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Natural Hazards
Yr 9 Geography
Term | Definition |
---|---|
drought: | a prolonged period of below average precipitation |
El Niño event: | the reversal (every few years) of the more usual direction of winds and surface currents across the Pacific Ocean. This change causes drought in eastern Australia and heavy rain in South America. |
epicentre: | the point on the Earth's surface directly above the focus of an earthquake |
fire front: | the edge of a fire that spreads fastest |
firebrand: | aerially burning fuel that blows ahead of a fire front |
firestorm: | an intense fire that may generate strong convection currents and violent winds causing long-range spotting and flame spirals |
flood mitigation: | measures aimed at preparing for floods and trying to reduce their effects, such as constructing artificial levees, strengthening bridges, raising road levels and enlarging drains |
La Niña event: | a period of well above average rainfall in eastern Australia that often brings floods |
natural disaster: | an extreme event that is the result of natural processes and causes serious material damage or loss of life |
natural hazard: | an extreme event that is the result of natural processes and has the potential to cause serious material damage and loss of life |
Richter scale: | used to measure the energy of earthquakes |
sclerophyll: | plants found in low rainfall areas; their leathery leaves help reduce water loss |
southern oscillation: | a major air pressure shift between the Asian and east Pacific regions. Its most common extremes are El Niño events |
storm surge: | a rise in sea level above the normal tide caused by very low atmospheric pressure and the stress of strong winds on the sea surface when a tropical cyclone approaches or crosses a coastline |
thunderstorm: | a storm associated with lightning and thunder, occurring with cumulonimbus clouds |
tropical cyclone: | a severe weather event that occurs where warm, moist, rising air begins to spiral upwards. Tropical cyclones are often accompanied by very strong winds, heavy rain and rough seas. |
longitude: | location represented by imaginary lines drawn around the Earth from north to south, which show the distance east or west of the Prime Meridian, measured in degrees, minutes and seconds |
latitude: | location represented by imaginary lines drawn around the Earth from east to west, which show the distance north or south of the Equator, measured in degrees, minutes and seconds |
gross national income (GNI) per capita: | total value of goods and services produced in a country in one year per person plus net income from abroad |