Iceland's Fagradalsfjall Fires

[bjdeming]

The only news is that Magnus Tumi said tonight, in a Visir interview, that this might go on a while.

The fountains seem to be much the same as during this morning. The cam view is better, and RUV live update reports that scientists are taking advantage of the weather inprovement to do some gas and lava measurements.

They're measuring HCl, too, so they haven't ruled out an ocean entry eventually.

As I understand news articles, this new lava is running over the initial flows, not increasing those. Apparently the only movement in the older flows is some creeping toward the main road, which is still clear.

Workers at Hraun, closer to the sea, did get a barrier across the road (and of course everyone there got their valuables together and evacuated last night). That situation is stable for now, I guess.

No more news yet about Svartsengi deformation, one way or the other. Given the interview with Magnus Tumi this evening, my guess is that at least they don't see DEflation (which did quickly show up on the GNSS graphic after the last two eruptions).

This layperson speculates that whatever has changed down there will likely turn out to be related to Mount Thorbjorn's 20-cm dash westward last month.

But this whole thing is weird; don't have the figures in front of me right now, but I've read that, during the reportedly very similar Krafla Fires from 1975 to 1984, dike intrusions were many but only nine in total led to an eruption.

That ratio is close to the average for Iceland's rifting episodes (as the fires are called formally -- each dike intrusion/eruption is considered a rifting event.)

But here on the peninsula, eruptions have happened much more frequently.

I'm still reading and found this post (autotranslated) at the University of Iceland website, reviewing things from the 2019 seismic unrest through late February 2024.

Just an excerpt:

The reason that the current activity is more dangerous than the activity at Fagradalsfjall is both its proximity to Grindavík, the Blue Lagoon, the power plant in Svartsengi and important infrastructure, as well as the much faster magma flow and lava flow. The reason for this is believed to be that the magma channel out of the Svartsengis magma area has a relatively large cross-sectional area, which enables a rapid flow of magma into the upper part of the earth's crust and to the eruption centers.

After reading the whole thing, it's hard to imagine anyone living full-time in Grindavik for years to come -- hope they get to keep using it as a port, though. Six thousand tonnes of Atlantic cod each year aren't going to harvest themselves (figure from an Iceland Review fact sheet).

 

[bjdeming]

From IMO about an hour ago:

The eruption now lasted longer than the last three eruptions​

Landris continues in Svartsengi.​

19.3.2024








Updated March 19 at 11:50 am

• The eruption continues and has been going on since March 16 at 20:23
• Eruption turbulence is measured and has been quite stable over the past two solar cycles, which is an indication that the power of the eruption has not decreased.
• Landris continues in Svartsengi, which indicates that magma is still flowing from depth into the magma accumulation zone under Svartsengi, as well as feeding the eruption.
• The risk assessment map that was updated yesterday remains unchanged

The eruption continues and has now lasted for over two and a half days, and has become longer than the three eruptions that have occurred in the area since December 2023. It continues to erupt in the same places as in the afternoon yesterday, which are south of the fissure. Crater rims continue to build and some magma jet activity remains. The edge of the lava, which was about 300 m from Suðurstrandarvegin yesterday, does not seem to have moved forward since yesterday. Lava flow from the craters remains mostly to the south, but active lava margins flow on top of what flowed at the beginning of the eruption. There has been no seismic activity in and around the magma tunnel since the eruption began, but eruption turbulence is measured and has been quite stable for the past two solar cycles, which is an indication that the power of the eruption has not decreased.


When magma flowed from Svartsengi across the Sundhnúks crater series on the evening of March 16, the land in Svartsengi was as sticky as when previous magma tunnels formed. GPS measurements and satellite images since then show that landrising continues in Svartsengi, which suggests that magma is still flowing from deep into the magma reservoir beneath Svartsengi, as well as feeding the eruption. It should be kept in mind that relatively few measurement points have been obtained in the short time that has passed since the eruption began, and the measurements are always subject to uncertainty. Deformation measurements that will be available in the next few days will make it possible for experts to estimate in more detail with model calculations the amount of magma flowing under Svartsengi.





