Contrasting Eruptions
This revision and study page provides a detailed account of two contrasting volcanic eruptions, namely Nyiragongo in DRC and Eyjafjallajökull in Iceland.
Two contemporary contrasting case studies for volcanic hazards. To include:
- geophysical hazard event profiles, including any secondary hazards
- varied impacts of these hazards on different aspects of human well-being
- why levels of vulnerability varied both between and within communities, including spatial variations in hazard perception, personal knowledge and preparedness
Hazard Profiles
Nyiragongo Eruption 2002
Timing: 09:30
Magnitude: VEI - 1
Speed of onset: Increased seismic activity and fumaroles prior to eruption. A 13 km fissure opened up in a matter of hours, and fast-flowing lava up to 40km/h. Lava lake drains out from the crater along fissures
Duration: 48 hours
Area Affected: 3 separate fissures with 13% of the city covered in lava
Frequency: Last eruption 1977
Predictability: High-value forecast, but exact timing impossible. The volcano was well monitored
Secondary Hazards: Open fissures, petrol station explosion, and unsafe lava flow when walking over it.
Proximity to hazard: City of Goma, 18km south of the volcano
Deaths: Approximately 147
Eyjafjallajökull Eruption 2010
Timing: 19-20 December
Magnitude: VEI 4
Speed of onset: 3 months of increased seismic activity prior to the eruption
Duration: 7 months, European flights were disrupted for 5 days
Area Affected: Large-scale disruption to European air travel, with smaller effects on local farmland in Iceland
Frequency: Last eruption 1821-1823
Predictability: High-value forecast, but exact timing impossible. The volcano was well monitored. Ash dispersal was not predicted
Secondary Hazards: Ash clouds affecting planes, localised flooding and Jökulhlaups (glacier outburst floods)
Proximity to hazard: Isolated farming communities and an important ring road connection
Deaths: 0
Contrasting Impacts
Nyiragongo Eruption
The volcano was well-researched, and although the scientific equipment being used at the time was outdated, it was providing regular data to suggest an imminent eruption. The problems with the early responses were based on poor communication. There was no real means to communicate the situation to the public, and so in the absence of any clear warning, a chaotic public evacuation occurred at the same time as fast-moving lava was entering the town.
A 13km fissure opened in the south flank of the volcano, spreading in a few hours from 2,800m to 1,550m elevation and reaching the outskirts of the city of Goma, the provincial capital on the northern shore of Lake Kivu. Lava streamed from three spatter cones at the end of the fissure and flowed in a stream 200 to 1,000m wide and up to 2m deep through Goma. At least 15% of Goma, comprising 4,500 buildings, was destroyed, leaving about 120,000 people homeless.
The lava flow hit the commercial centre and covered the northern end of the airport and runway at Goma International Airport, leaving two-thirds of it destroyed and out of use. Given Goma’s geographical isolation in DRC, this vital transport hub was a massive loss.
Belated evacuation warnings were given, and 400,000 people were evacuated from the city. 100,000 people moved west, and a further 300,000 crossed over into Rwanda. Immediately after the eruption stopped, a large number of earthquakes were felt around Goma and Gisenyi. This swarm activity continued for about three months and caused the collapse of more buildings.
Most estimates suggest that about 147 people died in the eruption from asphyxiation by carbon dioxide and buildings collapsing due to the lava and earthquakes. 50 people died in a single explosion at a petrol station. This is clear evidence of poor public awareness and low perception of risk. People were queuing to fill their cars with petrol at the time. Due to long-term political unrest and conflict impacting 6 countries in the region, displaced people were quick to return. This may have been because of the widespread looting that had been reported in the first few days. Within days, most people had returned and were either living in camps close to Goma or with host families in the city. Several thousand people remained at the Esco camp, a transit camp sponsored by the Goma-based Congolese Assembly for Democracy (RCD-G) located 8 km west of Goma. Some people were severely injured because they were walking on the crust of the lava. Communities showed incredible resilience, setting up market stalls and rebuilding within days.
