Mount Thorbjorn
Foreword
Like minds and all, both me and Albert set out to write an update article unbeknownst to each other. I guess that Albert has not yet fully come to grips with me returning back to “life”. But, this is a good thing for you as a reader, you get twice the fun from two different minds as a nice weekend surprise.
Albert is the top part of the article, and I will be down far into the bottom.
/Carl
Thorbjörn Update by Albert
Credit: Astrograph. Click here to see a high resolution 360 degree panorama in Google Maps of Grindavik, taken on 4th July 2021, with the first Fagra eruption in the background
O what a night.. At the last count, there were 252 earthquake of magnitude 3 or more, the largest at M5.2. That is 252 stars on the map, scattered all over the place as the automatic locator cannot cope with this amount of shaking. It is Christmas come early, with 252 stars of Grindavik. The evacuation of Grindavik adds another semblance of that first Christmas story. But so far, it is a lot of noise but no action. The magma has (so far) remained underground.
To recall, this all started with inflation over an area centred roughly on Thorbjorn, ‘child of Thor’. Thor, according to wikipedia, is a “hammer-wielding god associated with lightning, thunder, storms, sacred groves and trees, strength, the protection of humankind, hallowing, and fertility”. We get our name for Thursday from it. There is certainly a lot of thunder and hallowing going on at the moment – but the protection of humankind has been deferred to the lesser gods of the Icelandic authorities. They are rather good at it and overnight they evacuated both Grindavik and the power plant. Work to protect both against future lava flows has been started, by building embankments of several meters high. It worked for the flows two years ago, although in one case only because the lava did not actually reach the wall. The sign ‘lava – no access’ appeared to be sufficient. The risk, of course, is that a wall may deflect lava onto some other property, raising questions of liability. But not knowing where lava will surface makes planning more difficult.
The following map was uncovered by one of our commenters. It shows how far lava needs to travel to get to Grindavik from various locations. At the moment there is no ‘most likely’ location along the rift. The further north, the better, obviously.
It started mid October when inflation took off. A sill formed with an inflow of 5 m3/s. Over three weeks, that amounts to 10 million m3, or 0.01 km3. It added to previous intrusions which had been happening since 2020.
Why a sill? A sill is a horizontal magma layer, which pushes up the layers above it. This is what is causing the earthquakes and the inflation. The earthquakes happened at 5-6 km depth, suggesting the sill was just below this. How does it form? Magma in rock has to find a weakness, a crack where it can insert itself. This can happen at a place where two different layers connect, for instance where the lava pile which has build Reykjanes lies on top of the oceanic crust below. The two are already a bit separate and magma can prise them apart. This happened over an area of up to a few square kilometer: the sill would have been 10-20 meters thick, in my estimation. There is minor magma around than is in the sill: it has a feeder system below although we don’t seem to know where this feeder is.
Yesterday the sill found another weakness. To move up, it has top break rock and that is not easy in such an old, cold lava pile. So it looks for another connection which goes up. This can be a fault, but in this case it found something else: an old fissure system. The fissure sits on top of an ancient dike, and this dike means there is a vertical discontinuity between the rock and the dike. The first earthquakes along the fissure were several days ago, but yesterday it took off. The magma began to build a new dike along the side of the old one.
The magma moved up by 1-2 km but mostly moved sideways. The dikes here run along the direction of the rift, which in Iceland is SSW-NNE. Because of the spreading, it is easier for magma to insert itself in this direction. And now it went fast. As of this morning, the dike extended over 18 km, from a few kilometer off short to far in-land. That does not mean the magma has traveled all this distance. It means that the old fissure dike is breaking away from the surrounding rock.
So where is the magma? The GPS shows an indications. As this morning, Thorbjorn has sunk by 40 cm. This happened because the dike is forcing the rock apart. That the sinking is so much indicates the magma has shallowed. How shallow? My guess is 2 km but it is only a guess. Both Grindavik and Thorbjorn are moving northwest, but that is harder to interpret. Where would an eruption be? Impossible to tell. It can be anywhere along the line. The highest probability is in the original location which is east of the Blue Lagoon. There is a bit of a gap in the earthquakes and that can be a sign – or not. The second probability is indicated by the deflation – that would put the eruption in the harbour of Grindavik!
RUV put out the following (again taken from a comment)
“The signs of magma movement include significant subsidence in the Sundhnúkur craters, indicating that the magma might be shallow below the surface.
The southern end of the crater row is about 1 km from the nearest buildings in Grindavík and approximately 1500 meters from the Svartsengi power plant.
The Icelandic Meteorological Office notes a substantial change in seismic activity, moving south towards the town of Grindavík. According to the Icelandic Meteorological Office, there is a likelihood that magma movement has extended beneath the town of Grindavík.
The volume of magma involved is considerably larger than seen in the major magma intrusions related to the eruptions at Fagradalsfjall.”
Here is the onset of activity, with M2+ magnitudes twice per minute at one point.
An interferogram (thanks Gaz!)
And here is a list of cameras mentioned by our contributors
RUV
Other
View of power plant from Thorbjorn
Live from Iceland has views all over iceland, including:
Albert, 11 Nov 2023
Grindavik update by Carl
Grindavik, photograph taken by VC FB regular Roman Zacharij and used under Wikimedia Commons.
I promised everyone an update today, so here is an update about why I and every other volcanologist should go and drink some tea and ponder why we underestimated a volcanic risk. I will get back to this below.
This will mainly just be an update that I will edit as things unfurl, and I will throw in a little prognosis of what will happen, and where it will happen, based upon the situation at 11.00 Icelandic Time on Saturday.
Short Recap
Roughly two weeks ago Thorbjörn started to show signs of an eruption being possible as a secondary intrusion started, and a sill formed where magma accumulated.
On Sunday evening I felt confident that the prerequisites for an eruption was there based on GPS-data, spectrography over seismic data, earthquake locationing, etcetera.
And based on that data I pointed at a possible location for the eruption to break out, if activity had continued like that I would probably not have been far off, nor would IMO either, we are after all talking about as little as 800 meters between assumed centroids from our individual models.
IMO weighted GPS-data higher than I did, I tend to weight Earthquake-locationing higher. Both methodologies are solidly based on science, and give similar results most often, well similar enough to give an 800-meter difference. Something that in the greater scheme of things is not a lot.
Earthquake map by the Icelandic Met Office. Note that there are loads of “ghost-earthquakes” that never happened, this is caused by over-saturation of the system by signal reflections.
Yesterday at around 12.00 Icelandic time, Iceland decided to kick those models in the proverbial nuts and a dyke started to form that was NNE/SSW trending, putting the most likely location of breakout at Sundhnukagigar, East of Bláa Lonid (Blue Lagoon) and the Svartsengi Powerplant.
This later led to the powerplant evacuating the workers and going into remote controlled operations after some sort of minor accident that was probably caused by strong earthquake activity.
That part of the formative dyke rapidly stalled out, and the bulk of the activity switched down the other dyke leg towards Grindavik.
This forced the evacuation of Grindavik Town itself, a decision that was proven to be a very good idea, but perhaps not for the reason it was based on.
Right now, the dyke is hammering away South of Grindavik in under the sea.
What We Forgot
Let us leave aside the risk for an eruption, and the earthquakes, and even the dyke, and instead look at another side-effect of the earthquakes and the propagating and dilating dyke.
Iceland is truly spectacularly good at moving about, it is extending itself in all sorts of interesting tectonic ways. Faults spread and drift apart, micro-plates dance about and rotate… it is a mess of simultaneous movement.
One of those movements have a scientific name, and that is Graben-formation. It is when due to spreading-movement a lineament of land is dropping down into the void created by the spreading land.