Waveform diagram showing measured landris (red area) between March 17 and 18 after the eruption began. The image is based on data from the Iceye satellite.


According to the measurements carried out last night, the gas emission from the eruption has reduced to what it was at the beginning. However, there is still a chance that gas pollution will be noticed and the weather forecast indicates an increasing southwesterly wind, around 13-20 m/s at the eruption sites today, but the wind will decrease tonight. Gas pollution therefore travels to the northeast. See gas distribution forecast here .

It feels like a bummer, but this is what we all expected from December on, in each eruption, and then wondered why it stopped so soon.

The eruption is playing out typically at the moment and it feels weird -- shows just how unusual things have been up to now!

<Layperson speculation>

Perhaps this is continuing because earlier batches of magma contained less gas (which is what powers eruptions; I couldn't begin to state the principles involved, and there are diverse hypotheses about details, but my understanding is that lava fountains generally begin just under the vent, where gas and magma have combined into a rock foam).

Perhaps now "gassy" magma from a deeper source has risen to surface levels; fortunately, there isn't much power available in it to flood the land now.

A long-lasting eruption here, at these levels, isn't necessarily a bad thing, although it brings toxic gases and also moving lava that -- who knows? -- might inch its way to the sea and/or over valuable infrastructure.

It could even boost tourism! In addition, Iceland still has its fishing port.

One big question, though, is the continued inflation despite an ongoing eruption. The system is not yet stable, and there are just so many directions it could take AFAIK -- from shutting down to expanding in some way.

Haven't checked the online media sources yet...

</layperson speculation>

 

[bjdeming]

Thorvaldur and Armann see things differently (autotranslated links).

You wouldn't believe the number of highly cited papers on Google Scholar by all of these people -- who Icelanders know by their first names!

This unqualified layperson, though, is especially impressed by Thorvaldur's argument (and not because his pictures often show someone who looks as though he'd be a jolly companion to have along on a fishing or road trip).

Armann takes the long view. Thorvaldur has publicly made a specific prediction: the eruption is likely to stop within a few days, perhaps even overnight.

I can't follow all his reasoning (filtered through the journists as well as an online translation machine) here or in the interview he gave to Visir yesterday (autotranslated).

But that is how you do science, and it would provide an alternate explanation for ongoing Svartsengi inflation, particularly if the presence of at least two reservoirs here has been established (I don't know; the original pre-2021 view AFAIK was that each volcanic sysyem on the peninsula has its own reservoir -- a single elliptical domed chamber that follows the surface expression of its system -- but 2023-2024 Sundukhnur lava analysis, I believe, has thrown that long-held model into debate again).

 

[bjdeming]

As an organization, IMO really can't say anything more than what Benedikt says in this interview (autotranslated; the Eldvorp reference addresses Armann's hypothesis), including:

"There is no indication that it is ending now but it can happen suddenly." It is not certain that it has a big lead-up, but it is behaving differently than the other eruptions," he reports.


By that he means that the other eruptions started with noise and subsided quickly, as has been the case with this eruption, but then they stopped, unlike this eruption.


...

Benedikt Gunnar Ófeigsson. mbl.is​

Asked about a possible volcanic eruption in Eldvörp, he says he doesn't see any signs that something is going to happen there. He says it is extremely unlikely that while an eruption is going on, the magma will break its way somewhere else.

It's important to note that geology overall is like this: point/counterpoint, back and forth. These people specialize in processes that are planetary in scale, go on out of sight and also quite often in extreme conditions that can't be duplicated here at the surface (an unrelated but famous example), and usually involve thousands to millions of years' worth of possibly random, possibly intricately interconnected events that all must be considered.

It's wonderful to see this open discussion go on in public -- everyone benefits.

Iceland is an amazing place, for sure.

 

[bjdeming]

Three years ago today, fire flowed on the Reykjanes Peninsula for the first time in many centuries:



Here is more information on Fagradalsfjall.

The boffins tested that lava and found, among other things, that it had come up from mantle depths, which was rare and exciting.

When lava erupted out of the Svartsengi plain last December, analysis showed (autotranslated) that it was from the same general "batch" as the Fagradalsfjall lavas but had some unique features, including a higher sulfur content, and had sat underground longer.

