Where the lava flows: Volcano update from Iceland

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On 19 March 2021 a volcanic eruption started in the Geldingadalir valley at the Fagradalsfjall mountain on the Reykjanes peninsula, South-West Iceland. The volcano is situated approximately 30 km from the country’s capital city, Reykjavík. The main period of the eruption lasted from March to September 2021. A second eruption started on 3 August 2022 in Meradalir valley at the Northern end of the first eruption and lasted just over two weeks. In the most recent developments, a new fissure opened further North next to Litli-Hrútur on 10 July 2023 (ongoing at the time of writing) and keeps changing and transforming the landscape in surrounding areas as a result.

Meradalir Volcanic Eruption in Iceland, photo taken on July, 12 2023 by Fredrik Holm

Mapping an ongoing eruption poses a challenge: By the time a map has been produced, it already is out of date. Monitoring the dynamic activity therefore requires regular updates to understand how the eruption progresses. The following map can only provide a snapshot of the situation in the area. It shows the site of the Fagradalshraun named lava fields of the volcano with their original vent systems in their geographic context as they emerged during the active eruption period in 2021. Furthermore, this map now also includes the new eruption which started on 3 August 2022 in Meradalir at the northern end of the previous lava flows. The following map shows the first picture of the new and ongoing eruption and represents the lava flows as of 17 July 2022:

Map of the 2021-2023 Volcanic Eruptions and their lava flows at Fagradalsfjall/Iceland, updated July, 19th 2023
(click for larger version)

The main lava flows shown in this map are based on data collected and processed by the National Land Survey of Iceland, the Icelandic Institute of Natural History and the Institute of Earth Sciences. Lava mapping approaches are based on the recently published work by Pedersen et al., 2022.

What did this all look like in reality when the first episode of the eruption was in full swing in 2021? The following photograph was taken on April 14th, 2021, and shows how the eruption activity has changed from one vent system (with two active vents) in March to a total of six vent systems (with eight vents in total) along the main fissure of the eruption, marking one of the visibly most active phase of the eruption so far:

Geldingadalur Volcanic Eruption in Iceland, Overview photo taken on April, 14 2021
(click for larger version)

By mid-May, the picture had changed considerably. Four week after the above picture was taken, on 17 May 2021, all but one vent system had ceased activity. The eruption was now showing a geyser-style behaviour (see photo at the start of this page), erupting every few minutes up to a few hundred metres into the air and adding the highest volume of lava discharge to date with 12.4 cubic metres per second. By early June 54 million cubic metres of lava were released since the eruption had started.

Geldingadalur Volcanic Eruption in Iceland, Overview photo taken on May, 17 2021
(click for larger version)

Notes on the toponyms shown in the map above: Fagradalshraun (‘beautiful valley lava’) was decided as the name for the new lava fields that cover several of the valleys surrounding the eruption site. But several names have been making the rounds in the first months of the eruption, referring to the different geographic features in the area that are all marked in this map. Fagradalsfjall (‘Beautiful valley mountain’) is the name for the plateau to the west of the valley where the eruption started. The eruption itself started in Geldingadalir (‘Valleys of the geldings’). While in this latest map I use Geldingadalir as a toponym, I have made use of -dalur before, which is the singular form of the Icelandic word for valley which is also sometimes found in use (both in Icelandic and in English). Given the shape of the valley, this appears to make more sense geomorphologically (and in the Icelandic public you find both names used regularly). I eventually decided to change this in the map into -dalir since the register of placenames by the Icelandic Land Survey has this name listed as the sole name in their database (see Landmælingar Íslands – Örnefnasjá). The valleys to the east are called Meradalir (notice the plural again, literally ‘Valleys of the meres’). This is the area where where the lava flows first spilled over into, following the opening of the second vent system in early April. I also added Nátthagi, the valley where the lava now could flow into if the protection walls that are being built will not hold it back. This valley would then lead the lava flows towards the main road and would therefore affect some infrastructure should it continue to flow towards the south. More landscape features will be added shall they become relevant in the context of the eruption.

Geldingadalur Volcanic Eruption in Iceland, photo taken on May, 17 2021
(click for larger version)

The map on this website is updated as the eruption progresses and the lava flows keep changing. The following list gives an overview of all versions of this map that were published on this page (clicking the link opens the respective map in a new browser window). Each revision contains updated coverage of lava flows as well as additional adjustments as noted:

Meradalir Volcanic Eruption in Iceland, photo taken on August, 10 2022 by Scott Riddell

The content on this page has been created by Benjamin Hennig of the Spatial Analysis & Geovisualisation Research Group at the Faculty of Life and Environmental Sciences, University of Iceland using own field observations and data sources as referenced in the map. Please contact me for further details on the terms of use.