Some Graben like the Eldgjá-Graben form sharp sides, and if you have your house on the exact spot where that side form your house will start to lean, or even fall on its side. But if your house is in the middle of the forming graben you might end up with your house remaining perfectly straight if you are lucky.
This happens in large caldera volcanoes; I saw a house topple over in Amatítlan in Guatemala in a single night from this phenomenon. So, obviously it is well known thing among volcanologists, and something we take into our risk-calculations.
This time though it had an effect that I am pretty certain that nobody had considered, but that we will do in the future when applicable.
Let us phrase it as a question. What happens if a Graben form under a town adjacent to the ocean, and the Graben continues extensionally into said ocean?
Let us begin with numbers as of 11.00 Icelandic time, the Graben has dilated 120cm and the Graben floor has dropped a whopping 96cm (I will edit this as often as I can).
This means that conversely the ocean level has risen permanently 96cm in Grindavik. Obviously, it is not the water level that has risen, it is the town that has dropped.
Grindavik is built so that 96cm is not drowning houses, there is a margin to account for storm surges etcetera, but that margin has shrunk with said 96cm, meaning that storms are more likely to cause flooding along the shoreline and in the port.
Obviously, this is now. If the Graben continue to widen and drop it will get worse.
My favourite Graben in Iceland is Eldgjá, it is 8.5km long, 600 meters wide and 150 meters deep. Obviously the Grindavik-Graben will not become nearly that wide and deep, but a meter or two more depth is obviously not out of the question.
So, there is an idea to look at those Volcanic Hazard Maps and see if another town is at risk of Grabening itself into The Big Fishtank in the Ocean.
Prognosis
Station GRIC 4-hour solution. Image from Sigún Hreinsdottir’s page.
Remember that this is based on data at 11.00 on Saturday, so take into account that conditions could change with time, it is a snapshot of “now”, and based on future trends that are realistic and congruent with previous eruptions of similar nature in Iceland.
I am writing the above paragraph so that even Charles Gregory can understand, hopefully, that a prognosis changes over time and with shifting data. I do though not have great hope of that.
Eruptions are statistical games based on data, and the length of a dyke is indicative of where it will erupt. Thorbjörns dyke has two dyke-legs based on the breakout point (feeder), the shorter leg is the one running East of Bláa Lonid, and the longer leg is running out into the ocean south of Grindavik.
On a purely statistical standpoint it is more likely that a longer dyke-leg will encounter a weakness that the magma can use to pop up to the surface.
What we know so far is that the Northern leg up to now remains dry (uneruptive), but there are faults that way that may in turn end turn up to be the weakest spot along the dyke.
There are also faults and weaknesses on the longer Grindavik leg of the dilating dyke, but they are a bit more spaced out. There is though one thing that is probably going to affect things more than everything else.
It is that the ground level is constantly dropping as the Grindavik dyke-leg extends and dip its Grabening foot into the water. This means that the distance a breakout needs to travel to the surface is decreasing since the overburden become increasingly thin.
Let us assume that the top of the sheet-dyke is 2km deep at the breakout point from the sill near Bláa Lonid, as the dyke goes south in Grindavik the height of the overburden drops around the point it hits the water and it slowly get deeper until it hits the continental shelf, and it drops below the top of the dyke. But the continental shelf margin is quite some ways out.
On top of that the Graben itself is fertile ground for an eruption to pop up, and on Graben margins you often get a formation of a crater row, see Eldgjá and Lakí just as a couple of examples.
In other words, based on current data a breakout is most likely from about a kilometre north of Grindavik down to a couple of kilometres out into the ocean.
As magma rushed into the dyke, overall systemic pressure has dropped, so for the moment the pressure is probably somewhat to low for continued lengthwise progress, and to form an upwards directed conduit, but the last is depending on how firm the overburden is and how much resistance it can put up.
Eldgjá Graben, photograph by Andreas Tille, Wikimedia Commons.
The diminishing systemic pressure is why we are seeing a drop in the amount and strength of the earthquakes (11.00), it is though still quite impressive.
As magma continue to enter the system from the bottom feeder conduit from the mantle pressure will though go up, and we will get increased activity again, and probably the expected breakout. This can happen anytime from a few hours, up to a few days.
But, at this point it is pretty much a sure thing that something will pop up.
Here I would like to make a point, normally the initial breakout is 10-20 percent from the furthest point of dyke propagation, it is not clearly understood why really, it might have to do with some sort of fluid-dynamic hammer-effect, but why and how is not well understood as I said.
If that will turn out to be true here, we will see the eruption start outside of the port. It would be a tad ashy as it breaks the surface and “rooster-tails” form, but as soon as it is above the surface ashfall will rapidly decrease.
In other words, do not expect the end of the world, well perhaps the fishermen of Grindavik have a different opinion, for them it might end up as the end of the world.
I have seen people “biggying up” the upcoming eruption to proportions it just can’t take. No, it will not be even remotely near the size of Holuhraun. That being said, judging from magma-influx and previous eruptions a likely figure would be a peak average discharge rate doubling that of Fagradal eruptions.
If memory serves that was 40 cubic meters per second during the fountaining phase of Fagradal II eruption, so perhaps as high as 80 cubic meters per second during the peak hour, and then slowly falling to 10 to 20 cubic meters per second.
If we assume the length of the eruptive episode to be somewhat equal of Fagradal eruptions, we end up with an eruption at around 0.1km3, and that is not a bad figure as sizes go. In other words, it will most likely be a fairly impressive tourist eruption, but nothing more.
If the influx is steady and continue, we could end up with a longer eruption and the amount of magma would slowly climb upwards. At the extreme end of probability, we get a small shield formation that lasts for up to a century, but that is a very low probability indeed.
As a final thing I would mention that I seriously hope that Grindavik will be affected as little as possible, and that the lives of the inhabitants soon can return to normal.
CARL REHNBERG
P.S. Charles Gregory, “Told you so”. It is now the third time you have been rude and wrong and gotten “I told you so’d”. I suggest pulling in your attitude and stop trying to bully people. I am definitely unbullyable if nothing else.
Is there a way for Carl to ‘flag’ his update to the post so as to differentiate it from the voluminous follow-up comments populating my inbox?
Not to my knowledge, we will see if one of the more codious dragons has an answer to this.
That would be a most appreciated service.
Are you talking about email notifications from VC comments? If you just wanted to see Carl’s comments, you could set up an email rule to only keep ones containing Carl’s name/email/account name.
It looks like the tremor at Grindavik is pretty strong.
http://hraun.vedur.is/ja/oroi/allarsort.html
Bugger Grindavik, the significant thing there is that the tremor is visible on every flaming seismo across the entire country! This is powerful.
The big bump that affected the whole country was probably a windstorm. You’ll notice that Grindavik is still showing tremor while the other stations are not.
Is the region above which the dike is struggling to find or make a path of least resistance to the surface known to contain enough ground water for a maar (god forbid) to form? Would there be any precursor signals for this? Can a maar form under the sea or is that particular style of eruption limited to subsurface water on land or is it called something else? I have no idea how stupid this question is due to my ignorance, so please excuse me if it is really dumb. Be gentle kind people.
You mean a Lahar?
A maar, if I translate this correctly to german, is what happens wayyyy after a volcano outbreak. When the magma chamber collapses and subsequently fills with water. Typically you have an insula at the center. Lovely places actually, and not at all dangerous … unless the volcano decides to erupt again. In this case it’s a boiling pot of steam that can make for an explosive eruption.
A Lahar is a flow of debris, basically fluid soil and rock. This happens in volcano eruptions when there is a shield of ice or other source of water (see above) spilling over and taking with it all soil and stone it can carry along. One of the most swift and deadly forces during an eruption.
Finally we have the pyroclastic clouds which is not unlike a Lahar but it’s entirely hot gas and dust. That’s what killed the remaining people in Pompejii.
