856234
Description
Flashcards by John Ditchburn, updated more than 1 year ago
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Created by John Ditchburn
over 11 years ago
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| Question | Answer |
| Crust | the outer layer of the earth. |
| Plate | a section of the earth’s crust. |
| Plate margin | the boundary where two plates meet. |
| Mantle | the dense, mostly solid layer of the earth between the outer core and the crust. |
| Convection currents | the circular currents of heat in the mantle. |
| Destructive plate margin | a plate margin where two plates are moving towards each other resulting in one plate sinking beneath the other. |
| Constructive plate margin | a plate margin where two plates are moving apart. |
| Continental plate | a tectonic plate made of low density continental rock that will not sink under another plate. |
| Oceanic plate | a tectonic plate made of dense iron- rich rock that forms the ocean floor. |
| Subduction | when oceanic crust sinks under continental crust at a destructive margin. |
| Collision | when two plates of continental crust meet ‘head on’ and buckle. |
| Volcano | an opening in the earth’s crust through which molten lava, ash and gases are ejected. |
| Conservative plate margin | a plate margin where two plates are sliding alongside each other. |
| Earthquake | a sudden and often violent shift in the rocks forming the earth’s crust, which is felt at the surface. |
| Fold mountains | large mountain ranges where rock layers have been crumpled as they have been forced together. |
| Ocean trenches | deep sections of the ocean, usually where an oceanic plate is sinking below a continental plate. |
| Composite volcano | a steep-sided volcano that is made up of a variety of materials, such as lava and ash. |
| Shield volcano | a broad volcano that is mostly made up of lava. |
| Subsistence | farming to provide food and other resources for the farmer’s own family. |
| Terraces | steps cut into hillsides to create areas of flat land. |
| Irrigation | artificial watering of the land. |
| Hydroelectric power | the use of flowing water to turn turbines to generate electricity. |
| Natural hazard | an event over which people have little control, which threatens people’s lives and possessions. This is different from a natural event as volcanoes can erupt without being a hazard. |
| Primary effects | the immediate effects of the eruption, caused directly by it. |
| Secondary effects | the after- effects that occur as an indirect effect of the eruption on a longer timescale. |
| Aid | money, food, training and technology given by richer countries to poorer ones, either to help with an emergency or for long-term development. |
| Immediate responses | how people react during a disaster and straight afterwards. |
| Long-term responses | later reactions that happen in the weeks, months and years after the event. |
| Supervolcano | a mega colossal volcano that erupts at least 1,000 km3 of material. |
| Caldera | the depression of the supervolcano marking the collapsed magma chamber. |
| Geothermal | water that is heated beneath the ground, which comes to the surface in a variety of ways. |
| Geyser | a geothermal feature in which water erupts into the air under pressure. |
| Hot spot | a section of the earth’s crust where plumes of magma rise, weakening the crust. These are away from plate boundaries. |
| Focus | the point in the earth’s crust where the earthquake begins. |
| Richter scale | a scale ranging from 0 to 10 used for measuring earthquakes, based on scientific recordings of the amount of movement. |
| Epicentre | the point at the earth’s surface directly above the focus. |
| Shock waves | seismic waves generated by an earthquake that pass through the earth’s crust. |
| Mercalli scale | a means of measuring earthquakes by describing and comparing the damage done, on a scale of I to XII. |
| The three Ps: | the collective term for prediction, protection and preparation. |
| Prediction | attempts to forecast an event – where and when it will happen – based on current knowledge. |
| Protection | constructing buildings so that they are safe to live in and will not collapse. |
| Preparation | organising activities and drills so that people know what to do if an earthquake happens. |
| Tsunami | a special type of wave where an event, often an earthquake, moves the entire depth of the water above it. |
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