geography paper 1 (ai)

Destructive Plate Margin

Where an oceanic plate subducts beneath a continental plate or another oceanic plate due to denser oceanic crust. This causes features like ocean trenches, volcanoes, and fold mountains.

Constructive Plate Margin

Where two plates move apart, allowing magma to rise from the mantle, creating new crust. This results in mid-ocean ridges and rift valleys, often with volcanic activity.

Conservative Plate Margin

Where two plates slide past each other horizontally. No crust is created or destroyed, but friction builds up, leading to powerful earthquakes.

Subduction

The process by which one tectonic plate slides beneath another, typically an oceanic plate sinking beneath a continental or another oceanic plate at a destructive margin.

Convection Currents

Circular movements of magma in the Earth's mantle, driven by heat from the core. These currents are thought to be the primary force driving plate tectonics.

Focus

The point within the Earth's crust where an earthquake originates.

Epicentre

The point on the Earth's surface directly above the focus of an earthquake. It's often where the greatest damage occurs.

Richter Scale

A logarithmic scale used to measure the magnitude (strength) of an earthquake based on the amplitude of seismic waves.

Mercalli Scale

A subjective scale that measures earthquake intensity based on observed effects and damage (e.g., eyewitness accounts, structural damage).

Seismograph

An instrument that detects and records ground motion during an earthquake.

Primary Hazards (Earthquakes)

Direct impacts of an earthquake, such as ground shaking, ground displacement, and building collapse.

Secondary Hazards (Earthquakes)

Indirect impacts of an earthquake, such as tsunamis, landslides, fires, and liquefaction.

Lava

Molten rock that has erupted onto the Earth's surface.

Magma

Molten rock located beneath the Earth's surface.

Shield Volcano

A broad, gently sloping volcano built from layers of fluid, basaltic lava flows. Found at constructive plate margins or hot spots (e.g., Hawaii).

Composite Volcano

A tall, conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash. Characterized by explosive eruptions and found at destructive plate margins.

Pyroclastic Flow

A fast-moving current of hot gas and volcanic debris (ash, rock fragments) that moves down the side of a volcano, highly destructive.

Gases (Volcanic Hazard)

Release of various gases (e.g., sulfur dioxide, carbon dioxide) during eruptions, which can be toxic or contribute to climate change.

Lahars

Mudflows composed of volcanic ash, rock, and water, often triggered by melting snow/ice or heavy rain during or after an eruption.

Tsunami

A series of ocean waves caused by large-scale disturbances, most commonly undersea earthquakes or volcanic eruptions.

HIC (High Income Country)

A country with a high average income per capita, typically industrialized and developed.

LIC (Low Income Country)

A country with a low average income per capita, typically less industrialized and often dependent on agriculture.

NEES (Newly Emerging Economies)

Countries that have begun to experience rapid economic growth and industrialization, often transitioning from LIC to HIC characteristics (e.g., Brazil, China, India).

Management Strategies (Tectonic Hazards)

Methods to reduce the risk from tectonic hazards, including monitoring, prediction, protection (e.g., earthquake-proof buildings), and planning (e.g., evacuation drills).

Atmospheric Circulation

The large-scale movement of air in the atmosphere, important for distributing thermal energy across the Earth and creating global pressure and wind belts.

Hadley Cell

A large-scale atmospheric convection cell that circulates between the equator and approximately \text{30°} latitude in both hemispheres.

Ferrel Cell

An atmospheric circulation cell that lies between the Hadley Cell and the Polar Cell, located between approximately \text{30°} and \text{60°} latitude.

Polar Cell

The smallest and weakest atmospheric circulation cell, located between approximately \text{60°} latitude and the poles in both hemispheres.

High Pressure System

An area where air descends, leading to clear skies, calm conditions, and often dry weather. Associated with anticyclones.

Low Pressure System

An area where air ascends, leading to cloud formation, precipitation, and often stormy weather. Associated with depressions.

Coriolis Effect

The deflective force caused by the Earth's rotation, which influences the direction of winds and ocean currents (deflects to the right in the Northern Hemisphere, left in the Southern Hemisphere).