No to all three. It’s not that type of magma (not gaseous enough) or landscape required, and for a maar to form we’d have to be VERY patient. There is no ice, no steep slopes, no big sources of water (ocean doesn’t count because water generally doesn’t flow upwards) but the ocean poses a different issue: water + magma equals steam, thus explosive eruption.
Definition of a maar from Wiki
“A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow crater lake, which may also be called a maar.”
Source: https://en.wikipedia.org/wiki/Maar
If the graben was there for long enough before an eruption, it might fill with water. Iceland has a wet enough climate.
The bigger risk now is whether or not there are existing aquifers (underground water reservoirs) in the vicinity of the magma. Or if the eruption occurred offshore.
Base surges are a concern, too.
A maar forms when overpressured underground water is heated to boiling. As the pressure drops, all the water suddenly flashes to vapour giving a very large explosion. When it is surface water, you can still get explosions if lava covers it but nothing as severe. (Still, don’t get too close either. Even snow can explode and throw rocks at you.) An eruption in shallow water can also be explosive and produce a lot of ash. I think it is the ash they are most concerned about in this case. Of course all boats are being kept well away.
Do Maars usually happen in sedimentary rock or sediments? If magma intrudes into a soft ground with groundwater, it behaves probably very different then if an intrusion moves through solid basaltic rock.
It is normally in soft ground. They occur in moist places so regions where soils form. People may know of examples elsewhere though.
Isn’t that what happened in Hunga-Tonga? Overpressured underground water suddenly vaporized and hence the extreme explosivity?
Fairly recent post – https://www.facebook.com/groups/887053998798488/user/100029714911853/ shows graben cracks and apparently steam coming up from one of the cracks? (in Grindavik) If so, then things are closer than we realize.
“page not found” for me
https://www.facebook.com/groups/icelandgeology/permalink/1508268803343668/?mibextid=zDhOQc
My guess is that the steam is from hot water pipes or similar infrastructure.
It’s just from pipes, you’ll see this all the time, a side effect of having geothermal.
Seismic activity has dropped dramatically. I think the eruption clearly failed.
Not at all. That happened before all three eruptions at Fagradalsfjall. The last push through the crust is aseismic. The silent period can last a few hours to a couple of days.
Or it is the dreaded „quiet before the storm breaks lose“….
sometimes it just goes quieter when the rock is not so hard to get through
The size of the earthquakes is decreasing but otherwise the swarm is still very active. Magma has made it through the brittle crust layers, which produced the bigger quakes.
Piton de la Fournaise often made a pause of seismicity before an eruption. It can be the calm before the storm.
Any chance the huge tremor seen across the country was an otherwise un-noticed underwater event? Like what happens in (what was formerly known as) Lo-hi?
The risk of that is non-existent.
The Icelandic network can pick up direction that the tremor is coming from, and there was none back then out in the ocean.
No, it was the point where the volatiles started to nucleate and the magma “foamed”.
Think of it as the worlds largest sodapop “fizzing”.
Thanks! The reason I asked about the possibility of a maar is that I seem to remember that there are two old ones on the side of the mountain with the blue lagoon and power-plant. This very much could be mistaken. I couldn’t find the article so it could be a fever dream of mine. What happened in the past, I thought, could happen again in the future so it got me thinking about the ground water on the current side of the mountain where the dike is currently active. Wondered if this awfulness of a maar steam explosion was on the bingo card of bad things. Thanks everyone!
I think it’s more likely that they get a Surtseyan eruption, but on smaller scale than Surtsey. Maybe like the Eldey eruptions around 100 years ago.
I followed with deep interest all 3 eruptions of Fagradalsfjall, every day.
This eruption, if it ever happens, is very anomalous.
I am convinced that a good part of the strong earthquakes are linked to the fact that the area is rich in water.
The magma interacted with the aquifers.
Actually, Fagra and this upcoming eruption are pretty much similar.
Both started with a deep intrusion forming an upwards conduit, both the formed a sill structure, albeit the one over at Fagra was small and shorlived, both formed propagating sheet-dykes that are NNE/SSW trending.
Both seem to prefer popping out on the Southern end of the sheet-dyke.
If we to through all the eruption since 2010 we end up with most eruptions in Iceland being dyke eruptions.
2010 – Eyjafjallajökull started with a dyke from a sill structure in the central volcano.
2010 – Central volcano stage of Eyjafjallajökull.
2011 – Classic central volcano eruption.
2014 – The mother of dyking bonanza with one central volcano shoting a dyke into Bardarbunga, that shot out another dyke to Greip, and then fired of an ungodly long dyke that plopped up as Holuhraun.
2020 – Formation of the deep feeder conduit of Thorbjörn, and a sill formation.
2021 – Fagradalsfjall, formation of a sheet-dyke and Fagra I eruption.
2022 – Fagra II out of the same dyke.
2023 – Fagra III out of the same dyke.
2024 – Forming of a sill, that turned into a dyke, and almost certainly Thorbjörn/Grindavik eruption.
If we go deep into volcanic history we will find the same pattern of dyke eruptions being more common than Central Volcano Eruptions.
To the best of my knowledge only Askja, Bardarbunga, Grimsvötn, Thordharhyrna, Katla, Eyfjallajökull and Hekla has had central volcanic eruptions since 1900. The rest of them have all been dyke eruptions (forming a very long list).
Thank you Carl for this informative and clarifying information, which definitely has helped me to understand Iceland volcanics. I do remember watching the Bardarbunga feeder dike gradually working its way northwards until popping out a the Holuhraun location. If you remember, some of the venting which occurred was to the south, but they shut down, until the 3 main fissure vents predominated. I also do remember a helicopter flyby in Oct where you could see the tremendous forces involved as the liquid magma sloshed back and forth in the southward part of the lake. Very truly impressive! One of my conclusions on this is that gas seems to power it all.
Also Krafla Fires 1975-1984 had a lot of dyke eruptions, and much deformation between the often short eruptions. Before Fagradalsfjall began its first eruption I thought that it would do short eruptions like Krafla, but it appeared to be much different. But Krafla has a real central volcano (and magma chamber) which can drive volcanism that is different to the volcanic systems on the Reykjanes peninsula.
The reason I did not put Krafla in the list of central volcanoes that erupted is that it was all dyke eruptions, but they did indeed form from the central magma reservoir(s).
So, sort of a series of mini-Holuhrauns.
OK, I previously thought that Krafla also included a continental rifting episode on Iceland’s American/European border.
The rifting is fairly constant at 2.7cm year at that point, but that tension is causing rifting eruptions all the time along there, and that often take the form of dykes forming as faults rip open.
It is a synergistic thing really.
There isnt any calderas in the area, but Svartsengi kind of does behave like a centralized volcano. This dike was formed at 1000 m3/s and nowhere on the planet has capability to generate magma at that rate, probably not even during the most extreme LIPs does the magma generation rate get anywhere near this.
So the dike here formed by magma that build up in the sills formed over the padt few years finding a suitable weak spot and taking its chance. The sills are basically like a magma chamber, not a big one like Bardarbunga has, or whatever formed in the 1700s to spawn Laki (presumably somewhere under Grimsvotn or in the general area nearby). But the nechanism is basically the same. It is presumably what has happened here on repeat for millennia, based on the many long fissures in the area. What isnt clear is if the magma is kept active when the eruptions stop, it seems not.
It will be very important to see the composition of this magma whenever it erupts. The Fagradalsfjall magma was weird, and apparently turned into a composition that was similar to Vatnajokull, and distinct from what has erupted on Reykjanes in millennia past. Now another volcano in the area is active it can be tested if this composition is some weird local geochemistry of a system waking up after 6000 years or if something fundamental is going on under the whole area. Or, if these two systems are connected at depth, which is not unlikely but has no proof yet either.