That last point would make sense, if the Fagradalsfjall lava was some unusual type of eruption (as Haraldur and others say those events indeed were).

This recent stuff would have been sitting in the Svartsengi system reservoir for a while -- nothing unusual about that.

Only, it does not match the old Svartsengi lavas already in place. That is weird.

And, too, why does it resemble Fagradalsfjall material?

This is totally lay speculation, but could some little blob from the mantle plume well east of the peninsula have leaked into both Fagradalsfjall and this easternmost part of the Svartsengi system some, erupting first in Fagradalsfjall and now at the Sundukhnur area?

Very far-fetched, especially since the plume is believed to sit under Iceland, not in its crust, causing eruptions sort of like a burner causes water in a pot to boil. And I won't even attempt to explain how a blob of it might have gotten to the peninsula.

Much more likely is some Reykjanes Ridge process at work here, but what the heck. Layperson speculation is fun.

Today, the first test results on products from the current eruption were announced and show pretty much the same thing as back in December.

That's all the news right now, those lab results, apart from some sulfur reaching the capital, though not enough to cause an alert.

The vents carry on, though activity at the moment is more strombolian -- big gas bubbles popping, basically. It happens frequently at this type of eruption, alternating with fountaining.

More than that, I wonder if it might be the continuing activity of multiple vents that's a mark against Thorvaldur's idea of a short-lived eruption, since earlier eruptions have quickly dwindled down to one and then that died.

This layperson wonders what is keeping multiple vents going. It's just wait-and-see time still.

 

[bjdeming]

This news from the current RUV live update (autotranslated) is not bad:

The Met Office held a meeting this morning at 09:30 about the situation on the eruption at Sundhnúksgíga. Among other things, it was discussed that there are indications that expansion is not as great under Svartsengi as before. "We still need to wait a few days to see how this develops, says Elísabet Pálmadóttir, natural disaster expert at the Icelandic Meteorological Office. However, this may indicate that a balance is being reached in the system.

Activity is now mainly from the craters that have formed on the eruption, and from there a thick tongue of lava creeps to the south. There is no activity on the lava edges to the south and west.

Elisabeth says that the eruption has been very stable in the last 24 hours. It can be seen clearly on webcams and there were also very few tremors.

You can continue to follow the eruption on RÚV's webcam .

Screenshot from RÚV's webcam from 10:46 today.

3 hours ago

Believes that magma has an easier way to the surface than before​

Freysteinn Sigmundsson, a geophysicist, said on Morgunútvarp Rásar 2 that it is possible that the magma system under Svartsengi is reaching equilibrium in a different way than we have seen in recent months.

He says that the reason why the eruption is still erupting regularly on the fifth day is because magma can now easily reach the surface. Magma accumulation that used to occur underground is now flowing upward steadily.

Eruptions like the ones we've seen in recent months in this area have had to break their way through the ground each time, but there may now be an easier path for the magma.

"This is very similar to, for example, the first volcanic eruption in Fagradalsfjall," says Freysteinn. "The average amount of magma coming to the surface is the same. It just hasn't been able to form this steady flow to the surface where the channel has closed."

A possible consequence of this could be landris ceasing in Svartsengi where magma flows undisturbed to the surface. Although further measurements are needed to confirm this, this scenario could possibly become clear in the coming days.

Edit: Also, Visir interviewed Benedikt on it. (Autotranslated)

It has yet to be confirmed, but it could be the best possible short-term (human-scale) outcome, if the eruption level stays the same:

• Less likelihood of pressurized magma seeking an outlet -- perhaps behind the Grindavik lava barrier.
• Possibly reduced hazard to power plant (energy and drinking water) and the Blue Lagoon (major tourism venue), at least in short term.
• Not a high chance of magma-water interactions leading to explosiveness (with subsequent extension of ash hazards both horizontally and vertically), at least until lava reaches the sea.
• Stability for everyone whose lives have been in upheaval since November 10th.
• Grindavik gets to keep its harbor for a while longer, at least, while this younger lava inches along.
• A major tourism magnet that is accessible and near to other attractions could offset some of the country's expenditures during the volcano emergency.

