Iceland's Fagradalsfjall Fires

[bjdeming]

Latest update, about an hour ago, with some emphasis added:

Updated May 31 at: 3:30 p.m

• The activity of the eruption quite stable last solar cycle
• Lava flows mainly between Hagafell and Sýlingarfell
• The average lava flow during the first four hours of the eruption was estimated at 1500 m3/s
• Gosmóda was seen in many parts of the country. You can monitor air quality here
• Gas pollution could be noticed in Ölfus and in the capital area in the coming days. Follow the gas distribution forecast here
• See updated risk assessment here
• The natural hazard expert's comments will be updated as needed over the weekend

The activity of the eruption, which started around noon on May 29, has been fairly constant for the last solar cycle. Activity on the fissure is from the crater that erupted furthest from the last eruption, towards Sundhnúk and on the fissure north of it. Lava flows mainly from the crater towards the area between Hagafell and Sýlingarfell and also thickens near it. Lava from the northern part of the fissure flows most to the east. There has been no advance on the lava fields that crossed Grindavíkurveg towards Þorbjörn and west of the town. The lava around the old crater piles up in close proximity to the active crater.


There is little to no seismic activity in the area and the unrest has remained constant since the previous day. A considerable amount of deformation was measured in Svartsengi following the magma flow on Wednesday, but since then no significant changes have been detected that indicate that magma accumulation has started there again. Measurements over the next few days will provide more information on the development of magma accumulation under Svartsengi and the progress of the eruption.


The imaging team of the National Institute of Natural Sciences and Land Survey of Iceland has processed data from a measurement flight that took place about four hours after the eruption began, together with satellite images. Based on that data, it can be seen that the area of the lava on the afternoon of May 29 had already reached 8.7 km2 and its volume 24 million m3. The average lava flow during the first four hours of the eruption is estimated to be ~1500 m3/s based on the same data. Estimates of the flow of lava emerging from the craters have not been updated since then, but it can be assumed that now it is many times less than at the beginning of the eruption. For comparison, the average lava flow during the first hours of the eruption that began on March 16 was estimated at 1100-1200 m3/s. More about it on the website of the Earth Sciences Institute .

Gosmóda was noticed in many parts of the country​

Southwesterly until Sunday, when the wind turns to the west. A little wet in many places, especially in the southwestern part of the country. Gas pollution therefore travels to the northeast and later east and could be felt in Ölfus and in the capital area in the coming days. Gosmóða has been observed in many parts of the country during the last solstice cycle and has been measured by the Environment Agency. Soda is composed of very fine sulfur particles (SO 4 ) that have been created as a result of the chemical reaction of the soda mix with the moisture and oxygen of the atmosphere with the help of sunlight. When the day is long, as it is now, there is an increased chance of soda ash forming. Soda haze is not measured on SO 2 gas meters, but is visible as a gray-blue haze when a certain concentration is reached. An increase in fine particulate matter (PM 1 and PM2.5 ) can be an indication that SO 4 is present. You can monitor the air quality on the environmental institute's air quality meters.


Next week there is a chance of north and north-westerly directions and therefore a small chance of gas and air pollution in built-up areas.




Attached satellite image (Sentinel-5p) taken at 1:47 p.m. yesterday, May 30, shows the SO 2 plume that traveled from the eruption to the east and was observed, among other things, in the Austfjörður.

Updated hazard assessment​

The National Weather Service has updated the risk assessment in light of the evolution of the eruption. Zones 1, 5 and 7 go from high risk to considerable risk (orange). The main change is that the risk of gas pollution, pyroclastic falls and lava flows is now considered lower than before in those areas. There is still a very high risk in area 3 (purple), which is the Sundhnúks crater series and the source of the eruption. The overall risk in area 4 (Grindavík) remains unchanged and is still assessed as high (red), but the risk of eruption, lava flow and pyroclastic fall is estimated to be lower than before. The card remains valid until June 4.


(Click on the map to see it larger)

 

[bjdeming]

The UI Earth Sciences linked articles thus far only go to the end of the March 16th eruption, but new updates will probably appear there, too. Here is an autotranslating link.

If this turns out to be another Fagradalsfjall-style long one, at least the lava isn't flowing toward Grindavik -- I wonder about the major roads that currently are covered, and the power plant, though.

 

[bjdeming]

This Facebook post by the Southern Volcanoes group at the University of Iceland discusses the big blasts, but the translation is difficult to follow at times.

I think they're saying that lava got into some underground passages and somehow encountered a collection of groundwater there.

(Per other news, some of that lava ended up west of Grindavik near the US Navy radio station.)

 

[bjdeming]

That's still quite a line of fountains! Thankfully, it's to the north and the flow is to the east mostly, where it can do little damage.

