Tectonics

• Crust

  Earth's outermost layer
• Mantle

  The layer of hot, semi-molten rock between Earth's crust and core
• Outer core

  Liquid iron and nickel
• Inner core

  The solid ball of iron and nickel at the centre of the earth
• Continental crust

  • 30-50 km thick and less dense
• Oceanic crust

  • 5-10 km thick and more dense
• Tectonic plate

  Sections of the Earth's crust that move due to convection currents
• Destructive margin

  Two plates move towards each other. When this happens with a continental and oceanic plate, the denser oceanic plate is pushed underneath the less dense continental plate, creating volcanoes and ocean trenches. If this happens to two continental plates, a folded mountain range is created
• Constructive margin

  Two plates move away from each other, causing magma to rise from the mantle and fill the gap, creating new land
• Conservative margin

  Two plates move sideways past each other, or at different speeds in the same direction. Crust isn't created or destroyed
• Volcanoes

  • Found at destructive and constructive plate margins and hotspots in the mantle (e.g. Hawaii)
• Earthquakes

  • Found at destructive, constructive and conservative margins
• Formation of volcanoes at destructive plate margins

  When the oceanic plate sinks beneath the contintal plate and melts. This creates magma which then rises up through cracks in the earth called vents and erupts out forming a volcano
• Formation of volcanoes at constructive plate margins

  Magma rises into the gap created by the plates movinv apart and a volcano is formed
• Cause of earthquakes

  When plates move, and eventually jerk past eachother, it sends out shock waves that are the earthquake
• Epicentre


  The point on the Earths surface straight above the focus
• Focus


  The point in the Earth where the earthquakes start. This is where the shock waves are stongest
• Moment magnitude scale

  The measurement of an earthquakes strength
• Primary effects of earthquakes


  • Buildings and bridges collapse; people injured/killed by collapsed buildings; infrastructure is destroyed; electricity, gas, water and communication networks are cut off
• Secondary effects of earthquakes

  • Earthquakes trigger landslides and tsunamis; leaking gas can be ignited; people are left homeless and may die; shortage of clean water; lack of sanitation; aid can't be provided if roads are blocked; unemployment; reduced tourism; expences
• Immediate responses to earthquakes

  Rescue people who are trapped; recover dead bodies to prevent disease; extinguish fires; set up temporary shelters; provide temporary supplies; foreign countries and charities send aid workers, supplies and money; record damage
• Long-term responses to earthquakes

  Re-house people; repair and rebuild damaged buildings, roads, railways and bridges; reconnect broken electricity, water, gas and communications connections; improve building regulations; set up initiatives to provide economic recovery
• Primary effects of volcanoes

  • Buildings and roads are destroyed by lava flows; ash causes roofs to collapse; people and animals are injured/killed by lava and falling rocks; crops are damaged; water supplies are contaminated; people, animals and plants are suffocated by volcanic gases
• Secondary effects of volcanoes

  • Mudflows form as volcanic materials mix with water; flooding is caused as ice and snow is melted; transport networks are blocked or destroyed; people are left homeless; tourism decreases during the event but can increase afterwards; ash makes fields more fertile; recovery can cost lots
• Immediate responses to volcanoes

  Evacuation; provision of food, water and shelter; medical aid; rescue stranded people; provide temporary electricity, gas and communications; foreign aid; record damage
• Long-term responses to volcanoes

  Repair and rebuild buildings, roads, rail, power lines, communication networks; improve, repair and update monitoring equipment; attract tourists to boost the economy
• Reasons to live close to tectonic hazards

  • It's where their family and friends are; jobs in the area; confident in government support in case of disaster; don't think a disaster will happen; volcanoes create fertile soil; volcanoes provide tourism
• Monitoring of earthquakes

  Networks of seisometers and lasers are used to monitor the earths movement
• Monitoring of volcanoes

  Small earthquakes, escaping gas and bulges in the earth are recorded
• Prediction of earthquakes

  While they can't be reliably predicted, monitoring caan be used to forcast areas in danger
• Prediction of volcanoes

  This is done through well monitoring a volcano. It gives people a chance to evacuate and reduces casualties
• Protection against earthquakes

  Building can be designed to withstand earthquakes by using special design or strong materials
• Protection against volcanoes

  Buildings can be reinforced so they dont collapse under the weight of falling ash. The landscape can be altered to funnel the lava flow in a specific route
• Planning strategies

  • Emergency service training; education on what to do; avoid building in areas prone to tectonic hazards; governments can have emergency plans; emergency supplies can be stockpiled
• When the earthquake occurred

  Tuesday 12th January, 2010, at 16:53 local time
• Tectonic plates involved

  • North American and Caribbean plates
• The earthquake scored 7.0 on the Richter scale
• The epicentre was 25km away from Haiti's capital Port au Prince
• How people were affected

  • 230,000 people were killed
  • 300,000 people injured
  • 1 million people homeless
• How buildings were affected

  • 250,000 residential buildings collapsed
  • 30,000 commercial buildings collapsed
  • Landmarks such as the Presidential Palace, the National Assembly Building and the Port au Prince Cathedral collapsed