Managing tectonic hazards Cambridge IGCSE Geography revision

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In plain words

Nobody can stop an earthquake or an eruption. What can be changed is how many people are in the way, how strong their buildings are, how much warning they get and how fast help arrives.

7 things to know

  1. Primary responses happen immediately: search and rescue, emergency medical care, and shelter, food and clean water for survivors.
  2. Secondary responses happen in the weeks and years after: rebuilding homes and roads, restoring services, helping the economy recover, and improving plans for next time.
  3. Monitoring volcanoes: seismometers detect small earthquakes as magma rises, tiltmeters and satellites detect the ground bulging, and instruments measure gases and temperature. Eruptions can often be predicted, and people evacuated.
  4. Earthquakes cannot be predicted in time or place with any accuracy. Scientists can only say where they are likely, and some countries have systems that give a few seconds' warning once one has started.
  5. Protection: buildings designed to survive shaking, with deep foundations, cross-bracing, flexible steel frames and shock absorbers in the base. Sea walls protect against tsunamis.
  6. Planning: hazard maps to keep building away from the highest risk, evacuation routes, regular drills, emergency supplies and education.
  7. These measures cost money, so richer countries are generally better protected.

Worked example

Explain how the design of a building can reduce the damage done by an earthquake.

  1. Shock absorbers (base isolators) in the foundations let the ground move without shaking the whole building.
  2. A steel frame with cross-bracing lets the building sway without collapsing.
  3. Deep foundations hold it steady, and shatter-proof glass stops falling glass injuring people.

Tips and tricks

  • Volcanoes can usually be predicted. Earthquakes cannot. This contrast is a favourite exam point.
  • Use the syllabus's own headings to organise an answer: monitoring, prediction, protection and planning.
5 questions, about 2 minutes.

It lands in your notebook with its questions as flashcards.

Managing tectonic hazards: 5 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

  1. Which is a primary response to an earthquake?
    • rebuilding houses
    • searching for survivors (the answer)
    • changing building laws
    • repairing the economy

    It happens in the first hours and days.

  2. What does a seismometer detect?
    • gases
    • earthquakes and ground vibrations (the answer)
    • temperature
    • rainfall

    Many small earthquakes can mean magma is rising.

  3. Which is true about predicting tectonic hazards?
    • Earthquakes can be predicted to the day.
    • Eruptions can often be predicted, but earthquakes cannot. (the answer)
    • Neither can ever be predicted.
    • Both can be predicted years ahead.

    Volcanoes give warning signs. Earthquakes do not.

  4. What do base isolators in a building do?
    • make the building taller
    • absorb the ground's movement so that the building shakes less (the answer)
    • warn of an earthquake
    • stop the ground moving

    They sit between the building and its foundations.

  5. What is a hazard map used for?
    • to measure earthquakes
    • to show the areas most at risk, for planning (the answer)
    • to predict the date of an eruption
    • to count the population

    Building can be kept away from the most dangerous zones.

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