Iceland, Reykjanes Peninsula

Fagradalsfjall, Iceland, Aviation Code Raised to Orange

Good afternoon!

A large earthquake swarm started at Fagradalsfjall late on 21 December 2021, 2-4 km NE of Geldingadalir, thought to be caused by a lateral dike intrusion.  Due to the increased seismic activity, the aviation code was raised to Orange yesterday, 22 December 2021.

Fig 1: Icelandic Met Office, IMO’s map of the swarm.  Source: IMO

The eruption at Fagradalsfjall had stalled on 18 September 2021, with no new lava flows to the time of writing.  Ground deformation indicated that magma was still flowing into the crust.

Fig 2: Ground deformation at Krýsuvík.  The red line denotes the start of the March 2021 eruption. Source: IMO

We have downloaded and plotted the earthquakes from 1 September 2021 to 23 September 2021 (source for raw data: IMO ). This includes the swarm which started near Mount Kelir in late September 2021, which may or may not have heralded the current reactivation of the dike.

Fig 3: Geoscatter plot of the swarms from 1 September 2021 to 23 December 2021 by the author.  Colour denotes age: red being the earliest and yellow the most recent. © Copyright remains with the author; all rights reserved, 2021.
Fig 4: Scatter plot of the swarms from 1 September 2021 to 23 December 2021 by the author.  Colour denotes age: red being the earliest, and yellow the most recent. © Copyright remains with the author; all rights reserved, 2021.

While it is considered likely that the activity will result in a renewed eruption, when and where is not certain.

Armchair Volcanologist

23 December 2021

© Copyright remains with the author; all rights reserved.

Sources included in the text.