Volcanic Hazards Impacts and Responses - (Montserrat's Soufrière Hills Volcano Eruption - 1997) Flashcards
What type of plate boundary is Montserrat located on, and how does this relate to volcanic activity?
Montserrat lies above a destructive plate margin, where the North American plate is being forced under the Caribbean plate. This tectonic setting causes subduction, which leads to magma formation and volcanic eruptions.
🧠 Analysis: Subduction zones are known for intense volcanic activity, which is why Montserrat frequently experiences volcanic eruptions.
What types of volcanic hazards are associated with the Soufrière Hills volcano?
Nuées ardentes (pyroclastic flows)
Lava flows
Mudflows (lahars)
Pyroclastic and ash fallout
Gases and acid rain
Tephra (volcanic ash and fragments of rock)
🧠 Analysis: These hazards are typical of explosive eruptions at subduction zones, where high-pressure magma leads to violent releases of gas and pyroclastics.
How predictable were the volcanic events in Montserrat?
The volcanic events in Montserrat were partially predictable due to monitoring by the Montserrat Volcano Observatory. However, the eruption in 1997 was still sudden and caused significant damage.
🧠 Analysis: While predictions based on monitoring are improving, eruptions in areas like Montserrat can still be unexpected due to the complexities of volcanic activity and magma movement.
What was the magnitude and frequency of the eruptions in 1997?
The largest eruption in 1997 released about 4-5 million m³ of material over a 20-minute period.
Eruptions occurred frequently between June and September 1997, with pyroclastic flows covering several square kilometers.
🧠 Analysis: The magnitude of the eruption was massive, and its frequency over several months caused prolonged disruption and uncertainty.
What were the social consequences of the 1997 eruption?
19 deaths and 7 injuries.
Over 8000 of the 12,000 residents left the island. Many have not returned, leading to a population decline.
Fires destroyed key buildings, such as local government offices, the police headquarters, and petrol stations.
🧠 Analysis: The eruption caused significant loss of life, displacement, and disruption to normal social functions. The population decrease shows the lasting social impacts.
What were the economic impacts of the eruption on Montserrat?
Estimated loss of £1 billion due to destruction of homes and investments.
Over 20 villages and two-thirds of homes destroyed by pyroclastic flows.
Tourism suffered greatly, with businesses destroyed, but has since increased as tourists visit to see the volcano.
Key infrastructure such as schools, hospitals, the airport, and the port were destroyed.
🧠 Analysis: The eruption devastated Montserrat’s economy, particularly through the loss of homes, infrastructure, and tourism. However, tourism is now on the rise as people visit for volcano-related activities.
What environmental damage occurred due to the eruption of the Soufrière Hills volcano?
The capital city Plymouth was buried under 12 meters of mud and ash.
Vegetation and farmland were destroyed.
Volcanic ash improved soil fertility over time.
🧠 Analysis: While the volcanic material destroyed the capital and farmland, the ash may have long-term benefits for soil fertility, helping recovery in the future.
How did the political response to the eruption play out in Montserrat?
The UK government, as Montserrat is an overseas territory, provided £17 million in emergency aid.
Exclusion zone created in the south of the island where the volcano remains active.
Risk maps were created, and evacuation strategies were implemented.
🧠 Analysis: The political response involved immediate relief from the UK and ongoing support in the form of long-term reconstruction and disaster preparedness measures.
What were the immediate responses to the eruption in Montserrat?
Evacuation from the south to the safer northern regions of the island.
Shelters were set up to house evacuees.
Temporary infrastructure, such as roads and electricity supplies, was built.
Emergency services were deployed to search for survivors.
🧠 Analysis: Short-term responses focused on evacuation, providing shelter, and basic infrastructure to ensure safety and survival in the immediate aftermath.
What long-term recovery measures were implemented on Montserrat?
The UK government provided £41 million for the long-term development of the northern part of the island, including new docks, airport, and housing.
The Montserrat Volcano Observatory was set up to monitor volcanic activity and predict future eruptions.
🧠 Analysis: Long-term responses focused on rebuilding infrastructure and preparing for future volcanic risks, ensuring the island’s resilience against future eruptions.
What risk management strategies were used to reduce the impact of volcanic hazards on Montserrat?
Preparedness: Risk maps were created, and an exclusion zone was established to keep people out of high-risk areas.
Mitigation: Shelters and temporary infrastructure were set up immediately after the eruption.
Adaptation: Long-term rebuilding of the north of the island, with improved infrastructure.
🧠 Analysis: The response to the eruption involved both short-term and long-term strategies to protect the population and adapt to the new volcanic environment.
How did the nature of volcanic activity at Montserrat relate to the underlying tectonic processes?
Montserrat’s location above a destructive plate boundary caused intense volcanic activity. The subduction of the North American plate beneath the Caribbean plate generated the magma that led to the explosive eruptions in 1997.
🧠 Analysis: The volcanic hazards were a direct result of tectonic plate movements, and these eruptions are typical for regions located along subduction zones.
