AQA A Geography Restless Earth

Pregunta	Respuesta
The structure of the earth	Image: Structure (image/gif)
Convection currents	the circular current of heat in the mantle
Oceanic Crust	-Newer (less than 200 million years) -Denser -Can sink -Can be destroyed and renewed
Continental Crust	-Old (older than 1500 million years) -Cannot sink -Less dense -Cannot be destroyed or renewed
4 types of plate margins	-Destructive plate margin -Constructive plate margin -Conservative plate margin -Collision plate margin
Destructive plate margin diagram	Image: Destructive (image/jpeg)
Constructive plate margin diagram	Image: Constructive (image/png)
Collision plate margin diagram	Image: Collision (image/png)
Constructive plate margin diagram	Image: Conservative (image/png)
Fold mountains	-New fold mountains include the Andes and Himalayas -Older ranges like those in Cumbria have been weathered down
Ocean trenches	The deepest parts of the oceans
Formation of fold mountains and ocean trenches	-Fold mountains alone are formed at collision plate boundaries -Fold mountains and ocean trenches are formed at destructive plate boundaries -Sediment is deposited in layers over time -The plates moving next to each other pushes the sediment together, where it crumples into anticlines and synclines -If destructive, the submerging oceanic plates leaves a deep ocean trench behind
Andes What is it used for?	-Farming -Hydroelectric power -Tourism -Mining
Andes Farming	-Subsistence farmers in Bolivia -Farm on terraces that trap water and limit the downward movement of soil -Lamas are pack animals that can manage the terrain and carry 25% of their weight -Females farmed for meat, milk and wool
Andes Mining	-Peru and Bolivia top 10 for tin -Columbia has a l0t of nickel -Peru has a lot of gold -Half of Peru's export is from mining -Yanacocha gold mines are the largest in the world
Andes Hydroelectric power	-Steep slopes and narrow valleys are useful -Melting snow provides a lot of water, but variation throughput the year is a problem -2009 El Platanal power plant began to provide energy for Peru
Andes Tourism	-Natural attractions like mountain peaks, volcanoes, glaciers and lakes -Inca Trail, especially Machu Picchu in Peru
Nyiragonga The Eruption	-17 January 2002 Nyiragonga volcano in Democratic Republic of Congo was disrupted by plate movement in the African rift valley -Lava spilled sideways in 3 streams -Lava reached a speed of 60 km/h
Nyiragonga Primary effects	-Lava flowed over runways in Goma airport -Lava split the town in half -Destroyed homes, roads and water pipes -Started explosions in fuel stores and power plants -Killed 45 people
Nyiragonga Secondary effects	-Half a million people fled Goma into neighbouring Rwanda -Slept on the streets of Gisenyi -No shelter, electricity or clean water so couldn't cope -High risk of cholera -Looting occurred in Goma -People scared to return to Goma
Nyiragonga Response	-Water supplied in tankers -Christian Aid and Oxfam distributed food, medicine and blankets
Great Mountain Glacier, Iceland 2010 Location and eruption	-Iceland lies on the Mid-Atlantic ridge (constructive margin between Eurasian plate and North American) - March 2010 2 months of lava eruptions that were little threat -14th April a lot of ash was launched into the air
Great Mountain Glacier, Iceland 2010 Local impact and response	-Heavier particles of ash fell to the ground close to the volcano -Hundreds were evacuated -Glacier melted so flooding was an issue -Breached embankments to allow water to flow into the sea -Protected expensive bridges and embankments repaired within a few weeks
Great Mountain Glacier, Iceland 2010 International impact and response	-Mid-April fine ash cloud spread over western Europe -Western Europe airspace shut down due to fear of the effect of ash on the Jet engines -Business people and Tourists left stranded -Industrial production affected as raw material couldn't be flown -Kenyan farm workers lost jobs as fresh produce couldn't be flown to Europe
Great Mountain Glacier Positive effects	-Tourism to Iceland "The land of ice and fire" -Ash is rich in nutrients so good for farms -Sulphur can be found in volcanic crater for bleaching sugar, making matches and fertiliser -Small quantities of copper, gold, silver, lead and zinc are found in volcanic regions
Composite Volcano	-Steep slope, narrow base -Alternating layers of lava and ash -Have side vents -Explosive -Have a magma chamber -Destructive or collision boundaries
Shield Volcano	-Gently sloping sides -Very wide base -Formed by frequent, gentle eruptions of basaltic lava -Magma chamber -Formed at constructive boundaries
Predicting volcanoes	Measuring the: -Bulge -Gases -Earthquakes -Minor eruptions
Measuring the bulge	-A volcano bulging can indicate a rise of magma -Can place a tiltmeter on the volcano -Or use two laser points, satellites can pick up if the two points have moved a mm apart
Measuring Earthquakes	-Increase of earthquakes could mean magma is rising underneath the surface -Earthquakes can be measured using seismometers
Monitoring minor eruptions	-Digital cameras can be set up on the edge of a crater, allowing scientists to monitor them from a safe distance
Monitoring Gases	-Increase in percentage of Sulphur dioxide from gases emitted by a volcano can indicate that it is about to erupt
Supervolcano	-Much larger than normal volcanoes -emit at least 1000 km3 of material, compared to Mt St Helens 1 km3 -Have large depressions called calderas rather than a cone shape
Formation of a Supervolcano	-Magma rises and creates a large bulge -Ash and gases escape through fissures -Magma chamber collapses forming a depression called a caldera
