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how is geology evidence for the plate tectonics theory
areas of south america and Africa have the same agea and compositions // mountain ranges in Norway , scotland and Sweden are similar to the east coast of north america // must have formed under the same conditions
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how are fossil records evidence for the plate tectonics theory
mesosaurus fossils are found in south america and southern africa (they cant swim) // cynogathus found in south america and africa (unlikely they evolved in different continents or migrated across water )
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how is climatology evidence for the plate tectonics theory
similar glacial deposits are found in Antarctica , Africa , South America , India and Australia meaning their past climates must have been similar
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how is Paleomagnetism evidence for the plate tectonics theory
as magma erupts magnetic minerals allign with the earths magnetic field which changes direction periodically/ creating alternating magnetic stripes which show that the crust is older further away from the mid ocean ridge meaning they are moving apart
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what happens at a constructive plate margi
two plates move apart
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what forms at a constructive plate margin
mid ocean ridges and rift valleys
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what is a mid ocean ridge and how is it formed
when diverging plates are under water a mid-ocean ridge is formed // underwater volcanoes erupt along mid-ocean ridges and can build up above sea level. E.G. mid Atlantic ridge where Eurasian and North American plate move apart
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what is a rift valley and how is it formed
where plates diverge beneath land causing a fault line // when the plates move apart the crust between the fault lines drops forming a rift valley. volcanoes are found around rift valleys
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what is a destructive plate margin
when two plates move towards each other
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what happens at oceanic- continental destructive plate margins
the more dense oceanic crust is forced under the less dense continental crust (subducted). the oceanic crust is heated by friction and contact with the upper mantle which melts it into magma.
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what is formed at oceanic-continental destructive plate margins
fold mountains // deep sea trenches // volcanoes // earthquakes
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how are deep sea trenches formed
when the more dense oceanic crust is subducted below the less dense continental crust
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how is a fold mountain formed
they formed when a continental and oceanic plate are moving towards each other. they are made of sediments that have accumulated on the continental crust, that are folded upwards along the edge of the continental crust
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what happens at oceanic-oceanic destructive plate margins
the two oceanic plates move towards each other and which ever is more dense will be subducted forming a deep sea trech and triggering earthquakes and volcanic eruptions
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what happens at continental- continental destuctive plate margins
where the 2 move together neither is subducted so pressure builds up causing earthquakes and foldmoountains
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what is intrusive volcanic activity
takes place beneath the earth surface
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what is extrusive volcanic activity
takes place on the earths surface
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what is a batholith
when large chambers of magma cool underground they form domes of igneous rock
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what is a dyke
when magma has flowed into VERTICAL gaps in the surrounding rock and cools. they go across the layers of rock
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what are sills
when magma has flowed into HORIZONTAL gaps in the surrounding rock and cools. they go between the layers of rock
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what type of lava is made at constructive plate margins
basaltic
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what are the characteristics of basaltic lava
low silica content // low viscosity (runny) // high temperature at eruption over 950 degrees
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what lava is made at a destructive plate margin
andesitic and rhyolitic lava
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what are the characteristics of andesitic lava
medium silica content // medium viscosity // temperatures at eruptions between 750-950 degrees
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what are the characteristics of rhyolitic lava
high silica content // high viscosity (thick and sticky) // temperatures less than 750 degrees
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characteristics of a dome volcano
often occur at destructive plate margins // lava tends to rhyolitic or andesitic // steep sides caused by high viscosity lava
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characteristics of a caldera volcano
often at destructive plate margins // produce andesitic or rhyolitic lava // central part of volcano collapsed as magma chamber below is emptied // wide circular crater is created
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characteristics of a shield volcano
occur at constructive plate margins or hotspots // produce basaltic lava // gently sloping sides due to low viscosity
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characteristics of a fissure volcano
constructive margins // produce basaltic lava // long linear vent a few metres wide a kilometres long // fairly flat caused by low viscosity lava
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what are hot springs
if the groundwater source is close to intrusive volcanic activity the water is heated creating a hot spring which have high mineral content
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what are gysers
