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Iceland's Fagradalsfjall Fires

bjdeming

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Just FYI -- this is how an Icelandic fissure eruption starts. It was the July 10, 2023, Litli Hrutur eruption, which you can look up here (weekly reports are best).

It's also an excellent video that I just found; as mentioned somewhere in this thread, this is the one where Magnus Tumi was up on the hillside, politely following journalist instructions re: positioning, while probably wanting to do exactly what this man does (with more science mixed in).



Of note, see the intense fumes as the ground cracks open? There is no hint of anything approaching that in Grindavik, even with magma less than a kilometer down. I've seen tweets from reliable sources that suggest the boffins are puzzled by this "weak" SO2 degassing (though still strong enough to call for that evacuation).

Gosh, I hope this doesn't happen in Grindavik.

BTW, that was a 900-meter-long fissure. In a meeting over the weekend, Magnus Tumi said the oncoming eruption fissure, if it happens, could be 8 km long.
 
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bjdeming

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You sometimes see ground water changes in volcanic unrest -- wells dry up or overflow, etc.

This might be an extreme example (from RUV):

Staðuvatn at Grindavík has doubled in area​

In the Facebook post of the Southern Volcanoes and Natural Hazards Group, there is a graphical representation of major land changes at Grindavík, where ponds and lakes have expanded.

It says that the lake at the southwest corner of the town, at a place sometimes called Vatnsstæði, has almost doubled in area. The locals have never seen such large floating areas there.

This is due to a landslide [suspect mistranslation, ? deformation] that has occurred following a magma intrusion under the town. The land under the lake is on the southern edge of the area that has sunk the most, about a meter.

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fri_20231114_231527477
 

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"Everyone has to leave Grindavík​

For safety reasons, Grindavík is being evacuated after the Met Office's gas meters showed an increased SO2 value. This is not an emergency evacuation and the town will be evacuated in an orderly manner."
A geology professor's take on that and other information:

 

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Per RUV about an hour ago, earthquakes have increased since midnight (almost three hours ago) but an IMO representative says that there is still no sign of an eruption.

According to mbl.is (autotranslated):

More than 1,600 earthquakes have been recorded since midnight in the area surrounding the Sundhnúka crater series, and the most at the northern end of Grindavík and at Hagafell.


This is what Bjarki Kaldalóns Friis, a natural hazard expert at the Icelandic Meteorological Office, says in an interview with mbl.is.


Most of the quakes are at a depth of 4-5 kilometers, like the last few days, and Bjarki says that relatively little has changed since yesterday.

Jón Frimann reports, among other things:

  • There is strong wind on Reykjanes peninsula. That normally hides some of the smaller earthquakes happening. Icelandic Met Office continues to record 700 to 3000 earthquakes each day. Most of them are along the dyke and most of them are in the magnitude range of Mw0,0 to Mw3,1. With the stronger ones happening least often.
  • Inflow of the magma into the dyke is at the writing of this article around 73 m3/s to 75 m3/s. On Friday 10. November that inflow was 1000 m3/s.
Earthquake viewing page.
 
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bjdeming

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Just getting up to speed today, and it looks like the situation is unchanged. IMO's current update reports that some of the regional magma intrusion seems to be hardening -- but not in the magma tunnel area (again, that is an appealing informal term for the scientific word "dike").

Magma continues moving through the "tunnel," and if I understood them correctly, the regional feed also continues overall. Sigh.

One cool thing noted by IMO, who credits HS Orku (the company running the power plant), and also reported:



Don't know about other places, but Iceland has been using this new technology (jargon alert) to monitor volcanoes that are underneath glaciers -- they laid out a network of fiber optic cables over the ice cap covering Grimsvötn last winter, and it worked well.

Here is a little more about harmonic tremor. It's not a perfect comparison but close because of the hot spot.

At subduction-zone volcanoes, such tremor can be terrifying. For example, in 2010, as the climactic phase of Mount Merapi's VEI 4 eruption approached, on Java, the tremor felt like a high-scale Modified Mercalli earthquake, miles away from the volcano.

This will not happen in Iceland, although as everybody found out last Friday, magma can shake things up as it muscles its way through solid rock.
 