Does the sill mean that we’ve already witnessed the formation of a “magma chamber” below Svartsengi’s part of Reykjanes? Can the sill allow sustainable eruptions that last longer or with higher rate than the last Fagradalsfjall eruption?
Now waiting for an intrusion under Kristján Loftsson s home …. ; )
Now pondering why you want his house to be consumed in lava?
The whales know why.
One of those…
I will then cheer on Jesper in his divinations to put lava in his bedroom.
I like whales.
Woud be good with a dyke in the bathroom when he haves splort and the lava emerged through his grand throne… well well skip that
Anyway this insane whale addiction he have haves to be cured..
Well well .. Im just planning to send some of my pengiun saboteurs, sending special infiltrators that will emerge trough either through his toilet or the shower drain when Loftsson is sleeping at night in his bed
🙂 going to mess up the plumbing system
There is also a planned large scale invasion of Iceland that we are working on in Antartica .. trying to mass breed billions of giant gene modifyed Penguins as fast as its possible and arm them as fast as possible
( Penguins slapping Iceland polticans at the face 🙂 ) the whole Island is mine.. I Loves Iceland so much, after I have installed myself as the ”New ethernal leader” I will make Hallsgrimskirkja into my imperial palace my own Isengard and be served coffee by my penguin servants, all local Icelandic goverment persons will be replaced by my own pengiun crooks…and bandits and souch
Well well I have a Nordic Citizenship so moving to Iceland is very easy so I do not need to invade at all 🙂
You know this already happened, well, sort of. You might find this article interesting.
https://is.wikipedia.org/wiki/J%C3%B6rundur_hundadagakonungur
O wow but I dont need to do that since I have a Nordic Citizenship
I Will move to Iceland once I have more work experience
Loftsson will be inprisoned in a windy stormy lighthouse at Jan Mayen… IF my penguin takeover plan becomes real
But I can just move to Iceland anyway as Nordic
Does Iceland know its in a nationwide panic? https://www.dailymail.co.uk/news/article-12737847/Iceland-earthquake-map-locations-eruption-risk.html
Oh dear!
Does any Icelandic person even know what panic is?
At least volcanic panic?
I am fairly certain that has been genetically bred out by now.
I agree Carl. The world could learn a great deal from the Icelandic ability to deal with emergencies and how to rebuild after. I believed a lot has to do with a society that supports each other for the common goood and listens to the common sense and expertise of the authorities and p.ublic services
And teaching about disaster management in school is a very good thing.
Something we should start doing again in the rest of Europe.
They have a point actually. Because we probably should, a little bit, but no. Panicking isn’t cool.
spot on
I am NOT impressed with any articles put out by the Daily Mail. Already I had to correct a misleading article which somehow has Fragradasfall confused with Litli-Hrutur. I think these columnists are really quite ignorant of things, and under tremendous pressure then write articles which turn out to be really hack productions.
There is a reason so many people call it the Daily Fail.
Terribly written articles with very poor spelling, no proper research on the subject and mostly filled with rubbish from TikTok.
You are being overly generous to them, in that it implies their articles are possibly the result of incompetence and/or ignorance. They and The Express are the arch purveyors of sensationalism and click bait, they are fully aware that their articles are often inaccurate tosh.
@ Alice. Loved your reply/ Thanks. Growing older here too. Forgetful also. However some things I never forget like good friends, dalecks, sheep and long hours watching webcams and waiting. The science stuff is getting a little beyond me but and I cannot often keep up with things here. However I still lurk and follow even if I cannot add any useful comments. Warm hugs to all especially Carl and Albert and all the Oldtimers. My thoughts also are wiith the Icelanders who are affected .
Hello Diana!
Happy to see your friendly face around here.
Miss our sheepy discussions.
Baaaaa! You can’t keep a gppd sheep down unless it is turned on its back! I avoid that position these days as I need help to get back onto my feet !
Baaaaa! You can’t keep a good sheep down unless it is turned on its back! I avoid that position these days as I need help to get back onto my feet !……….. major typo. Apologies….Hands very shakey these days
Hi Guys! I’ve also crawled out of the woods to see what’s happening. Glad to see a lot of you are still around.
Well…
I do not know if I am the sort of person who want sheeps on their back. 😉
I prefer them to be galumphing about on webcams infront of volcanoes.
Nice to see your comments Diana, I have been around from before the birth of VC. Thankyou for the tip years ago on chewing sage leaves to ease a sore throat.
LOL johnMac. The funniest thing about growing Really old is seeing things I did fifty or more years ago being discovered by a generation who think they have discovered it! Here’s to our generation who were incredibly ecofriendly ,not reliant on GPS to find our way and were experts at Make do and mend. ( The GPS mention is because I have Just watched a fire engine with Blue lights flashing hurtling up our lane (again) If they had an OS Map they would see our lane IS a short cut to the next town BUT the Tarmac ends . Only pedestrians
and horses can manage the ancient track between the fields. GPS sends everyone down this way for some reason including coaches full of rugby, players, police vans and removal lorries. Gives us hours of entertainment!),,
We used to watch articulated lorries trying to reverse back up the road to the car park at our offshore emergency response centre, (they turned right at the wrong roundabout).
Yes, I mostly lurk too, when I have time. Like now in the middle of the night when I cannot sleep, I can catch up on comments when they are coming too fast for my tired brain.
After a weak of crossing the old continent Baltica by ferry to Helsinki (and back), I am a bit surprised by the rapid development on Iceland. I noticed that an earthquake swarm continued around Grindavik but missed the whole volcanic escalation.
Even all that has happened until now is a scary development for those who live around Grindavik. A digital earthquake swarm with microquakes that’s only observed by computers, is no problem. But if you get an analog sensible earthquake swarm that can well be felt by humans, it gets thrilling. The current earthquake swarm around Grindavik is even worse than that in the way that the earthquakes do damages to houses, roads and the whole ground. This Article of RUV publishes some photos of cleavages through roads and a golf course: https://www.ruv.is/frettir/ithrottir/2023-11-11-umf-grindavik-bydst-adstod-ur-ollum-attum-manni-hlynar-i-hjarta-396532
I think that Iceland government and agencies are doing a really good job. In particular I think that nearly all the weight is upon the Iceland Meteorological Office, who has to output reliable information when things are so uncertain.
Maybe you should write the IMO and tell them that they are doing a fabulous job?
They tend to read VC, so they are aware that we are generally positive with the work that they are doing.
They’re doing a wonderful job. I think we should also understand their mission. They have an important public role in supporting the whole public emergency administration. Their job is not to entertain online volcano tourists in the world.
It is a bit trickier than that.
IMO is also sort of involved in the tourist business since volcano tourism is a bit ticket for Iceland’s revenue stream.
And they know that we, among others, do a great job in show-casing these eruptions.
In a way they have sub-frenchised out part of the “information business” side to us, if you catch my drift.
Hence we are tollerated and sometimes even helped by them.
BBC tonight: https://www.bbc.co.uk/news/world-europe-67387827
50 years ago the Heimaey fissure eruption was essenial viewing on BBC2 every night – in colour !!
I have many times thanked the IMO. I agree they do such a fantastic job. Heimaey was another fine example of Icelandic thinking and cooperation. our TV was still black and white lol
Yep, black and white for us too. I had forgotten those days when the TV would start rolling upwards as you were trying to watch the screen. Then my brother would take it to a farm labourer he knew who was a dab hand at fixing TVs. Now I almost never watch television. Far prefer to read a book and have gleaned a few on Icelandic volcanoes from trawling second-hand book shops. Husband sees a bookshop and diverts me across the road.:)
Think we had got our first colour TV the year before – £300!!!
True. Iceland was also very lucky at Heimaey. If the eruption had happened 800 meters close to town, it would have in it. Nowadays there are many more more warning systems and hopefully such events can be foreseen better. The authorities were on the ball with the evacuations. I felt the Blue Lagoon was a bit slow but they had to deal with pre-paying customers.
