Reykjanes from aeroplane arriving into Keflavik. Image – @astro_graph
I would normally be guiding in Iceland at this time of year for Rayburn Tours, but due to the Covid pandemic, I have been stuck at home. This has been particularly frustrating, as there has been a great deal of tectonic activity in the country in recent days, and I have had to follow events from afar.
After gathering relevant reports and resources from the internet and social media, I wanted to put them together in a blog entry – but how long should I wait? With some sort of new eruption a distinct possibility, it would have been neat to match the resources to a spectacular event, if it should happen. This could well be tomorrow, but it might not take place for another hundred years, so here is the information I have gathered about the current situation as it stands today.
Background to Recent Tectonic Activity
Reykjanes Peninsula – Image: wikipedia.org
The current activity is taking place (as we speak) in the Reykjanes Peninsula, in the south west of the country, 17 miles southwest of the capital city of Reykjavik. The centre of concern is quite close to the Keflavik airport, and is passed by virtually all incoming visitors as they travel from the airport to the capital city of Reykjavik on the west coast.
It is well-known that Iceland sits on the northern part of the Mid-Atlantic Ridge, a split in the seafloor that stretches down the length of the world, right to Antarctica. Here, lava erupts and cools to make new oceanic crust on either side of the rift. The North American tectonic plate sits to the west of the rift, with the Eurasian plate to the east, and they are pushed away from each other at roughly the same speed as your fingernails grow. Most of the Mid-Atlantic Ridge is underwater, but the Reykjanes Peninsula sits on the northern part of the ridge, so it’s gradually being pulled apart all the time.
Reykjanes Peninsula Relief (blue 0m to red 500m) – Image: GDM Pedersen
The last major eruption on the Reykjanes Peninsula happened eight centuries ago—not long after people first settled in Iceland. Since then, this picturesque area has been relatively quiet, but molten rock continues to churn below the surface.
There have been 4 periods of volcanic activity on Reykjanes Peninsula since Iceland was inhabited around 800AD. The map below shows these four main periods and the associated lava flows. The last eruption was in 1240 – which marked the end of a 450 year long eruption period.
Reykjavik Activity History. Image from @GisliOlafson
Shake murmurs from the recent activity were first detected in this region over a year ago, but the situation has intensified with more than 20,000 earthquakes being recorded since things began on 24th February. A magnitude 5.7 quake in February shook the region, and this week, the quakes were coming thick and fast. Twitter has been flooded with information about the new earthquake activity, reported literally as it was happening. Headlines like this have been common:
Some scientists believe that the thousands of quakes occurring in southwestern Iceland in recent days could signal the beginning of a new period of heightened geologic activity that may last 100 years. If this transpires, the Reykjanes Peninsula could be bathed in the glow of volcanic fires that ignite, disappear, and then reappear intermittently for an entire human lifetime.
Earthquakes in last 14 Days. Image – @Verdurstofan
Experts monitoring underground magma movements in the Reykjanes Peninsula, have recognised the type of activity that would be expected in the run-up to some form of surface activity. They believe the magma is running at a depth of around 2 km, and moving laterally and not yet finding a way to the surface. However, they have warned of a “possible volcanic eruption” taking place here in the very near future. But so far, nothing has happened. Scientists though are very aware that the current situation can change rather quickly if the magma manages to break its way upwards.
Image – @IcelandEditions
An interesting portrayal of the geology of the Reykjanes area can be found at:
Screenshot from above interactive site
Alternatively, to get an interesting view of the geology of the Reykjanes area, check out the following interactive 3D viewer:
Screenshot from above web site
Fargardasfjall – Centre of All The Action
On March 3rd, seismometers detected the movement of magma through the crust close to the peninsula’s Fagradalsfjall flat-topped mountain and the Krýsuvík-Trölladyngja volcanic system, a series of fissures streaking through the ground. Volcanologists and civil authorities began to suspect an eruption was on its way.
Fagradalsfjall and the surrounding area is considered to be the epicentre of the earthquake swarm that started on the 24th of February 2021. Thousands of earthquakes have been detected in the area during the last weeks, with the biggest measuring magnitude 5,7.
Fagradalsfjall is a tuff mountain (or moberg), the highest on Reykjanes peninsula at 385 metres. The mountain is believed to have been formed during the Ice Age and is a result of a volcanic eruption under a glacier. This small volcanic system hasn’t erupted in 6,000 years. On May 3rd, 1943, an American airplane crashed into Fagradalsfjall, resulting in 14 casualties and 1 survivor. Among the casualties was Frank Maxwell Andrews, a senior officer in the American army. Some sources indicate that he had been selected to be the commander of the invasion of Normandy. There is an interesting video on You Tube that tells this story in detail.
Initial tremors detected in Fagradalsfjall volcano developed into an intensive earthquake swarm that included a number of quakes in excess of magnitude 5.0. Every day from 2500 to 3000 or more earthquakes are being recorded, and at the time of writing, since February 24th, over 24000 earthquakes have been recorded here.. There is a massive inflation happening from Fagradalsfjall volcano and that is what is causing the earthquakes west and east of the dyke location between Fagradalsfjall mountain and Keilir mountain. Many of the earthquakes are happening close to the town of Grindavík. There have been heightened concerns about the effects of even larger earthquakes and also of a possible eruption from the nearby Krýsuvík volcanic system.