In total, 12,500 families lost their homes, leaving 120,000 people homeless. International non-governmental organisations (NGOs) estimated an increase in unemployment levels from 80 to 95%. 45 of 150 schools in Goma were destroyed, leaving 24,000 children out of school. 5 of the 20 health clinics and one important hospital were lost.
In total, UN aid amounted to just over $33 million. With a large presence of humanitarian agencies already in the region due to conflict, many secondary factors, such as malaria and cholera outbreaks, were avoided. Financial agricultural support was given to both the worst-hit families and the host families.
Physical Factors
- Highly exposed to risk from fast-flowing lava from multiple fissure eruptions in close proximity to the city
Dynamic Pressures
- Population growth in the city
- Very low educational base - poor perception of risk
Root Causes
- A very underdeveloped country and an even poorer region
- Distance from the capital city and the central government leads to underinvestment
- Remoteness and poor accessibility
- High dependence on international aid and NGOs
Unsafe Conditions
- Poor communication and disaster response measures
- High levels of political instability and militia groups
Eyjafjallajökull Eruption
Eyjafjallajokull is a stratovolcano the that lies under a glacier. The eruption was well monitored and forecast, with increased seismic activity and displacement taking place prior to the eruption phase. Iceland has a huge amount of experience in managing tectonic hazards, and so the operation of evacuation was relatively smooth, and the families involved were cooperative and well-prepared. The nature of the eruption was also well understood, and so the South Road was closed, and temporary bridges were removed.
The initial eruption was effusive, with lava visibly shooting out from the crater. The second phase was phreatic (caused by magma mixing with ice) and caused a 9,000-meter-high tephra cloud to form. Over 4 weeks, it is believed that 250 cubic tonnes of ash were ejected from the volcano.
In the immediate phase of the eruption, 800 local people were evacuated from nearby homes and farms, with only short temporary visits permitted to tend to livestock. The coastal plain and ring road were subjected to localised flooding from the Jökulhlaup, (glacial flood). In total, the economic cost to Iceland in managing these impacts amounted to $7.5 million.
Due to the eruption coinciding with an infrequent prevailing wind and positioning of the Polar Jet Stream, the ash cloud was dispersed across Northern Europe, causing widespread disruption to the aviation industry. Flights in Northern Europe were grounded for the first 6 days of the eruption. It’s estimated that the closure of European airspace left 5 million travellers stranded abroad, with several thousand people affected as far as Asia and the US. The International Air Transport Association (IATA) estimated that the aviation industry lost $200 million a day. Other impacts included supply-side problems with small electronic hardware products and fresh fruit and flowers. On each of the 6 days, Kenya was forced to destroy 400 million tonnes of flowers, costing its sector $millions. Other sectors included the supply of pharmaceuticals and the export of electronic hardware out of Europe. Schools were particularly impacted, with many students and teachers stranded abroad due to the timing of the Easter holiday. In addition, some major sporting events and several high-profile global conferences were cancelled. In total, the estimated global cost of the eruption is thought to have been $5 billion.
Physical Factors
- A highly active region for tectonic hazards
- Volcanoes under glaciers create a huge risk for dynamic hazards such as Jökulhlaups
- Eruption coinciding with the Polar Jet Stream and prevailing wind patterns is rare and highly infrequent
Dynamic Pressures
- N/A
Root Causes
- None - Highly developed society, strong governance, scientific expertise and low population
Unsafe Conditions
- Lack of funding and research into the impacts of ash on plane engines means European countries were forced to take a precautionary approach in their response and economic disruption may not have been necessary
Timing: November 2023 to February 2025
Deaths: None
Cost: €538 million – €668 million EUR).
Homes Lost: Entire town evacuated with extensive structural damage
Displacement: 4000 people permanently evacuated
Health: None
The volcano type is a fissure volcano. Fissure volcanoes form as fountains of lava along a visible crack in the surface. The eruption from November 2023 to February 2025, is called the Sundhnúksgígar eruption. This 7km-wide, 30 km-long system lacks a typical volcanic cone or a central active volcano. Instead, it's dominated by fissures and clusters of volcanic cones or vents. A key vulnerability is the challenge of forecasting where exactly the fissure will erupt.
