Iceland's Fagradalsfjall Fires

[bjdeming]

Still waiting, but here is a gorgeous 360° view of the area as it was yesterday, August 7th.

 

[bjdeming]

The Reykjanes Peninsula tip area is really rockin' out this morning, with very frequent but mostly low-level seismicity, and earlier this morning, a few moderate quakes occurred offshore and southwest of Eldey (which is an active system, as is the mostly offshore set of Reykjanes fissures that some experts ID just east of Eldey and consider as a volcanic system, although IMO and others include Svartsengi, Eldvorp, Sundhnuks, Fagradalsfjall, etc. in a broader Reykjanes system -- the distinction looks to this layperson to be very academic and confusing, but not necessary to this thread, and IMO is who we've been following anyway; let's roll with it, just noting in passing that there are almost as many well-defined volcanic systems on the RP as there are volcanologists and geothermal engineers studying it).

Sources in this autotranslated article note that the quakes today are unrelated to the Svartsengi/Sundhnuks volcanism.

IMO notes today that there is more than 20 million cubic meters of magma estimated to be in the sill and that an eruption could happen any time, probably in the usual place, maintaining the two possible scenarios they described earlier.

This layperson suspects (FWIW, which probably isn't much) that tectonics is playing a role, too, both because of how the May-June eruption suddenly whiffed out, as if it were a candle blown out and for reasons mentioned on the blog yesterday:

...
The IMO is using a monitored eruption at a similar tectonic setting — Krafla, 1975-84, in or near the Grimsey rift area — to help them say intelligent, helpful things about the current fires.


One thing they say over and over is that it took larger volumes of magma to trigger each successive eruption/dike intrusion in the Krafla Fires, and this seems to be happening again with the Svartsengi sill.


So, okay — we’ll have to wait longer for each eruption now.


Only this layperson gets the (totally unscientific) impression that the tectonics here play a crucial role. AFAIK, there was no Thorbjorn equivalent skating around in 1975-84, and while I understand that every set of Fires like Krafla and Fagradalsfjall/Svartsengi is a rifting episode (divergence of North America and Eurasia plates) and is made up of multiple rifting events (individual eruptions/intrusions), this layperson feels that something else contributes to the current fires on the Reykjanes Peninsula.


Don’t ask me what — I’m not a scientist and this is not a reasoned argument.


It’s not exactly a hunch, either.


As far as I know, there was no November 10, 2023-style plate separation event, with powerful quakes and a Great Magma Run, before the Krafla event.


And it seems significant, for reasons that I cannot articulate, that the Fagradalsfjall fires occurred in the one system area that did not erupt in the last peninsula volcanism cycle; also, that the Svartsengi sill intruded close to the site of the very last eruption, in the 13th century, of that previous cycle (the Eldvorp craters a few clicks southwest of Svartsengi — see drone pano linked above).


It isn’t just magma pressure dictating events here, I suspect — it is the tectonics involved with mid-ocean ridge reactivation locally.


It makes me wonder if Earth is done with rifting episodes here — of course, it probably is. Enormous amounts of energy stored for many centuries were released on November 10th and that much stress hasn’t even really started to reaccumulate yet.


But it looks to these very ignorant eyes as though whatever tectonics shut down the cycle last time must be overcome to start the next cycle — and about a third of Iceland’s population, important infrastructure and energy suppliers, and key things like an international airport and the nation’s capital, must go along for the ride.


It must be so difficult to understand the geology here, let alone predict what will happen next, and yet so much is riding on their information and actions — I don’t envy Iceland’s volcanologists at all.


Okay, maybe a little for their helicopter trips and access to eruptions and other cool stuff.

Had to include that last part, too.

 

[bjdeming]

Regarding the barriers -- Grindavik's mayor in mbl.is (autotranslated), emphasis added:

...We have had to wait before, but the biggest concern is usually about where the source of the eruption will be. And if the wait is this long and the land giant continues and more accumulates in the magma chamber, we fear that the eruption will be bigger, there will be more flow and the crack will be bigger," says Fannar in an interview with mbl.is.

