VOLCANOES STIR AGAIN BENEATH ICELAND’S GLACIERS. WHAT IS HAPPENING UNDER VATNAJÖKULL AND MÝRDALSJÖKULL?
Iceland has once again been reminded of its volcanic nature. Over the past few days, seismologists have recorded earthquakes beneath two of the country’s enormous glaciers – Vatnajökull and Mýrdalsjökull. Beneath the first, Bárðarbunga was shaken by a magnitude 4.7 earthquake on Monday, while several earthquakes were recorded beneath the second over the weekend, inside the caldera of Katla. So far, however, there are no signs that an eruption is imminent.
A STRONG EARTHQUAKE BENEATH VATNAJÖKULL
The most significant event occurred on Monday, October 5. At 5:28 p.m. local time, Icelandic seismologists recorded a magnitude 4.7 earthquake in the Bárðarbunga area, approximately 7.4 kilometres southeast of its caldera.
The Icelandic Meteorological Office (Veðurstofa Íslands) says that earthquakes of similar magnitude occur regularly in the Bárðarbunga caldera. The last earthquake of the same magnitude was recorded on July 28. Several smaller aftershocks followed Monday’s earthquake, all with magnitudes below 2.
The most important point is this: seismologists are currently detecting no signs of volcanic unrest indicating that an eruption is developing.
Bárðarbunga is nevertheless a volcano that has shown in the past how dramatically the situation can develop following increased seismic activity.
IN 2014, SOMETHING FAR MORE DRAMATIC HAPPENED BENEATH THE GLACIER
Bárðarbunga became highly active in August 2014. Hundreds of earthquakes began occurring beneath the glacier as magma gradually forced its way through the Earth’s crust.
A roughly 49-kilometre-long magma intrusion developed, extending northeastward from the caldera. A series of eruptions followed in the Holuhraun area. The first brief eruption began on August 29, 2014, followed by a much larger eruption beginning on August 31. It continued until February 2015.
The events showed that earthquakes beneath a glacier do not necessarily mean that magma will reach the surface directly beneath the area where the earthquakes occur. Magma can travel considerable distances through the Earth’s crust and find a different route to the surface.
Bárðarbunga is therefore one of Iceland’s most fascinating places for studying the relationship between earthquakes, magma and glaciers.
THEN KATLA SPOKE UP
Several days earlier, seismologists had also recorded increased activity beneath Mýrdalsjökull, where the powerful Katla volcano lies beneath hundreds of metres of ice.
On Saturday evening, October 3, several earthquakes occurred within its caldera, with magnitudes around 3. The strongest, measuring magnitude 3.0, struck at 9:44 p.m. It was followed by several weaker tremors.
At around the same time, an increased presence of geothermal water was detected in the Múlakvísl river. According to Icelandic authorities, however, similar events have occurred several times during the summer. There are no signs of an imminent eruption this time either.
This is particularly important in the case of Katla. The volcano is highly active, and its last eruption that broke through the ice occurred in 1918. Since then, episodes of increased seismic activity have repeatedly occurred within its caldera without necessarily being followed by an eruption.
KATLA IS ALMOST ENTIRELY HIDDEN BENEATH THE GLACIER
Katla is not simply a volcano that happens to lie “under a glacier”. Its central volcano is actually located within Mýrdalsjökull.
The volcanic system is approximately 80 kilometres long. The central volcano rises to around 1,500 metres above sea level, while its caldera measures approximately 9 by 14 kilometres. It is filled with ice.
Katla is one of Iceland’s most active volcanic systems. At least 21 eruptions have been documented over roughly the past 1,100 years. Its eruptions are typically explosive and can trigger enormous floods of meltwater from the glacier, known as jökulhlaups.
It is precisely this combination of volcano and glacier that makes Katla one of Iceland’s most hazardous volcanoes..
SO WHAT IS HAPPENING BENEATH THE GLACIERS?
At first glance, the current events might look like the beginning of something major: two well-known volcanoes, two episodes of seismic activity and, in Katla’s case, changes in geothermal water.
The reality is more reassuring.
Earthquakes are a normal part of life for both volcanic systems. A magnitude 3 earthquake – or even a magnitude 4.7 earthquake – does not automatically mean that magma is rising toward the surface.
Scientists are primarily watching for a combination of signals: the number and characteristics of earthquakes, their depth and distribution, any deformation of the ground surface, changes in geothermal activity and, above all, so-called volcanic tremor – continuous ground vibrations that can be associated with the movement of magma or fluids inside a volcano.
It is precisely the combination of these indicators that would be far more significant than a single strong earthquake.
A GLACIER HIDING AN ENTIRE VOLCANIC WORLD
One of the most fascinating things about Iceland is that you often cannot see the volcano beneath your feet at all.
Beneath the white surface of Vatnajökull lies an extensive system of volcanoes, calderas, valleys and other geological structures. Bárðarbunga is just one of them.
And beneath Mýrdalsjökull lies Katla – a volcano whose eruptions can melt enormous amounts of ice in a short time and generate devastating flood waves.
The current earthquakes are therefore no reason for panic. But they are a reminder that beneath Iceland’s glaciers, a continuous geological process is taking place – one that is largely invisible from the surface.
That is precisely why Icelandic scientists monitor both areas around the clock.
CURRENT STATUS
Bárðarbunga: A magnitude 4.7 earthquake occurred on October 5. The Icelandic Meteorological Office says earthquakes of this size occur regularly within the caldera. There are currently no signs of volcanic unrest.
Katla: Several earthquakes of around magnitude 3 were recorded on October 3. Increased geothermal activity was also detected in the Múlakvísl river. Authorities currently see no signs of an imminent eruption here either.
In other words: the volcanoes have spoken, but there is currently no reason to say that they are waking up for an eruption.
Sources
Icelandic Meteorological Office (Veðurstofa Íslands) – current seismic activity in the Bárðarbunga area and information on the Bárðarbunga volcanic system.
Icelandic Meteorological Office (Veðurstofa Íslands) – information on the Katla volcanic system, its eruptions and its relationship with Mýrdalsjökull.
RÚV – report on earthquakes in the Katla caldera on October 3, 2026, and current geothermal activity in the Múlakvísl river.
RÚV – report on a magnitude 3.4 earthquake in the Vatnajökull area on October 4, 2026.
Icelandic Meteorological Office – historical documentation of the Bárðarbunga and Holuhraun eruptions of 2014–2015.
Icelandic Meteorological Office – monitoring of geothermal water and outflows in the Múlakvísl and Mýrdalsjökull area.
About the Author
Iceland has fascinated me for many years. Over the course of numerous journeys across the island, I have driven tens of thousands of kilometers, experienced storms that changed travel plans within minutes, and witnessed days when choosing the right route meant discovering places that most visitors never see. I documented many of these experiences in my documentary film Island in the North.
Through this website, I share practical travel advice, up-to-date information, and firsthand experiences from the field to help others explore Iceland more safely and gain a deeper understanding of its unique landscapes and ever-changing nature.
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