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expert reaction to Fagradalsfjall volcano eruption concerns

Scientists react to the Fagradalsfjall volcano eruption in Iceland. 


Dr Matt Genge, Senior Lecturer in Earth and Planetary Science, Imperial College London, said:

“The situation in Grindavik is dangerous. The dyke is a magma filled fracture and allows the magma to move in the crust. The tremors are caused by this fracturing and allow seismologists to trace the movement of the magma. This one is long and contains a substantial volume of magma. Ground movement caused by magma in the dyke is causing fissures to open at the surface within Grindavik, and they have a high heat flow. Eruption could occur with little notice.

“Most likely an eruption would consist of lava flows and fire fountains. It is possible it could become more explosive with the production of ash. Furthermore, contact with surface water could cause explosive behaviour. Mostly these types of eruption are hazardous in the local area.”


Professor Saskia Goes, Professor of Geophysics, Imperial College London, said:

“The eruption is likely to be an “effusive” eruption, i.e. one that creates lava flows, similar to the eruption that occurred on La Palma last year. The lava would likely cover an area around the eruption site. The lava itself is dangerous (because so hot), but usually moves slow enough that people can get out of the way and properties can be evacuated. Together with the lava, there may be some fire fountains (of hot rock fragments and gas), and as Michele already said some the gases released may be quite toxic (and hot), which is another reason to evacuate people and life stock.

“A dike is a more or less vertical linear magma body that forms when magma infiltrates into the crust, for example along a fault.  Dikes are essentially magma feeder structures (they are the pathways that form to allow magma to travel from deep in the Earth towards the surface). Small earthquakes happen around it because as the magma pushes through the crust it creates stress and this stress is partially released in earthquakes. Earthquakes often surround migrating magma and are thus used as a common hazard assessment method to track magma flowing through the subsurface. For example, if the magma starts to move faster than the earthquake activity often also intensifies.”


Dr Michele Paulatto, NERC Independent Research Fellow, Department of Earth Science & Engineering, Imperial College London, said:

“The eruption, if it happens, is very likely to be effusive. It would involve possibly lava fountains from one or more craters and fast flowing rivers of lava, quickly forming one or more lava ponds in low lying areas. If the eruption happens under water, or if the lava flows reach the sea then it can turn explosive.

“Past examples of these two possible scenarios are the eruption at nearby Fagradalsfjall in 2021 and 2022 (effusive lava fountains and flows) and the 1963 Surtsey eruption (explosive eruption involving lava and water). An effusive eruption is more likely since the strongest volcanic activity is on land and only part of the dyke extends under the sea.

“The eruption is likely to be bigger than the 2021 and 2022 Fagradalsfjall eruptions. This estimate is based on the extent of the seismic activity and ground deformation. Both are more intense than in those previous eruptions. “


Dr Phil Colins, Dean and Reader in Geology & Geotechnical Engineering at Brunel University London, said:  

“The potential eruption at Fagradalsfjall is the latest in a recent series of volcanic events affecting the Reykjanes Peninsula. Other recent eruptions took place in 2021, 2022 and earlier this year. In general, these occurred in less populated areas than the area now under threat. Before these, the last eruptions in the area were several hundred years ago. 

“It’s currently unclear how large a potential eruption might be, though the characteristics of the intense earthquake swarm that has been affecting the area suggest that the total volume of magma is much larger than in 2021 or 2022. This does raise the concern of more widespread impacts, such as occurred in 2010 as a result of the Eyjafjallajökull eruption. During that, enormous volumes of fine ash were ejected into the atmosphere. This drifted with the wind across much of western Europe causing significant disruption to air transport. Part of the reason was the location of part of the Eyjafjallajökull eruption under a glacier. This supplied water to the erupting magma, generating steam and leading to the creation of fine particles. 

