Tectonic Hazards

• 60% of active volcanoes occur at plate boundaries
• Volcanoes occur at destructive and constructive plate margins
• Earthquakes are caused by tension at all 3 plate margins
• Moment magnitude scale


  Measures the amount of energy released by an earthquake
• A magnitude 7 earthquake is 10 times more powerful than a magnitude 6
• How earthquakes occur


  1. Plates jerk past each other, causing shockwaves

  2. Shockwaves spread out from the focus

  3. Stronger shockwaves from shallow focus
• Effects of tectonic hazards


  • Primary effects
  • Secondary effects
• People live in hazard-prone areas due to family/employment ties, confidence in government support, belief that severe events won't happen in their lifetime, fertile volcanic soil, tourism opportunities, geothermal energy
• Monitoring tectonic hazards


  1. Seismometers and lasers to detect earth movements

  2. Remote sensing to detect heat and shape changes

  3. Monitoring for precursor signs like earthquakes, gas release, bulging
• Predicting tectonic hazards


  1. Earthquakes difficult to predict, but locations known

  2. Volcanic eruptions can be predicted from monitoring
• Planning for tectonic hazards

  1. Land zoning to avoid high risk areas

  2. Emergency services training

  3. Public education

  4. Evacuation planning

  5. Emergency supplies stockpiling
• Protecting against tectonic hazards

  1. Earthquake-resistant building design

  2. Strengthening existing structures

  3. Automatic shut-off for utilities
• Haiti


  Lower middle-income country in the Caribbean
• 7.2 earthquake struck Haiti

  14th August 2021
• Plate boundaries around Haiti


  • North American Plate lies to the north and the Caribbean Plate to the south
  • Earthquake took place at a conservative plate boundary, where the Caribbean plate moved eastwards
• Haiti Earthquake

  • Focus was only 10 km deep
  • Epicentre was 125 km from the capital Port-au-Prince
• The estimated cost of damages from the Haiti earthquake is around US$1.6 billion. This amounts to 9.6 per cent of Haiti's GDP.
• Christchurch Earthquake


  • Occurred on New Zealand's South Island, 10km west of Christchurch, at 12.51 pm on 22nd February 2011 and lasted just 10 seconds
  • Measuring 6.3 on the Richter Scale and, at 4.99 km deep, the earthquake was very shallow
  • Occurred along a conservative margin between the Pacific Plate and the Australasian Plate
• Christ Church 2011 earthquake


  Population of 376,700
• Time and Date of Christ Church 2011 earthquake

  22nd February 2011 – 12-51pm
• Christ Church 2011 earthquake

  • Magnitude of 7.1
  • GDP per capita $27,700
  • Adult literacy rate 99% over 15 years can read/write
  • 100% people have access to clean water
• Liquefaction in Christ Church 2011 earthquake


  1. Ground shaken, everything from buildings to roads to cars and trees sunk into the ground

  2. Sand boils most common type of liquefaction
• Impacts of Christ Church 2011 earthquake

  • 181 people were killed, 80 of which from Christchurch TV building collapsed
  • 2,000 people were injured
  • 1 in 5 people lost their jobs because many buildings were destroyed
  • 6,000 companies and institutions with over 50,000 employees in the CBD of 45% of them are likely to retain their jobs in another location
  • $40billion worth of damage need to repair infrastructure
• Haiti 2010 earthquake


  • Population of 9.7 million
  • GDP per capita $343.89
  • HDI 0.456
  • More than half of Haiti's population – between 5 and 6 million people – live in rural areas
  • About 85% of the rural population practise some agriculture which accounts for about 26% of Haiti's economic output and makes agriculture
• Impacts of Haiti 2010 earthquake


  • 3,500,000 people were affected by the quake
  • 220,000 people estimated to have died
  • 300,000+ people were injured
  • Over 188,383 houses were badly damaged and 105,000 were destroyed by the earthquake (293,383 in total)
  • 1.5m people became homeless
  • 4,000 schools were damaged or destroyed
  • 25% of civil servants in Port au Prince died
  • Over 600,000 people left their home area in Port-au-Prince and mostly stayed with host families