Tectonic plates and boundaries

The Earth's crust is split into tectonic plates that float on the semi-molten mantle and move due to convection currents.

There are four main boundary types.

• Destructive (convergent): oceanic and continental plates collide, denser oceanic plate subducts, causing volcanoes and powerful earthquakes (e.g. Nazca and South American plates, Chile).
• Constructive (divergent): plates move apart, magma rises to fill the gap, forming shield volcanoes and shallow earthquakes (e.g. Mid-Atlantic Ridge, Iceland).
• Conservative: plates slide past each other, no magma so no volcanoes, but huge friction builds and releases as powerful earthquakes (e.g. San Andreas Fault, California).
• Collision: two continental plates meet, neither subducts, crust crumples upward into fold mountains (e.g. Indian and Eurasian plates forming the Himalayas).

Volcanoes

Composite (strato) volcanoes form at destructive boundaries: steep sides, alternating ash and lava layers, violent eruptions due to thick, viscous magma.

Shield volcanoes form at constructive boundaries: gentle slopes, runny basaltic lava, frequent but less violent eruptions.

Common mistake: students confuse which boundary produces which volcano type - remember destructive = explosive/composite, constructive = effusive/shield.

Earthquakes

Measured on the Richter scale (magnitude) or Moment Magnitude Scale (Mw) for size, and the Mercalli scale for observed impact/intensity.

Focus = point underground where the earthquake starts; epicentre = point on the surface directly above the focus.

Primary effects happen immediately (building collapse, deaths); secondary effects follow afterwards (fires, disease, landslides, tsunamis).

Managing tectonic hazards

Monitoring: seismometers detect tremors, tiltmeters detect ground bulging, gas sensors detect rising sulphur dioxide.

Prediction is possible for volcanoes (warning signs build slowly) but NOT reliably possible for earthquakes - this is a key exam point.

Protection: cross-bracing, base isolators and automatic shutoff valves in buildings in earthquake zones.

Planning: evacuation routes, hazard maps and exclusion zones around active volcanoes.

Comparing a rich and poor country example

AQA expects a case study pair - e.g. L'Aquila (Italy, 2009, HIC) vs Haiti (2010, LIC) or Nepal (2015, LIC/NEE) vs Christchurch (NZ, 2011, HIC).

Key contrast: richer countries have stricter building codes, faster emergency response and lower death tolls; poorer countries often have higher death tolls but sometimes lower economic cost simply because there is less infrastructure to lose.

Always learn specific numbers for your case study: magnitude, death toll, cost in dollars, and named primary/secondary effects.

Tropical storms (if on your spec)

Form over oceans at least 26.5 degrees C, between 5-30 degrees latitude (not on the equator, as the Coriolis effect is too weak there).

Common mistake: forgetting storms need warm water AND enough distance from the equator to spin.

Weather hazards

The UK gets extreme weather from time to time, like storms, floods and droughts, but these are becoming more frequent as climate changes. Tropical storms (hurricanes/cyclones/typhoons - same thing, different names) form over warm ocean water above 27 degrees C, between 5 and 30 degrees north and south of the equator. They spin due to the Coriolis effect and need low wind shear to develop. They lose energy over land because the warm moist air supply is cut off.

Tropical storm structure

• The eye is calm, low pressure, no cloud.

The eye wall has the strongest winds and heaviest rain.

• Spiralling rain bands bring heavy rain outward from the centre.

UK weather hazards

The UK experiences drought, flooding, extreme cold and storms. A well-known case is Storm Desmond (December 2015), which caused flooding in Cumbria. Common mistake: don't say the UK gets hurricanes - it gets ex-tropical storms that have weakened crossing the Atlantic.

Climate change causes and evidence

Evidence includes ice cores, tree rings, temperature records and sea level rise. Natural causes include orbital changes (Milankovitch cycles), volcanic activity and solar output. Human causes are the main focus: burning fossil fuels releases CO2, and deforestation reduces carbon storage, both boosting the greenhouse effect.

Managing climate change

• Mitigation means reducing the causes, e.g. renewable energy, carbon capture, planting trees, international agreements like the Paris Agreement.
• Adaptation means preparing for the effects, e.g. changing agricultural systems, managing water supply, building flood defences.

Ecosystems

An ecosystem is a community of living organisms and the non-living parts of their environment, all interacting. A food web shows how energy passes between producers, consumers and decomposers.

Global biomes

Key biomes for the exam are tropical rainforests and hot deserts.

• Tropical rainforests: near the equator, hot and wet all year (temp around 27 C, rainfall over 2000mm/year), incredible biodiversity, distinct layers (emergent, canopy, under canopy, shrub layer).
• Hot deserts: around 30 degrees north/south (e.g. Sahara), very low rainfall (under 250mm/year), huge temperature range between day and night, plants and animals are adapted (e.g. camels store fat not water, cacti have shallow wide roots).