“While a potential Fagradalsfjall eruption would emit some fine particles, it might not be as substantial as during the Eyjafjallajökull eruption due to the lack of a glacier on top of the eruption. However, there may be a substantial release of volcanic gases such as sulphur dioxide which reacts with water in the ground and atmosphere to create tiny droplets of sulphuric acid, and fluorine. This may cause a significant health hazard to people in the region. A large Icelandic eruption at Laki in 1783 released enough toxic gas to kill large numbers of livestock on Iceland, leading to a famine. The gas spread across northern Europe, including the British Isles, leading to changes in weather patterns and a significant number of deaths from lung problems. There were knock-on effects elsewhere in the northern hemisphere. 

“At present, it doesn’t look like a Laki-scale disaster is likely, but there will be local and regional effects. Significant numbers of people have already been evacuated from the town of Grindavik, where cracks have opened up on the surface indicating the magma has reached a shallow depth. If the eruption does occur, there may be significant lava flows which could destroy peoples’ homes and other infrastructure, as well as block valleys and change surface drainage. Gas and dust emissions may also disrupt air travel to and from Iceland, leading to further economic damage. 

“While an eruption will pose problems for the Icelandic people, they are also very well prepared and have lots of experience in dealing with eruptions.”


John Smellie, Professor (Volcanologist), School of Geography, Geology and the Environment, University of Leicester, said:

“Regarding the 2010 Eyjafjallajökull eruption: initial information suggests that there are no real similarities apart from with the first eruptive phase on Eyafjallajokull, when the magma erupted onto essentially ice-free land and formed scoria (cinders) cones and lavas. Very tourist friendly – spectacular but safe (at that initial stage; i.e. red hot lava streams and lava fountains). The main Eyafjallajokull eruption was under c. 200 m of ice and highly explosive due to melting of the ice, probably not at all like this new one given the lack of ice at the new eruptive site.

“Possible disruptions to aviation are possible but unlikely. However, if water gets into the vent, it might become more highly explosive and the resulting ash will impact on flights, but probably not for long as the water supply shall probably be exhausted relatively quickly.

“The effect on local populations/tourism is likely very limited unless any lavas flow into houses or across any roads. The potential scale/size is probably very small, i.e. a few football fields, but the likely duration of the eruption is not known at this stage and a greater area might ultimately get covered by lavas and scoria.

“The production of toxic fumes is likely and one of the few possible impacts on people, but probably very localised (downwind). The fumes can also cause fluorosis (ultimately death) in grazing animals from fluorine leached out of any fine ash particles being incorporated in grass.”


Dr Margaret Hartley, Lecturer in Earth Sciences at The University of Manchester, said:

“The earthquake activity at Fagradalsfjall over the weekend indicates that a new phase of magma intrusion is occurring. The seismic swarms have decreased in intensity since the peak on Friday evening, although hundreds of earthquakes are still being detected. The three previous eruptions at Fagradalsfjall in 2021, 2022 and 2023 were all preceded by decreases in seismic activity, so this isn’t necessarily an indication that the volcanic unrest is dying down. Scientists at the Icelandic Meterological Office consider that the chance of a volcanic eruption is still very high. 

“The magma is located in a 15 km-long dike at about 2-5 km underground. The magma build-up is concentrated about 3.5 km northeast of Grindavik, so the town has been evacuated as a precaution. The Blue Lagoon tourist attraction and a major geothermal power plant also lie above the dike path. These areas are being closely monitored in real-time for any indications that magma may be moving towards the surface. However, it is extremely challenging to forecast when and where an eruption may begin. The level of disruption to lives, infrastructure and tourism all depends on where the magma breaks the surface, and the size and style of the eruption. 

“If an eruption begins, it is likely to be similar to the eruptions of 2021, 2022 and 2023: fairly gentle explosions, with fire fountains feeding lava flows. The possible exception is if the eruption occurs at the southern tip of the dike, which is located offshore. A submarine eruption could generate ash clouds with potential to affect air traffic at Keflavik interational airport – but we are unlikely to experience aviation disruption on the scale of the 2010 Eyjafjallajokull ash cloud events.”


Dr Marc K. Reichow, Associate Professor in Igneous and Metamorphic Geochemistry, School of Geography, Geology and the Environment, University of Leicester, said:

Are there similarities/differences to the 2010 Eyjafjallajökull eruption?

