geography unit 1- Dynamic planet

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  • Created by: Aine
  • Created on: 02-06-13 21:26
what is the lithosphere?
the uppermost layer of the earth which is cool and bittle. the crust and he upper part of the mantle.
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what is the lithosphere split up into?
tectonic plates
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what is the layer that tectonic plates move on?
asthenosphere.
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what are the 2 types of crust?
continental and oceanic crust.
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what is continental crust? what is it made of?
it forms the land and is mostly made of granite, which is a low density igneous roclk.
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what is oceanic crust?
its under the oceans and it is much thinner than continental. made of igneous rock called basalt.
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what is some evidence that there is a lubricating layer under the lithosphere (asthenosphere)?
because of the movement of tectonic plates. people think its liquid but if it was the plates would sink into it and they dont so geologists think it is molten rock and partly solid rock. think an dense, HOT PORRIDGE.
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what do earthquake waves tell us? and how?
about the physical state of the Earth. tey speed up, change direction or stop when they meet a new layer in the earth
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what edidence comes from meteorites?
that the earths core is metl mostly nickel and iron.
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how do we know that the inside of the earth is hot? give 2 reasons?
molten lava spewing from active volanoes. and hot springs.
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what is geothermal heat?
heath from inside the earth.
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how is geothermal heat produced?
by radioactive decay of elements such as uranium in the core and mantle which raises the cores temperature to over 5000degrees.
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why does the inner core remain solid?
because its so deep and under high pressures.
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why is the outer core liquid?
because it is under lower pressure.
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what happens as the heat rises from the core?
it creates convection currents in the liquid outer core and mantle which are then strong enough to move the tectonic plates.
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what is the engine of tectonic plates?
radioactivity in the core and mantle.
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what are plumes?
the parts of convection currents where the heat moves towards the surface. they are concentrated zones of heat.
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what do plumes do?
they bring magma to the surface. They form constructive plate boundries. They form hot spots.
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what is a magnetic feild?
it protects the earth from harmful radiation from space and the sun and is made mby the outer core.
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what is special about the supercontinent pangea?
scientists formed it. it tells us that africa and South America were once joined. pangea started to split apart 200 million years ago and plate tectonics have moved to new positions today.
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what is a plate boundary?
where two plates meet.
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what are the 3 types of plate boundary?
constructive, destructive and conservative.
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what is a constructive plate boundary?
two plates moving apart.
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what is a destructive plate boundary?
when two plates collide.
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what is a conservative plate boundary?
when they slide past eachother.
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what is subduction?
oceanic crust sinking into the mantle at a destructive plate boundary. as the crust subducts it melts back into the mantlle.
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why is there an age difference between oceaic and continental crust?
because new oceanic crust formsconstantly at constructive plate boundarys.
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how does oceanic crust form?
convection currents bring magma up from the mantle which is injected between the seperating plates and as the magma cools it forms new oceanic crust.
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how is oceanic crust destroyed?
by subdction at desructive plate boundarys- recycled by earth.w
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why cant continental crust be destroyed or subducted?
because it is less dense than oceanic crust
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what are tectonic hazards?
earthquakes and volcanoes.
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give an example of a tectonic hazard at a conservative plate boundary?
San Andreas fault in California. North American and Pacific plates sliding past eachother. Desstructive earthquakes with a magnitude 8.5.
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give an example of a tectonic hazard at a destructive plate boundary?
Andes mountans in peru and chile. oceanic plate subducted under the South American continental plate.
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what are collision zones?
a type of destructive plate boundary. the form mountain ranges like the Himalayas.
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what actually happens at constructive plate boundary?
as plates move apart magma rises up through the gap and it is basalt and very hot and sunny and forms lava flows and shallow sided volcanoes.
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list 4 hazards that volcanoes can produce?
ash and gas, lava bombs, landslides, acid rain.
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CASE STUDY- SAKURAJIMA JAPAN- EXPLAIN.
Destructive plate boundary when the pacific plate is subducted beneath the Eurassian plate. it is STRATOVOLCANO.
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how is Sajurajima in japan monitored?
becuase japan is arich country it sepnds money on monitoring, protection and evacuationn. people will have insurance and the government will help repair damage to homes etc.
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what are the effects of tectonic hazards in developed country's?
damage property (economic costs) but cause less harm to people (social costs)
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give 3 ways that the japan sakurajima is monitored?
aircraft used to measure the amount of gas th volcano gives off. tiltmetres detect when the volcano swells up as it fills with magma. concrrete shelters are bulit to protect against volcanic bombs and ash. concrete lahar channels divert dangerous mud
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why are people in the developing world more at risk from tectonic hazards than those in developed countries?
they often live in risky areas because there is nowhere else to live. they cant afford safe, well built houses. governments dont have enough money and resources to provide aid.
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MOUNT NYIRAGONGO- DEVELOPING WORLD CASE STUDY VOLCANO- EXPLAIN.
it sits in the african Rift Valley on a constructive plate boundary where the continent of africa is literally being pulled apart. in JAN 2002 hot runny basalt lavas poured out of it. it flowed 20km into the city of Goma. 14 villages were destroyed.
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what were the results of mount nyiragongo erupting?
100 people died, it triggered earthwquakes and buildings collapsed, 12,500 homes were destroyed. many people became refugees.
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what are refugees?
people who are forced to move due to natural hazards of war.
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what were the relief efforts for Africa?
the United Nations sent 260 tonnes of food in the first week. in the uk a tv appeal asked people to donate. governments around the world gave $35 to give aid to refugees.
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what are earthquakes and how do they happen?
a sudden release of energy caused by underground tectonic plates trying to push past eachother and building up pressure and the pressure is suddenly released along faults which are cracks in the crust sending out a huge pulse of energy.
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what is magnitude?
the power of an earthquake how much the ground shakes. measures using a seismometer.
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why did the earthquakes of the same magnitude in niigata and kobe have such different effects?
because kobe was close to the epicventre.
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what is the epicentre?
the point on the earths surface above the focus which is the first place to shake.
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how does japan use long term planning?
they do earthquake drills each year, emergency services plactice rescuing people , people keep emergency kits at home providing them with food, water, a torch and radio.
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how are buildings in japan earthquake proof?
deep foundations to prevent collapsing, strong double glazing to stop broken glass, strong steel frames which is flexable to stop cracking.
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what is a tsunami?
aa series of waves produced by an andersea earthquake.
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SICHUAN EARTHQUAKE- EXPLAIN.
MAY 2008. NO WARNING. primary effects were 70,000 people died, 5 million made homeless. secondary- 200 aftershocks.
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what were some local responces to the Sichuan earthquake?
pprime minister flew to the area very soon after the earthquake. 50,000 soldiers were sent to dig for survivors, helicopters were used to reach the most isolated areas. chinease people donated $1.5billion in aid.
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what were some international respnces to the sichuan earthquake?
uuk gace $2 million. finlnd sent 8000 six person tents and indonesia sent 8 tonnes of medicines. rescuse teams flew in from russia, Hong Kong, singapore.
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why did the sichuan earthquake happen?
tthe indian and eurasaian plate were colliding.
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Other cards in this set

Card 2

Front

what is the lithosphere split up into?

Back

tectonic plates

Card 3

Front

what is the layer that tectonic plates move on?

Back

Preview of the front of card 3

Card 4

Front

what are the 2 types of crust?

Back

Preview of the front of card 4

Card 5

Front

what is continental crust? what is it made of?

Back

Preview of the front of card 5
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