Hazardous Earth Definitions

• Asthenosphere


  The semi-molten layer at the top of the mantle which flows due to convection currents, moving the solid lithosphere above
• Atmospheric circulation


  The general movements of air around the Earth due to pressure and temperature
• Climate change


  A distinct change in global or regional patterns of climate, such as changes in temperature or precipitation patterns
• Conservative plate boundary


  A plate boundary where two plates are moving alongside each other
• Continental crust


  The thicker, less dense crust that makes up the continents
• Convection current


  The movement of a fluid caused by a difference in temperature or density
• Convergent plate boundary


  A plate boundary where two plates are moving towards each other
• Coriolis Effect


  The effect of the Earth’s rotation on wind movements
• Cyclone


  A tropical cyclone that hits Oceania or Madagascar
• Divergent plate boundary


  A plate boundary where two plates are moving away from each other
• Eccentricity


  The changing of the orbit of the Earth around the Sun from a circular shape to an ellipse
• Eye


  An area of a tropical cyclone with extremely low pressure and calm conditions
• Eyewall


  An area of a tropical cyclone with the most intense, powerful winds and torrential rain
• Ferrel Cell


  At around 60° either side of the equator, moist air rises, 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

  A 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


  At the equator, hot moist air rises, moves to higher latitudes (30°) and sinks
• Hazard risk


  The probability that a natural hazard will negatively affect a population
• Hotspot


  An area where unusually hot magma breaks through the middle of a plate and travels up to the surface, creating a volcano
• The Quaternary Period started


  2.6 million years ago
• Richter scale


  A logarithmic scale used to measure the magnitude of earthquakes
• Secondary effects


  The effects that are a result of the primary effects
• Storm surge


  A rise in sea level caused when a tropical cyclone pushes a large amount of sea water onto the shore
• Subduction


  1. A process that occurs at a destructive plate boundary when a plate is pushed below another plate

  2. Forcing it to sink into the asthenosphere
• Tectonic hazard

  A 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


  A 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


  A natural process where greenhouse gases trap the energy from the Sun inside the Earth’s atmosphere, warming the Earth’s surface
• Track


  A typical pathway that a tropical cyclone takes which is driven by global wind circulation
• Tree rings


  A ring in a tree trunk that grows annually, indicating the conditions in the year it grew
• Tropical cyclone


  A very large, spinning storm with high winds and torrential rain that forms in the tropics
• Tsunami


  A large wave caused by a large amount of water being displaced when plates move
• Typhoon


  A tropical cyclone that hits India, Japan or the Philippines
• Hurricane


  A tropical cyclone that hits the USA, Latin America or the Caribbean
• Ice core


  A cylinder of ice extracted from an ice sheet or glacier, which is used to analyse 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


  A solid ball of iron/nickel at the Earth’s centre. Radioactive decay within the inner core provides Earth’s internal energy
• Inter-Tropical Convergence Zone (ITCZ)


  An 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