Volcanoes and volcanic eruptions - Eduqas Case study - volcanic eruption - La Palma, 2021
Composite and shield volcanoes are found along plate boundaries. They have distinctive characteristics and can have both positive and negative effects on people and the landscape.
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Case study - volcanic eruption - La Palma, 2021
La Palma is one of the Canary Islands, which lie in the Atlantic Ocean. The Canary Islands are an autonomous region of Spain. The Cumbre Vieja volcano on La Palma erupted from the 19th September to the 13th December 2021.
- The Canary Islands have over 30 volcanoes, 10 of which lie on the island of La Palma.
- The volcanoes are unusual in that they are intraplate. This means that they are located above a ‘hot spot’ rather than along a plate boundary.
- Hot spots occur where columns of superheated magma, or mantle plumes, cause the Earth's crust to melt and become thinner.
- The Canary Island hotspot is located on the African plate, which is estimated to be moving between 2cm to 3cm per year.
- A build-up of magma swelled beneath the ground a week before the first eruption. Warnings were sent out and nearly 7,000 people evacuated the affected areas.
Increased vulnerability – physical factors
- An ‘earthquake swarm’ took place in the days and weeks before the eruption. This consisted of more than 20,000 earthquakes, some of which were sizeable.
- It was feared that the volcano could create a tsunami, which could reach Portugal and western African countries.
- Vigorous lava flows and explosive activity took place over a three-month period in total.
- Social - More than 7,000 people had to leave their homes. Over 1,300 homes were destroyed by the lava flow. Many other buildings, such as churches and schools, were damaged or destroyed.
- Economic - Hundreds of acres of farmland, including banana plantations, were destroyed. Flights were cancelled and tourist resorts closed, which affected the local economy.
- Environmental – Vast swathes of forest were destroyed by the lava. However, the molten rock increased the size of the island as it flowed into the ocean.
More guides on this topic
- Plate boundaries - Eduqas
- Earthquakes and tsunamis - Eduqas
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White Island Volcano Case Study
New Zealand’s Whakaari/White Island volcano erupted on Monday 9th December 2019. The strato or composite volcano, located on New Zealand’s east coast, erupted at 14:11 NZDT on 9 December 2019.
Whakaari lies at the northern end of the North Island’s ‘line of fire’ – a large volcanic plateau which stretches from the Bay of Plenty on the coast, to Mt Ruapehu inland. The line of fire forms part of the wider ‘Ring of Fire’ around the Pacific ocean.
It also has a water-filled crater lake. When water reacts with hot rock or magma, it can create explosions, and therefore, can make eruptions even more difficult to forecast.
The uninhabited island covers an area of approximately 325 ha (800 acres), which is only the peak of a much larger submarine volcano.
White Island is privately owned. It was declared a private scenic reserve in 1953. Visitors cannot land without permission, however, it is accessible by authorised tourist operators by boat and helicopter.
Why did White Island volcano erupt?
There are several volcanoes in New Zealand, like White Island, that have the ability to produce sudden explosive eruptions at any moment. In the case of White Island, the magma is very shallow, and the heat and gases produced by it affect ground and surface water to create vigorous hydrothermal systems.
Water is trapped in a super-heated state in pores of the rocks. An external influence, such as gas input from below, an earthquake or a change in water level can release the pressure on the hot water trapped below.
Experts identified the event as a phreatic eruption. A phreatic eruption involves the release of steam and volcanic gases which caused an explosion, launching rock and ash 3km into the air. The speed of the expansion of water into steam is supersonic, and the liquid can expand to 1,700 times its original volume. The expansion energy is enough to shatter solid rock, create craters and throw volcanic material several kilometres away.
What were the impacts of the eruption of White Island?
It was reported that there were 47 people on the island when the eruption occurred. Eighteen people were killed and a further 26 were seriously injured, many critically. Many of the surviving tourists on the island experienced burned lungs from inhaling sulphur dioxide and volcanic ash, and “very significant” deep-tissue burns, some to more than half of their body. Twenty-seven of the 31 people injured in the eruption of the Whakaari/White Island volcano had burns to more than 30% of their body.
The bodies of two victims have not been recovered and may have been lost to the sea.
