Icelandic volcanoes: A beginner's guide

Iceland is one of the most fascinating and geologically active places on Earth. Its dramatic landscapes, endless lava fields, black sand beaches, and towering volcanoes all tell a story written by fire and ice over millions of years. But why is Iceland so active geologically, and what makes its volcanoes so unique?

Why is Iceland so geologically active?

The secret to Iceland’s fiery nature lies beneath its surface. The country sits directly on the Mid-Atlantic Ridge, a massive underwater mountain range where two of the Earth's tectonic plates—the Eurasian Plate and the North American Plate—are slowly moving apart. As these plates drift away from each other, magma rises from deep within the Earth to fill the gap, creating new crust and triggering volcanic activity.

On top of this, Iceland is also located above a hotspot, an area where extra heat rises from deep within the Earth’s mantle. This hotspot intensifies the volcanic activity even further. The combination of the diverging plates and the hotspot is what makes Iceland one of the most volcanically active places in the world.

Today, Iceland has around 130 volcanoes, many of which are still considered active. On average, a volcanic eruption occurs somewhere in Iceland every 4 to 5 years.

What types of Volcanoes exist in Iceland?

Iceland's volcanic landscape is incredibly diverse. Here are some of the most common types of volcanoes found across the country:

Stratovolcanoes

These are tall, steep-sided volcanoes built by layers of lava and ash over thousands of years. Examples include Hekla, one of Iceland’s most famous and active volcanoes, often referred to in medieval times as the "Gateway to Hell."

Shield Volcanoes

These volcanoes are broad and gently sloped, formed by highly fluid lava that can travel long distances. Skjaldbreiður is a textbook example of a shield volcano in Iceland.

Fissure Volcanoes

Instead of erupting from a single crater, these volcanoes erupt along long cracks in the Earth’s surface. The Laki fissure is one of the most infamous examples, responsible for one of the largest eruptions in recorded history.

Subglacial Volcanoes

These volcanoes lie beneath Iceland’s vast glaciers. When they erupt, they can cause explosive interactions between lava and ice, leading to dangerous glacial floods known as jökulhlaups. Grímsvötn and Katla are two of Iceland’s most active subglacial volcanoes.

Caldera Volcanoes

These volcanoes feature large, bowl-shaped depressions formed when a volcano collapses after an eruption. Askja in the central highlands is a well-known example, with a beautiful crater lake at its center.

Notable volcanoes in Iceland

Some of the most iconic and historically significant volcanoes in Iceland include:

• Eyjafjallajökull – Gained worldwide fame in 2010 when its eruption disrupted air travel across Europe.

• Katla – One of the most powerful volcanoes in Iceland, located under the Mýrdalsjökull glacier. Known for its explosive history and potential to cause catastrophic floods.

• Hekla – Often called the "Queen of Icelandic Volcanoes," it has erupted more than 20 times since settlement.

• Grímsvötn – Iceland’s most frequently erupting volcano, also located beneath a glacier.

• Þríhnjúkagígur – Dormant for around 4,000 years, this volcano is unique because visitors can descend into its empty magma chamber—the only place in the world where this is possible.

  
  

Important eruptions in Icelandic history

Iceland’s volcanic history is filled with powerful eruptions that have shaped the country’s landscape, history, and even affected the world:

The Eldgjá Eruption (939 AD)

Considered the largest lava flow in the last two millennia, the Eldgjá fissure eruption spewed out more lava than any other eruption in Icelandic history. It likely impacted the climate and may have been recorded in medieval chronicles.

The Laki Eruption (1783-1784)

This was one of the most catastrophic volcanic events in human history. Over eight months, a 27-kilometer-long fissure opened, releasing around 15 cubic kilometers of lava. The eruption produced massive clouds of toxic gas, killing about 20% of Iceland’s population due to famine and disease. The resulting climate effects led to crop failures across Europe and even contributed to global cooling.

Eyjafjallajökull (2010)

While not the largest eruption, Eyjafjallajökull’s 2010 eruption gained international fame because of the ash cloud it produced, disrupting air travel across Europe for weeks. It served as a reminder of how Iceland’s volcanoes can have a global impact.