A massive vulnerability was the quantity of earthquakes. Rising magma caused more than 20,000 earthquakes. These earthquakes caused immense damage to the town of Grindavik. The earthquakes caused large land deformation of up to 12 cm in 24 hours, causing widespread disruptions to water, electricity, and heating supplies. Severe damage to buildings, including homes, businesses, and the town’s sports centre, took place. As a result, the entire town (4,000 people) was evacuated.
Support loans up to ISK 49 million ($353,000) were offered to businesses to help them relocate or maintain operations elsewhere. However, most companies have been forced to close as the town was predominantly focused on fishing. The total cost was estimated to be €538 million – €668 million EUR.
No lives were lost due to the incredible management of volcanoes in Iceland. Iceland is a world leader in monitoring volcanoes.
Monitoring and Prediction
Before an eruption, authorities keep a careful eye on how a volcano is behaving. Icelandic authorities maintain a permanent monitoring station close to craters that provides live data to central control. As magma rises and exerts pressure in the magma chamber, scientists can monitor several changes. Often, gas emissions increase. Scientists take regular samples to monitor carbon dioxide and sulphur dioxide levels. Scientists also monitor the shape of the volcano. As magma rises upwards, the surface changes shape. Scientists use a small network of GPS units that are read by satellites. Computer models are then able to produce accurate 3D maps of the changing topography. In Iceland, drones are also deployed and can produce 3D maps of the volcano that reveal its changing shape. Drones are fitted with infrared cameras that can monitor changes in heat on the surface. Together, these monitoring techniques provide a range of data that is used to make accurate forecasts of eruptions.
Advanced Seismic Monitoring and Analysis - Iceland's Meteorological Office uses a sophisticated network of seismographs across Iceland to detect earthquakes. Small earthquakes indicate moving magma below the surface. As earthquakes increased in frequency, the Meteorological Office raised the alert level to a state of emergency and raised the aviation threat to orange.
During the eruption phase, there is close monitoring of the air quality to ensure the safety of key emergency services.
Planning and Protection
The Police and Civil Protection Agency, as well as local volunteer groups such as Iceland's Association for Search and Rescue (ICE-SAR), are highly trained in terms of planning and protection. They are in close communication with the Meteorological Office. The national media increases public awareness through regular news bulletins.
The emergency services worked together to coordinate an evacuation of Grindavik. This was organised swiftly and calmly. To avoid panic, residents were allowed to return to their homes briefly to collect important documents, medicine, and pets. In addition to the evacuation of people, farm animals, including horses and sheep, are evacuated.
Following this, the authorities built defence walls around critical infrastructure. These are built to divert lava flow and to hold it back. In total, 16 km of earth and rock barriers were built, some over 8 meters high. These were used to protect homes, key infrastructure, such as the Svartsengi power station, the main road and the Blue Lagoon Hotel and Geothermal Pool.
In addition to the construction of defence walls, the Civil Protection Drone Unit monitor the lava flow. Drones are used to sample air quality and track the speed, volume and direction of the lava flow. This not only helps in managing the lava flow and protecting infrastructure, but it also protects the Civil Protection officers on the ground. The drones provide a live stream of the lava flow to the Meteorological Office, emergency services, and engineers.
Physical Factors
- A highly active region for tectonic hazards
- Fissure volcanoes are unpredictable in terms of exact locations. A new fissure can erupt with very short notice.
Dynamic Pressures
- N/A
Root Causes
- None - Highly developed society, strong governance, scientific expertise and low population
Unsafe Conditions
- Grindavik, unfortunately, sits right along the fissure. It experienced earthquake swarms that caused significant structural damage to over 90% of buildings, making the town unlivable.
- Lava flows reached the edge of the town, shifting location inside the defence walls. Three houses were destroyed, but losses could have been much worse had the lava flow continued.