Still similar power in the eruption as it has been​

The power of the volcanic eruption at Sýlingarfell is similar to what it was yesterday and last night, according to a natural disaster expert at the Icelandic Meteorological Office. The greatest magma flow seems to be to the east. Seismic activity has been very low this night.​

Markús Þ. Thorhallsson
June 1, 2024 at 06:40 GMT

The power of the eruption has not changed overnight.
RÚV – Ragnar Visage​

-- Source (autotranslated)

It will probably wind down to that area on the right, perhaps going on for weeks to months like last time.

<Layperson speculation>That northern activity this time around is interesting because there were very intense swarms of microquakes both at this area AND up at Fagradalsfjall, just hours before the eruption started:

Somehow it seems to me that we can't write off the possibility of eventually more activity in the general 2021-2023 eruption area, too, although the reason for that is unclear -- certainly to me and perhaps to the experts, too.

If anyone is interested in more info on Laki 1783-84, Dr. Thordarson (a/k/a Thorvaldur to Iceland's journalists) also has a paper (Researchgate PDF download) analyzing contemporary sources, and this (also Researchgate download) is the "Thordarson et al." reference mentioned in that work.

Besides the academic points addressed, there are descriptions of the eruption itself, which seems to have been of biblical proportions (literally, too: one flow stopped juust in time after the Fire Sermon was preached; got that from the "Haze Famine" chapter of Clive Oppenheimer's 2011 book Eruptions That Shook The World which is good, too.)

It's probably good to mention Laki in this context because it and at least two earlier known flood lava Fires -- Eldgja (900s, shortly after settlement) and Thjorsa (~8600 years ago) -- happened in the part of Iceland that is thought to be generally centered over the mantle hotspot anomaly. I have not read of any flood eruptions ever on the peninsula (or in its tectonic twin, the Grimsey oblique rift in northern Iceland), which is an encouraging thought perhaps: as disruptive and damaging as this Reykjanes wakeup is for the most densely populated part of the country, it could have been much worse if the tectonic setting had been different.</Layperson speculation>

 

[bjdeming]

This has trouble potential: UI's Southern Volcanoes group just posted that smoke -- rjúka, per GT -- is coming from a crack near Grindavik. It seems to be increasing, they note, and could be from lava meeting groundwater.

This is the cam they got that screenshot from but weather makes viewing difficult:

 

[bjdeming]

It does seem to be developing a bit of a plume.

 

[bjdeming]

That plume isn't present now but steaming is still visible; in fact, someone posted images and a video as comments to the Southern Volcanoes group's Facebook post showing steam rising within the ramparts.

Mbl.is is on that (autotranslated) and also has an update on the overall lava situation (which does not appear to be threatening anything at present although there is some ponded lava to monitor).

The eruption is beautiful.

 

[bjdeming]

Per Visir (autotranslated), IMO says there is no lava under the barrier crack, which they say is superficial.

And the spot out on the flow field no longer shows up in cam.

 

[bjdeming]

There is a change of pattern -- not the eruption winding down but the continued subsidence of the plain, per IMO (autotranslated):

...Attached are two pictures from the National Weather Service's web camera, which is located on top of Þorbirn and looks over the eruptions. In the previous picture, taken at At 02:00 magma is seen coming out of two craters, but the second picture taken an hour later shows only magma coming out of the larger crater.

Recent data indicate that magma accumulation continues under Svartsengi as before​

Deformation measurements show that land continues to subside in Svartsengi. When the magma flow started on the eve of the eruption on May 29, the land in Svartsengi subsided by 15 cm, but has now subsided by an additional 4-6 cm in recent days. The fact that land continues to sink this many days after the start of an eruption is different from what has previously been seen in the Sundhnúks crater series.


In previous magma flows/volcanic eruptions, most of them have only been measured in the very first days, but immediately afterwards they started to be measured on land. The subsidence indicates that at this stage, a greater amount of magma flows from the magma accumulation area under Svartsengi into the Sundhnúks crater series, than flows into it from depth.


Deformation measurements in the Svartsengi area and the evolution of the eruption in the coming days will give a clearer picture of the continuation of magma accumulation under Svartsengi....

 

[bjdeming]

Yes, the translation is inconsistent, saying magma continues to accumulate AND that there is subsidence. It's too early to be sure, but this might be another way of saying (in Icelandic) what they do say elsewhere in the report: that the sill is being fed but in smaller amounts than the volume that is leaving it.

 

[bjdeming]

There is no eruption news yet, other than that geoscientists think the sill might be starting to inflate again -- IMO isn't sure enough yet to make a statement, though RUV mentioned it.

Here is another gorgeous drone-view pano from a few days ago. There are labels, including one for the crack in the barrier.

I don't really understand much about Iceland's setup but believe that a government agency has bought up 700 or so properties owned privately in Grindavik and is in the process (autotranslated) of working out disaster insurance details with the appropriate national agency.

