarithmic (each step = 32× more energy)
Liquefaction	When saturated, loose soil loses its strength during shaking and behaves like a liquid
Tsunami	A series of large ocean waves caused by displacement of the sea floor during a submarine earthquake
Primary effects	Direct impacts caused by a hazard event (e.g., building collapse from ground shaking)
Secondary effects	Indirect impacts resulting from primary effects (e.g., fires caused by ruptured gas pipes)

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Revision Checklists

Use these checklists to ensure you have covered every part of the specification. Tick off each point as you revise it.

Sub-Topic 1: Global Climate

• Explain how the atmosphere redistributes heat energy from equator to poles
• Describe the three-cell model (Hadley, Ferrel, Polar)
• Explain how pressure belts and surface winds are created
• Define and explain the Coriolis effect
• Explain the role of ocean currents (surface and thermohaline) in heat transfer
• Describe evidence for natural climate change (ice cores, tree rings, historical records, sea-floor sediments)
• Explain Milankovitch cycles (eccentricity, axial tilt, precession)
• Explain how volcanic eruptions and solar output affect climate
• Describe the enhanced greenhouse effect and the role of different greenhouse gases
• Present evidence for human-caused climate change
• Explain the impacts of climate change on environments and people
• Compare mitigation and adaptation strategies

Sub-Topic 2: Tropical Cyclones

• List and explain the conditions required for tropical cyclone formation
• Describe the structure of a tropical cyclone (eye, eyewall, spiral rainbands)
• Explain the Saffir-Simpson scale and its limitations
• Describe the global distribution and seasonal patterns of tropical cyclones
• Explain primary hazards (wind, storm surge, rainfall)
• Explain secondary hazards (flooding, landslides, disease)
• Describe factors affecting severity (physical and human)
• Case study: Typhoon Haiyan 2013 — causes, effects, responses
• Case study: Hurricane Sandy 2012 — causes, effects, responses
• Compare Haiyan and Sandy — how development level affects impacts

Sub-Topic 3: Tectonic Hazards

• Describe the internal structure of the Earth (crust, mantle, outer core, inner core)
• Compare oceanic and continental crust
• Explain the evidence for continental drift and plate tectonics
• Explain convection currents, ridge push and slab pull
• Describe all four plate boundary types and their associated hazards
• Give examples for each boundary type
• Explain focus, epicentre and seismic wave types (P, S, surface)
• Compare the Richter and moment magnitude scales
• Explain primary and secondary effects of earthquakes
• Case study: Nepal 2015 — causes, effects, responses
• Case study: L'Aquila 2009 — causes, effects, responses
• Compare Nepal and L'Aquila — how development level affects impacts
• Evaluate prediction, protection and planning for tectonic hazards
• Explain why management differs between HICs and LICs

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Edexcel B Exam Command Words

Understanding command words is essential for answering exam questions correctly. Each command word tells you exactly what the examiner expects:

Command Word	What It Means	What to Do
State	Give a brief, factual answer	One word, phrase or short sentence. No explanation needed
Define	Give the meaning of a term	A precise, clear definition. Use geographical terminology
Describe	Say what something is like	Give details of features, characteristics or patterns. Use data where possible
Explain	Say why or how something happens	Give reasons and causes, not just descriptions. Use connective words: "because", "this means that", "as a result"
Compare	Identify similarities and differences	Explicitly link the two things being compared. Use phrases like "whereas", "in contrast", "similarly", "both"
Evaluate	Make a judgement based on evidence	Consider strengths and weaknesses, or arguments for and against, and reach a conclusion
Assess	Weigh up the importance or effectiveness of something	Similar to evaluate but may focus on significance or success
Discuss	Explore different perspectives or viewpoints	Present multiple sides of an argument with evidence, then give your view
To what extent	How far do you agree?	Argue both sides and reach a balanced conclusion that acknowledges complexity

Exam Tip: Always underline the command word in an exam question before you start writing. This ensures you answer the question that has been asked, not the question you wish had been asked. Many students lose marks by describing when asked to explain, or by explaining when asked to evaluate.

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Structuring 6-Mark Extended Answers

Edexcel B Geography exams include 6-mark extended response questions that require a structured, well-evidenced answer. Here is a reliable framework:

The PEEL Structure

Step	What to Do	Example
P — Point	State your main argument or point clearly	"The level of development is the most important factor in determining the impact of tropical cyclones"
E — Evidence	Support your point with specific case study data	"Typhoon Haiyan (2013) killed 6,300+ people in the Philippines, while Hurricane Sandy (2012) killed 233, despite Sandy being a large storm"
E — Explain	Explain how the evidence supports your point	"This contrast is primarily because the Philippines lacked the earthquake-resistant buildings, effective warning systems and well-resourced emergency services available in the USA"
L — Link	Link back to the question or develop the argument further	"Therefore, while storm intensity matters, the human factors of poverty, infrastructure and governance are often more important in determining the death toll"

Model 6-Mark Answer Plan

Question: "Explain why tropical cyclones cause more deaths in LICs than in HICs." (6 marks)

Paragraph 1 — Warning systems and evacuation

• Point: HICs have better warning systems and evacuation capacity
• Evidence: The National Hurricane Center gave 5+ days warning before Sandy; NYC evacuated 375,000 people. PAGASA gave 48-hour warnings for Haiyan but communication in remote areas was limited
• Explain: Early, accurate warnings + good transport infrastructure = effective evacuation = fewer deaths

Paragraph 2 — Building quality and infrastructure

• Point: LIC buildings are more vulnerable to cyclone damage
• Evidence: In Tacloban (Haiyan), 90% of buildings were damaged or destroyed — many were made from wood and corrugated iron. In the USA, engineered buildings survived Sandy with damage rather than collapse
• Explain: Weak buildings offer no protection against high winds and storm surge; people inside are killed by collapsing structures and flying debris