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bjdeming

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Meanwhile, it looks like they are going with a shorter barrier, at least for now, to block lava from the Grindavik/Hagafell (?sp) area as the most likely eruption site.

Smart move, considering an eruption could start at any moment (or not). Over the longer term, it's likely that much more will be needed.

It's in Icelandic but there is a diagram of the planned barrier.

 

bjdeming

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Here we are:



Again, the barrier protects the Svartsengi geothermal power plant, which has some 30,000 customers, I understand.

I haven't read this anywhere, but there might be concerns, too, as there were during the 2018 Kilauea eruption, that an event with lava covering the plant might trigger explosive release of the nasty gases and brines that are a side product of geothermal energy production, if the wells aren't capped.

Not saying that this is a concern in Iceland, only that it was when lava approached a Hawaiian geothermal plant in 2018 (but stopped in time).

That plant came back online a year ago but is controversial.

 
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bjdeming

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The new cam, on Husafjall and pointing across Grindavik to Hagafell -- the main expected eruption site area now (just north of Grindavik to the hill), if one occurs, doesn't seem to be affected by the outage:



Place name map (source):

f-_drkcxuaa9wmo.jpg
 

bjdeming

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A sobering update from Jón Frimann just now -- a layperson; it's unofficial; but his accuracy thus far impresses me.

Re: the Grindavik power outage, guess it was new developments after all :( :

Parts of Grindavík town has lost power, hot and cold water because of sinking of the ground and movements. Emergency repair is going to be attempted tomorrow if it is safe.
 

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This might be a good time for some [LAYPERSON SPECULATION]: Every eruption is different but this one has some unusual features because of its setting on the Mid-Atlantic Ridge.

Not every eruption is going to trash a town this badly (though see my note above on Merapi 2010; there are other examples, notably Nyiragongo's 21st-century eruptions wreaking havoc on Goma, in the Congo).

I think -- for reasons mentioned in a recent update on the blog -- that this (not just the current crisis but also the earlier Fagradalsfjall Fires) might be less the "ordinary" volcanism that most of us are ever likely to experience and more of a mid-ocean ridge magmatic event centered (if you believe Páll Einarsson in a very academic 2020 video discussion) under the power plant, Blue Lagoon, and Grindavik.



His opinions might have evolved since then, but this layperson is impressed that he called the current trouble site precisely in 2020 (the video is in response to the strong earthquakes that happened throughout the peninsula long before lava first broke through the ground in Geldingadalir valley).


In an earlier post in this thread, I mentioned that the Reykjanes Peninsula might be on the North American plate. That was incorrect, per this video.

The Ridge is the peninsula. Reykjavik is in North America. Grindavik might be sitting on Eurasia, or perhaps it (and everything around it) has been sitting on a segment in the central spreading valley, inactive until ~2020, with Eurasia a bit farther east.

In any event, it looks to this layperson as though the rifting (sinking) that Jón describes is connected to mid-ocean ridge spreading rather than the sort of thing that volcanism would do in another setting, in terms of intensity.

Oh, it's still the same process because physics, and the Icelanders are handling it fine because this sort of thing happens in Iceland (and farther inland they also have to deal with hot-spot effects, explosions under glaciers, etc.)

What is probably going to happen over the next several decades to century or two is that the Fagradalsfjall-Elvdorp part of this map (source, autotranslated) --

1260836.jpg


-- is going to fill in like all the other segments where color indicates geologically recent volcanism.

To Icelanders, I imagine, this is just the Fagradalsfjall Fires (if that's what they eventually name it, though Elvdorp appears involved, too). The consequences, such as the possible loss of Grindavik, the need for widespread infrastructure protection and so forth, is tragic, but they know it's only because the land fooled them, with an eight-century quiet, into settling here.

But to us outsiders it seems like end times -- Houses being ripped apart! Harbors and possibly urban areas sinking into the sea! Dogs and cats sleeping together! (The cats, and some 285 Grindavik domestic animals, are rescued, BTW.)