(Side note: Ruining a major town isn't the only way volcanoes can mess us up financially. I have heard that Mount Ruang in Indonesia was covered by catastrophe bonds; if so, its plinian eruption recently must have triggered a payout but I haven't found any news about it yet.)

Back to Iceland. They were going to take six days to restore electricity to businesses in Grindavik and it took a day, reportedly, although the cable capacity is limited and there apparently is uncertainty for the longer term (particularly since this line is close to the Eldvorp craters that Armann, at least, believes eruptions will migrate to).

Here is RUV's article on that (autotranslated).

 

[bjdeming]

Not much eruption news -- at the moment activity looks a little slow; this crater developed a side hole early today, just as it did during the March 16 eruption.

Eye-opening news in terms of bills, though.

Per RUV (autotranslated):

...
The state's total investment for Grindavík, that is, the purchase of residential buildings and the construction of defense walls, is estimated at 70 to 80 billion according to a memo from the town's business team.

A large crack in an industrial area by the harbor in Grindavík.
– Karl Sigtryggsson
Fourteen to nineteen billion ISK is still required to make the town habitable again, according to a report prepared by Deloitte. Therefore, the costs for Grindavík are expected to be up to ISK 100 billion, according to the memorandum....

If Iceland follows the UK idea of a billion being a thousand million (and if my calculations are correct -- always a big "if"), that works out to $7,200,000,000 at the current conversion rate.

And that might not include roads, which got lava-covered widely this time around.

 

[bjdeming]

Last night whatever was holding the lava pond gave way and the resulting flow crossed that north road out of Grindavik towards Reykjavik -- the Grindavikurvegi, per news reports -- and flowed along the power plant ramparts, getting close to topping them in some places, apparently (on closer reading, it's possible that lava did top them in these places -- a little bit).

Mbl.is has multiple stories (autotranslated; link is time dependent) and here is IMO (autotranslated) on it:

...Last night, Saturday night, the lava flow north of Sýlingarfell to the west and towards Grindarvíkurvegi started to increase. This morning, Saturday, they started to close the gap in the defense wall at Grindarvíkurveg, and around half past eleven, Hrauntungan reached the road just north of the defense wall. Lava has also reached down along the garden and it is very thick at the garden and collapses from it over the garden in sections. The speed of the lava has decreased in the afternoon. The front end of the lava bed has reached a distance of about 800 meters from the hot water pipes and is slowly moving towards them.

It can be concluded that the raid is over for the time being, but it can be expected that it will continue. The situation will be closely monitored and it is not excluded that another raid may take place in the coming days.

The photo was taken at 10:10 this morning from a camera owned by the Icelandic Meteorological Office located in Þorbirn. It shows the lava front moving towards Grindavíkurveði and workers in the area closing the opening in the defense wall L1. ​

Nobody was endangered (they did evacuate the Blue Lagoon); it's just more road work eventually. I think they might have been holding off on a repeat of the "build a road over fresh lava" exertions just in case something like this happened (also because of the large area of lava-covered roadways this time).

In other news, IMO has gone so far as to say that the sill has stopped subsiding; the Southern Volcanoes group at UI noted on Facebook that they think it's inflating again.

<Geonerd mode>Whatever. The team that we saw in a video somewhere earlier in this thread, collecting samples from an earlier eruption, did so with this one, too, of course. Preliminary findings were released yesterday, and it was a surprise (emphasis added):

...Our preliminary geochemical data likely suggests that a different magma has been accumulating under Svartsengi since the beginning of April. This magma was most likely stored in a separate, isolated mid-crustal reservoir distinct from the one feeding the eruption in March. The magma now erupting at Sundhnúksgígar has a K2O/TiO2 ratio resembling that of the magma which erupted in Fagradalsfjall at the beginning of the 2021 eruption. One possible explanation for this is that the two systems are connected at depth, close to the crust-mantle boundary. For the first time since the start of the 2021 Fagradalsfjall eruption, low K2O/TiO2 melts are dominating the eruptions…

Nice arcane stuff, but IMO put it in a more practical way for yesterday's update:

...
Monitors possible changes in magma accumulation under Svartsengi

As mentioned in the last news update, it was the first time, since volcanic activity began in the Sundhnúks crater series in December 2023, that subsidence was measured in Svartsengi during an eruption. Yesterday, the University’s Institute of Geosciences published the first rock and geochemical data from the ongoing eruption. The data show that the chemical composition of the magma that is now coming to the surface is not different from that which has arisen in the last four volcanic eruptions in the Sundhnúks crater series, but is similar to the magma from the beginning of the eruption in Geldingaðalur in 2021. These results are a sign that the magma collection area under Svartsengi is changing. At the moment, it is not possible to assess exactly what kind of changes are taking place, but in the near future more data will be collected and analyzed to try to shed light on them.

