An M5.1 earthquake woke residents across Southwest Iceland at 3.14 am last night, one of over 700 earthquakes that were registered on the Reykjanes peninsula between midnight and 8.00am this morning. Most of the seismic activity is occurring by Fagradalsfjall mountain, situated at the southern end of a magma intrusion that has formed between 1-2 kilometres (0.6-1.2 miles) under the earth’s surface. According to the Met Office, this morning’s seismic activity likely indicates the magma intrusion is growing, and an eruption in the area continues to be a possibility. Experts have stated that if an eruption occurs, it will most likely be relatively calm and not affect inhabited areas.
Eruption Increasingly Likely
The magma intrusion is in the shape of a horizontal corridor stretching some 7 kilometres (4.3 miles) between Fagradalsfjall and Keilir mountains. The corridor is around 2km (1.2mi) below the surface by Keilir but 1km (0.6mi) below the surface at Fagradalsfjall. The magma is also hotter by Fagradalsfjall, making it the more likely site for a possible eruption.
In an interview this afternoon, the IMO’s Natural Hazards Co-ordinator Kristín Jónsdóttir stated an eruption on the Reykjanes peninsula appeared more and more likely with each passing day. “There is pressure building up in this magma chamber. While this is going on, while we are seeing these transfers, that magma is clearly entering this corridor and these earthquakes are a reaction to that, we have to expect that there could be an eruption there.”
According to Kristín, it is difficult to predict exactly when an eruption would occur. “Possibly in the coming days but it’s difficult to say.”
The ongoing earthquake swarm on Reykjanes began two weeks ago. Today, the Icelandic Met Office reported that the total number of quakes in the swarm has surpassed 34,000, more than the total number of quakes measured in the same area in 2020. The average number of quakes in the area ranged between 1,000-3,000 in the years 2014-2019.