I remember well watching it on the news every night but we only had a black and white tv
Eldfell is an aim for a future possible Iceland tour. It is easy to access and is a real young volcanic cone without volcanic (or glacial) threats.
I enjoyed the Heimaey part of the Krafft’s documentation. They had the unique skills to combine science with high quality journalism.
https://twitter.com/volcaholic1/status/1723482063796343179
Mount Dukono in #Indonesia erupted on Sunday, November 12 2023, at 05:31 WIT. The height of the ash column was observed to be ± 800 m above the peak
One thing that I would like to see Volcano Cafe comment upon , or release an article is the issue of public knowledge versus maintaining control during a potential disaster situation. Yesterday I was on a YouTube video feed of 4 Iceland web cameras monitoring the situation which also included earthquakes from the https://vafri.is/quake/#close webpage. One person in the chat stream stated that she had inside information on the 3d picture of the quakes occurring in the Reykjanes Peninsula, but then told everyone that she had to have permission to give out the link.
As you know, the 3d models of the quakes in Iceland in nearly real time don’t seem to be made publicly available, but it’s not due to a software issue or lack of information. Certainly a nice 3d display of quakes on a website could be made available. (perhaps I am NOT knowledgable and such links already exist, please post them)
But the impression that I got was that such detailed information would not be released publicly for 2 reasons: the public would not know how to make sense of it and unscrupulous people would take advantage of ignorance to both gain a following of accolytes and to also introduce fear (which is a powerful motivator) into the audience.
I have had some personal experience in this issue, having documented elevation rise in Mount Hood in Oregon in the 2011-2014 timeframe, but not being able to really share too much about this publicly, because of civil defense issues. I believe that I understand the need of government to maintain stability and order in society, but how can we balance this concern with people’s need to know, such as the situation right now in Iceland?
IMO is giving out information that the more serious “actors” have the skillset to make into 3D data.
Sadly unserious actors like DutchIncense have forced them to be a bit more reclusive and stingy on the data.
I full well understand that they need to way things on a scale in this regard.
But, I also freely admit to being a purveyor of all data I can get my grubby and grabbing hands on. 🙂
I am though always thankfull for the pieces of information that I get from them.
well put, Carl
It might well be for technical reasons too. The databases might be an in-house system designed for a certain load.
Now when things get spicy everyone and his dog wants an api-token to suck all the data, all the time.
If my forecasting and emergency planning is dependent on the same data source I would surely not jeopardise it by overloading it.
Cloud servers i hear someone say? Is there any AWS or Azure datacenters on Iceland?
Sadly these days you are right. Informtion is often used uunscrupulously and the IMO has to help prevent this. education is the answer.However what is considered essential is in the hands of governments and rightly we do not discuss politics here. maybe an old fashioned education including basic geology in the curriculum would help the understanding of the workings of the world we live in and how to accept natural disasters as part of this. Our responsibility is to find ways to mitigate the effects of these often unforseen but expected at some time , happenings
I don’t agree fully with your comment that we must mind our own business (if I am understanding your post correctly, please correct me if I am not). As a researcher and scientific investigator myself, I don’t like being shoved into a corner and told to be quiet. We need more trusting communications.
well said
I work in UK education. Geology is taught as it always has been to an age appropriate level including Volcanoes. It sits in the science curriculum not Geography, but Volcanoes / Tectonics are in both. Currently Geography is on the rise amongst post 16 students choosing the A level. Teachers have access to amazing animations and videos so I would argue the basics are understood by more students not just the higher achievers compared to when I started with a chalkboard.
However today there are so many distractions designed to keep young minds occupied with specialist teams of psychologists informing commercial online content from games to social media. There is research that this changes how minds work as they develop. Those of us who could only have B&W TV in our youth are very likely to only dream in B&W for example.
We have allowed those motivated by profit to swamp the information space. Education has to walk in to this headwind for which it is getting much better at tackling. I’ll go back to lurking now. 🙂
Well, some of us still have the Advancec 3d Bulge link bookmarked and hit it every ten minutes… I’m a bit reluctant to share it in case it gets overwhelmed.
unfortunately you gave it away.. I hope the server does NOT go down.
I really like this 3D earthquake map… it’s just missing an actual surface map, but at least it has the town names. https://skjalftar.is/3d/?size=1
If I’m interpreting that model correctly, it looks like there is a dyke and a large magma chamber where there are no earthquakes.
The graben extension may increase the risk in case of a Surtseyan eruption close to Grindavik. That may cause volcanic waves that threaten mainly the dropped parts of Grindavik.
1926 Eldey had the last Surtseyan eruption. So it’s not a whole century since the southwestern end of Iceland has had the last eruption! 1926 no island emerged, but I’d assume that an eruption of that size still would be a threat for Grindavik.
I think that ash and continued “Grabenification” are the largest threats if an eruption occur.
I am not overly worried about the waves as such, the harbour is quite sturdy with nice wave-breakers.
And, the town is picking up eleveation at a fairly good clip as you go from the harbour.
In your article you mention “normally the initial breakout is 10-20 percent from the furthest point of dyke propagation, it is not clearly understood why really, it might have to do with some sort of fluid-dynamic hammer-effect, but why and how is not well understood as I said.”
Can we already estimate how far off-shore this would be? I imagine that the worse case would be a very shallow eruption close to the beach.
I tend to agree with you, upon careful consideration of past events showing the 10-20% rule of breakout on the fissure line. Should we expect the likelihood of a close-in phreatic eruption next to Grindavik? The ash issue will be major if this happens.
I think it means on flat ground the breakout will be close to the point of origin of the dike. But rarely is this the only variable, the eruption will probably erupt at the point with the lowest durface elevation along the rift. The problem is that the area now is both flat but does have a gradient towards Grindavik so it us hard to predict…
However, judging by the way the crater row above looks, it is unlikely the eruption will be so localized. If ut is like Fagradalsfjall then an eruption now might be somewhat small but with constant magma flow into the sill it will just keep refilling and repeat.
There is also the problem that each such repeat-eruption would occur further up the dyke, same as Fagra 1, 2 and 3 did.
So, even if a first eruption happened at a safe distance, if another eruption occurs it would pretty much be sure to hit Grindavik, and a hypothetical third eruption would start above Grindavik and hit whatever is left.
I am here speculating darkly on things, so let us hope this will not be the case.
Speculative maybe but rifting fissures do tend to behave as such, its not alarmist to talk of the possibility just to claim it is absolutely the most likely and only option right now.
Although, things dont look good now either, all things considered 🙁
Yeah, not optimistic for Grindavik. One promising thing though might be that most of the fissure cone lines seem to peter out well short of the sea in that region. Of course that still has risk instead flows down on Grindavik.
3D map of earthquakes:
https://brew.is/quake
In the Catalogue they allow to put on map layers of the “Reykjanes-Svartsengi lavas” the more light colors show historical lava flows. They lie some km west of the current intrusion. But the line of craters is very parallel to the present intrusion. So we may get – compared with the Middle Age eruptions – a shift a few km to the east.
which catalogue is this?
This one:
https://icelandicvolcanos.is/
My favourite map resource when it comes to all things geological in Iceland is this:
https://arcgisserver.isor.is/?lon=-21.63763&lat=64.76294&zoom=7&layers%5B%5D=satellite
Here you can activate different layers and if you click on a lava field you get information about it.
Thanks for those links Tomas, they will be useful.
This one is lovely, too
https://map.is/base/@334519,377599,z6,1
Thank you for the links!
The Catalogue of Icelandic Volcanoes. The lava field “Eldvarpahraun” around 3km to the west of Thorbjörn and Grindavik was the lava field of historical eruptions.
