Return to Iceland—viewing lava from the 2021–23 eruptions
In July 2022, I visited Iceland for the first time with a group of geologists. On August 15, 19, and 20, I posted blogs about this visit. These posts can be found by date or by selecting “Iceland” under Categories. I’ll also refer to these posts below. I’ve now returned in winter with Jay, who wanted to celebrate his big birthday by traveling to where he could photograph the Aurora Borealis, also known as the Northern Lights. We are here for about three weeks, from February 25 to March 17.
Of course, there is plenty to interest two geologists in Iceland. In this post, I’ll describe our several days in the Reykjanes Peninsula, where we could see the lava flows from recent eruptions.
Plate tectonic setting
I encourage you to refer to my August 15 post about the plate tectonic setting: https://landscapes-revealed.net/standing-between-tectonic-plates-in-iceland/. I’ve included a figure from that post below.
The recent eruptions (2021–24) have been on the Reykjanes Volcanic Belt (RVB), located on the Rekjanes Peninsula near the capital city of Reykjavik and the international airport in Keflavik. Other abbreviations: RR=Reykjanes Ridge (the Mid-Atlantic Ridge segment south of Iceland); WVZ=West Volcanic Zone (where Þingviller National Park is located); EVZ=East Volcanic Zone; MIB=Mid-Iceland Belt (a volcanic zone that connects the WVZ and the EVZ); SISZ=South Iceland Seismic Zone (another connector between the WVZ and the EVZ); NVZ=North Volcanic Zone (where we will go later this week); TFZ=Tjörnes Fracture Zone (transform fault connecting the NVZ and the KR); KR=Kolbeinsey Ridge (the Mid-Atlantic Ridge segment north of Iceland); ÖVB=Öræfi Volcanic Belt (overlies a mantle hot spot today); and SVB=Snæfellsnes Volcanic Belt. For more information about the tectonic setting, see the link to my 2022 post above this figure, which is from: https://steemit.com/geology/@sooflauschig/geology-of-iceland-part-3-an-island-being-ripped-apart.
The eruptions in 2021 heralded a new period of activity in the RVB. Evidence indicates long periods of dormancy interrupted by periods of high activity. Before 2021, it had been about 800 years since the last active period, and it seems that we are in another active period that is likely to continue for years—although how many years it will continue is unknown.
The Fagradelsfjall eruption in 2021–23
The 2021 eruption was the first in the Reykjanes Peninsula Belt (RPB) for ~800 years. The eruption started on March 19, three weeks after an intense earthquake episode that started with a magnitude 5.7 earthquake and continued with thousands more, smaller-magnitude earthquakes, all indicating magma on the move and culminating in an eruption that lasted for five months, until September 18. “Visit Iceland” has a good web site with information about that eruption: https://www.visiticeland.com/article/fagradalsfjall-eruption.
When I visited in July 2022, we were able to visit the southern terminus of the 2021 flow: https://landscapes-revealed.net/volcanoes-galore-in-iceland/. Two weeks after I left Iceland, the 2022 eruption began; this one only lasted a few weeks, from August 3–11. The following year, Fagradelsfjall erupted again, this time for about a month, from July 10 to August 5, 2023. The map below shows the area of lava that flowed during each of these three eruptions.
The colored boxes show the distance and timing of hikes visitors can take to view these lava fields. Jay and I completed the hike in red that goes along the ridge west of the flows. We did not have time to reach the northern end and see the 2022 and 2023 flows, but we had good views of the 2021 flow and its eruptive center—see my photos below.
Well, sure enough, this part of the Reykjanes Volcanic Belt erupted again in 2024, but at a more westerly location. We were able to see the 2024 flows, which I’ll describe in my next post.