Section A

• What is the earth's surface separated into?

  Tectonic plates
• What are the components of the earth's structure as mentioned in the study material?

  • Crust: outer layer
  • Mantle: layer of semi-molten rock
  • Tectonic plates: float on the mantle
• What are the two types of crust that tectonic plates are made of?


  Oceanic and continental
• How does oceanic crust differ from continental crust?


  Oceanic crust is thinner and more dense, while continental crust is thicker and less dense.
• What are the three types of plate margins?


  1. Destructive
  2. Constructive
  3. Conservative
• What happens at a destructive plate margin?


  Two plates move towards each other, with the oceanic plate being subducted into the mantle.
• What geological features are created at destructive plate margins?


  Volcanoes and ocean trenches
• Give an example of a destructive plate margin.


  The Nazca plate subducting beneath the South American plate, creating the Atacama trench.
• What occurs at a constructive plate margin?


  Two plates move away from each other, allowing magma to rise and create new crust.
• What is an example of a constructive plate margin?


  The Mid-Atlantic Ridge formed by the Eurasian and North American plates moving apart.
• Describe what happens at a conservative plate margin.


  Two plates move sideways past each other or in the same direction at different speeds, without creating or destroying crust.
• What is an example of a conservative plate margin?


  The San Andreas Fault.
• What are the three main reasons why tectonic plates move?


  1. Convection currents: Hot rock rises and cools, sinking back down.
  2. Ridge push: New magma rises at mid-ocean ridges, causing plates to move apart.
  3. Slab pull: Sinking plates pull the rest of the plate along with them.
• How does tension build at destructive plate margins?


  One plate gets stuck as it moves past the other.
• How are earthquakes measured?


  Using the moment magnitude scale.
• What is the process of an earthquake?


  1. Tension builds up until plates jerk past each other.
  2. Shockwaves are generated, spreading out from the focus.
  3. The epicenter is the point on the Earth's surface above the focus.
• What is the focus of an earthquake?


  The point in the Earth where the earthquake starts.
• What is the epicenter of an earthquake?


  The point on the Earth's surface directly above the focus.
• What do volcanoes emit when they erupt?


  Lava and gases, including pyroclastic flows.
• Where do volcanoes typically form?

  • At destructive margins: magma rises through cracks in the crust.
  • At constructive margins: magma rises into gaps created by moving plates.
  • At hotspots: areas of the mantle that are very hot, e.g., Hawaii.
• What are primary and secondary effects of natural hazards?


  • Primary effects: Immediate impacts caused by the hazard (e.g., buildings destroyed).
  • Secondary effects: Later impacts resulting from primary effects (e.g., spread of disease).
• What are immediate and long-term responses to natural hazards?

  1. Immediate responses: Actions taken right after a disaster (e.g., evacuation, providing aid).
  2. Long-term responses: Actions taken to recover and rebuild (e.g., repairing buildings, improving monitoring).
• Why might people choose to live in hazardous regions?


  They may have always lived there, believe in government support, or find the soil fertile.
• What are the methods of managing tectonic hazards?


  • Monitoring: Using seismometers and lasers for early warning.
  • Prediction: Forecasting where hazards may occur by monitoring tectonic plate movements.
  • Planning: Preparing emergency services and educating the public.
  • Protection: Strengthening buildings and using reinforced materials.
• What are some protective measures for buildings against earthquakes?

  • Use of reinforced concrete to absorb energy.
  • Strengthening existing buildings with steel frames.
  • Automatic shut-off switches for gas and electricity.
• What are some planning measures for managing tectonic hazards?


  • Avoiding high-risk areas for future developments.
  • Preparing emergency services and practicing evacuation routes.
  • Stockpiling emergency supplies.