Tropical Storm (Cyclone/Hurricane/Typhoon)

An intense low-pressure weather system with torrential rain and strong winds (over 74 mph or 119 km/h), forming over warm tropical oceans.

Eye (Tropical Storm)

The calm, clear center of a tropical storm, an area of very low pressure.

Eyewall (Tropical Storm)

The ring of intense thunderstorms surrounding the eye of a tropical storm, where the strongest winds and heaviest rainfall occur.

Global Warming

The observed increase in average global temperatures due to the enhanced greenhouse effect, primarily linked to human activities.

Climate Change

A long-term shift in global or regional climate patterns, including changes in temperature, precipitation, and sea level, often attributed to human activity.

Greenhouse Effect

The natural process by which certain gases in the Earth's atmosphere trap heat, warming the planet. Essential for life on Earth.

Enhanced Greenhouse Effect

The amplification of the natural greenhouse effect due to increased concentrations of greenhouse gases (e.g., CO_2, methane) released by human activities, leading to global warming.

Fossil Fuels

Natural fuels (e.g., coal, oil, natural gas) formed from the remains of ancient living organisms, whose combustion releases greenhouse gases.

Methane (\text{CH}_4)

A potent greenhouse gas, less abundant than CO_2 but more effective at trapping heat, released from sources like agriculture (livestock) and landfills.

Carbon Dioxide (\text{CO}_2)

The most significant human-produced greenhouse gas, primarily from the burning of fossil fuels and deforestation.

Adaptation (Climate Change)

Strategies to adjust to the actual or expected effects of climate change, such as building sea walls, developing drought-resistant crops, or managing water resources.

Mitigation (Climate Change)

Strategies to reduce or prevent the emission of greenhouse gases, thereby lessening the severity of future climate change effects, such as using renewable energy, carbon capture, or international agreements.

Renewable Energy

Energy derived from natural processes that are replenished constantly, such as solar, wind, hydro, geothermal, and biomass.

Carbon Capture and Storage (CCS)

Technology that captures carbon dioxide emissions from power plants and industrial sources and stores them underground to prevent their release into the atmosphere.

Ecosystem

A community of living organisms (biotic components) interacting with their non-living physical environment (abiotic components).

Biome

A large-scale global ecosystem characterized by its dominant vegetation type and climate, such as tropical rainforests, deserts, or tundras.

Biodiversity

The variety of plant and animal life in a particular habitat or in the world as a whole; a measure of the health of an ecosystem.

Food Chain

A linear sequence showing how energy is transferred from one living organism to another through feeding relationships (e.g., producer \rightarrow primary consumer \rightarrow secondary consumer).

Food Web

A complex network of interconnected food chains within an ecosystem, showing multiple feeding relationships.

Decomposers

Organisms (e.g., bacteria, fungi) that break down dead organic matter, recycling nutrients back into the ecosystem.

Producers

Organisms (e.g., plants, algae) that produce their own food, typically through photosynthesis, forming the base of a food chain.

Consumers

Organisms that obtain energy by feeding on other organisms.

Nutrient Cycling

The movement and exchange of organic and inorganic matter back into the production of living matter; includes processes like decomposition and absorption by plants.

Deforestation

The clearing of forests for other land uses, such as agriculture, logging, or urban development, leading to habitat loss and CO_2 emissions.

Sustainable Management

The use of resources in a way that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Ecotourism

Tourism directed towards exotic, often threatened, natural environments, especially to support conservation efforts and observe wildlife.

Selective Logging

A sustainable forestry practice where only a few specific trees are cut down, leaving the majority of the forest intact, to minimize environmental impact.

Permafrost

Permanently frozen ground, often found in polar and high-altitude regions, which contains trapped greenhouse gases.

Glacial Retreat

The shrinking back of glaciers due to melting, often caused by rising global temperatures.

Desertification

The process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture.

Erosion

The wearing away and removal of material by a moving force such as water, wind, or ice.

Weathering

The in-situ breakdown and decay of rock by natural processes at or near the Earth's surface (physical, chemical, biological).