a type of hot spring where hot water is ejected from the surface due to the groundwater being heated above boiling point so it becomes pressurised and is forces out from a vent
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what are boiling mud pools
another type of hot spring formed in areas with very fine-grained soil. the water and soil mixes to create a hot muddy pools
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how are hotspots formed
caused by a magma plume rises up from mantle // volcano forms above the plume // magma plume is stationary but the crust moves above it // volcanic activity decreases as a volcano moves away from plume // new volcanoes form above the hot spot
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what are the 3 types of seismic waves
primary waves // secondary waves // surface waves (love and rayleigh)
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what are primary waves
can travel through solids and liquids // they push and pull the earth in the same direction // fastest wave
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what are secondary waves
can travel through solids not liquids // move the earth at 90 degress to the direction they travel // cause a lot of damage // slower than primary waves
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what are love waves
only travel through solids // move the surface side to side // cause a lot of damage // move slower than P and S waves
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what are rayleigh waves
can travel through solids and liquids // move the surface in a rolling motion // are slower than P and S waves
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what is the inner core made of and what temp
solid up to 5500 degrees
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what is the outer core made of
liquid iron and nickel
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what is the mantle made of and what temp
soft molten rock up to 3800 degrees
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what are the characteristics of oceanic crust
5-10km thick // dense // form at constructive margins // destroyed at destructive margins
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what are the characteristics of continental crust
25-100km thick // less dense // very old - 3-4 billion years // is not destroyed or created
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how do you monitor volcanoes
seisometers show an increase in earthquake activity when magma is rising // tiltmetres measure a slight change in the tilt of the ground // gas emission indicate an imminent erruption // laser beams measure change in the distance between 2 fixed poi
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what is the richter scale
measures the strength/ magnitude of an earthquake / logarithmic scale (8 is 10x more powerful than 7) / measured using a seisometer / no upper limit
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what is the mercalli scale
measures the effect of an earthquake / goes from 1 to 12 / 1 is only detected by instruments / 12 is total destruction / measured using observations
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what is the epicentre
the point on the earths surface directly above the focus, this is where most damage happens
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what is the focus
the point at which the earthquake occurs, shock waves spread out from here
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what are the 3 p's
predicts // protect // prepare
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what does prepare mean
includes schools and hospitals practives for major disasters and having emergency supply kits and shelters
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what does predict mean
involves monitoring radon gas and water levels, using laser beams to detect movement using seisometers and monitoring animal behaviour
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what does protect mean
involves designing buildings that can withstand movement such as having deeper foundations, interlocking steel and counter weights
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how do earthquakes cause tsunamis
if an earthquake's epicentre is underwater the seabed moves which displaces large amounts of water. waves then radiate out from the epicentre towards land. the greater the movement the larger the waves
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how does a less developed country increase the severity of the impacts
less money// poorer building structures// poor healthcare// rely on agriculture which is destroyed // poor infrastructure means harder to get aid
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how does the population increase the severity of the impacts
higher population means more are affected // densely populated areas have big impacts // harder to evacuate // more casualties to treat
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how does timing increase the severity of the impacts
if they occur in the middle of the night its harder to evacuate and people get out of buildings slower // in winter people can dye of hypothermia if they dont have shelter
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how do you spell EYJAFJALLAJOKULL
E Y J A F J A L L A J O K U L L
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what was the nature of the eyjafjallajokull
composite volcano / ash plume reached 11,000m into the air / very fine ash / volcano covered by a glacier which melted / lava reached 150m into the air
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cause of the eyjafjallajokull eruption
north american plate and eurasian plate moving apart (constructive)
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economic impacts of eyjafjallajokull
london lost 102 million pounds in tourism / flight bans meant 50,000 farmer were temporarily unemployed / in the UK alone 13 travel firms collapsed / euro-star and ferries benefited
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social impacts of eyjafjallajokull
500 farming families were evacuated / medicines could not be brought due to flight ban / europe was experiencing anticyclone weather so the ash was spread out / route 1 in iceland was washed away completely
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envoronmental impacts of eyjafjallajokull