Can't stand endless effort​

Fannar says that in the past few weeks, work has been going on to raise the dikes and extend them, but it appears that they cannot withstand an endless flood with a similar amount as the last eruption. He says that this is a very uncomfortable situation.


"Pumping equipment has arrived in the country to be used to try to slow down the lava flow, and I think that everything that can be done has been done to try to protect the town and the structures in Svartsengi."...

That equipment is reportedly some high-capacity water pumps that the UK recently sent them. There are also water lines in place on expected flow fields, per news stories, and plans are to get water from the Blue Lagoon and the power plant (without disrupting residential drinking water supplies).

 

[bjdeming]

Soon, perhaps. This article (autotranslated and updated within the hour) is pretty good, although someone missed IMO's recent statement that there is a volume of more than 20 million cubic meters of magma down there.

Excerpt:

...

• 18.8.2024 | 16:53 | Updated 18:47

The biggest earthquake since the last volcanic eruption​

"It is certainly the trend over the past two days that we are getting slightly bigger earthquakes." Kort/Map.is

Agnar Már Másson

...

An earthquake of magnitude 2.5 was recorded northeast of Hagafell at noon today, and it is the largest that has been seen in the area of Sundhnúkagíga since the last eruption began in May.
In recent weeks, around 60-90 earthquakes have been recorded per day, but today they have already reached 100-120.

Jóhanna Malen Skúladóttir, natural hazard expert at the Icelandic Meteorological Office, tells mbl.is that the number of earthquakes is clearly increasing - and they seem to be getting bigger.

Other parts of Iceland are rocking, too. Per the current IMO geoscientist note (autotranslated):

Comments of a geoscientist​

Yesterday at At 04:39 there was an earthquake of magnitude 3.1 in Bárðarbunga. Earthquakes of this size are very common in Bárðarbunga.

Yesterday at 16:55 the magnitude 3.0 earthquake occurred in Mýrdalsjökull. One aftershock followed and there was no subsequent unrest. Quakes of this size are rather common in Mýrdalsjökull...

This is the first I've noticed that they don't give the note's time. News reports via GT translation have said that IMO is "on standby" for a couple of weeks -- perhaps now "the situation is fluid"?

Myrdalsjokull is Katla, basically.

Bardarbunga, mostly hidden under Vatnajokull's ice cap a little to the east of Myrdalsjokull, is where that spectacular Holohraun fissure eruption happened in 2014-15. After that, its caldera collapsed and it went to sleep again. It is slowly waking up, IMO spokespeople have been saying for months now, adding that it is not connected to the Reykjanes Peninsula activity.

Askja, just northeast of Bardarbunga and not subglacial, appears on the quake graphic on and off, and it does have its own thing going, as does Katla.

There is a very large swarm at Hengill right now, just one of several swarms there recently.

Not mentioned in that particular note but likely relevant to the peninsula are the powerful quakes on the Snaefells peninsula over the last week or so.

I'm not sure about Hengill's relevancy.

It is where the Reykanes ridge and the rest of Iceland's structures first meet up (a "triple point" between the ridge, the Southern Iceland Seismic Zone, and the Western Volcanic Zone), so yes, likely related.

Then there are Eldey's swarms of rather large quakes (with a swarm currently showing on vafri.is) along with a couple active seismic centers on the ridge farther offshore.

Stress triggering caused by buildup of pressure underneath Svartsengi is probably behind some of those recent quakes at Eldey, anyway; the others, ?, but I believe that they do occur on the basalt "continental shelf"-like plateau that encircles the island, built out of lavas from excessive hotspot melting.

The hotspot, by the way, is considered to be centered under Vatnajokull and adjacent areas.

This layperson still thinks that tectonism is playing a big role in these Reykjanes fires. The boffins' carefully bland-sounding public statements are a little frustrating sometimes, but they know that there are no direct data on processes that make the peninsula's volcanism wake up and that there could be surprises at any time.