Askja (1875)

The explosive eruption of Askja covered much of East Iceland with volcanic ash, causing major damage to farmlands. This eruption triggered a wave of emigration, as many Icelanders left the country for North America due to the devastation.

The recent eruptions at Reykjanes Peninsula

After almost 800 years of dormancy, the Reykjanes Peninsula entered a new volcanic era in 2021. This southwestern corner of Iceland, located close to Reykjavík and Keflavík International Airport, is part of the Mid-Atlantic Ridge, where the Eurasian and North American plates meet.

Fagradalsfjall eruptions (2021–2022)

The eruption at Fagradalsfjall, which began on March 19, 2021, marked the first volcanic activity on the Reykjanes Peninsula in over 800 years. This event was particularly notable for its accessibility and relative safety. Located just a short drive from Reykjavík, the eruption quickly became a popular destination for both locals and tourists, offering a rare opportunity to witness lava flows in person.

This was a fissure eruption, characterized by lava emerging through cracks in the earth’s surface rather than from a central volcano. The lava was fluid and basaltic, flowing slowly across the landscape. There were no explosive events, and the eruption posed no immediate threat to infrastructure.

After several months of activity, the eruption paused in September 2021, only to briefly resume in August 2022. While relatively small in scale, the Fagradalsfjall eruption was significant for signaling the reawakening of the Reykjanes volcanic system.

Litli-Hrútur (2023) and Sundhnúkagígar (2023–2024)

The volcanic activity continued in July 2023 with a new eruption near Litli-Hrútur, followed by another fissure eruption in December 2023 at Sundhnúkagígar, northeast of the town of Grindavík. These eruptions confirmed that the Reykjanes Peninsula had entered an active volcanic phase.

Both eruptions shared common characteristics with the earlier Fagradalsfjall event: they were effusive, meaning they produced flowing lava rather than explosive ash clouds. They also created new lava fields across previously untouched terrain, contributing to the ongoing reshaping of the peninsula's landscape.

While these eruptions were closely monitored by scientists and emergency authorities, they did not immediately threaten populated areas. However, temporary road closures and localized gas pollution occasionally impacted nearby communities.

Grindavík and the 2024–2025 eruptions

Beginning in late 2023, the Sundhnúkur crater row near Grindavík became the focus of continued volcanic unrest. A series of eruptions in this area extended into 2024 and 2025, with the most recent outbreak occurring in April 2025. These eruptions are part of the Svartsengi volcanic system, which lies beneath and around the town of Grindavík and the nearby Blue Lagoon geothermal area.

Unlike earlier eruptions, this latest series of events has had more serious consequences. Repeated lava flows have posed risks to roads, pipelines, and buildings, and residents of Grindavík have faced multiple evacuations due to concerns over both lava flow and ground instability. Infrastructure has been damaged, and some lava flows have come dangerously close to residential zones.

These ongoing eruptions represent a shift in the nature of volcanic activity on the Reykjanes Peninsula—from relatively isolated lava flows in uninhabited areas to events that can have direct impacts on populated communities. As a result, the Icelandic Meteorological Office and civil protection authorities have heightened surveillance and response measures in the region.

Geologists now believe that the peninsula may be entering a new volcanic era, potentially marked by decades of intermittent eruptions. This pattern mirrors activity seen in other parts of Iceland’s geological history, such as in the 12th and 13th centuries.

What does this mean?

The recent eruptions are part of a volcanic cycle that could last for decades or even centuries, similar to what has happened in Iceland's past. Scientists believe that we may see frequent eruptions on the Reykjanes Peninsula in the coming years, reminding us that Iceland’s geological story is very much alive and still being written.

How volcanoes have shaped Iceland

The volcanic activity that created Iceland continues to shape its land, culture, and people. Every eruption changes the landscape, creating new lava fields, craters, and mountains. Volcanic eruptions have also deeply influenced Icelandic folklore and history, inspiring stories about trolls, elves, and the raw power of nature.

Today, volcanoes are an essential part of Iceland’s identity and economy. They fuel geothermal energy, attract millions of visitors every year, and serve as a reminder of our planet’s dynamic nature.

At Lava Show, we aim to make this geological story come alive—allowing visitors to safely experience the breathtaking sight of real, molten lava up close. In this section, Lava Academy, you’ll find more articles and educational content to help you dive deeper into volcanoes and geology.