Iceland Erupts; Volcanic Activity on the Reykjanes Peninsula

Saturday, 20th March 2021

Jo Coles

iceland fagradalsfjall eruption site 20mar2021 by rth sigurdsson

While the rest of the world is missing getting to visit and explore Iceland’s epic landscapes, nature has been building up to change that landscape once more!  

Location Background

The Reykjanes peninsula is an active volcanic system located in southwest Iceland. As with much of Iceland, there is only a sparse local population aside from the town of Reykjanesbaer, however the main international airport at Keflavik and the infamous Blue Lagoon are found here and it is just a short drive to the capital Reykjavik. The area boasts beautiful coastlines, dormant and active volcanoes, vast ancient lava fields, bubbling and steaming hot springs and geothermal areas, and traditional Icelandic stories. 

Map Credit: Icelandic Met Office – 

edu iceland erupts map

Recently, seismic activity has begun to increase along the ridge fault zones. The volcanic belt here is a continuation of the Mid-Atlantic Ridge, creating various areas of displacement and fissures alongside craters, ravines and faults. Hengill is the most famous of the volcanoes here, and received media attention in 2020 when activity increased. The peninsula is composed mostly of basaltic lavas from historic eruptions (please see our resource ‘Lavas of Iceland’ for a geology map). Iceland is famous for its geology and volcanic activity, having been created by rifting, as well as hotspot activity with upwelling of magma from the mantle that is then released as the plates separate. The peninsula itself originated some 6-7 million years ago during a ‘rift jump’ when the active rift had drifted away from the hotspot and then activity moved eastwards towards the mantle plume under Vatnajökull glacier. Volcanoes along the peninsular are both aerial and in places partially submarine, comprising an array of shield volcanoes, fissures and crater rows.

Timeline of activity

Since 24th February earthquake swarms of moderate intensity (including over 5M) have increased in the area, and at shallow depth. By 4th March the Icelandic Met Office, which gives warnings and information regarding hazards, placed a warning of larger earthquakes across the whole area and advised the public to avoid steep terrain and beware of rockfalls and unstable ground. Geoscientists and geologists were deployed to take gas measurements and assess indications of potential volcanic activity. The Civil Protection Department then declared an alert phase for the peninsula and you can find official guidance on earthquake preparedness here. 

From 5th March officials advised against all travel into the immediate vicinity (other than for scientists and emergency services), due to the risk of avalanches and rock falls, as well as unstable ground and potential for gas venting. On 11th March an ash-radar detection station was installed on a lava field at Strandarheiði to be used for monitoring atmospheric particles in the event of a future eruption, with the intention of using the information to model the path of ash flows and predict any spread that could lead to the necessity to cancel air traffic across Europe as in 2010. 

Powerful swarms such as these are known to occur in the area approximately every 25 years, however the most recent earthquake swarm was powerful enough to be felt across the island and it was predicted that these were due to magma movements towards the crust and that an effusive lava-producing eruption may occur close to Keilir. Analysis of data from InSAR (satellite-based radar) and modelling throughout the week of 14th March showed displacement and ground deformations were taking place, indicating a likelihood of magma intrusions with magma estimated to have reached one kilometre below the surface. The earthquake swarm registered over 34’000 events in a fortnight, more than was measured throughout the whole of 2020! Any eruption here would be the first for 800 years, and it was therefore considered ‘due’. 

Iceland Erupts!

In the middle of the evening on Friday 19th March, the eruption finally began! Interestingly, according to seismographs, earthquake activity actually lessened in the hours just preceding the eruption. The dyke intrusion finally broke the surface, and subsequent basalt lava flows were released. 

The volcano itself is in a closed valley called Geldingardalur (which literally means Valley of Castration!), at the foot of a large volcanic ridge called Fagradalsfjall, which translates to: ‘Fagra’ (beautiful), ‘dal’ (valley), fjall (mountain). The area had been dormant for nearly 800 years and there has been no eruption at the volcano itself for 14000 years! However, it is likely that activity could now be ‘jump started’ with potential volcanism in the region for the next thirty years (as occurred during the 1210-1240 eruption, with sporadic episodes). It is unknown how long the current eruption will last, until more remote sensing is possible to detect whether the magma reservoir has been exhausted or is being replenished. 

The eruption is effusive style, creating fire fountains that have, at times, reached 100m high, and with two main pahoehoe lava streams. There are live web cams (links below) that show the eruption is not currently creating a large lava flow, although activity can of course change. There is no eruption column cloud, and the lack of interaction with water means there is minimal ash production and explosivity. However, there are toxic gases, particularly SO2. Computer modelling and meteorological surveys have allowed authorities to warn residents downwind to keep windows and doors closed, and to avoid going outside. Currently the active fissure has reached 500m in length, with lava flows covering 1km2. 

Management of the area:

Iceland is extremely well organised with regards to volcanic activity, with specialist organisations and agencies involved in providing real time information to the public. Ahead of the eruption, airports were closed to reduce the risk of potential volcanic aerosols causing damage to aircraft, but they have currently reopened and you can witness the lava flows as your plane lands!

Popular blog posts

Over-tourism in Iceland – myths dispelled by the experts

Don't be put off Iceland. We'll tell you the facts about tourism in Iceland you need to know!

Friday, 10th November 2017

Destination Specialist

Ten volcanoes you can visit with Discover the World Education

What are your favourite volcanoes? We have picked ten very different volcanoes you can visit with us, from the Azores to New Zealand.

Thursday, 16th March 2017

Destination Specialist

10 Air Travel Tips For Effortless School Trips

We asked former teachers and current group tour leaders for their advice on how to make your journey as smooth as possible, from Departures to Arrivals.

Wednesday, 14th February 2018

Destination Specialist

Experience Iceland – Classroom Ideas

How to use our new GIS video map - GIS Iceland

Thursday, 25th April 2019

Jo Coles

Why You Should Visit West Iceland

A day or two in the West fits in nicely to a 5 day itinerary including the Golden Circle highlights so you don’t have to choose between them.

Tuesday, 13th November 2018

Destination Specialist