Well, time will tell if this stabilization is real or not. More flow models probably are needed, too, since the initial flow fields changed topography.

 

[bjdeming]

From mbl.is (autotranslated):

A family from Haywood County in North Carolina describes in the American media their frightening experience in Iceland, but they were at the Blue Lagoon when the volcano erupted on Saturday.


The father of the family, Tom Roberts, had always wanted to go to Alaska to see the northern lights, but the family decided instead to go to Iceland to see the northern lights....

 

[bjdeming]

Visir has some nice images (autotranslated) of the active vent row, including this one:

March 20, 2024 10:38 am

The seven to eight craters that have begun to form. The picture was taken around ten o'clock this morning. Indicator/William ​

The fissure that erupts between Stóra-Scógfell and Hagafell seems to be consolidating into seven to eight craters. ..

Seen at that angle, and recalling that Fagradalsfjall eruptions had just one big spatter rampart instead of a row of them, I remembered that other volcanic structures exist in Iceland besides lava flows and spatter ramparts (which is what I think the old Sundnukhur craters are).

Per RUV, the volcanologists are still working to confirm that this might turn into a lengthy eruption of the type seen from 2021 through early 2023.

<Layperson speculation>Though no authoritative source is speculating about this to my favorite online media sources yet (as they did in 2021 at first), Iceland also has shield volcanoes and they do occur near plate boundaries.**

I'm not sure if Thorbjorn is one; the only lava shield named in my reading this far is Skjaldbreidur.



(Video came up on an online search; I know nothing about the creator or their facts. My source gives the shield's volume as 15 cu km.)

Conditions are no longer as ideal for lava shields, but I suppose it's not impossible that one could grow here on the Svartsengi plain, too. Nothing would change about the eruption, in the short term, I think -- it just would go on and on (they are said to form all at once), giving H. sapiens enough time to get out of the way and also to come from all over the world to enjoy/study/take selfies with the spectacle.

I'm not saying this will happen. It might just be one of the longterm options for Earth here. </layperson speculation>

**Sources of information:

• Gudmundsson, A. (1987). Geometry, formation and development of tectonic fractures on the Reykjanes Peninsula, southwest Iceland. Tectonophysics, 139(3-4), 295-308
• Gudmundsson, A. (1995). Infrastructure and mechanics of volcanic systems in Iceland. Journal of Volcanology and Geothermal Research, 64(1-2), 1-22.

 

[bjdeming]

However, an expert tweeted this about tall volcanoes five hours ago:

 

[bjdeming]

IMO's update today covers a lot of ground, so I'll just paste it all in below.

Of note, they say that lava flow rate is similar to that in the Fagradalafjall events. This layperson finds it interesting that there is so little seismicity -- don't quote me on this but it might indicate that the sill is completely filled during this whole process, all the time, without collapse of any empty spaces. It's quite "happy," IOW, and since inflow from below -- where magma supply is basically unlimited perhaps, although I have to look into what is said about crustal magma chambers more -- has been srable for a long time, it might just go on and on.

Factors that could change that are mostly unknown (to me, at least) but could include an earthquake -- this magmatic event isn't the only thing that causes earthquakes, although it has dominated lately; some other magma pathway opening up, perhaps up at the Fagradalsfjall end? This is just too speculative.

The area covered by lava remains the same as reported a couple of days ago, so the initial lava hasn't advanced much and this current stuff hasn't yet traveled as far. There is more than 16 meters piled up at the vents.

In reading, I have not yet seen any discussion of details of what could be expected of a, say, Geldingadalir event (the first one, in hilly country) in this flat area. There is no speculation yet about shields, either. Just for the record, the smallest existing lava shield here apparently has a volume of about 1 cu km, with the largest, again, around 15 cu km.

We'll just have to see how it goes.

