Mitigation & Adaptation (Edexcel A Level Geography): Revision Note

Disaster Modification

• Strategies to manage and reduce the impact of tectonic hazards can be divided into three groups - modification of the:

  • Event

  • Vulnerability, increasing resilience

  • Loss

• These strategies involve mitigation or adaptation

Modification of the event

• This happens before the event occurs

• Modifying earthquakes is challenging because they occur without warning 
  

  • Construction of earthquake-resistant buildings can help to reduce the impacts on people 

• Modifying volcanic hazards can be achieved by:

  • Hazard risk mapping using Geographic Information Systems (GIS) to identify areas at highest risk followed by land use zoning to prevent development in these areas

  • Draining crater lakes reduces the chance of lahars

  • Barriers and channels can also be constructed to divert lava flows

• Modifying tsunamis can be achieved by:

  • Using land use zoning to prevent construction at the coast

  • Building offshore barriers 

  • Building sea walls - Japan has increased the height of sea walls in some areas to over 12 meters 

  • Replanting mangrove forests 

The role of engineers and planners

• Modifying the event is mainly the work of engineers and planners — the key players here

• Structural engineers design earthquake-resistant buildings (cross-bracing, shock absorbers, deep foundations)

• Civil engineers build lava-diversion barriers, drain crater lakes and construct sea walls

• Urban planners enforce land-use zoning through building codes and regulations

Modelling future impacts

• Modelling means using computer models to predict what a future disaster might do

• It lets planners compare the impacts with and without protection, such as sea walls

• A good example is the Tohoku disaster in Japan (2011):

  • A huge undersea earthquake caused a massive tsunami

  • It killed around 16,000 people and badly damaged the Fukushima nuclear power station

  • Planners can model how many lives and how much money higher sea walls and tougher building rules would have saved

• Models like this help governments decide how much to spend on defences

• But models are not perfect:

  • The Fukushima sea wall was built too low

  • The tsunami was bigger than expected and flooded over the top of it

Reduction of Vulnerability & Increasing Resilience

Modification of vulnerability

• This happens before the event occurs

• Vulnerability can be reduced and the resilience of populations increased in a number of ways:

  • Land use zoning - ensuring that people are not living in high-risk areas

  • Hazard resistant buildings 

  • Improved services and infrastructure

  • Hazard risk mapping using Geographic Information Systems (GIS)

  • Planning of evacuation routes

  • Education of the population to ensure that they know the actions to take when a hazard event occurs - earthquake drills

  • Improved storage of food, water and medical supplies so sufficient are available

  • Monitoring and warning systems to allow people time to evacuate

Hazard resistant buildings

• In many countries building design and engineering is commonly used to reduce the impact of earthquakes

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

  • Shutters on windows prevent falling glass

  • Cross-bracing of steel frames

  • Foundations sunk deep into the bedrock

  • Frames which sway with the earthquake tremors

  • Rubber shock absorbers to reduce tremors moving through the building

• These reduce the risk of building collapse, reducing the numbers of deaths and injuries

Geographic Information Systems (GIS)

• Geographic Information Systems (GIS) provides layers of data such as:

  • Vulnerable areas

  • Land use

  • Infrastructure such as roads, airports and power lines

• GIS data is then used to assist with land use planning by mapping the vulnerability of areas and using to zone land use

  • Not building residential areas in the most vulnerable locations

Reduction of Loss

Modification of loss

• This happens after the event occurs

• Loss can be reduced by efficient and effective aid and recovery, which can be achieved in a range of ways:

  • Evacuation - moving people away from the area that has experienced destruction/damage

    • This is particularly important after earthquakes when there are likely to be aftershocks which cause further damage

  • Search and rescue teams, who are well-equipped and trained

  • Emergency aid - food, water, medical aid to ensure survival 

  • Short-term aid - shelter, reconnecting of water and electricity supplies

  • Development aid - long-term aid to help with reconstruction and recovery

  • Insurance - to help people rebuild 

  • Local communities - supporting each other, providing shelter and helping with the search and rescue effort

• Aid may be provided by:

  • Non-governmental Organisations (NGOs) such as the Red Cross, Medicin San Frontiers and Disasters Emergency Committee

  • Intergovernmental Organisations (IGOs) such as the UN and World Bank

  • National and local government

The role of NGOs and insurers

• Recovery and the reduction of loss are shaped by two key players: NGOs and insurers

• NGOs (listed above) deliver emergency and short-term aid in the days and weeks after an event

• Insurers and re-insurers fund longer-term rebuilding and set the price of future risk

• Low insurance cover in many developing countries slows recovery and increases long-term loss