The Fargardasfjall area is shown in this panoramic view, but the screenshot doesn’t really do the image justice. Check out the fully interactive version at:
The map below offers information about the magnitude, depth, and time of each major earthquake in the area. Click on an icon to open up this data. Information is updated daily and comes from the Skjálftalísa website of Veðurstofa Islands (Icelandic MET office).
At the time of writing, the tremors signifying magma movement have died down. They could reappear, but they may not return. It is always possible that intrusions of magma like that beneath Fargardasfjall will get stuck, cool, solidify, and simply remain underground. The whole event may just slowly decline and then stop – but it could, of course, turn into something rather more dramatic. It is very much a matter of ‘wait and see.’
If you want to follow the unrest in the Reykjanes ridge fault zones, and perhaps watch a ‘live’ eruption, there are a number of ‘live cams’ available on line:
What Type of Volcanic Eruption Are We Talking About?
If magma eventually reaches the surface in this area, it is unlikely to form an explosion of lava and ash like the 2010 eruption of Eyjafjallajökull that caused so much disruption across all of Europe. It will more likely take the form of a fissure eruption, where lava emerges more slowly from cracks in the earth’s surface, with little explosive activity.
As explained in a recent tweet by @subglacial:
When seismic tremor indicates magma is moving, concern about an #eruption is understandable. But, eroded #volcanoes in East #Iceland show that over 80% of magma movements do NOT produce eruptions: they form dykes. Pro tip. Most of the spreading in Iceland occurs underground
The molten rock beneath the Reykjanes Peninsula is runny and not-too-gassy, and struggles to build up enough pressure as it rises to the surface to create big, ashy explosions. The relative lack of ice cover here also starves the magma of water, which in small amounts is vaporized so violently by molten rock that it triggers ash-producing blasts. There’s also no sign that an eruption in Reykjanes would involve the same volume of magma as the prolific outpourings of the Laki eruption between 1783 and 1784.
Consequences of a Volcanic Eruption in Reykjanes
Whatever happens, the outcome is not likely to be disastrous for Iceland. Fissure eruptions like this are often referred to as “tourist eruptions” as they are relatively safe and predictable. Unfortunately, due to the current travel situation, few visitors are able to get to Iceland right now to enjoy the experience – and give a welcome boost to the country’s tourist economy. However, this may just be the beginning of something far greater. Research has shown that when a new cycle of volcanism begins in Reykjanes, it doesn’t involve one eruption, but many. It appears that magma has been gathering at not one, but three different spots beneath two of the peninsula’s volcanic systems, and it is possible that recent activity could herald the start of another hundred years of intermittent volcanic fires along the southwestern peninsula of Iceland. If this does end up being a long-term event, tourism could ultimately benefit when travel restrictions are relaxed.
There may be some spectacular fountains of lava, the build up of small cones, and flows of lava from higher areas to lower ground. Although any lava flows near Mount Keilir are unlikely to reach populated areas, they could interrupt air traffic to and from Keflavík international airport, which is about 12 miles from the main area of seismic activity and is currently on orange alert. There are contingency plans in place to divert flights and passengers to the island’s other airports should lava flows disrupt traffic links to Keflavik.
Road damage this week at Grindavik
It is possible that lava flows might affect infrastructure by overrunning roads or knocking over a couple power lines. Magma could rise into an aquifer—or even into the Blue Lagoon tourist attraction, triggering explosive activity, but that is considered a very unlikely scenario.
The only settlement of any size that could experience problems is Grindavík, a town on the peninsula’s southern coast. It has certainly been recently shaken by the barrage of earthquakes, and could be imperiled if lava emerges close by.
There are certainly no internationally concerns about a fissure eruption in south west Iceland. There will be no super-emissions of ash and dust to disrupt air travel in Europe (and beyond) as was experienced in the 2010 eruption of Eyjafjallajökull.
How Will The Newsreaders Cope?
When Eyjafjallajökull erupted in 2010, newsreaders across the world struggled badly to get the name right. How will they fare should an eruption result from the present activity? If a new eruption does kick off—which seems pretty likely at this moment—the technical name for it would be Sundhnjúkagígaröð in Þráinsskjaldarhraun. How will they cope with that? Come back, Eyjafjallajökull, all is forgiven!
Correct pronunciation is given here:
How to Pronounce Icelandic Volcano: Þráinsskjaldarhraun
The eruption is likely to be close to Fagradalsfjall, and that’s enough for me! At least some of the name parts are easy to get your head around – Skjöldur is a shield, hraun means lava, and fjall means mountain. Well, it’s a start!
With a bit of luck, when I get chance to visit Iceland again, there will be some evidence of a new eruption to add to itineraries and show to students. Maybe some juicy dykes like the one below in an image from @subglacial (Dave McGarvie):
I will update things in following blogs depending on how situation develops.