“Volcanism on Iceland is mostly similar in composition, but eruption style can vary. We don’t know the composition yet, so we have to base it on volcanism occurring the area previously. The 2010 eruption was more explosive as magma got in contact with the overlying ice. This is unlikely to happen this time as there is no substantial amount of ice in the area where an eruption is expected to occur. My short answer is therefore no.


Have you have noticed anything misleading/inaccurate in the news so far?

“Yes – videos including those used by the BBC are showing the 2021 Fagradalsfjall which is several km to the east of the current location and cone shaped so could have developed into a shield volcano. The current site is a 15 km long rift so most likely to erupt as a fountain. Another mis information: Quote: “The volcano will release more CO2 than human activity all together.”  This is not only grammatically but also factually incorrect. CO2 release annually account to only 3%!  So the anthropogenic output is still far more significant. I saw posts with millions of views and people commenting on this.


Could there be possible disruptions to aviation?

“Difficult to say, the airport is nearby so disruption could be caused by erupted material obstructing flight paths. Although this may have only a local effect but flights from and to Iceland could be disrupted. Earthquake and tectonic movement can cause damage, as already observed on a golf course, and damage the airfield making landing and taking off dangerous or impossible.  


What is the possible effect on local populations/tourism?

“After or during the 2021 Fagradalsfjall people went to Iceland so tourism saw a huge increase and is still attracting interest. Depending whether this eruption will take place the proximity to local residences could be dangerous and cause damage to buildings (similar to what happened on La Palmas). The area has been evacuated and hazard to life is currently minimal.


What is the potential scale/size?

“Difficult to say.


Is there a possibility of toxic fumes?

“Judging by the magma erupted in the area we can expect CO2, CO, SO2 and smaller amounts of HF and Cl. Mostly SO2 will be dangerous. Las Palmas has areas where people still cannot return because of the continued release of fumes from the cooling lavas. This could potentially go on for years.”


Dr Dave McGarvie, Volcanologist, Honorary Researcher, University of Lancaster, said:

“The first point to note is that this is not the Fagradalsfjall volcano. Icelanders consider it to be an adjacent volcano (Reykjanes) which is showing unrest, and which currently has an Orange aviation colour code. See

The rapidity with which this new unrest developed has surprised me and many others. I do not think that the very sudden appearance of a c.15 km long underground wall of magma (a dike/dyke) was anticipated, and I cannot recall of a similar event in Iceland in modern times.


“There are two key points on the recent unrest timeline.


“This first is that from around 25 October, Icelandic scientists started monitoring a new area of unrest (near to a small mountain called Thorbjörn) in which magma had started accumulating c.5 km underground. This unrest was gently developing, but causing concern because of the potential for an eruption that could damage the important geothermal power plant of Svartstengi upon which c.30,000 people across the Reykjanes Peninsula rely for electricity and hot water for space heating. This was an aspect of particular concern given that the coldest months are approaching. There was also concern that lavas produced by an eruption could move towards the fishing town of Grindavík (around 2 km away) and destroy homes and so on.


“The second is that on 10 November a new area of unrest suddenly appeared to the east. A major release of seismic energy heralded the appearance of a 15 km long vertical intrusion of magma (a dyke/dike) that is now causing great concern, and that led to the evacuation of the fishing town of Grindavík. The text below focuses on this second area of unrest.


Are there similarities/differences to the 2010 Eyjafjallajökull eruption?

“A potential future eruption arising from the current unrest will not lead to disruption like that of the Eyjafjallajökull 2010 eruption, for the following reasons:

  • The Eyjafjallajökull 2010 eruption was unusually disruptive because of a rare (if not unique) combination of factors. Things have changed, lessons have been learned. Consequently, should an identical eruption to that of the Eyjafjallajökull eruption of 2010 occur in future, there would only be about one-third of the flight cancellations compared to what occurred in 2010. Part of this is due to flight rules having changed, and part of this is due to a greater understanding of ash production and transport mechanisms.
  • Eruptions on the Reykjanes Peninsula are dominated by basalt lava production with only minor ash production, whereas the Eyjafjallajökull 2010 eruption was dominated by ash production.
  • The chemistry of the magma that erupts has a huge effect on ash production, and the basalt eruptions that typify volcanic activity on the Reykjanes Peninsula do not produce much ash. Consequently, the volcanoes on the Reykjanes Peninsula do not have the ability to produce the disruptive ash clouds that characterised the Eyjafjallajökull 2010 eruption.