It's not end times. It's just Iceland being Iceland and only comes to world attention, as Dr. Willsey noted in that last video, because a populated area is affected. [/LAYPERSON SPECULATION]

Things could change but I just wanted to lessen fear, here outside of Iceland, that a neighborhood volcano could act this way -- it won't unless you happen to be on a mid-oceanic spreading ridge that's also a hot spot.

The best way for you to figure out what to expect from your neighborhood volcano -- or one where you might be traveling -- is to check online volcanology sources. This is a good place to start.
 
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bjdeming

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Another night of waiting; no new developments. I did see a post concerning ER visits but couldn't translate it all -- apparently ERs are very busy. (Update: Per a new post in this thread, it's COVID.)

Stress and traffic accidents -- though these latter are not an issue during this well-managed, long-duration crisis -- can be killers during volcano emergencies. And this waiting must be terrible for everyone locally: I noticed the cam viewer numbers shot up from about 6 a.m., local, onward.

Watching and waiting...

Speaking of which, I'm usually not online between about 1000 and 1900 UTC (which is also Iceland time), if anyone here is in a position to do some of that watching and waiting.

Saw this. The video is in Icelandic but the graphics present a good overall view (and are heart-breaking when they show the down-drop):



The last updates, mostly from yesterday, mention the area north of Grindavik to Hagafell as the most likely eruption site, but a number of sources also include Sundhnukur as likely.

Others also mention that eruption at one of the earlier Fagradalsfjall vents is a possibility, too, and mbl.is has a couple of cams over there, streaming live from Litli Hrutur (where that video on the eruption start was filmed).
 
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Magnus Tumi is coauthor of this paper (autotranslated) discussing Grindavik-area lava flow paths in various eruption scenarios, posted today on the Icelandic Web of Science page.
 

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There really isn't any new development, but RUV presented this two hours ago (via browser translator -- Google Translate doesn't well in RUV stories now; it's okay on other sites):

Eruption likely in the next few days​

Kristín Jónsdóttir, head of the volcanic activity department at the Icelandic Meteorological Office, believes that the most likely scenario is that an eruption will begin in the next few days. However, the situation of earthquakes is similar to the last day.

"We are seeing seismic activity in the magma tunnel. We think it is most likely to have an eruption. We are seeing signs that indicate that the magma has reached a depth of several hundred meters," says Kristín. Therefore, there are more chances than less that an eruption will start.

The most likely location of the fountain is in the middle of the corridor. "There is of course the entire magma tunnel underneath, but we are seeing the most activity in the middle of the tunnel. So that's the most likely place, but it's just west of Hagafell," she says...
 

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Still no news, although the latest IMO geoscientist note, a couple hours ago, reported 2,000 quakes since midnight on the 16th.

Just wanted to share this explainer thread with diagrams -- it's helpful, though no one yet knows why the magma isn't coming up after being high-volume and high-pressure enough last week to rock the peninsula and force open an old fault.



BTW, Dr. Willsey made a good point in one of his videos: there aren't that many people in Iceland, and Grindavik contains 1% of the nation's citizens. It's also an important commercial fishing center.

So the evacuation and damage has an impact on the country similar to what would affect us if, to use Dr. W's example, Chicago was evacuated and badly damaged.

He didn't mention it, but if that fissure eruption occurs at sea, there goes Grindavik's harbor.

Just awful, any way you look at it. But they are hanging tough.
 

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They interviewed Dr. Einarsson (autotranslated, more or less).

Geophysicist Páll Einarsson says it is difficult to assess the future of the Reykjanes Peninsula. All possibilities are still open and it is unclear which possibility will be on top, whether there will be an eruption or not.


Earthquakes on the Reykjanes Peninsula have been frequent over the past three years. Five times, corridors have set off from the magma chamber with the accompanying earthquake, but only three of them have reached the surface, according to Pál. The fifth is still unclear.
 

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Just an update -- no changes, as the English tweeter notes. The graphic retweeted, from those "volcano chasers" in the Canaries, shows only the area of greatest concern (per IMO, there is activity throughout the dike and rifting does continue, still at a slower rate).

 

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This is the lava-barrier goal, based on that area of concern, and as he notes in the thread, you can already see a barrier in one of the cams. :cool:

 
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