TAG: GS 1: GEOGRAPHY
THE CONTEXT: Iceland, one of the most volcanically active regions on Earth, experienced another volcanic eruption on May 29, 2024.
EXPLANATION:
- The eruption, which occurred in the southwest part of the country near the small fishing town of Grindavik and the popular geothermal Blue Lagoon spa, is part of a recent trend of increased volcanic activity.
- This event underscores Iceland’s unique geological characteristics that make it a hotbed for volcanic eruptions.
Recent Eruption
- The latest eruption took place at Sundhnuksgigar, located south of Iceland’s capital, Reykjavik.
- It marked the fifth volcanic event in the region since December of the previous year.
- The eruption led to the evacuation of residents in Grindavik and visitors at the Blue Lagoon spa, highlighting the immediate risks posed by such natural events.
- Historically, Iceland witnesses a volcanic eruption every four to five years.
- However, since 2021, the frequency has spiked to nearly one eruption per year, indicating a notable shift in volcanic activity patterns.
What Are Volcanoes?
- According to the US Geological Survey, volcanoes are openings or vents where lava, tephra (small rocks), and steam erupt onto the Earth’s surface.
- They can be found both on land and underwater.
- Volcanoes form when material significantly hotter than its surroundings erupts onto the Earth’s surface.
- This material can include liquid rock (magma when underground, lava when it reaches the surface), ash, and gases.
- Magma Rise Mechanisms:
- Tectonic Plate Movements:
- Magma can rise when tectonic plates move away from each other, creating space that magma fills.
- This process often leads to the formation of underwater volcanoes.
- Subduction Zones:
- When tectonic plates move towards each other, part of the Earth’s crust is forced deep into the interior, where it melts due to high heat and pressure, causing magma to rise.
- Hotspots:
- These are hot areas within the Earth’s mantle where magma is heated, becomes less dense, and rises to the surface.
- Types of Volcanoes
- Stratovolcanoes:
- Characterized by steep sides and a conical shape, stratovolcanoes are formed from highly viscous magma and have explosive eruptions due to the high gas content in the magma.
- Shield Volcanoes:
- These have a low profile, resembling a shield lying on the ground, and are built from low-viscosity magma that flows easily, leading to broad, gentle slopes.
- Volcanic Features:
- Various volcanic features can form from erupted magma, including cinder cones, lava domes, and volcanic rift zones, each shaped by the nature of the magma and the eruption processes.
- Stratovolcanoes:
- Tectonic Plate Movements:
Why Is Iceland So Volcanically Active?
- Iceland is situated on the Mid-Atlantic Ridge, the world’s longest mountain range, located in the North Atlantic Ocean.
- Here, the Eurasian and North American tectonic plates are diverging, moving apart by a few centimeters each year.
- This divergence creates volcanic rift zones, where the Earth’s crust is pulled apart and fractured.
- Magma from the mantle rises to fill these fractures, leading to frequent volcanic activity.
- In addition to its position on the Mid-Atlantic Ridge, Iceland sits over a geothermal hotspot.
- This hotspot enhances volcanic activity by providing an additional source of magma from deep within the Earth’s mantle.
