Quick Update on the Earthquake Swarm on the Reykjanes Peninsula

A large earthquake swarm started on the morning of 19 July at around 1:30 am at Fagradalsfjall on the Reykjanes Peninsula.  The largest earthquake had a magnitude of 5.1M.  At the time of writing, there had been 1,635 earthquakes in the last 48 hours recorded on IMO’s website (note that not all of these have been confirmed). IMO’s map and breakdown of the swarm are shown below:

Fig 1: Map of earthquakes in Iceland over the past 48 hours.  Source: IMO

Close up of the Reykjanes Peninsula:

Fig 2: Map of earthquakes in the Reykjanes Peninsula over the past 48 hours.  Source: IMO
< 1.0720
2.0 -3.0162
Fig 3: Breakdown of earthquakes by magnitude

This swarm is occurring on the east side of the swarms on the Reykjanes Peninsula which started late last year.  IMO have reported that these swarms (still ongoing) are associated with multiple magma intrusions.  The aviation code for the area is still green (IMO). IMO are in the process of evaluating the Fagradalsfjall swarm. 

The swarm at the Tjörnes Fracture Zone is still ongoing.

The eagle-eyed amongst you will note that there is some seismic activity at Katla.  Whether this will result in anything is anyone’s guess at the moment. 

We have not yet updated our earthquake data-set for the current swarm.  We will wait until IMO has had a chance to confirm more earthquakes

Update 24 July 2020

The swarm at Reykjanes is now less intense. In the meantime, Katla produced a shallow 3.0 M. IMO have remarked that earthquakes in the summer at Katla are not uncommon.

From memory, Katla was seismically active before the intense swarms started in August 2014 at Barðarbunga in the run up to the eruption at Holuhraun. This may have been a coincidence.

Fig 4: Map of earthquakes in Iceland over the past 48 hours.  Source: IMO

For further updates, please consult IMO.

The Armchair Volcanologist

21 July 2020

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Source and Further Reading

“An earthquake swarm in Fagradalsfjall”, 20.07.2020  https://en.vedur.is/about-imo/news/an-earthquake-swarm-in-fagradalsfjall