That's even before you factor in the hotspot and interactions between it and the mid-Atlantic ridge, as well as how little detail is known about how mid-ocean ridges work -- all of Iceland is the "transform" zone between the Reykjanes Ridge segment and the next one up, called the Kolbeinsey Ridge.

Volcanologists are doing the best they can in a very challenging situation.

 

[bjdeming]

Still waiting.

Here is a view from the street (also, incredibly beautiful Icelandic scenery):



Gylfi (Just Icelandic is his YouTube handle) isn't happy with the Met office (IMO) forecasts, both geologic and meteorologic. There is some gorgeous cloud/landscape footage, BTW, at around 5:25.

Yet he ends the video by calling the Reykjanes situation a guessing game, just as IMO has been doing, sometimes even using those exact words during media interviews.

Part of the problem is public confusion whenever volcanologists don't speak with one voice -- one of the recommended "best practices" for professional fire-mountain forecasting.

Come to think of it, Armann and Thorvaldur don't appear in the media much these days.

But unfair as it is, meteorological offices, even when they don't also cover volcanology, do serve as public kicking posts in hazardous but uncertain crises.

He doesn't mention Hofsjokull, BTW; it's joining in on the current land dance, too.

The potholes shown are probably on an "F road." These get you to remote locations in central Iceland, where no permanent settlements exist. Their quality failings are infamous, I understand, and not only because they cross shallow rivers -- not by a bridge.



Is that a motorbike in one of those shots?

 

[bjdeming]

Seven hours ago, IMO got about as definite as I've ever seen them:

Magma flows and even eruptions in the Sundhnúks crater series can start at any time​

Increase in seismic activity over the weekend​

19.8.2024



Updated August 19 at 10:00 am

• Increase in seismic activity at the magma tunnel this weekend
• About 110 earthquakes were recorded yesterday, last week there were about 60-90 per day
• More than 50 tremors since midnight
• Seismic activity is very similar to the activity in the days before the last eruption
• Landris and magma gathering at a similar pace in the last few days
• The volume of magma under Svartsengi is estimated to be more than before the last eruption on May 29

In recent days, there has been an increase day by day in the number of earthquakes around the Sundhnúks crater series. About 110 earthquakes were recorded yesterday, August 18, but last week there were about 60 to 90 per day. More than 50 earthquakes have been recorded since midnight today.

Most of the earthquakes measured are below 1.0 in magnitude, but during the weekend two earthquakes were measured above 2.0 in magnitude. One of them was a short distance east of Sýlingarfell and the other between Hagafell and Sýlingarfell. The latter had a magnitude of 2.5 and is the largest earthquake recorded in the region since the last eruption.

The current seismic activity is very similar to the seismic activity in the days before the eruption that began on May 29.

In the future, it is likely that the Sundhnúks crater series will be affected by magma flows and even volcanic eruptions.

Three and a half hours ago, there was another Grindavik 2-pointer along with more swarming. Again, "magma flow" is how GT translate the Icelandic word(s) for dike intrusion.

With these unprecedented stronger events near Grindavik, combined with other swarms in Keiilir (Fagradalsfjall), Hengill, and those recently on the Snaefells peninsula, I wonder just how powerful a dike intrusion it might be on a scale running from the usual microquakes this area experiences in between eruptions to last year's plate boundary shift on November 10th.

That can't be predicted, of course.

(Gets the popcorn popper out...)

 

[bjdeming]

Spectacular view of aurora on live webcam focussed, from some distance, on the entire flow field, which is still dark. The moving lights are work teams doing everything they can before the eruption comes. (Link is Icelandic so the video will work; just run it through your favorite translator for the text.)

It's time-dependent, so here is a screenshot:

 

[bjdeming]

It's chilly up there, and some folks in Reykjavik and environs know it. They've been without geothermal heat for over a day, and reportedly the system won't be fully pressurized until later this week. (Source, again in Icelandic because of the video.)

The authorities have switched over that heating system somehow. I don't understand the local business names and/or local references in translated news articles; and no article I've seen has said anything connecting it to the peninsula volcanism; but my guess is that it might have something to do with that low-temp geothermal source, out on a peninsula near Keflavik and away from likely lava flows, that will serve as back-up survival heatinf in case the Svartsengi geothermal heat ("hot water") supply route, or the plant itself, gets breached by lava over the winter again.