Here is a pano of the area yesterday; I'm not sure of the source but suspect it was taken during that survey flight they mention here:

Constant activity in the volcano​

Lava flows south from the craters in an active lava river​

21.3.2024


Updated March 21 at 13:50

• Average lava flow from the craters 17 - 20 March about 14.5 m 3 /s
• The area of the lava is 5.58 km 2 and its volume is about 20.9 million cubic meters.
• Magma that previously collected under Svartsengi and caused a land giant is now mostly flowing directly to the surface and feeding the eruption
• Small deformation is measured in the Svartsengis area and around the magma tunnel.
• Gas pollution spreads to the east and southeast, and it could be felt in South Iceland. Gas distribution forecast is here .

The activity of the volcano has been fairly constant over the past 24 hours. The same vents still appear to be active and craters continue to form around them. Lava flows south from the craters in an active lava river on the surface and below the solidified surface of the lava.





A photo taken from an aerial photo flight taken by the Icelandic Institute of Natural Sciences yesterday, March 20, at around 9 in the morning. This data collection is a joint project of the Institute of Geosciences of the University of Iceland, the Institute of Natural Sciences of Iceland, Land Survey of Iceland and the Icelandic Meteorological Office.

Average lava flow from the craters 17 - 20 March about 14.5 m3/s​

Yesterday morning, experts from the Institute of Natural History and Land Survey of Iceland went on a survey flight over the eruption centers. Based on the data collected during that flight, it is estimated that the average lava flow from the craters in the period from March 17 to 20 was around 14.5 m3/s. It is similar to the lava flow that was measured in the volcanic eruptions at Fagradalsfjall 2021 – 2023. However, there was much more lava flow from the craters during the first 24 hours of the eruption, which began on the evening of March 16. The area of the lava is 5.58 km2 and its volume is about 20.9 million cubic meters. The attached map shows the extent and thickness of the lava as mapped yesterday morning, March 20. It shows that the lava is over 16 m thick, where it is thickest closest to the craters.









Caption: A map showing the extent of the lava formed in the current eruption. Purple covers show lava that has flowed in the area since December 2023.

Landris flowing directly to the surface and feeding the eruption​

Small deformation is measured in the Svartsengis area and around the magma tunnel. Movements are so small that no significant changes can be seen between days. It therefore takes a few days to a week of measurements to assess whether landris is still running at Svartsengi. However, it is immediately clear that magma that previously gathered under Svartsengi and caused a land giant is now mostly flowing directly to the surface and feeding the eruption.


Today's weather forecast is northwest and west 8-15 m/s, gas pollution is reaching the east and southeast and it could be felt in the South, such as in Þorlakshöfn and in Vestmannaey. A more northerly wind tomorrow (Friday) and then gas pollution will travel to the south and southeast and it could be felt in and around Gríndavík. Gas distribution forecast is here .

 

[bjdeming]

Per RUV (autotranslated), "a pile of lava" -- ? if one of the lava ponds from the initial flow or a combination of lavas older and new -- threatens to overtop the Grindavik barriers in a couple of places.

 

[bjdeming]

Here is a close-up the area from yesterday's pano:

and here is the Visir cam. RUV reports that they are trying to raise the barrier -- that's what the lights are about.

 

[bjdeming]

I would be tempted to devote the little time remaining to building defenses in that open area before the town's buildings start. It's about a km, I think, and there is cool enough lava from earlier for material.

A little lava overtops it and then it has to spread out. You've bought time.

But it also makes sense to establish a higher point out front that, if successful, can be expanded forward a bit, forcing this new lava to divide and go round the town.

That's difficult, though: the lava ponding brought it high up all along that wall.

But it could redirect the whole flow safely over time, as the lava can then head seaward.

 

[bjdeming]

Given that plume off to the left, spotlit, and the occasional flashing light over that area, which I think might be outside the barrier, wonder if they're using water as Heimaey did when Eldfell erupted.

This far inland, it would require air dumps...

Also, judging from cloud direction, they're getting dosed with toxic gases from the eruption just upwind, too.

 

[bjdeming]

That plume was probably construction related. There's no report of water use (it would be big news) and, per an mbl.is story about lava flowing into one of the quarries, they're still just preparing to raise the barrier:

...
Ari Guðmundsson, an engineer at Verkís, says that the flow of lava into the mine will not affect the elevation of the defenses that are being undertaken now.


