Managing the Impacts of Tectonic Hazards (Cambridge (CIE) IGCSE Geography) : Revision Note

Primary and secondary responses

• Types of response to tectonic hazard

  • The responses to any tectonic hazard can be divided into two groups

    • Immediate or emergency

    • Long term

Immediate or emergency responses

• The immediate or emergency response is the action taken immediately after a hazard event, such as an earthquake

  • Rescue teams search for survivors

  • Medical assistance for injured people

  • Shelter provided for those people made homeless

  • Food and water provided

  • Recovery and burial of bodies

  • Evacuation if needed

  • Clearing ash and debris

  • Reconnect gas, water and electricity supplies

• This response has to be coordinated, as many NGOs and government organisations, including the armed forces, may be involved

Long term responses

• The long-term responses happen over the months and years after the hazard

  • Rebuilding homes and other buildings

  • Improve building regulations

  • Improve drills, evacuation plans and warning systems

  • Money given to farmers for seed and new livestock

  • Data used to inform future hazard planning

  • Government planning improved

  • Transport routes rebuilt

Park's hazard response curve

• The stages of hazard response can be seen in Park's hazard response curve

Strategies to manage the impacts of tectonic hazards.

• To reduce the risks from tectonic hazards, the five key management strategies and techniques are:

  • monitoring

  • prediction

  • protection

  • planning

  • technology

Monitoring 

• Active volcanoes are monitored using a range of equipment

  • Seismometers record earth movements and can detect the slightest tremor

  • Lasers and tiltmeters are used to detect ground deformation; changes in land shape can be a sign of rising magma

  • Remote sensing is where satellites are used to detect heat increases within the volcano, another sign of rising magma

  • Gas sensors detect increases in gases such as sulphur and radon which increase before an eruption

• Earthquakes

  • Seismometers record earth movements and can be used to detect foreshocks

  • Gas sensors detect increases in radon gas, which some scientists believe is released before an earthquake

  • Groundwater level changes have been recorded before earthquakes

Prediction

• Volcanoes:

  • Monitoring of volcanoes now allows more accurate predictions to be made of when eruptions will happen

  • This allows for evacuation and exclusion areas to be put in place

  • Accurate timings for eruptions are not possible 

• Earthquakes: 

  • Impossible to predict the date, time or location because it is a very sudden release of stress that has built up over long periods

Protection

• Volcanoes:

  • Evacuation and exclusion zones move people out of areas at risk 

  • Buildings cannot be protected against lava or pyroclastic flow

  • Strengthening of roofs to support the weight of falling ash

• Earthquakes:

  • Building regulations and codes require new buildings to include earthquake-resistant features, including:

    • shutters on windows prevent falling glass

    • cross-bracing or diagonal bracing of steel frames

    • flexible building materials

    • foundations sank deep into the bedrock

    • frames which sway with the earthquake tremors

    • rubber shock absorbers to reduce tremors moving through the building

    • reinforce walls/pillars with concrete

    • shatterproof/reinforced glass

    • fire-resistant materials

    • automatic cut-off for gas/electricity

  • In many countries, earthquake drills are regularly carried out

    • The drills help people prepare for what to do in an earthquake to protect themselves

  • Educating people about how to prepare homes means they are less likely to be injured by falling objects and furniture

  • Sea walls to protect against tsunami

Planning

• Volcanoes and earthquakes:

  • Hazard mapping and risk assessment are used to identify areas which are at greater risk – this means people can be moved or buildings restricted in those areas, particularly essential buildings (hospitals) and transport

  • Evacuation plans

  • Education about what actions to take, including drills

  • Stockpile of emergency supplies

  • Training of emergency services

Technology

• Hazard mapping and geographical information systems (GIS) can be used to:

  • Map the areas where earthquakes are most likely to occur

  • Enable planning of where important services and infrastructure should be located – land use zoning

  • Identify the correlation between risk and vulnerability

• Remote sensing of the Earth's surface by satellites such as Sentinel 1 provides data about changes in ground movement