Geography - Hazardous Earth glossary (Edexcel B )

Asthenosphere

Asthenosphere

Semi-molten layer at the top of the mantle that flows due to convection currents, moving the solid lithosphere above

Atmospheric circulation

General movements of air around the Earth due to pressure and temperature

Climate change

Distinct change in global or regional patterns of climate, such as changes in temperature or precipitation patterns

Conservative plate boundary

Plate boundary where two plates are moving alongside each other

Continental crust

Thicker, less dense crust that makes up the continents

Convection current

Movement of a fluid caused by a difference in temperature or density

Convergent plate boundary

Plate boundary where two plates are moving towards each other

Coriolis Effect

Effect of the Earth's rotation on wind movements

Cyclone

Tropical cyclone that hits Oceania or Madagascar

Divergent plate boundary

Plate boundary where two plates are moving away from each other

Eccentricity

Changing of the orbit of the Earth around the Sun from a circular shape to an ellipse

Eye

Area of a tropical cyclone with extremely low pressure and calm conditions

Eyewall

Area of a tropical cyclone with the most intense, powerful winds and torrential rain

Ferrel Cell

Moist air rises at around 60° either side of the equator and travels to lower latitudes at around 30° where it sinks, along with air travelling from the equator

Fossil fuels

Fuels made up of the remains of organic material, such as oil, coal and gas

Geological hazard

Hazard caused by processes on the land

Greenhouse Gases

Gases in the Earth's atmosphere that trap energy in the Earth's system and contribute to the greenhouse effect (carbon dioxide, methane, water vapour and nitrous oxides)

Hadley Cell

Hot moist air rises at the equator, moves to higher latitudes (30°) and sinks

Hazard risk

Probability that a natural hazard will negatively affect a population

Hotspot

Area where unusually hot magma breaks through the middle of a plate and travels up to the surface, creating a volcano

Hurricane

Tropical cyclone that hits the USA, Latin America or the Caribbean

Ice core

Cylinder of ice extracted from an ice sheet or glacier, used to analyze past environmental conditions

Immediate responses

Actions taken as soon as the hazard happens and in its immediate aftermath (hours, days, and potentially a week or so after the event)

Inner core

Solid ball of iron/nickel at the Earth's center, providing Earth's internal energy through radioactive decay

Inter-Tropical Convergence Zone (ITCZ)

Area surrounding the equator where global winds converge, causing an area of low pressure with rainy conditions

Lithosphere

Solid rock that lies on top of the asthenosphere. The top of the lithosphere is the crust, which is broken up into tectonic plates

Long-term responses

Actions taken after the immediate responses when the effects of the hazard have been minimized (weeks, months, and years after the event)

Magma

Molten rock found beneath the Earth's surface

Mantle

Area underneath the crust which contains magma

Milankovitch Cycles

Cyclical variations in the Earth's orbit around the Sun

Natural hazard

Naturally occurring event that is a threat to a population

Obliquity (or axial tilt)

Tilt of the Earth's axis, which changes from 21.5° and 24.5°

Ocean currents

Predictable, continuous circulation of ocean water which transfers heat around the globe

Oceanic crust

Thinner, denser crust that makes up the ocean floor

Outer core

Molten layer of iron and nickel that surrounds the inner core and transfers energy by convection currents

Plate boundary

Point at which two plates meet

Polar Cell

Moist air rises at 60° north or south of the equator and travels to the poles (90°), where it sinks

Precession

'Wobble' of the Earth's axis

Pressure belt

Region of the Earth which is generally under the same pressure

Primary effects

Effects that are directly caused by the hazard itself

Quaternary Period

Geological time period that started 2.6 million years ago and extends into the present

Richter scale

Logarithmic scale used to measure the magnitude of earthquakes

Secondary effects

Effects that are a result of the primary effects

Storm surge

Rise in sea level caused when a tropical cyclone pushes a large amount of sea water onto the shore

Subduction

Process that occurs at a destructive plate boundary when a plate is pushed below another plate, forcing it to sink into the asthenosphere

Tectonic hazard

Natural hazard caused by the physical processes and movements of tectonic plates

Tectonic plates

Large slabs of the Earth's crust that sit and move on top of the liquid mantle

The Enhanced Greenhouse Effect

Process where the Earth's surface is heated by the greenhouse effect at a higher rate due to increased greenhouse gas emissions from human activities

The Greenhouse Effect

Natural process where greenhouse gases trap the energy from the Sun inside the Earth's atmosphere, warming the Earth's surface

Track

Typical pathway that a tropical cyclone takes which is driven by global wind circulation

Tree rings

Ring in a tree trunk that grows annually, indicating the conditions in the year it grew

Tropical cyclone

Very large, spinning storm with high winds and torrential rain that forms in the tropics

Tsunami

Large wave caused by a large amount of water being displaced when plates move

Typhoon

Tropical cyclone that hits India, Japan or the Philippines