Mass Movement

The downslope movement of material (rock, soil, debris) under the influence of gravity, such as landslides, rockfalls, or slumps.

Freeze-thaw Weathering (Physical)

Water enters cracks in rocks, freezes and expands by about 9\% causing the crack to widen. Repeated freezing and thawing breaks the rock apart.

Chemical Weathering

The decay of rock due to chemical reactions (e.g., carbonation, hydrolysis, oxidation), often involving rainwater.

Biological Weathering

The breakdown of rocks caused by living organisms, such as plant roots growing in cracks or burrowing animals.

Longshore Drift

The movement of sediment along a coastline, determined by the prevailing wind and wave direction. Waves approach the shore at an angle, but swash carries material straight back down.

Attrition (Erosion)

Pebbles and rocks grind against each other, becoming smaller and rounder.

Abrasion (Corrasion)

Sediment carried by waves or rivers grinds against rock faces, wearing them away (like sandpaper).

Hydraulic Action (Erosion)

The force of water (or air trapped in cracks) hitting against a rock surface, causing it to break apart.

Solution (Erosion & Transport)

Dissolved chemicals in water (e.g., from limestone) wear away rock (erosion) or are carried away (transport).

Swash

The movement of water up the beach after a wave has broken.

Backwash

The movement of water back down the beach after the swash, usually under gravity.

Wave-cut platform

A flat area of rock left at the base of a cliff as the cliff retreats inland due to wave erosion.

Headland

An area of land (often resistant rock) that extends out into the sea, forming cliffs and bays on either side.

Bay

A broad, curved indentation of the coastline, typically formed where softer rock has been eroded more rapidly than surrounding resistant rock.

Cave

A hollow forms in cliffs as waves exploit weaknesses (cracks/joints) in the rock.

Arch

A natural opening in a headland, formed when two caves on opposite sides of a headland erode through to meet each other.

Stack

A pillar of rock left standing alone in the sea after an arch has collapsed.

Stump

A low-lying rock feature, visible at low tide, formed when a stack has been eroded by the sea.

Spit

A long, narrow ridge of sand or shingle projecting out from the land into the sea, formed by longshore drift.

Bar

A spit that has grown across a bay, connecting two headlands and often enclosing a lagoon behind it.

Lagoon

A shallow body of water separated from a larger body of water (like a sea) by a narrow landform like a bar or barrier island.

Managed Retreat

A coastal management strategy involving the deliberate movement of the coastline inwards, allowing land to flood to create new intertidal habitats and relieve pressure on hard defenses elsewhere.

Hard Engineering (Coastal)

Man-made structures built to control coastal processes (e.g., sea walls, groynes, rock armour).

Soft Engineering (Coastal)

Environmentally friendly, typically less intrusive methods of coastal management that work with natural processes (e.g., beach nourishment, dune regeneration).

Groynes

Wooden or rock structures built at right angles to the beach to trap sediment moved by longshore drift, widening the beach.

Sea Wall

A concrete or rock barrier built parallel to the coast at the foot of cliffs or at the top of a beach to protect against erosion and flooding.

Gabions

Wire cages filled with rocks, used as a form of revetment (slope stabilization) or earth-retaining wall along coastlines.

Rock Armour (Rip-Rap)

Large boulders or rocks placed at the base of cliffs or in front of sea walls to absorb wave energy and protect the coastline.

Beach Nourishment

The addition of sand or shingle to an existing beach to make it higher and wider, absorbing wave energy more effectively.

Delta

A landform that is formed at the mouth of a river where its current slows down, depositing sediment, typically triangular in shape.

Drainage Basin

The entire area of land drained by a river and its tributaries, often separated from adjacent basins by a watershed.

Watershed

The boundary separating one drainage basin from another, typically following the highest ground.

Source (River)

The starting point of a river, often in uplands, mountains, or a lake/spring.

Mouth (River)

The point where a river enters a larger body of water, such as another river, a lake, or the sea.

Tributary

A smaller river or stream that flows into a larger river.

Confluence

The point where two rivers or streams meet.

Discharge (River)

The volume of water flowing through a river channel per unit of time, usually measured in cumecs (m^3/s).