Impact of Earthquakes & Volcanoes (SQA National 5 Geography): Revision Note

Case Study: Nepal

• Located between India and China, Nepal is a landlocked country

• In 2015, Nepal was a low-income country, with a GDP per capita of less than $1000

• 80% of the population lived in rural, often remote, communities 

Earthquake, April 2015

• In April 2015, at 11.26am, Nepal was struck by an earthquake, magnitude 7.8

• The epicentre was 80km northwest of the capital city, Kathmandu, in the Gorka district

• The focus was shallow, just 15km below the surface

• Over 300 aftershocks followed the main earthquake

Cause

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

Impacts on people

• Approximately 8600 deaths

• Over 20,000 people were injured

• Many survivors suffered stress, anxiety and trauma

• Electricity and water supplies were cut, reducing the standard of living

• Approximately 8300 schools were damaged or destroyed, reducing access to education 

• Over 1000 health facilities were destroyed, reducing access to healthcare

• Almost 3.5 million people were made homeless

• Job losses and reduced tourist income meant that people were unable to make a living

• Damages estimated between $7 and $10 billion (about 35% of total GDP) 

Impacts on the landscape

• More than 20,000 landslides blocked roads and rivers

  • Rivers were blocked by landslide dams, creating large temporary lakes, which increased the risk of sudden and catastrophic flooding

• Avalanches on Mount Everest and in the Langtang Valley

• Sediment from landslides choked rivers, contaminating water sources and threatening aquatic life

• Large areas of forest were damaged and destroyed, causing loss of biodiversity and wildlife habitats

• Thousands of homes, offices, shops and factories were destroyed

• Many historic temples and UNESCO World Heritage sites were destroyed, e.g. Dharahara Tower

Case study: Mount Merapi, Indonesia

• Indonesia forms part of the Pacific ‘Ring of Fire’

• There are around 130 active volcanoes in Indonesia

• Mount Merapi, located on the island of Java, is the most active volcano in Indonesia

• Its name means ‘Mountain of Fire’

• The area is very densely populated, with hundreds of thousands of people living within a few kilometres of the volcano 

Eruption, October 2010

• Mount Merapi began to erupt on October 25, 2010

• The eruption lasted for around a month

• The magnitude was VEI 4

• It was the most significant eruption since 1872 

Cause

• A destructive plate boundary where the Indo-Australian plate is subducting below the Eurasian plate

Impacts on people

• Over 350 people died

• Injuries and illnesses e.g. sulphur dioxide gas, caused skin irritation and breathing problems

• 350,000 people were displaced

• Many survivors suffered stress, anxiety and trauma

• Services like healthcare and education were disrupted

• Roads and bridges were damaged, disrupting trade and economic activity

• Crops were destroyed and livestock killed, leading to rising food prices

• Job losses and reduced tourist income meant that people were unable to make a living

• Economic losses of £450 million 

Impacts on the landscape

• Thick layers of ash covered the landscape, reaching up to 480km from the volcano

• Ash mixed with rainwater during the rainy season, causing lahars (volcanic mudflows)

• Farmland was buried under thick layers of ash and mud

• Over 200 hectares of forest were damaged, causing loss of habitats and biodiversity

• Ash and acid rain contaminated rivers, damaging ecosystems and threatening aquatic life

• Over 3000 homes and buildings were destroyed

Make sure you can explain the impacts of a named earthquake and a named volcanic eruption on both people and the landscape. Make revision cards to test yourself on details such as magnitude, location and death toll.