Could there be possible disruptions to aviation?

  • “It is extremely unlikely that an eruption arising from the current unrest will cause disruption to transatlantic air travel.
  • “If the current unrest leads to an eruption on land, then there is likely to be only local and short-term disruption caused by minor ash production, which was the case during the three smallish eruptions from the Fagradalsfjall volcano in 2021, 2022, and 2023. If the potential eruption is much larger and more powerful, then this could produce more ash, but again this is likely to cause only local disruptions, and the degree of disruption would depend largely on wind direction. The international airport of Keflavík lies around 17 km northwest of the area of unrest, and as prevailing winds generally have a westerly component, prevailing winds will carry ash away from Keflavík. Of course, any winds from the southeast would carry ash towards Keflavík. The domestic airport at Reykjavík lies about 44 km to the northeast and is very unlikely to experience any disruption from ash.


What is the possible effect on local populations/tourism?

It is well known that the town of Grindavík, with a population of around 3,300, has been evacuated. This is because of the proximity of the 15 km long vertical intrusion of magma (a dyke/dike) that lies underground and that lies beneath the western part of Grindavík. There have also been numerous cracks and collapses in the area, some of which have led to road closures. The evacuation of Icelanders – either during periods of unrest or during eruptions/floods – does not happen often, so this is a major disruption. The last evacuation of entire sizeable settlement in Iceland occurred 50 years ago during the 1973 eruption on the island of Heimaey off the south coast of Iceland. The displaced people of Grindavík will be understandably anxious because there is considerable uncertainty over the future of their town. Until the current unrest reveals its final outcome(s) this uncertainty will prevail.


What could lead to significant ash production?

“There are two main scenarios in which ash production could be higher that ‘normal’ from a basalt eruption at Reykjanes. The first involves uprising basalt magma encountering geothermal and/or groundwater (e.g. in an aquifer), because at depth there would be steam explosions that would fragment crustal rocks as well as basalt magma. These explosions would typically be short lived, and could produce a feature that we call a maar or explosion crater: there are several older ones on the peninsula. The second involves a submarine eruption, where again there are steam explosions that fragment erupting basalt. These eruptions usually produce ‘wet’ ash that does not travel far. The 1963-1967 eruption of the island of Surtsey typifies such eruptions. Rare and powerful eruptions through water may have inner ‘cores’ that can bypass any contact with water and spread more ash around (e.g. the Grímsvötn eruption of 2011). It is not anticipated that a Reykjanes eruption could be so powerful. As the southwestern extremity of the 15 km long dike lies under the ocean, a submarine eruption is a more likely possibility than the geothermal/groundwater mechanism described above.


What is the best-case scenario?

“It is known from past eruptive episodes in Iceland (e.g. Krafla Fires, 1975-1984) that not all dikes breach the surface to form eruptions, and that only minority do so – perhaps one in every three or four. The best-case scenario is that this happens to the 15 km long dike that has just formed, and that it simply cools and solidifies – and does not erupt.


Concluding comment

“The Icelandic scientists who are directly involved in monitoring unrest, along with authorities such as the Police and the Department of Civil Protection and Emergency Management, have an excellent track record of dealing with earthquakes, floods, and eruptions, and they get frequent practice due to (for example) volcanic eruptions in Iceland occurring every 3-5 years on average. The most accurate and up-to-date information on this developing unrest will be provided by them, though of course they are understandably very focused right now. Here is a key link to this information, and note that the news articles provide helpful summaries


Mike Burton, Professor of Volcanology, Department of Earth and Environmental Sciences, University of Manchester, said:

Are there similarities/differences to the 2010 Eyjafjallajökull eruption?