The current dyke goes from the NW border of Grindavik’s populated area towards NE and SW. Towards the SW the dyke crosses the 425 road and leaves Iceland at Bjarnagjá peninsula where there is a small playground. If the dyke keeps this direction, an offshore eruption would happen in the bay of Hustoftavöllur. There a Surtseyan eruption would be relatively safe for Grindavik and mainly hurt the golf course of Grindavik and the playground.
Something to keep in mind about the ash in the case of a Surtseyan eruption just offshore of Grindavik ……Low level winds are from the east and will stay that way probably until Thursday. If the eruption were to reach higher levels, say 5-10km, winds will be from a more southerly direction. My guess is that ashfall from a Surtseyan eruption in the next few days might stay west of the town of Grindavik. However, it is probably worth pointing out that this would not apply to ash distributed by a base surge if the vent was close enough to the shore.
I’m a lurker that’s rarely commented, but I wanted to take the opportunity to thank all of VC for putting this together, it’s a lot of work and very much appreciated.
Alright, for my location prediction for the eruption location my vote is somewhere between the golf club/Arfaadalsvik Bay and 1km north of Grindavik. The southern part (okay for Grindavik, besides tendency for eruptions to creep up-dike) of that is in that sweet spot of 10-20% of the length of the dike in from the end on the longer arm of the dike. The northern part (very not okay) is near some higher ground which could cause subsurface awkwardness with surface implications. Of course there is the risk that this prediction looks *very* silly if instead it erupts at the other end of the dike a good 10km away from my zone…
Not sure the chances are actually very high of an ocean eruption. Dike parallels the ocean, but inland (which also means very minimal elevation drop), for a ways SW of Grindavik but at most the last 2km are in the ocean.
On another note, one thing I’ve noticed looking at when flows are dated is they seem to come in bunches 1000, 2000, 4000, 5000 years ago. Otherwise very little other than the post-glacial shields, would expect at least traces since plenty of turf that seems theoretically suitable to be drowned. So good odds only 4 ‘normal’ cycles before this one and not all of those seem to have effected all systems.
I wonder if we are overthinking Fagradalsfjall when it may have been nothing more than the luck of the draw. Like most of the area generally marked as part of the Reykjanes system doesn’t have anything newer than the shield. The current dike is a few km east of the 1100s eruption, maybe there will be another one this cycle a few km west of it. Which would be both be on land that hasn’t erupted in any of the cycles and clearly meaningless.
That is a good point. The volcanic centres on Reykjanes may just come from past events, and not be a useful predictor of future ones. Over the past 5 years, the intrusions have been in this area, Fagradalsfjal-Thorbjorn, which is (was) not a volcanic centre before. But will be.
One way of visualizing what is going on under Svartsengi and surrounds might be this: picture a dormitory with a row of beds crammed side by side, each with a box spring and mattress, with sheets over top. Magma comes up through one of the box springs until it reaches the bottom of the overlying mattress and begins to spread to the sides there, because it’s less work to push apart the layers than to dig vertically more. So, a lens-shaped pool builds up between mattress and box spring, which pushes up the mattress above, making it bulge in the middle.
That’s your sill and inflation, the activity from 2020 until yesterday.
Now the stuff’s expansion eventually reaches the nearest edge of a bed (= vertical fault, in this case alongside an old dike). It pushes up between two mattress, and pushes those apart sideways. (That’s the new dike.) The mattresses pushing apart opens a gap between them and the overlying sheets sag down above this gap. (And there’s the graben.)
A bit simplistic, for one thing completely ignoring the brittle-ductile transition, but that might help some to visualize what is going on underground there.
(As for the brittle-ductile transition, imagine the sheets overlain by crumbly pastry, which easily breaks when undermined.)
That is pretty much what I thought was happening too, that magma was forming a sill and all that was needed was a weak spot. Sills cant erupt but often turn into dikes at the edge, so the edge of the deformation we were seeing us what I was expecting to break and not the middle. I guess, eventually if the ground was pushed up enough there would be an axial fracture which could erupt but to get that would have required immense levels of uplift that would never happen before it escaped, not with such a fluid magma.
I did actually point out the swarm developing at tge Sundhnjukagigar fissure swarm before it went and did its thing. It could have just as easily done exactly the same thing near to Eldvorp, but maybe it preferred an older area that was less brittle. Either way at least for the next few years the new rift will probably be active, its not great but all the other eruptions in the area were extensive and fast, it wouldnt be a safe bet to think this will be dufferent. However I was wrong about the timescale, which I am thankful for. I thought that this would need maybe a couple more years and that when it broke it would erupt as fast as it went sideways… It went a bit early for that it seems, the end result in 5 years time may unfortunately be the same but it wont be associated with 3000 fatalities and that is important.
Should say preferred an older area that was less *hot* not brittle. Eldvorp is about 800 years old where the last eruptions in the Sundhnjúkagígar was apparently 2400 years ago, so 3x as old roughly. Its clear the ground in Eldvorp is still hot even now given the steam known to steam and the power plant is there, the magma may prefer colder ground to break at first then keep using that rift until it stops being supplied, whenever that is.
This geothermal area is another clue to there being crustal storage here. There is also geothermal activity near Stampar, and at Krysuvik and Hengill, while there is none at Brennisteinsfjoll or Fagradalsfjall. The volcanoes with geothermal systems do fast eruptions, the others do shields or similar slow eruptions. Whether you want to call all of these central volcanoes is debatable but I would personally. The designation is somewhat arbitrary anyway, if silicjc volcanism is required then neither Bardarbunga or Grimsvotn qualify, and if a caldera is required Hekla doesnt either,
Cold rock is easier to break than hot rock. Something that is ductile deforms and spreads out thus reducing pressure. Cold, brittle rock can’t do that. One could wonder whether the Blue Lagoon power plant had an effect. It circulates hot water at a few km depth and will increase the mobility of water there. It is too shallow to have had any effect on the intrusions themselves, but may have made it harder for the magma to break through below it, at the centre of the sill. Just a thought.
It’s quite interesting how different materials fail in different temperature regimens.
Take steel/brass as an example. A really cold (cryogenically frozen) alloy will shatter easily. This is how you force a pad lock using a bottle of liquid nitrogen and a hammer.
Room temperature steel you can smash away at until the cows come home.
And we all know the meme jet fuel can melt steel beams, but it for sure messes with it’s compressive strength.
So there’s the brittle – ductile axis and then there’s resistance to plastic deformation. Furthermore we have the atomic structure to consider. The more complicated (heterogeneous, amorphous, cracked), the more ways to fail. Cold basalt is a really complicated thing, a homogeneous ball of steel is a relatively simple thing.
And everything is dynamic too, so gradients in space/time matters. Even a small magnitude pressure gradients in time can be absolutely lethal, if the shock is narrow enough in time. Temperature gradients in space can easily mess up the hardest and strongest things.
Matter can undo itself in the most interesting manners!
(I’m mostly replying here on order to gauge when I can comment/like – had to reset my password)
Not 3k fatalities. Even at 1000m^3 per second, given it would likely open many km of ground in that scenario, most people would make it out though very likely some fatalities on NW side of town. Fortunately didn’t happen, largely evacuated and even if there are a few stubborn souls around should be slower eruption.
I guess the number isnt important, just that it is going to be 0
Axial fracture route might be a concern though for a certain WWII battlesite though… Whether you call them sills or magma chambers they are absolutely enormous by now and 100% ticks the immense uplift bit…
Adding new land to Iceland?
Nothing happened so far. Less seismicity somebody wrote.
Is there any possibility that lava is spilling into the sea “out of port”?
If a closed system is under pressure, and then suddenly the pressure is reduced, there must be an outlet. What about a submarine outlet?
