sudden, servere events which makes them dificuilt to manage they disrupt human life and have huge economic, and social impacts .
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When does an event become hazardous / a disaster?
if they are in unpopulted areas they arenot considered hazardous however if they cause high levels of death injury damage or disrupton then they are considered a disaster
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What is 'Hazard Risk'?
the chance of being affected by a naturoul hazard
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Why do people choose to live in hazardous areas?
accept the risk(advantages outway the dsadvantages) they have little choice where to lie
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What factors affect risk?
urbanisation poverty farming and climate change
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What is the global pattern of earthquakes?
Most occure at the margins of slowly moving techtonc plates. Friction and sticking between plates creates enormous pressure and stresses which build to breaking point
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What is the global pattern of volcanoes?
Like earthqakes most volcnoes occure in belts along the plate margin. However some occure at hot spots where the crust is thin and magma breaks through the surface
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What are the two types of crust?
oceanic - dence and thin and continental - thicker and less dence
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Why do plates move?
driven by convection currents within the mantle and under gravity
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What happens at a constructive plate margin?
two plates move appart and magma forces itself to the surface. As it braks the crust it causes mild earthquakes. The magma is very hot and fluid allowing the lava to flow a long way before cooling. This resaults in typically broard and wide shieald
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What happens at a destructive plate margin?
two plates move towards eachother and the dence oceanic plate is subducted beneath the continetal plate.Friction causes strong eathquakes. The sinking oceanic plate creates sticky gas rich magma which causes steep sided composite volcanoes
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what happens at a conservative plate margin?
Two plates move past each othe at different rates. Friction between them build stresses and trigger earthquakes when they slip. There are no volcanoes as there is no magma
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Nme three reasons why people choose to live in tectonic areas?
people in poverty have no choice, olcanoes can bring benefits, effective monitoring prediction protection and planning reduces the risk
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How do people in iceland benefit from living on a plate margin?
geothermal energy (generates 25% of electricity) volcanic rocks used in building supports a huge tourist industrie and naturually ocuing hot water ( centeral heating hot water) supplies 90% of all buildings
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What are the four management stratagies for reducing the risk from techtonc hazards?
monitoring/prediction protection & planning
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How can we monitor earthquakes ?
generally occure wihout warning but a number o events can ocre before an earthquakethese include: micro-quakes bulging of the ground and raised water ground levels
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How can we predict volcanoes?
monitorung is now allowing accurate prediction and effective ecavuation
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How can we predict earthquakes?
accurate prediction is impossible but historical records can help determine probobilaty and so help in planning for them
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How can we protect against volcanoes?
Little can be done but earth emabankments and explosives have been used to successfully divert lava flow
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How can we protect against earthquakes?
drills and buildings:
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How can we plan against volcanoes?
risk assesment and hazard mapping to identify areas to practice evacuation or restrict buldings
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how can we plan against earthquakes?
risk assesment and hazard mapping to identify areas to protect buildings and infastructure
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What does sinking air and rising air crate?
sining air creates high pressure and rising air creates low pressure
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How do surface winds transfer heat ?
they move from high pressure to low pressure transfering heat and moisture as they go
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Why do surface winds curve?
due to the eaths rotaton and change seasonaly as the tilt and the rotation of the earth causes relative change in the positions of the overhead sun
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Other cards in this set
Card 2
Front
When does an event become hazardous / a disaster?
Back
if they are in unpopulted areas they arenot considered hazardous however if they cause high levels of death injury damage or disrupton then they are considered a disaster
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