Common mistakes

• Mixing up weather (short-term, day to day) with climate (long-term average pattern).
• Forgetting specific case study names, dates and figures - AQA rewards precise detail.
• Confusing mitigation with adaptation - mitigation stops the cause, adaptation copes with the effect.

River processes

Rivers change shape along their long profile. In the upper course, erosion dominates: vertical erosion cuts down, using hydraulic action (force of water), abrasion (load scraping the bed), attrition (rocks smashing together, getting smaller and rounder) and solution (dissolving rock). Steep V-shaped valleys, interlocking spurs and waterfalls form here.

Landforms to know

• Waterfalls: soft rock undercuts hard rock, forming a plunge pool; the overhang collapses and the waterfall retreats upstream, leaving a gorge.
• Meanders: fastest flow (thalweg) on the outside bend causes erosion, forming a river cliff; slower flow on the inside deposits a slip-off slope (point bar).
• Oxbow lakes: a meander neck is eroded until cut through in a flood; deposition then seals off the old bend.
• Levees: repeated flooding deposits coarse material closest to the bank, building raised natural embankments.
• Flood plains: wide flat land either side of a river, built up by deposition during floods.

Coastal processes

Same four erosion types as rivers, plus deposition (longshore drift moves sediment along the coast in a zigzag, driven by prevailing wind direction and the swash/backwash pattern). Weathering (freeze-thaw, biological, chemical) and mass movement (rockfall, slumping) also shape cliffs.

Coastal landforms

• Headlands and bays: alternating bands of resistant and less-resistant rock erode at different rates.
• Wave-cut platforms: erosion at the base forms a notch; the cliff collapses and retreats, leaving a gently sloping rock platform.
• Caves, arches, stacks, stumps: sequence formed by erosion widening cracks in a headland, roof collapse creates an arch, arch collapse leaves a stack, further erosion leaves a stump.
• Spits: longshore drift deposits sand/shingle where the coastline changes direction; a hooked end can form if wind direction changes, and a salt marsh can build up in the sheltered water behind.
• Bars: a spit that grows fully across a bay, cutting it off to form a lagoon.

Management strategies

• Hard engineering: sea walls, rock armour, gabions, groynes (rivers: dams, embankments, channel straightening).
• Soft engineering: beach nourishment, dune regeneration, managed retreat (rivers: flood warnings, planting trees, river restoration).

Exam questions often ask you to evaluate costs vs benefits, so always weigh economic, social and environmental impacts, not just whether it 'works'.

Common mistakes

• Mixing up erosion processes: hydraulic action is water force, abrasion is load doing the scraping.
• Forgetting that longshore drift direction depends on prevailing wind, not just tide.
• Describing a landform instead of explaining the process that formed it (always use 'because' and sequence words: first, then, finally).
• Confusing hard and soft engineering examples.

Urban growth patterns

Over 50% of the world's population now lives in urban areas, and this is rising fastest in newly emerging economies (NEEs) like Nigeria and India, not high-income countries (HICs). Urban growth in NEEs is driven by rural-urban migration (push factors: poor services, few jobs, natural disasters; pull factors: jobs, education, healthcare) and natural increase (high birth rates minus lower death rates once in the city).

Case study cities

• LIC/NEE example: Lagos, Nigeria — Africa's largest city, growth linked to oil wealth and rural push factors. Know: causes of growth, one social/economic opportunity (e.g. Makoko floating school, informal economy), and one challenge (e.g. slum housing in Makoko, waste management, traffic congestion) plus how it's being managed (e.g. slum upgrading schemes).
• UK city example: usually Bristol or Birmingham — know inequalities (housing, income, ethnicity), the causes of urban change (deindustrialisation, migration), and regeneration (e.g. Bristol's Harbourside/Temple Quarter, use of brownfield vs greenfield sites).

Sustainable urban living

• Key strategies: water and energy conservation, green space creation, waste recycling, and reducing traffic congestion.
• Traffic management examples: congestion charging (like London's £15 daily charge zone concept), park and ride schemes, cycle lanes, and integrated public transport.
• Urban greening reduces the urban heat island effect and manages surface run-off (SuDS — sustainable urban drainage systems).

Common mistakes

• Mixing up push and pull factors — always link push to the origin (rural area) and pull to the destination (city).
• Forgetting that NOT all urban growth is bad — always give both opportunities AND challenges for named cities.
• Vague answers without place-specific detail. You MUST name real places, schemes and (where possible) figures for the named case study cities — generic answers score few marks.
• Confusing brownfield (previously developed land) with greenfield (undeveloped land) — brownfield is usually preferred for sustainability but can be more expensive to develop due to contamination clean-up.
• Forgetting urbanisation is a GLOBAL pattern but the exam wants specific country-level detail (one NEE city study + one UK city study minimum).

Exam tip

Questions are often 6 or 8 markers asking you to 'assess', 'evaluate' or 'discuss' management strategies — always give a balanced answer with named examples and a clear judgement in your conclusion.

What is the changing economic world?