fine ash silted nearby river leading to flooding / flight ban caused a decrease in carbon emissions / the melting glacier caused large flooding // soil and water sources were polluted affecting livestock
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responses to eyjafjallajokull in iceland
700 evacuated / 24 hour emergency hotline / goggles and facemasks were distributed quickly
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international responses to eyjafjallajokull
1500 emergency bed were set up in amsterdam airport / tesco flew the kenyan produce to spain then drove the rest of the way / british red cross psycho-social teams went around Europe to support stranded brits
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synopticity to eyjafjallajokull
flooding / tourism / weather / health issues
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values and attitudes of eyjafjallajokull
farmers / tourists / tour operators / local people
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nature of the chaiten eruption
last eruption was 9400 years ago / rhyolitic lava / started may 2008 / 17km high ash cloud / consisted of pyroclastic flows and lahars
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causes of the chaiten eruption
destructive plate margin (nazca plate subducted beneath the south america plate) / volcanoes along the benioff zone
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economic impacts of chaiten
30% of the town was completely destroyed / costs of emergency resuces was around $36 million / trade was disrupted due to lack of communication
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social impacts of chaiten
1 person died due to stress / schools and highways were closed / airports closed and airports 2300km away were affected / respiratory health issues across Argentina and Chile
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environmental impacts of chaiten
animals suffocatd due to falling ash / forests destroyed due to pyroclastic flow / 90% of chaiten was flooded to to increased discharge / contaminated water supplies
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responses to the chaiten volcano
the government issued a monthly disaster spend of $1200 to $2200 per month / local businesses were offered financial aid / 90 freeze of loan payment / forcable evacuation / masks distributed / frsh water distributed
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synopticity of chaiten volcano
flooding / weahter / health
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values and attitudes of chaiten volcano
farmers / locals / government / air passengers
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nature of the Christchurch earthquake
22nd feb 2011/ was technically an aftershock of a 7.1 earthquake from september / 6.3 i=on the richter scale / shallow earthquake only 5km deep meaning more damage
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causes of the Christchurch earthquake
conservative fault line between pacific plate and Australian plate moving in opposite direction
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economic impacts of the Christchurch eruption
$40 billion worth of damage // hotel guest numbers fell by 75% // unemployment rose / rugby world cup could not be held there
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social impacts of the Christchurch eruption
185 people died and around 2000 injured // 11,000 building had to be demolished due to destruction // schools had to share classrooms // fire in the Kings education centre
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environmental impacts of the Christchurch eruption
100s of kilometers of water and sewage pipes were damaged / large glaciers broke off // 3.5 m tsunami waves occured in tasman lake / liquefaction meant some parts of the areas still cant be built on
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Christchurch eruption responses
temporary accommodation / areas zoned as different colours so areas could be identified and prioritised / roads cleared of soil so aid could be transported / 30,000 had access to clean toilets / 16 ambulances mobilased in 30 mins / builldings improve
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nature of the Nepal earthquake
25th april 2015 / 7.8 on the richer scale/ 395 aftershocks have been felt
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causes of the nepal earthquake
fault line between the Indian and eurasian plate / depth was 15km meaning it was shallow and devastating
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economic impacts of the Nepal earthquake
estimated cost of $10 billion / tourism has fallen by 90% leading to businesses closing/ many workers have left the country to find work in the middle eastern states
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social impacts of the Nepal earthquake
due to socia norms men recieved help and aid first / human trafficers preyed on young girls / 8964 people were killed / epidemics broke out due to lack of clean water
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environmental impacts of the nepal earthquake
triggered an avelanchh on mount everest killing 19 people / landlsides occured throughout the Napalese valleys / crops were destryoed affecting subsistence farming
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responses to the Nepal earthquake
within 15 minutes india sent 10 teams to nepal / tonnes of aid ended up in katmandu airport due to poor transport & communication / UK sent £33 million worth of aid / priority of many helicopters was rescue mt everest climbers (criticised by many)
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Card 2

Front

how are fossil records evidence for the plate tectonics theory

Back

mesosaurus fossils are found in south america and southern africa (they cant swim) // cynogathus found in south america and africa (unlikely they evolved in different continents or migrated across water )

Card 3

Front

how is climatology evidence for the plate tectonics theory

Back

Preview of the front of card 3

Card 4

Front

how is Paleomagnetism evidence for the plate tectonics theory

Back

Preview of the front of card 4

Card 5

Front

what happens at a constructive plate margi

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Preview of the front of card 5
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