The ongoing seismic and volcanic activity in the area and subsequently heavy rainfall as well as low visibility and toxic gases all hampered recovery efforts.
What are the long-term impacts of the eruption?
It is too early to say what the long term impacts of the eruption will be, however, there is likely to be a negative economic impact on the companies providing island tours.
What were the immediate responses to the eruption of the White Island volcano?
23 people were rescued from the island. It was estimated that there were less than 50 people on the island at the time of the eruption.
Seven helicopters were dispatched to the island by St John Ambulance.
Tour operators rescued people roughly 15 minutes after the eruption.
A national warning was issued for the eruption
Aviation authorities implemented a 26 nautical mile no-fly zone around the island to help rescue crews. White Island is 22 nautical miles offshore.
The New Zealand Red Cross activated the Family Links website for those concerned that their loved ones may have been caught up in the incident.
The military deployed drones at first light the following day to assess the situation on the ground.
A team of six New Zealand soldiers wearing breathing apparatus and special fire-retardant suits battled heat stress as they recovered six of the victims of the Whakaari/White Island volcano eruption four days after the eruption.
Australia offered additional support to the New Zealand medical services after requests from the New Zealand government.
New Zealand health authorities reportedly ordered 1.2 million sq cm of skin from the US in order to treat those injured: 27 of whom had burns to more than 30% of their body, with some having burns to 90-95% of their body. For context, experts say the palm of a hand is about 1.5% of the area of the body.
Why were there no warnings?
In this age of technology and volcanic monitoring , it seems strange that there should be little or no warning for eruptions such as this. However, the eruption is not caused by magma, but by steam, and this is much harder to track in our current monitoring systems.
Monitoring and warning for phreatic eruptions are very challenging. It is difficult to predict when they will occur. Most systems are already primed for explosive eruptions, but their triggers are poorly understood.
The warning period for such eruptions is in seconds to minutes. The potential for monitoring and anticipating these events lies in tracking vapour and liquid pressure in the system. Unfortunately, there are no simple rules to follow as each hydrothermal system is different.
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Learn about and revise different types of volcanoes and their characteristics and effects with GCSE Bitesize Geography (Eduqas).
Nov 7, 2019 · It is important to understand how volcanoes are formed, why eruptions occur, and the signs of an eruption. Scientists have been collected this information for centuries, and now in the present, we have the ability and the technology to identify when a volcano may erupt.
Level of Development in Iceland: Iceland is a developed country with a strong economy. It has advanced infrastructure, healthcare, education, and a high standard of living. Volcano Details: Eyjafjallajökull is a composite (stratovolcano) covered by an ice cap.
Jan 3, 2023 · White Island Volcano Case Study - find out about the causes, effects and responses to the White Island volcanic eruption in December 2019.
• A typical volcano has a crater, a vent and a magma chamber. • Dissolved gases drive an eruption. • Rock melts either through decompression or addition of volatiles. • Active volcanoes currently show signs of activity (seismic, gas emission, eruption). • Dormant volcanoes are currently not active but erupted in historic times (last ...
Many volcanoes are located under ice caps and can produce highly explosive eruptions when water interacts with magma, with plumes exceeding 12 km in height and fine-grained ash that can traverse great distances in the atmosphere.
The unloading of the summit of the volcano by the debris avalanche triggered the expansion of high temperature‐high pressure steam trapped in the cracks and voids in the volcano and the vesiculation of gases dissolved in the dacitic magma that had created the northward bulge noted earlier.
On May 18, a magnitude 5.1 earthquake occurred, and the volcano’s summit slid away in a huge landslide—the largest on Earth in recorded history. With the weight of the rock gone, the magma could explode like a shock wave out of the volcano. Rocks, ash, volcanic gas, and steam were blasted upward and outward to the north.
Roza refers to a flood basalt eruption in the northwestern United States. Graph from Rampino and others (1988). The pages in this section explore the following case studies for their impact on global climate. Impact of some major historic eruptions. Data from Rampino and Self, 1984.
Investigations carried out as part of the USGS Volcano Hazards Program provide case studies of monitoring two of the world's most active and best understood volcanoes, Mauna Loa and Kilauea on the "Big Island" of Hawaii. Since 1980, the USGS has expanded its monitoring studies to include other volcanoes in the United States and, in cooperation ...