"It was planned to get material from elsewhere, but it is very sad to lose the mine because we needed it for further construction in the area, road construction and other things," says Ari.


He then adds that material is being collected for the elevation from the channels that the contractors have created along the defenses. Work on the increase has not started.


"Materials are still being spewed out and work is being done on the construction of work roads in order to be able to start the rise."


That work will continue into the night. There has been bad weather in the area, but it should not affect work in the area, says Ari.

I think that flow into the quarry was what this drone pilot was following -- saw it on Mastodon and didn't understand where it fit into the Grindavik picture:

 

[bjdeming]

Okay, reportedly (autotranslated) what happened is that a lava pond at the craters burst, sending a lava front downstream.

Also, yes, they're building a road over fresh lava.

 

[bjdeming]

Per RUV about an hour ago (autotranslated), they did almost get flooded, but the quarry's being there diverted the lava:

Gunnar Schram, chief police officer in Suðurnes, says that there was a lot of preparedness at the defenses yesterday when lava was about to overflow them. The lava spread rose considerably so that it became higher than the ramparts.

"And for a period of time the lava was about to overflow. But then a stream led along these gardens in the direction of Melhólsnáma, where contractors have been taking material for defenses and other work."

Contractors were working in the mine when the raid started and they had to leave it. Later, a small amount of water flowed into the mine. Lava also flowed towards Suðurstrandarvégur and there was a lot of preparedness in the area to monitor the progress. Now it looks like the rush is over for now.

"Yesterday, those who are working on these defenses went through a response process on how to react, and in a certain section there, the defenses will be raised. That work will probably start today, in the morning," says Gunnar Schram.

It's times like these when lava's tar-like consistency is actually helpful -- water, of course, would have gone right over.

Am just getting back online today, but thus far, looks as though the eruption is continuing at much the same intensity.

 

[bjdeming]

A "Cantore moment" at the lava flow yesterday:



Reportedly they're okay but a backhoe operator at the Blue Lagoon (which is closed) was hospitalized yesterday because of the gases.

 

[bjdeming]

Per news reports, as the eruption continues stably, lava is moving north and east of the Grindavik barriers as well as into the quarry it invaded the other night.

Because of the relatively low power, though, much of it is ponding around the craters. The big concern expressed in some news stories is that there could be repeated episodes like the one recently in which a dam holding in a pond breaks and the subsequent wave affects everyone downstream.

Work to raise the barrier is reportedly ongoing. To some of us outside Iceland it may seem like a lost cause, so here's a view from inside, in English, from a layperson whose drone videos have sometimes helped boffins, especially back in November and December:



I hope that his view this could end soon works out but can't help thinking (though only as a layperson) that the scale of this rifting event -- especially major quakes/the "Great Magma Run" on November 10th and then Mount Thorbjorn's shift in February -- suggests that this steady-state eruption isn't likely to end any time soon.

Of note, though, Thorvaldur is reportedly (autotranslated) still hanging in there:

I have been wondering if the flow out of the craters has been constant, but it seems to me that it has been gradually decreasing. That's why I think the eruption probably won't last very long, although that possibility certainly can't be ruled out. "

Þorvalður believes that the outflow in the eruption is now close to 4-5 cubic meters per second, which is similar to what was for a long time in Geldinga Valley. "But when the outflow gets down to 3 cubic meters, I think you can say that it will gradually die down."

In their updates (autotranslated), IMO on March 21 noted an average lava eruption rate of 14.5 cu m/second; on the 22nd, they reported the possibility of slight landrise, though difficult to measure -- conceivably a sign of reduced rate although I don't see an updated rate estimate.

Here, below, is a look at road-building efforts on what is apparently the road to Grindavik and the power plant (the video's interview itself might be incomprehensible but stay with it for the shot, from inside the cab, of operating heavy equipment next to an active lava flow):



Molten material reportedly is only about a meter below the surface. Iceland might be channeling their inner berserker a bit just now, but they do need that road.

 

[bjdeming]

Just for the record -- something humanity has always dreamed of doing but thought impossible until 2024:

Live cam: