Reducing the Impact of Earthquakes & Volcanoes (Cambridge International IGCSE Geography)

Reducing the Impacts of Earthquakes & Volcanoes

Spec point — 2.1.6 · Explain what can be done to reduce the impacts of earthquakes and volcanoes

• The responses to earthquakes and volcanic eruptions can be short-term or long-term

  • Short-term responses are those which happen straight after an event and include aid and disaster relief
  • Long-term responses aim to reduce the impact of future hazardous events and include risk assessments and hazard mapping

Earthquakes: long-term responses

• Accurate prediction of earthquakes is not currently possible, but monitoring is

• Many different methods of monitoring are being used to help research possible prediction methods, including:

  • tiltmeters, which monitor ground changes
  • clusters of small earthquakes
  • changes in radon gas emissions
  • changes in animal behaviour
  • remote sensing of ground movement using satellites

• In developed countries, building design and engineering are commonly used to reduce the impact of 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

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

Volcanoes and earthquakes: long-term responses

• There are some examples of planning which are used in both areas vulnerable to earthquakes and those vulnerable to volcanic eruptions

• In vulnerable areas:

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

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

    • vulnerable areas
    • land use
    • infrastructure such as roads

  • GIS data is then used to assist with land use planning

  • Land Use Planning

    • Mapping of areas most at risk from earthquakes
    • Planning can ensure that valuable services such as the fire service and hospitals are not built in high-risk areas
    • Densely populated housing can be located away from high-risk areas

Worked Example Explain how new buildings can be earthquake-proofed so they are less likely to be damaged in an earthquake.

[4 Marks]

Final answer: Answer

• Build deep/stronger/sturdier foundations/base [1]
• Reinforce/use concrete/bricks for buildings/walls/roofs [1]
• Use metal, steel, and aluminium beams [1]
• Use diagonal bracing [1]
• Flexible building materials [1]
• Use dampers/shock absorbers in the base of the building [1]
• Computers controlled weights/counterbalances on roof/weight on the roof [1]
• Automatic window shutters [1]
• Shatterproof/strong/reinforced glass [1]
• Use fire-resistant materials [1]
• Build low building/do not build high rise [1]
• Use automatic cut-off for gas pipes/electricity cables [1]

Case Study: Nepal

Spec point — 2.1.6 · An Earthquake

Case Study

• Nepal is one of the poorest countries in the world, with a Gross Domestic Product (GDP) per capita of under $1000
• Located between China and India, Nepal is a landlocked country
• In 2015, 80% of the population lived in rural, often remote, communities

Earthquake, April 2015

• In April 2015, at 11.26 am, Nepal was struck by an earthquake, magnitude 7.8
• The epicentre was 80 km northwest of Kathmandu in the Gorka district
• The focus was shallow at only 15 km beneath the surface
• Over 300 aftershocks followed the main earthquake

Location of Nepal's earthquake

Cause

• Nepal is located on a collision boundary between the Indian and Eurasian plates

Effects

• Approximately 9000 deaths
• Over 20,000 people injured
• Electricity and water supplies cut
• 7000 schools and 1000 health facilities were damaged or destroyed
• Almost 3.5 million people were made homeless
• Offices, shops and factories were destroyed, meaning people were unable to make a living
• UNESCO World Heritage were sites destroyed as well as many temples
• Loss of tourist income, which Nepal is reliant on
• Avalanches on Mount Everest and in the Langtang Valley
• Landslides which blocked roads and rivers
• Damages estimated at between $7 and $10 billion, about 35% of the GDP

Immediate responses

• Donations of money and aid from around the world totalled $3 billion, including $3.3 million from China and $51 million from the UK

• Many countries sent aid in the form of:

  • temporary shelters
  • medicines
  • food
  • water
  • clothing
  • search and rescue teams
  • medical staff

• Approximately 90% of the Nepalese army was mobilised

• Tent cities were set up in Kathmandu for those made homeless

• GIS crisis mapping tool was used to coordinate the response

• A $3 million grant was provided by the Asian Development Bank for emergency relief

Long-term response

• Landslides were cleared and roads repaired to restore access to remote rural communities
• Schools were rebuilt
• Earthquake drills were introduced to provide people with education about what to do in the event of an earthquake
• Stricter building codes with more enforcement
• About $200 million was provided by the Asian Development Bank for rebuilding
• A new government task force was set up to plan for future earthquake events

Case Study: La Palma

Spec point — 2.1.6 · A Volcano

Case Study

• Part of the Canary Islands, La Palma is located in the Atlantic Ocean off the coast of North Africa
• The Canary Islands are an autonomous region of Spain
• There are 33 volcanoes across the Canary Islands, 10 of which are in La Palma
• La Palma has a population of 85,000

Eruption, September 2021

• The Cumbre Viejo volcano on La Palma began to erupt on September 19, 2021 and the eruption lasted for almost three months
• The eruption was VEI 2 to VEI 3

Location of the Cumbre Vieja eruption

Cause

• La Palma and the other Canary Islands are located on the African plate
• The islands are an archipelago which has formed as the result of a hot spot
• This means that they are not located on a plate boundary but over a magma plume

Signs of eruption

• Deformation of the mountain indicated rising magma about a week before the eruption
• Between 10 and 19 September, there were over 25,000 earthquakes—an 'earthquake swarm'

Effects

• Over **7,000 **people had to be evacuated from their homes
• Almost **1,500 houses **were destroyed by the lava flow
• Over 1,500 other buildings, such as churches, shops, and schools, were destroyed
• The lava flow cut across the coastal highway
• The water supply was cut off for almost 3,000 people
• 400 hectares of banana farms were destroyed
• Almost 1,300 hectares of land were effected
• 1 death
• About 20,000 people were exposed to the eruption and its effects
• Air traffic disruption
• €1 billion damages

Immediate response

• A warning was issued of an eruption on 13th September and 40 people and livestock were evacuated
• A further 1000 people were evacuated after the eruption began on the 19th September
• 5600 more people were evacuated over the next few weeks
• The alert level was raised to red
• Air traffic was briefly suspended
• Constant monitoring of lava flow and gas emissions to ensure the safety of the population
• Food and shelter were provided for those made homeless
• A** €5.4 million** advanced payment donated by the** EU**

Long-term response

• Spain promised €400 million to La Palma for rebuilding
• Prefabricated housing was built for those made homeless but six months on, many people were still living in hotels and with family and friends
• Constant monitoring of the volcano and others on La Palma
• Improved crisis management processes are now in place for future eruptions