Formation of a Supervolcano diagram	Image: Supervolcano (image/jpeg)
Yellowstone Size	-Magma chamber is 80 km by 40 km by 8 km -Eruptions 2 mill, 1.3 mill and 630 000 years ago
Yellowstone Potential effects	-Would destroy 10 000 km2 of land -kill 87 000 people -15 cm of ash in 1 000 km radius, killing 1 in 3 affected -Global dimming caused by ash would cause crops to fail
Characteristics of an earthquake	-Focus is the point in the earths crust where the earthquake begins -Epicentre is the point directly above the focus on the crusts surface -Radiating out from the focus are seismic waves that cause the ground to shake
Measuring Earthquakes	Richter scale: -10-fold increase every time the scale increases by one -Measures the strength of an earthquake with a siesmometer on a seismograph Mercalli scale - measures effect of an earthquake from I to XII -Subjective
Where do Earthquakes occur?	-Destructive margins -Constructive margins -Conservative margins
Earthquakes at destructive margins	Pressure from subduction can cause strong earthquakes as it is periodically released
Earthquakes at constructive margins	Less severe earthquakes as pressure from plates moving apart is less intense
Earthquakes at conservative margins	Plates stick as they slide past each other causing pressure build up. This pressure is released suddenly often resulting in a powerful earthquake
Kobe Causes	-5:46 17 Jan 1995 Philippines plate shifted under the Eurasian plate -seismic waves travelled along the Nojima fault line under Kobe -7.2 on the Richter scale -Tremors lasted 20 seconds
Kobe Effects	-6434 people dies -Over 4000 seriously injured -300 000 homeless -Gas mains ruptured and water pipes cracked -Railway lines buckled and sections of elevated roads collapsed -2 mill without electricity and 1 mill without water for a week -Fire due to ruptured gas mains, couldn't be put out due to water pipes cracking and damaged roads -Damage in excess of £220 bn
Kobe Response	-Friends and neighbours searched through the rubble,helped by emergency services when access was possible -Hospitals operated in corridors -7-eleven helped provide essentials -80% of railways operational within a month -80% of port operational within a year, but most of the trade gone -Building regulations changed
Haiti Causes	-12 January 2010 -Stress build up between conservative boundary of north american and Caribbean plates -7.0 on the Richter scale -15 km south west of Port-au-Prince -following minor tremors of 5.0
Haiti Effects	-230 000 people killed -2 million affected -1.5 million homeless -180 000 homes destroyed -Homeless put in 1100 temporary camps where hundreds died from cholera -19 million cubic meters of rubble -5000 schools damaged -Electricity, water, sanitation and communications destroyed or badly disrupted -$US 11.5 bn damage
Haiti Response	-Search and rescue teams with trained medics, sniffer dogs and heat sensing equipment flown in -Food, water and medicine flown in from USA and Dominican Republic -UN and USA provided security to maintain law and order -UK charity raised over £100 m which supported 1.2 m people -3/4 damaged buildings assessed and repaired -200 000 people received cash/food for clearing rubble -World Bank pledged $US 100 m
Haiti Why was it so badly affected?	-Very poor so unprepared and couldn't cope -80% of people lived in poorly constructed buildings that just collapsed -Earthquake very close with a shallow focus -Port destroyed and airport damaged making it hard to get emergency supplies -Lack of stable government caused chaos -Lack of doctors, hospitals (destroyed) and medicine
3 P's	-Prediction -Preparation -Protection
Prediction	-Very hard to do -Know where but hard to say when -Haichen (China) evacuated 1 mill people due to unexplained animal behaviour -West sceptical of animal behaviour
Protection	-Appropriate building standard -Following building reguations
Preparation	Hospitals, emergency services and inhabitants practise with drills so people know what to do to increase their chance of survival
Tsunamis VS normal waves	-Normal waves are 100 m crest to crest but tsunamis are 200 km -normal wave is 2 m high, tsunami is 1 m high -Tsunamis approach almost unnoticed at 800 km/h -As they near land they reduce in length but gain in height
Formation of a Tsunami	-Slip in the margin displaces water -Wave splits -Half travels towards land, the other half out to sea
Formation of a Tsunami diagram	Image: Tsunami (image/jpeg)
Tohoku Causes	-Pacific plate subducting under north american plate -200 km of rock slipped under causing an upward flick of 5-10 m -This triggered the Tsunami
Tohoku The Tsunami	-11 March 2011 -9.0 on the Richter scale -100 km east of Sendai -In 30 min 40 m high wave hit Sendai -9 additional waves 10 m high -3000 km coastline affected -Water went 10 km upshore
Tohoku Effects	-20 000 people killed -500 km2 coastal plane inundated -Sendai (port city of 100 000) virtually destroyed -200 000 buildings destroyed -Ruptured gas pipes led to fires that continued for days -Explosions at Fukushima power plant as tsunami over-topped defences -6 mill homes without electricity 1 mill people without water -Heavy snow, roadblocks from debris and landslides
Tohoku Response	-100 000 soldiers distributed food and blankets and helped in search and rescue -Exclusion zone around Fukushima -Huge reconstruction programme planned -New Tsunami defences to be over the standard 12 m

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	Creado por Natalia Cliff hace más de 7 años