This topic looks at global development gaps, why they exist, and how countries try to close them. You need at least one case study of a Newly Emerging Economy (NEE) - usually Nigeria or India - and one case study of economic change in the UK.

Measuring development

• Development is uneven across the world - there is a 'development gap' between rich and poor countries.
• Economic measures: GNI per head (Gross National Income), rate of literacy, employment structure.
• Social measures: birth rate, death rate, people per doctor, access to safe water.
• The Composite measure Human Development Index (HDI) combines life expectancy, education (mean years of schooling) and income - scored 0 to 1, closer to 1 is more developed.
• Common mistake: GNI alone does not show inequality within a country - always pair an economic measure with a social one.

The Demographic Transition Model (DTM)

• 5 stages, tracking birth rate, death rate and total population over time.
• Stage 1: high birth and death rates, low/stable population (rare today).
• Stage 2: death rate falls fast (better healthcare/food), birth rate stays high - rapid population growth. Many LICs sit here.
• Stage 3: birth rate starts falling, population growth slows. Many NEEs sit here.
• Stage 4/5: low birth and death rates, stable or falling population - most HICs.

Causes of uneven development

• Physical causes: climate (drought/flooding harms farming), remoteness/landlocked location, natural hazards, limited natural resources.
• Historical causes: colonialism stripped resources and left poor infrastructure; trade agreements can still favour HICs.
• Economic causes: unfair trade terms (low prices for raw materials), high debt repayments, lack of foreign direct investment (FDI).

Consequences of uneven development

• Wealth: HICs consume far more resources per person than LICs.
• Migration: economic migrants move from poorer to richer areas/countries for jobs.
• Health: disease is more common where clean water and healthcare are scarce - e.g. malaria limits productivity in parts of sub-Saharan Africa.

Strategies to reduce the development gap

• Investment: FDI builds factories and infrastructure, e.g. from TNCs.
• Industrial development and tourism: creates jobs and export income.
• Aid: short-term (emergency) vs long-term (development) aid; top-down (government-led) vs bottom-up (small-scale, community, often via NGOs like intermediate technology - hand-dug wells, solar cookers).
• Fair trade: producers get a guaranteed fair price.
• Debt relief: cancelling debt frees money for health/education.
• Microfinance loans: small loans to help set up businesses, especially for women.

Common exam mistakes

• Confusing LIC/NEE/HIC categories - know which bracket your case study country sits in.
• Forgetting to name specific places/figures in extended answers - examiners reward precise detail (name the TNC, the % GNI growth, the scheme).

Resource management basics

Food, water and energy are the three key resources examined. The UK relies on imports for a big share of its food (around 40-50% of food consumed is imported), and demand for all three resources is rising due to population growth, economic development and changing diets and lifestyles.

Food

• The UK imports foods it cannot grow (out-of-season fruit, exotic produce) and has a growing 'carbon footprint' from food miles.
• Agribusiness (large-scale, intensive commercial farming) has increased UK food production but raises concerns over pesticides, water use and biodiversity loss.
• Organic farming and urban farming schemes are examples of sustainable approaches, reducing chemical inputs and transport distances.

Water

• Areas of water surplus (north and west UK, e.g. Scotland, Lake District) contrast with areas of water deficit (south and east, e.g. London), because population is concentrated where rainfall is lowest.
• Water transfer schemes (e.g. proposed transfers from Kielder Water) move water from surplus to deficit areas but are costly and can harm river ecosystems.
• The average person in the UK uses about 140-150 litres of water per day; conservation methods include water meters, fixing leaks and low-flow fittings.

Energy

• The UK's energy mix is shifting from fossil fuels (coal, oil, gas) towards renewables (wind, solar, hydro, biomass) and nuclear, driven by climate targets and North Sea reserves declining.
• Fracking (hydraulic fracturing) for shale gas is controversial: it could boost UK energy security but risks water contamination and minor earthquakes.
• Energy security means having a reliable, affordable supply; energy insecurity increases reliance on imports, exposing the UK to price shocks.

Fieldwork skills

• All GCSE Geography courses require TWO fieldwork enquiries: one physical (e.g. river or coastal study) and one human (e.g. urban or shopping study).
• The enquiry process follows six stages: title/hypothesis, planning, data collection methods, presentation, analysis, and conclusion/evaluation.
• Primary data is collected by you (e.g. questionnaires, pedestrian counts, river velocity); secondary data comes from existing sources (e.g. census data, maps).
• Sampling methods include random, systematic (regular intervals) and stratified (proportional to population groups) — know the difference and when each is used.
• Common presentation techniques: choropleth maps, located bar/pie charts, cross-sections, scatter graphs and annotated photos.
• Evaluation must discuss limitations: sample size, weather on the day, human error, and how results could be improved.

Common mistakes

• Confusing water surplus/deficit regions (remember: north/west = surplus, south/east = deficit).
• Forgetting fieldwork must have ONE physical and ONE human enquiry, not two of the same type.
• Mixing up primary (collected yourself) and secondary (already existing) data sources.