Restless Earth

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  • Created by: hibawot
  • Created on: 11-05-14 14:31

Crust + Margins

Oceanic Crust:

  • New
  • Dense
  • Renewable &Destroyable 

Continental Crust:

  • Older
  • Light
  • Not renewable or destroyable 


Destructive Plate Margin: Move together and the oceanic plate sinks below the continental one in a process called: subduction

Constructive Plate Margin: Plates move apart and the magma forces its way up through the cracks to form volcanoes. 

Conservative Plate Margin: Plates slide past each other in a similar direction at a slightly different angle and speed. 

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Volcanoes

Composite Volcano

  • Steep slopes
  • Layers of thick ash and lava 
  • Infrequent but Violent

Shield Volcano

  • Gentle slopes
  • Layers of runny lava and little ash
  • Frequent but not Violent 

Supervolcanoes

  • 1000x more emissions of material 
  • No cones but a caldera
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Earthquakes

Characteristics of Earthquakes

  • Focus: Deep within the crust
  • Epicentre: Point on the surface

Shock waves:

  • Primary: fast and move back and forth
  • Secondary: slower and move side to side
  • Longitudinal: up and down 
  • Transverse: side to side

Occur in:

  • Destructive margins: pressure from subduction
  • Constructive margins: less severe bc less intense friction and pressure
  • Conservative margins: pressure builds when plates jam

Prediction

Protection: Window shutters to prevent shatter, steel frames, foundation sunk into the ground and panels for flexibility. 

Preparation

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Tsunamis

Formation:

Triggered by earthquakes. Crust shifting and water diplacement above is the start of the tsunami. A normal wind-driven wave increases in height and decreases in wavelength as it approaches the shore.

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The Andes

Farming:

  • Home for many susbsitence farmers
  • Terraces are used to create flat land because it retains water better
  • Cash crops like soybeans, rice and cotton
  • Llamas and Alpacas used to carry irrigation materials 
  • Female llamas used for meat, milk and wool

Mining:

  • Tin, Nickel, Silver and Gold
  • Yanacocha gold mine is the largest gold mine in the world
  • Town population grew --> lack of services and increased crime rate

HEP:

  • Steep slopes are more easily dammed 

Tourism:

Mountain peaks, volcanoes, glaciers and lakes - Inca Trail


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Mt St Helens

March 1980: earthquake, steam filled with ash exploded onto the summit, 8 km exclusion zone around the crater /// 18th of May: 5.1 Richter scale caused landslide + sideways blast of pulverized rock, glacier ice and ash wiped out all living things 27 km north of the crater + trees were uprooted 

57 people died

Aftermath:

Immediate Responses:

  • Mobilising helicopters
  • Tourists caught in mudflow
  • Ash clogged everything 
  • Ash cleared from streets within 3 days
  • President Carter sent 2 million masks

Long-term Responses:

  • Buildings and bridges rebuilding 
  • Traces of green have appeared: insects, birds and animals returned
  • $1.4 million for transformation 
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Yellowstone Supervolcano

Old Faithful - Norris Geyser basin

Caldera has bulged up to 70 cm in places and the magma chamber is believed to be 80 km long, 40 km wide and 8 km deep.

Erruption likely to:

  • Destroy 10,000 km squared of land
  • Kill 87,000 people
  • 15 cm of ash would cover buildings within 1000 km 
  • 1/3 people affected would die
  • Lahars are a possibility
  • Ash affects transport, electricity, water and farming 
  • UK would await arrival of the ash 5 days later
  • Crops would fail
  • Climate will change
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Kobe Earthquake

17th January 1995: Phillipines Plate shifted beneath the Eurasian Plate along the Nokima fault line that runs beneath Kobe - this caused a 7.2 earthquake

  • 6434 dead, 40,000 injured, 300,000 homeless
  • Gas mains and water pipes fractured
  • Roads collapsed
  • Railway lines buckled
  • 2 million homes w/out electricity
  • 1 million homes w/out water
  • Fires in the city 
  • $220 billion and economy suffered 
  • 7-Eleven retailers helped provide essentials
  • Motorola maintained free telephone connections 
  • Railways 80% fuctional within a month 
  • By Septemeber 1996 Hanshin Expressway was fully open again
  • Port was 80% functional a year late
  • New buildings were built according to the new code
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Sichuan Earthquake

On 12 May 2008 at 2:28 pm - Indian Plate collided with Eurasian plate along the Longmenshan fault line that runs beneath Sichuan. 7.9 earthquake.

  • 69,000 dead, 18,000 missing, 374,000 injured, 5 million homeless
  • Beichuan: 80% of buildings collapsed
  • Dujiangyan city - Juyuan middle school: 900 pupils dead
  • Communications brought to a halt
  • Roads blocked by landslides
  • Rivers blocked by landslides - risks of floods
  • $75 million costs
  • 20 helicopters
  • 1000s of army troops deployed
  • Immediate needs: clean water, food supplies, tents and shelter
  • 3.3 million tents needed
  • 14th of May - International help requested
  • Red cross doations - 100 million pounds
  • 1 million temporary homes built
  • $10 million rebuilding fund
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Indian Ocean Tsunami

26 December 2004 - Indo Australian Plate subducting beneath the Eurasian Plate. 9.1 earthquake. 

  • Coast of Sumatra - Banda Aceh devastated first, then Sri Lanka and Thailand 
  • 220,000 dead, 650,000 injured, 2 million homeless
  • 1500 settlements in Banda Aceh completely wiped out. 
  • Bodies littered the street and were buried in mass graves
  • Fresh water, water purification tablets, food and tents all poured in as aid
  • UK government gave 75 million pounds + public donations of 100 million pounds
  • 372 million pounds donated by public
  • 40 million pounds on projects in Sri Lanka and Indonesia
  • Indian Ocean Tsunami Warning System set up in June 2006
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