I mean if we open a bottle of champagne in a pool we wouldn’t necessarily hear it, would we, but the pressure from the bottle would be gone. Pretty quietly. If instead we shake the bottle to enhance pressure, put it under a table (nice teak table called Grindavik) and leave it alone, the table might be in pieces.
No, we’d know if that happened, both visually as the dike doesn’t go into deep water and also from the earthquakes. The reason there is less pressure is the dike ripped open and so magma can sprawl out to some extent. It was so aggressive early on because the sill was getting squeezed out into the dike like toothpaste by the 4km of rock on top of it. Now it is reduced to the feed rate at the bottom and also expansion at the top of a dike (toward the surface!) tends to be less noisy than at the bottom.
Thank you for the double-piece, what a rare treat.
“Its good to have the both of you back” (the ballad of Carl and Albert).
I sure missed you, Carl, not because you are so great, but because you are both entirely different which gives a lot of charme to the site.
One is very precise, and because of being a British professor in an enviable position, also (overly) politically correct. I surely hope that we get rid of the politically induced correctness over the next ten years as it curbs freedom and free thought and debate. But very knowledgable and always eager to explain the background of things going on in the tummy of Earth, thank you for taking the time.
The other one being independant and therefore more daring and more willing to utter an opinion, not only in volcanism and tectonics, but also, in rare cases, politically (Nyiaragongo), and here the idea to take that event out of port, interesting.
So brillant to have the contrast back. Héctor, an outstanding author, is more sticking to his topic and is running aside of this competition.
So, what where you doing, Carl? Taupo, New Zealand like you once hinted at? Going north-east from time to time to see your family on the other beautiful border of the Pacific Ocean? Anyway, you might not want to tell – good to have you back here.
Who do you like more, my daughter tends to ask? Can’t tell is the answer. They are both great as a contrast.
As a reminder, first-time comments have to wait for approval, which is sadly necessary. There have been a number of new commenters with the Iceland situation. There’s nothing wrong, it’s just to make sure spam doesn’t get posted, future comments will show up immediately.
Grindavik now down by 1m20. They may want to re-site the proposed lava wall to keep out the sea as well. In fact, to counter future sea level rise, it might be best to keep the lava in and the sea out.
880 quakes since midnight
Between midnight and six this morning, 880 earthquakes were recorded on the Reykjanes Peninsula. All the quakes are below magnitude three. It has therefore been much quieter in the earthquake areas than the last two nights, despite frequent earthquakes: they are smaller than those that came before.
Elísabet Pálmadóttir, a natural hazard expert at the Icelandic Meteorological Office, said just before 6am that the activity was still highest just northeast of Grindavík. It does not extend into the sea at the moment.
“At least we see that the activity is not extending to the southwest. The greatest activity is just northeast of Grindavík. We haven’t seen any dips in activity either. This was to be expected. When the magma is this close to the surface, we don’t see such large earthquakes. It will be interesting what scientists say after the 9.30am meeting when they have all compared their data.”
Data received by the meteorological office at 2am and reviewed last night do not show much change and do not indicate that the activity is approaching the surface.
New sheep. Nice haircut:
https://www.dailymail.co.uk/news/article-12738129/Netflocks-Fiona-Movie.html
Just for fun: Today’s quakes from the IMO table (including non-checked ones) in an animation. Don’t know if the system allows animated gif for animated lurkers…
Colors are just defined so as to distinguish the points (roughly lat minus lon).
I think the magma was just shuffling around until it found a comfy space. It has a nice crustal blanket, it’s not interested in getting out of bed. It’s cold outside.
I think it’s over now
Well… As recent history has shown a few times now… The moment somebody on Volcanocafé says ‘it’s not going to happen’, it WILL happen VERY SOON…
Such is the rebellious spirit of Reykjanes… She’s not being told anything by anyone. This is probably the last chance to grab your popcorn. Today might be the day she shows her fury.
With all respect, these sorts of eruptions are rarely so simple… this dike could fail to erupt, or have a tiny (but possibly still very intense) eruption that lasts a few hours and does nothing. But magma is still flowing into the sill complex under Thorbjorn, which had significantly emptied to create this dike but still exists. As long as that magma flow continues then the new rift will keep rifting and the chance that somehow stays completely underground is unfortunately just not worth considering.
Rifts like this, fed by a central source and along a fissure swarm both directions, they often fail to do anything significant immediately, but repeated injection of magma fills the rift and also makes the path easier. Early eruptions are small but later eruptions are much larger because the magma is basically forced to go out immediately and not stay underground, and because the path is now so open the eruptions are fed at the same rate as the earlier dikes were opened. This dike that just formed had a peak flow rate of about 1000 m3/s, an eruption now will be slower but if magma can build up again and repeats the process it might go up immediately, erupt within hours and could well peak at similar values…
The only way that all stops is if magma stops flowing into Svartsengi. And, unfortunately, the only way that is probably going to happen is if a neighboring volcano steals it, which doesnt really solve the problem. The active cycle of the Reykjanes peninsula seems to last a few centuries, last time the area of relevance only woke up towards the end in the last 40 or so years of the cycle. This time around it has begun here. I wouldnt expect the magma to stop flowing in this area for the rest of our lives now…
Whats the chance for a shield? seems very possible with current setup or coud just be Krafla eruptions every year
Not in this system. Fagradalsfjall is a better bet.
I don’t think so, but I hope so. Or a better scenario might be a moderate eruption NE of Thorbjörn with lava flows that don’t mess things up too bad, rather than having a huge lump of eruptive magma just sitting under everything waiting to go boom when it contacts groundwater.
I doubt that. Once a dike is within 1km of the surface it is very hard not to erupt as starts degassing. It is still getting fed from depth it seems, that is just much lower now the toothpaste has been squeezed out of the sill. It took 3 weeks for the Fagradalsfjall dike to form and then erupt! It will do it at its own pace, takes awhile is back down to the longterm 5-10m^3/s to finish growing a rift that size. That versus the 1000m^3/s of the sill being squeezed out will mean less noise as slower increase in pressure. Also the top of a dike doesn’t tend to be *that* noisy.
I wondered where the famous golf course shots were taken and in which direction the cracks go. You will find the place just south of the main street from Grindavik to the peninsulas tip. The crevices seem to follow the general ‘fissure direction’ of that region, i.e. south west to north east. Looks for me (<-layperson) as if there were cracks before, covered by sand/grass?
63°49'50.38" N 22°30'41.93" W
Henceforth known as Golfagraben…
Thank mother nature for roots…
What I am thinking of? Well. Envision the magma-highway beneath Iceland as an upside down oak with the strongest roots mainly carrying the magma under and past Iceland on it’s way to where ever. From time to time some of the smaller roots leading upwards are activated. We don’t fully understand for what reasons and under which geological conditions this happen, but they do.
A root/canal is gradually filled. Sometimes it stops, sometimes it moves on to finer roots higher up. Grond cracks in the process creating eq’s. Some places have reservoars fairly shallow beneath the surface, some don’t. As in this instance. When “a root” is filled/pressurized something has to give if the infill from the first amentioned deep root continues. I’d say that happened friday.
Fortunately it found another dormant “root” (graben) to fill and infill continued mostly horizontally. Because it was a “mess” in there from last time somebody was there (and didn’t clean it out with gas) the fast flowing magma running into this shallow “root” met resistance and thus produced a lot of strong eq’s friday. Many plumbers were at work, probably at at 100% overtime-rate into friday night. Freshly plumbed and somewhat tectonical stretched it was (more than) big enough to hold the available magma under pressure wo. causing high renewed vertical pressure, thus giving time for the Grindavikans to leave in a safe and timely matter. Imagine if it only held 30% of the volume from what it probably does… When this “root” is full is anybodys guess, but it seems like it has room to stretch and heat for now.
So thank mother nature for “roots”.
