Iceland’s Volcanic Fury: Exploring the Geology Behind the Recent Earthquakes and Impending Eruption

Thousands of earthquakes in Iceland’s Grindavík have sparked fears of an imminent volcanic eruption, but why is Iceland so volcanically active?

The picturesque fishing town of Grindavík in Iceland has been rattled by thousands of earthquakes in recent weeks, leading to evacuations and concerns about a possible volcanic eruption. While tourists visiting the nearby Blue Lagoon geothermal spa were undoubtedly alarmed, the resilient residents of Iceland have learned to coexist with their island’s volatile geology. This article will delve into the reasons behind Iceland’s volcanic activity, exploring the role of tectonic plates and the presence of a hotspot.

Life on the edge of two tectonic plates

Plate tectonic theory, which emerged in the 1960s, revealed that many volcanoes are located in zones where tectonic plates meet. Tectonic plates are massive sections of Earth’s outer layer that carry continents and oceans, constantly in motion like pieces of a jigsaw puzzle. Subduction zones, such as the Pacific’s Ring of Fire, where thinner oceanic plates sink into Earth’s mantle, are home to many of these volcanoes. These explosive stratovolcanoes, like Mount St. Helens, can erupt catastrophically due to their high gas content.

Another type of volcano forms where tectonic plates pull apart, leading to the volcanic activity witnessed near Grindavík. The mid-Atlantic ridge, which separates the Eurasian and North American plates, cuts through this part of Iceland. Visitors to Thingvellir National Park can walk between these two plates, witnessing the topographic scars of the rift and the recent earthquake swarm and ground deformation.

Radar satellite data from the Icelandic Meteorological Office has revealed that the area around Grindavík has sunk by about 3 feet over 10 days, with significant cracks appearing in streets and houses. This sinking and the movement of the GPS station indicate the underlying processes of mantle rising and melting, which ultimately lead to volcanic activity.

Sitting on a hotspot

In addition to the tectonic plate activity, Iceland is also situated over a mantle plume, similar to Hawaii. These large volcanoes in Iceland’s interior tend to erupt basalt lava, which flows easily due to its high temperature and low gas content. As a result, eruptions are generally not explosive, allowing tourists to safely observe lava flows in places like Hawaii and Iceland.

The exact cause of hot material rising at hotspots is still debated, but the prevailing theory suggests that plumes of super-heated rock originating at the core-mantle transition drive these phenomena. Hotspots serve as a mechanism for the Earth to release internal heat.

If an eruption occurs in Iceland, the basaltic lava will likely flow downhill peacefully until it reaches the sea. However, when lava at temperatures of 1,800 degrees Fahrenheit (about 1,000 Celsius) encounters water, it rapidly turns to steam, causing explosive reactions and scattering ash over a wide area.

A silver lining of Iceland’s volcanoes

Living in an active volcanic area presents unique advantages, particularly in terms of energy production. Iceland derives 30% of its electricity from geothermal sources, utilizing underground heat to drive turbines and generate power. This reliance on geothermal energy has helped make Iceland one of the cleanest economies on Earth.

The Svartsengi hydrothermal plant near Grindavík harnesses the underground heat to provide hot water for homes and generate 75 megawatts of electricity. By pumping water through wells drilled into the volcanic field, the plant produces steam for power generation and heat exchangers for direct heating. This plant’s wastewater, rich in dissolved silica, has given rise to the famous Blue Lagoon, a geothermal spa that has become one of Iceland’s top tourist attractions.


Iceland’s recent earthquake swarm and the potential for an imminent volcanic eruption highlight the country’s unique geological setting. The interplay of tectonic plates and the presence of a hotspot contribute to Iceland’s volcanic activity. While the threat of eruptions poses challenges, Iceland has harnessed its volcanic energy to become a global leader in geothermal power generation. As the residents of Grindavík brace for potential volcanic activity, they also appreciate the benefits that living on an active volcano brings to their daily lives.






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