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Geography Glossary 3
Geography Key Words and Definitions Tectonics Topic
| Question | Answer |
|---|---|
| Risk | The potential danger or damage created by an event |
| Short term | A hazard lasting for a short period (less than a day) |
| Medium term | A hazard that lasts for a few weeks |
| Long term | A hazard that lasts for over a month |
| Tectonic | Associated with the movement of the tectonic plates in the Earth’s crust. |
| Natural hazard | A danger or threat to human life caused by natural processes such as climatic change or tectonic activity |
| Prediction | Volcanoes can be monitored to warn of an eruption |
| Protection and Preparation | Can be as effective as prediction in reducing impact |
| Plate | Also called a tectonic plate. The Earth’s crust is broken into huge slabs of rock |
| Oceanic crust | Crust beneath the oceans. Mainly basalt, it is younger, heavy and dense |
| Continental crust | Less dense crust forming continents (25-90 km thick). Floats on the mantle |
| Core | The centre of the Earth |
| Mantle | The layer of semi-molten rock between the Earth’s crust and core |
| Magma | The molten rock below the Earth’s surface |
| Convection currents | The slow circular movements of molten rock in the mantle caused by the heat rising from the Earth’s crust |
| Crust | The solid layer of rock around the outside of the Earth |
| Plate margins/ boundaries | Where two plates meet |
| Ring of Fire | A line of volcanoes following the destructive plate boundaries around the sides of the Pacific Ocean |
| Mid-oceanic ridge | A long undersea mountain chain formed on a constructive plate boundary. (e.g. Iceland is on the Mid-Atlantic Ridge) |
| Ocean trench | A long, deep valley in the ocean floor. They are formed at destructive plate boundaries |
| Destructive margin | An oceanic and a continental plate are moving towards each other. The oceanic plate will sink |
| Subduction zone | Area where an oceanic plate is sinking, melting and being destroyed at a destructive plate boundary |
| Fold mountains | Mountains formed by the bending and buckling of rocks, where two tectonic plates are colliding |
| Sedimentary rock | Rock formed from particles of sediment which have been compressed and cemented together |
| Constructive margin | Tectonic plate boundary where new oceanic crust forms |
| Collision margin | The place where two continental tectonic plates collide. The plates are not dense enough to sink into the mantle and therefore both crumble to form fold mountains |
| Transform boundary/ Conservative margin | Two plates are sliding past each other |
| Pyroclastic flow | A cloud of extremely hot gas, ash, lava fragments and rock which is ejected during a volcanic eruption and runs down the side of a volcano |
| Volcanic bombs | A lump of lava which is thrown high into the air when a volcano erupts |
| Active volcano | A volcano which has erupted recently and is expected to erupt again in the future |
| Long term effects | Impacts which develop later, such as fall in global temperatures |
| Lahar | Mudflow or debris flow originating on a volcano |
| Albedo effect | Reflection of sun’s rays by particles in the atmosphere – leads to cooler temperatures |
| Short term effects | The initial impact of the volcano |
| Lava | The molten rock which is erupted from a volcano |
| Basic lava | Thick and sticky lava thrown out by some volcanoes, mainly along destructive plate boundaries |
| Acid lava | Thin and runny lava thrown out by some volcanoes, mainly along constructive plate boundaries |
| Shield volcano | Volcanoes which are wide and low with gently sloping sides due to basic lava |
| Tsunami | A huge wave triggered by an earthquake |
| Aftershock | A small earthquake following a major earthquake |
| Secondary effects | Long term impacts such as businesses closing |
| Richter scale | Size of earthquakes is measured on a 9-point scale; level 2 is 10 times the size of level 1 |
| Primary effects | The immediate impact of the earthquake |
| Epicentre | The place on the Earth’s surface which is directly above the focus of an earthquake |
| Focus | The point below ground where an earthquake begins |
| Seismometer | These machines detect vibrations beneath the surface. Readings are passed to a seismograph |
| Tilt meter | These machines measure how much the angle of the land is changing (e.g. to see if magma is welling up below) |
Created by:
sallyfizz
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