Tectonic Hazards » Case Study - Volcanic Eruption Example

What you'll learn this session

Study time: 30 minutes

Understand what volcanic eruptions are and why they occur
Learn about different types of volcanic hazards and their impacts
Study the 2010 Eyjafjallajökull eruption in Iceland as a detailed case study
Examine the primary and secondary effects of volcanic eruptions
Explore immediate and long-term responses to volcanic disasters

Understanding Volcanic Eruptions

Volcanic eruptions are one of the most dramatic tectonic hazards on Earth. They occur when magma from beneath the Earth's surface erupts through a vent in the Earth's crust, releasing lava, ash, gases and other materials.

Key Definitions:

Volcano: An opening in the Earth's crust through which molten rock, ash and gases erupt.
Magma: Molten rock beneath the Earth's surface.
Lava: Magma that reaches the Earth's surface.
Pyroclastic flow: Fast-moving currents of hot gas and volcanic matter that flow down the sides of a volcano during an eruption.
Ash cloud: A cloud of ash formed by volcanic eruptions that can travel thousands of kilometres.

🌋 Why Volcanoes Erupt

Volcanoes form at plate boundaries where tectonic plates move apart or where one plate is forced beneath another (subduction). As plates move, pressure and heat build up, causing rocks to melt and form magma. When this magma finds a way to the surface through cracks or weaknesses in the Earth's crust, a volcanic eruption occurs.

🔥 Types of Volcanoes

There are three main types of volcanoes: shield volcanoes (gentle slopes, fluid lava), composite volcanoes (steep sides, explosive eruptions) and cinder cones (small, steep-sided). The type of volcano affects the nature of its eruption and the hazards it poses.

Volcanic Hazards and Their Impacts

Volcanic eruptions can cause a wide range of hazards that affect both people and the environment. Understanding these hazards is crucial for predicting and managing the risks associated with volcanic activity.

🔥 Primary Hazards

Lava flows, pyroclastic flows, volcanic bombs, ash falls and toxic gases are all immediate hazards during an eruption. These can cause death, injury and destruction of property and infrastructure.

🌊 Secondary Hazards

Lahars (mudflows), landslides, tsunamis and climate change can occur as a result of volcanic activity. These secondary effects can sometimes be more destructive than the eruption itself.

🌎 Global Impacts

Large eruptions can affect global climate by releasing ash and gases into the atmosphere, blocking sunlight and causing temporary cooling. They can also disrupt air travel, as ash clouds damage aircraft engines.

Case Study: Eyjafjallajökull Eruption, Iceland (2010)

The 2010 eruption of Eyjafjallajökull (pronounced: AY-yah-fyah-lah-YOH-kuutl) in Iceland provides an excellent case study of a volcanic eruption with significant local and international impacts.

Case Study Focus: Eyjafjallajökull

Location: Southern Iceland, about 125 km east of Reykjavik

Date: March to June 2010, with the main explosive phase from 14-20 April

Type of volcano: Stratovolcano (composite volcano) beneath an ice cap

Tectonic setting: Located on the Mid-Atlantic Ridge where the North American and Eurasian plates are moving apart

Causes of the Eruption

Eyjafjallajökull is located on the Mid-Atlantic Ridge, a divergent plate boundary where the North American and Eurasian plates are moving apart at a rate of about 2.5 cm per year. This movement creates cracks in the Earth's crust, allowing magma to rise to the surface. The eruption was triggered by a series of small earthquakes that began in December 2009, indicating magma movement beneath the volcano.

Timeline of the Eruption

20 March 2010: Initial eruption begins on the eastern flank
14 April 2010: Second, more explosive phase begins under the glacier
16-21 April 2010: Peak of ash production and disruption to air travel
June 2010: Eruption officially declared over

🚨 Primary Effects

Ash plume reached heights of 9 km
Melting of the ice cap caused flooding (jökulhlaups)
Farmland was covered in ash
Local evacuations (around 800 people)
Minimal casualties (no deaths directly attributed to the eruption)

✈ Secondary Effects

Airspace closure across Europe affecting 10 million travellers
Over 100,000 flights cancelled over an 8-day period
Economic losses of approximately £1.1 billion to the airline industry
Supply chain disruptions for businesses relying on air freight
Tourism losses in Iceland and across Europe

Responses to the Eruption

🚒 Immediate Responses

Evacuation of 800 local residents
Emergency services distributed masks to protect against ash
European air traffic control closed airspace
Stranded travellers accommodated in hotels or offered alternative transport
Icelandic government provided financial assistance to affected farmers

🛠 Long-term Responses

Improved monitoring systems for Icelandic volcanoes
Development of better ash detection technology for aircraft
Revised protocols for managing airspace during volcanic eruptions
Enhanced emergency planning for future eruptions
Increased tourism to Iceland as the volcano became famous

Why This Eruption Was Significant

The Eyjafjallajökull eruption was relatively small in volcanic terms, but its impacts were far-reaching for several reasons:

Location: Its position in Iceland, close to European air routes, meant that the ash cloud affected one of the busiest air spaces in the world.
Timing: The eruption coincided with the peak travel season in Europe.
Duration: The prolonged nature of the eruption meant that disruption continued for weeks.
Type of eruption: The interaction between magma and ice created especially fine ash that stayed airborne longer and could travel further.
Weather conditions: Prevailing winds carried the ash directly towards Europe.

Contrasting Impacts: Local vs. International

One of the most interesting aspects of the Eyjafjallajökull eruption was the contrast between its local and international impacts:

Local impacts in Iceland: Relatively minor - some flooding, ash fall on farms, temporary evacuations, but no casualties.
International impacts: Massive disruption to air travel affecting millions of people and costing billions in economic losses.

This demonstrates how in our interconnected world, even a relatively modest natural hazard can have global consequences.

Lessons Learned

The Eyjafjallajökull eruption taught several important lessons about managing volcanic hazards:

The need for better international cooperation in responding to natural hazards
The importance of accurate monitoring and prediction systems
The vulnerability of modern transport systems to natural events
The economic interdependence of countries in a globalised world
The need for flexible emergency planning that can adapt to unexpected scenarios

Since the eruption, scientists have improved volcanic ash monitoring systems and aviation authorities have developed more nuanced approaches to managing airspace during eruptions, balancing safety concerns with the need to maintain air travel.

Exam Tip: Using This Case Study

When writing about the Eyjafjallajökull eruption in your exam:

Be sure you can spell and pronounce the name (or refer to it as "the 2010 Icelandic eruption")
Focus on both local and international impacts to show the range of effects
Compare immediate effects with longer-term consequences
Discuss both physical processes and human responses
Use specific facts and figures to support your points

🧠 Test Your Knowledge!