“The common theme to most Icelandic volcanism is ascent of buoyant magma from a melting zone in the mantle, driven by a thin crust causing low pressure-driven melting and a hot mantle plume. This creates magma which ascends into the shallow crust. Most such intrusions do not reach the surface, and the crust under Iceland must be full of stagnant magma bodies. At the start of the 2010 eruption there was an eruption of recently intruded magma before the major eruption which caused all the airline disruption. That larger eruption was fed by an older magma reservoir which was reactivated by the intrusion of fresh magma. In the areas where the intrusion is happening now in the Reykjanes peninsula its unlikely that there is a major older reservoir, so while the initial process of fresh magma intrusion  is the same now as in 2010, the outcome is likely to be much more like the eruptions of 2014/15 of Holuhraun and 2021/22/23 in Fagradalsfjall The deformation associated with this current intrusion is much larger than the 2021/22/23 eruptions though, and more similar to Holuhraun, which lasted for longer and erupted more lava.

We are though in a critical point where the uncertainty is high, while its likely there will be an eruption its not a certainty, and things could calm down to background levels with nothing happening. Its not clear where and at what rate any lava would erupt. We have to wait and see. We have very good systems for detecting intrusions using geophysical observations of deformation and earthquakes, and the Iceland Meteorological office and University of Iceland has lots of experts with huge experience on volcano monitoring with such methods but these only tell part of the story, the detail of what is happening is hidden from us. I wrote a couple of relevant tweets about earthquake around intrusions If an eruption did start, we could then use other approaches like gas measurements and geochemical analysis of the lava to better forecast the evolution of the eruption. We recently saw in the 2021 eruption of La Palma, Canary Islands, clear signs of declining gas emission rates which allowed a forecast of the end of that eruption. Our knowledge and understanding of eruption is improving all the time, but still key details elude us.”


Have you have noticed anything misleading/inaccurate in the news so far?

“A lot of people are saying an eruption has started and show video of the previous Fagradalsfjall eruptions, but this is not true. So far there has been no eruption from this intrusion. There was an eruption just a few months ago in July 2023, but this was small.”


Could there be possible disruptions to aviation?

“Unlikely unless there is a submarine eruption, in which case interaction with water will cause more explosive and ash-rich plumes, but these will be probably low altitude and only affect the local airport of Keflavik, which is 30 km from Grindavík where the deformation is observed. Even then any impact is likely to be minor and only when the wind is in a narrow range of directions.”


What is the possible effect on local populations/tourism?

“There has been an evacuation of 3000+ plus people from Grindavík. This is a huge impact for the people involved and itself can produce a major damage on livelihood and families, with the uncertainty on what will happen and how long the evacuation will be in place. Its necessary because if a lava flow started it could cut off the town, which is on the coast, or even run into the town itself. There is an exclusion zone now in place so tourists cannot go there. Previous eruptions have been tourist hotspots but as this is near a populated area the situation is completely different. There will be much stricter control on access in case of eruption.”


What is the potential scale/size?

“Likely between Fagradalsfjall and Holuhraun eruptions, weeks/months of effusion. But again, while eruption is likely it’s not a certainty.”


Is there a possibility of toxic fumes?

“If there is an eruption there will be a lot of acid gases and liquid droplets, and if there is a submarine eruption or lava flowing into the sea there will be a further source of toxic gases as sea water contains dissolved salt, which is converted into hydrochloric acid fumes during interaction with lava. So, it will be very unpleasant to be close by, and drifting clouds of these gases could affect people further away too. The Iceland Met office is expert in monitoring and forecasting these events and will provide recommendations to stay indoors if necessary.”


Dr David Neave, Senior Lecturer and NERC Independent Research Fellow at The University of Manchester, said:

“As ever with these things, the most important thing to stress is that the most up-to-date information can be sourced from the Icelandic Met Office  and Icelandic Civil Defence:


Are there similarities/differences to the 2010 Eyjafjallajökull eruption?

“The current magma injections is mostly beneath land but also extends offshore. If it breaks to the surface on land the eruption would most likely be like the fairly low intensity eruptions Fagradalsfjall in 2021, 2022 and earlier this year. If it occurs offshore, the 1963 eruption of Surtsey of the south coast of Iceland, which produced lots of ash from water-magma interaction is probably a better analogue as the 2010 Eyjafjallajökull eruption erupted under ice rather than water.”