This is all longer-term stuff, as things stand now, but it matters since AFAIK it goes against the prevailing view over the last five decades of how this peninsula's volcanism works. (Here's a seminal paper on that for anyone who's interested and doesn't mind jargon.)

Don't have the notes in front of me, but I think it was Dr. Thorvaldur Thordarsson who wrote in a paper that the idea of Reykjanes Peninsula volcanic systems doesn't actually have much solid evidence behind it (it's hard to study structures down there, I understand), but it's a very useful concept -- one that underpins everyone's understanding of Iceland geology.

Now that the Peninsula is firing up again, these geochemical lava findings might be suggesting that things aren't that simple after all.

Given that some of the best minds on the planet -- in Iceland and internationally -- have been studying this peninsula intensively for fifty-some years, though, it's likely that any resulting changes to their conceptual pictures will be relatively small ones. </Geonerd mode>

 

[bjdeming]

Per the Southern Volcanoes group, lava did overtop the barrier at one point and set vegetation on fire. They have the spot marked on an image in this post.

 

[bjdeming]

Just Icelandic released this drone video showing the scale of the lava flow blocking that highway -- this was not one of those thin, hot, fast-moving initial surges and so they can't just roll out a new track insulated with a thick layer of basalt and ask everyone not to stop while on the flow road, which was audacious but worked last time.

Worse, they can't make plans right now because the eruption continues and the lava could either collect again in a pond, eventually having another surge, or it might just keep oozing forward.

Reportedly the flow front is about 700 meters from the geothermal pipe now and the power plant is at full operation.

I hope the pipe shielding is tested now, in summer.

 

[bjdeming]

Those lava barriers are costly, but without them they would no longer have Grindavik, the power plant, or the Blue Lagoon.

 

[bjdeming]

Meanwhile, elsewhere in 40,000-square-mile Iceland (per X translation): "You can catch a rainbow! If you have the chance, don't miss it."



(Disclosure: She runs a tourist business of some sort, but I don't know about that -- the tweets about Iceland from a different perspective interest me.)

 

[bjdeming]

The air isn't quite so clear today in Reykjavik --



-- and besides noting that the sill began to inflate over the weekend again (the eruption goes on), IMO says (autotranslated) that the "midnight sun" phenomenon contributes to it:

Considerable pollution is now being measured from the volcanic eruption in many places in the capital area and in the western part of South Iceland. According to data from the Environmental Agency, the highest levels of SO 2 in the capital area have exceeded 500 µg/m3 and the pollution is expected to persist throughout the day. People with respiratory sensitivities may experience discomfort. It is advisable to limit physical activity outdoors and avoid letting infants sleep outdoors when the activity is high.

This morning, clouds of fog have covered the western part of the country, and there has also been a visible haze caused by the transformation of SO 2 gas into SO 4 . Soda is composed of very fine sulfur particles (SO 4 ) that have been created as a result of the chemical reaction of the soda mix with the moisture and oxygen of the atmosphere with the help of sunlight. When the day is long, as it is now, there is an increased chance of soda ash forming. Soda haze is not measured on SO 2 gas meters, but a blue haze is visible when a certain concentration is reached. An increase in fine particulate matter (PM 1 and PM2.5 ) can be an indication that SO 4 is present. Air quality can be monitored on the Environmental Agency's air quality meters.

The weather watch's forecast for gas distribution is a rather slowly changing direction, and gas pollution can be felt in many places in the southwest corner. Turns in a southerly direction in the afternoon, gas blows to the north and pollution could be noticed in Vogur and Reykjanesbær. Southeast direction tomorrow, gas blowing to the northwest.

 

[bjdeming]

Sheesh!

A lot of pollution has left the volcanic eruption today and it affects the capital area.​

Ragnar Jón Hrólfsson
June 11, 2024 at 14:32 GMT,updated at 17:01
A
A
A

From the volcanic eruption at the Sundhnúks crater.
Rúv – Jónmundur / Rangar Visage
The Norwegian Meteorological Agency's measurements on the Reykjanes Peninsula indicate that landfall has started again. The land subsidence that was measured in the first days after the eruption began has ended...

-- Source (autotranslated)

<Layperson speculation>While it's impossible AFAIK to prove that the two news items are related, stuff coming from the crust-mantle boundary -- where UI's petrology results suggest this eruption's lava was sourced -- likely would have a high sulfur content.

Come to think of it, the last Fagradalsfjall eruption, almost a year ago, was polluting, too, but I think it was more from wildfires.</Layperson speculation>

 

[bjdeming]

Bad as it looks, the air quality only gets to yellow on this map (Icelandic -- can't get it to load with translation).

As IMO said, it's unhealthy for infants and folks with respiratory problems, but it's not setting off SO2 meters.