 

[bjdeming]

State of emergency declared and Grindavik is being evacuated, per RUV (autotranslated). Nothing shows yet on the cams (RUV mosaic covers a broad area):

 

[TornadoFan]

It just kicked off!

 

[bjdeming]

IMO hazn't updated the former update text, but their front page (GT):

magma run has begun. Volcanic eruptions are likely to follow-22.8.2024​

Updated August 22 at 21:25
At 20:48, an intense series of small earthquakes began in the Sundhnúks crater series between Stóra-Skógfell and Sýlingarfell.

Increased pressure in boreholes has also been observed. These are clear signs that a magma flow has started and that a volcanic eruption is likely to start as a result.
The news will be updated as information is received.

So there's a dike intrusion ongoing. Will it break the surface?

 

[bjdeming]

 

[bjdeming]

RUV live updates (autotranslated).

Here's a screenshot from the same cam as that northern-lights screenshot the other day.

A bit brighter now. That work they were doing on the Sylingarfell wall to protect the power plant is or soon will be tested.

It's going to be tough at Grindavik, too, even if the lava doesn't get into town via the Hagafell cracks.

 

[bjdeming]

There are very intense spotlights in Grindavik, on mbl.is' Hagafell cam, pointed at the barriers, plus blue flashing lights on the other side of the old lava flow -- watching for any signs of increased heat in those cracks, I bet.

By the way, Iceland is having some heavy weather right now, with winds rocking some cams. The evacuations reportedly went well, though.

 

[TornadoFan]

There was a magnitude 4.2 quake.

 

[bjdeming]

Visir cam shows the lava and the power plant:

 

[bjdeming]

There was a magnitude 4.2 quake.

RUV reported there was some uncertainty about whether it had anything to do with the eruption but it's weird. That hasn't happened in other eruptions, I think. Sigh.

 

[bjdeming]

Those new fountaims to the north are bigger ones. Why should that area be more pressurized?

 

[bjdeming]

Half an hour ago, RUV: "The fissure now extends as far north as the fissure that opened during the eruption in December last year. There is a lot of seismic activity at the northern end of the crater, but a magnitude 4 earthquake occurred around half past eleven..."

They turned the Visir cam to look at the vents, and the erupting fissure was extending northward a bit still, but then it stopped. The fountains there are highest in the whole line just now.

The good news: Little southward activity -- Grindavik might get a break.

The ¿bad? news: Layperson view only, but is anything going on between Svartsengi and Fagradalsfjall to the north?

 

[bjdeming]

It looks to me as though the first fountains are dying down, right about on schedule, but that northern group is intensifying; I still see no more extension yet.

RUV just now:

...

The greatest power in the crack on the north side​

The greatest power is in the northern part of the eruption, and the activity is much further north than has been seen in this amount before, says Jón Haukur Steingrímsson, geoengineer at Efla.
Jón Haukur says that although the activity at the southern end of the fissure has decreased, the lava flow from there will probably reach Grindavíkurvegu sooner rather than later. Further on is Grindavíkurveg where the crack stretches to the north.
Jón Haukur says that it is in itself good news that the activity is greater on the north side, away from the main risk areas in Grindavík and Svartsengi, but there is a certain uncertainty about what scenarios can arise since there has not been so much force in a crack this far north before.

Jón Haukur Steingrímsson.RÚV / Guðmundur Bergkvist

And in an interview with Magnus Tumi posted about five minutes ago:

...
Is there no danger of this extending too far north and threatening the infrastructure in the north of the peninsula?

"Then it would have to behave completely differently than the other eruptions have done. These eruptions are very powerful for the first few hours, and then the lava flows farthest, but then there are much weaker phases that last longer, but they still pile up closer to the craters. It's best not to say anything, but the outlook is brighter than last time. It's far too early to start worrying about the Keflavík road or something like that, it's far from that," says Magnús Tumi.