Have you noticed anything misleading/inaccurate in the news so far?

“Not so much, apart from the proportion of articles describing recent eruptions that imply an eruption has already started, which it hasn’t.”


Could there be possible disruptions to aviation?

“Grindavik is very close to Keflavik international airport, which is by far the largest airport in Iceland, with considerable transatlantic traffic. If there is an eruption on land, the Icelandic aviation authorities may be able to work around it as they have done during recent eruptions at Fagradalsfjall. The situation may be very different if the eruption occurs offshore and generates a lot of ash. That said, we know a lot more about ash-aircraft interactions than we did in 2010, which will help to improve safety and minimise disruption.”


What is the possible effect on local populations/tourism?

“Perhaps the biggest concern is whether any possible eruption affects Grindavik, a town and significant fishing port of a few thousand people, which is why evacuations have been ordered. Risks to the Svartsengi geothermal plant which supplies electricity and hot water to the surrounding area are also considerable. Moreover, the activity is very close to where the famous Blue Lagoon spa is located, which is currently closed. This will have considerable knock-on effects on tourism in the area, though the vast majority of Iceland’s tourist sites are well away from the current activity. The biggest potential effects are likely to be felt though any closure of airspace or by the inability to access Keflavik airport from Reykjavik, Iceland’s largest city.”


What is the potential scale/size?

“Very hard to say at the moment, though the Icelandic Met Office report that the magma injections are larger than those recorded previously, which may mean a larger eruption than the recent eruptions at Fagradalsfjall that were actually quite small by Icelandic standards. On the other hand, it is still possible that the magma may stall where it is and not erupt at all.”


Is there a possibility of toxic fumes?

“All volcanic eruption emit hazardous gases, with sulfur, fluorine and chlorine being of particular concern. The Icelandic authorities have considerable experience in monitoring the emission and dispersal of these gases to protect public health. The approach may however need rethinking if there is an offshore eruption that produces a lot of ash, which presents a major respiratory hazard. Up-to-date info will always be provided by the Icelandic Met Office:


David Pyle, volcanologist and Professor of Earth Sciences at the University of Oxford, said:

“Events in the Reykjanes Peninsula, Iceland, developed rapidly over the weekend. Scientists monitoring the locations of earthquakes and measuring signs of ground movement determined on Friday that a large intrusion of magma has formed a dike (or ‘magma tunnel’ as some reports describe it). It stretches for about 15 kilometres in length, and lies at about 3-5 kilometres underground. This dike extends directly underneath the town of Grindavik. Over the weekend, the numbers of earthquakes fell, but the ground deformation continued. The scientists at the Icelandic Met Office consider it likely that magma is rising closer to the surface, and that there is a substantial chance of an eruption.

“At the moment it isn’t possible to determine when or where along the 15 km length of the dike an eruption might start; and this is why the town has been evacuated.

“If there is an eruption, it is likely to follow the pattern of the eruptions of 2021 – 2023 at nearby Fagradalsfjall volcano with lava flows and  ‘fire fountaining’ if the eruption begins onland. This will pose a threat to local infrastructure, depending on how far the lava flows. If an eruption begins within the town of Grindavik, the effects could be similar to those of the eruption of Eldfell on Heimay in 1973, which buried part of a town.

“There is also a chance that the eruption may start at the southern end of the dike, which extends offshore and under the sea. If there is a ‘submarine’ eruption, this could generate ash clouds, and may release noxious gases from the boiling of sea water. This is unlikely to have effects as widespread as those of the 2010 Eyjafjallajökull eruption – but even a small submarine eruption would be challenging for the authorities to manage, due to the possibility of small-scale explosions, and local ash fallout.

“The IMO team in Iceland has some of the most advanced volcano monitoring capacity in the world, and their experience from the recent eruptions at Fagradalsfjall and Holuhraun (2014) means that they are well prepared to detect the final stages of build up to any eruption, and to manage the consequences of any eruption.”


Bill McGuire, Professor Emeritus of Geophysical & Climate Hazards, UCL, said:

“Earthquake activity has died down a little overnight, but an eruption in the next few days is still highly likely. Modelling suggests that magma is rising along a 15km-long fracture and is now as close to the surface as 800m or even less.

“Where the eruption will start along the fracture is not known. If it is on land, which is most likely, it will be dominated by spectacular lava ‘fountaining’ and the production of lava flows.

“If magma breaks the surface at the southern end of the fracture, however, it could erupt beneath the sea. This would be a more explosive event that would build a cone of fragmental material.

“Once the cone breaches the sea surface, the eruption could generate a significant ash cloud. This would have the potential to disrupt aviation – either locally or further afield, but this would depend on the size and volume of the eruption.

“The evacuated town of Grindavik is very close to the position of the new fracture, and its survival is far from assured. Everything depends upon where magma eventually reaches the surface, but the situation doesn’t look good for the residents of the town.

“There is no reason, currently, to think that this eruption will be especially big. Having said this, it is notoriously hard to forecast how big an eruption will be.”


Dr Michele Paulatto, Imperial College London, said:

“The ground inflation and earthquakes are caused by magma flowing into a 15 km long dyke near the town of Grindavik and the popular tourist spot “Blue lagoon”. The Iceland Met office which is in charge of volcano monitoring and response believes that an eruption is likely in the next few days. This is likely to be an effusive eruption similar to the ones that happened just to the east in 2021 and 2022 at Fagradalsfjall.

“It could become explosive if the magma interacts with sea water. Based on the location of the earthquakes, the dyke extends offshore beneath the Atlantic Ocean. If it erupts undersea it could cause a Surtseyan eruption similar to the one that happened in 1963, also in Iceland, and created the island of Surtsey. That particular eruption lasted several years, so this is a possibility.

“The Eyjafjallajokull eruption of 2010 was quite different as it was associated with a shield volcano topped by a glacier. It was the interaction of the magma with ice and melt water that made that eruption so explosive and dangerous for aviation. This is not the case for Grindavik

“The population of Grindavik have been evacuated and will likely have to stay away for some time. Blue lagoon is also closed so it’s not good for tourism in the short term, but the eruption could bring thrill seeking tourists and increased international attention to Iceland. Thousands of tourists hiked to witness the 2021 and 2022 eruptions at Fagradalsfjall.

“Toxic fumes are a real concern, the main being SO2 which can be corrosive and cause breathing problems. It’s not something we need to worry about in the UK, but the local population and tourists can be affected depending on the prevailing wind direction.

“So, in summary, at Grindavik any eruption is likely to be effusive, unless it happens under the sea or very near the coast. It could be large, based on the size of the dyke and the magnitude of the ground deformation, but is unlikely to be similar to the Eyjafjallajokull eruption of 2011. Evacuations could last a long time but are likely to affect only a relatively small area.”


Lionel Wilson, Emeritus Professor of Earth & Planetary Sciences, Lancaster University, said:

Are there similarities/differences to the 2010 Eyjafjallajökull eruption?

“Eyjafjallajökull involved an eruption through or next to glacial ice that melted and provided water that made the eruption more explosive than it would otherwise have been, hence the high eruption plume and very wide ash dispersal.  This should not happen at Fagradalsfjall so they will just be dealing with weakly explosive lava fountains feeding lava flows.”


Could there be possible disruptions to aviation?

“Only very local, as per my previous comment, though of course Keflavik is not very far away, so all will depend on the local wind pattern.”


What is the possible effect on local populations/tourism?

“Obviously drastic if the fissure opens in the town, which is possible but not guaranteed. They have already evacuated everyone as far as I can tell from the news reports, but they will not be able to rebuild on the same sight after the eruption is over for a long time, so possibly permanent re-location elsewhere.”


What is the potential scale/size?

“Hard to tell. Sorry.”


Is there a possibility of toxic fumes?

“Yes, high chance close to the vent(s).”



Declared interests

For all other experts, no reply to our request for DOIs was received.


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