A sunday fairly-tail. 🙂
They’re discussing letting people back into Grindavík for a few minutes to grab their things, rescue animals, etc. Surely it’s not gonna be allowed? If this is anything like Fagradalsfjall, an eruption is imminent. I have a bad feeling about this, what do you think?
When you take a look at the length of that dike plus a look at the heights above sea level you or I at least get to the question why the heck it should erupt on land when there is lots of room in the submarine realm.
I think that dike might have gotten longer since the two articles were written.
Heights:
https://www.flattestroute.com/elevation-Grindavik?utm_content=cmp-true
Not exactly parallel to the MAR, but not too far off. I am wondering about a new rift propagation:
Well nevermind, they are allowing it apparently. .
There are emergency services in situ. So providing it is well organised and done calmly (it’s Iceland, the don’t really do chaos and panic) risk for today is something they think they can manage.
Rescuing pets however, if the intent is to try and locate Tiddles the moggy who will probably be spooked by earthquakes, the old adage of herding cats springs to mind. That and the film Alien.
Right now might be the best time to do it.
And remember that theres thousands of animals left in town.
From RÚV:
“Less inflow into the magma tunnel but unchanged probability of eruption
The meeting between representatives of the Meteorological Office, Civil Defense and experts from the University of Iceland about the situation on the Reykjanes Peninsula ended at around 11 o’clock.
Magnús Tumi Guðmundsson, professor of geophysics, who attended the meeting, says that inflow into the magma tunnel has decreased. The probability of an eruption is the same as before, but the course of events in the last 24 hours indicates that the entire fissure will not erupt at once. Chances are that the eruption, if it happens, will resemble previous eruptions on the Reykjanes Peninsula in recent years.”
This is a rifting event, the problem with those is that as long as the source is still being fed then dikes will keep being intruded into the rift, and there is only so much space available. It is not uncommon for a rift to form with a huge dike that barely scratches the surface, it is the later events that are the biggest danger. If this dike fails to erupt then magma will resume filling the sills under Thorbjorn, and repeat the process again at some point. When that is depends on whether the dike drained out everything from the past 3 years or was just a result if the last few weeks. But next time it tries the dike that just formed will be in the way, so magma cant go sideways. So, it goes the only other direction it can go, up… at a rate of 1000 m3/s…
Oof. I really feel bad for the residents of Grindavík. Neither option is good, an eruption now or later.
Chad, can you explain why a (relatively recent) dyke is also in the way for a new intrusion? That’s one thing which is sort of a mystery for me. We also noticed it at Fagradallsfjall, the last intrusion ended up with a new eruption site and a new dyke. It would be totally understandable if the magma of the “old” dyke would be solidified or very evolved.
But I guess the magma in the dyke was probably still liquid or at least as mush. Wouldn’t it be much easier for a new batch of magma to join or mix with this magma and use the established pathway rather than fighting a new way through the rock?
Sorry if this a stupid question but I still don’t understand why some volcanoes are polygenetic and others not.
Polygenetic conduits are mostly driven by gas, I think. From what I’ve seen magmatic gasses can seep through rock breccia and open paths for the magma, I think a pipe of weak breccia is often the conduit of polygenetic cone/crater. Because tholeiitic basalt like that of Iceland is poor in water and carbon dioxide, the main magmatic gasses, it is not very prone to developing polygenetic volcanoes, each time a new sheet intrusion makes a volcano; dike in a fissure swarm or a cone sheet on the edge of a caldera.
Chad, I partially agree, that the past 3 years of inflation magma drained into the dike from the large sill, but how do you get 1000 m^3/sec when the actual feed rate is less than that? It would imply that the sill is blocked again from the dike and thus refills until the magma bursts through the obstruction back into the dike. My opinion is that the dike at 5 km depth or so, is going to stay hot for a long time and thus plastic open for any feed from the sill.
Randall; little suggests it is blocked again, but if the sill was heavily over pressurized at the time it found a way to spill into the graben the initial pressure and flow-rate would be high. Combine that with restrictions in the graben that had to be plummed, and pressure and flow falls when fully allowing the flow to enter the graben.
If you have real good waterpressure in your house you can see the same upon opening a tap fast or esp. when restricting a gardenhose and then reopening the restriction fast; more water at higher pressure intially until system equlibrium pressure is resumed.
So i seems we are in a resumed “normal inflow” phase after magma under pressure found the way into the graben. Which we knew from 2009 field-studies was there. Though it was estimated to be 3-4,5 km long if I remember correctly.
https://www.researchgate.net/publication/225556671_Controls_on_the_geometry_of_a_Holocene_crater_row_A_field_study_from_southwest_Iceland
Thank you very much for the science paper, much appreciated!
The feed rate is complicated. There is the magma supply at depth, that is what is listed as 7 something m3/s. At Fagradalsfjall that seems to get pretty much to the surface so eruptions tend to average around that, although the last eruption seems to have had some pressure behind it at the start. Svartsengi though is very different, that magma gets trapped and builds up for a long time. When it finds a weak point there is weeks of supply ready to go all at once, maybe much more. So the supply to the dike is way higher than the rate of magma generation.
Its literally the same as how a tiny stream that gets dammed can become a mighty flood if that dam fails, only it is magma and moving underground in 3 dimensions.
Perhaps I needed to explain myself a bit more, I am aware of the sudden pressure release into the dike which was rather dramatic, but can we not assume that now the dike has opened up that the lower sill inflation rate will take precedence even for when the magma in the dike breaks the surface? That is my understanding at the moment.
Brief update on Grabenfication!
It is now visible on the Grindavik cam that the ocean has “moved in”.
Port and houses are still fine, but what will happen during a high tide and a storm surge is beyond me to calculate.
Grabenification in numbers based on GRIC 4-hour plot:
North is now at 16.5cm, down from 19cm
East component is now at -33cm, in other words it is going West
Up-component is now a staggering -120cm but slowing down. In other words, Grindavik has dropped 1.2 meters down.
It is the down-component that is the real problem, it has slowed down, but it is probably gonna continue, especially when the dyke in the end start to empty out as the eruption start.
The final tally might end up being larger, probably beyond 2 meters of total drop, and that might be somewhat bothersome to fix.
What is clear is that if the town survives the eruption, it will still need to repair houses, roads, warehouses, civil infrastructure such as pipes…
And, also increase the height of port infrastructure such as docks and seawalls.
There is though a potential advantage, if everything survives the port will be able to take ships with higher draft, Grindavik got a costly dredging equivalent for free.
And there is not a port captain on the planet who wouldn’t be happy about a couple of more depth in the port.
Otherwise I am now waiting for the influxing magma at depth to raise the systemic pressure enough to set off the next earthquake swarm, I expect that to happen within the next 24 hours.
After that one we will probably see the onset of the eruption, I do not think the systemic pressure right now is high enough for the eruption to start.
But, as pressure rises the eruption could start if a tendril is high enough to break through silently.
Riveting stuff even for me!
As was noted yesterday, there was also a uplift before the slide down. So, looking at the GRIC GPS, we have 500-(-600)~1100 mm actual movement? Is this important? Surely not**, but I wanted to demonstrate that we are good pupils.
** Only in a dramatic action movie plot, where somebody (<- Mr. Craig?) is caught in a sinking Grindavik. Then the +10mm could be exactly a nose length …
Total uplift was 15cm, total down component is 105cm.
I would say that comparatively the uplift was inconsequential.
The significant westward movement could perhaps be caused by the dike not being vertical?
More likely that GRIC is on the westward side.
The downward jump suggests GRIC is inside the graben. That area should not move much horizontally. If it is on the west side, it should not have gone down as much?
Thank you for this update, Carl. I think your insight into the situation is so valuable for us amateurs watching. I want to ask you what signs will indicate an imminent eruption as the pressure builds? Will there be a jump on the tremor charts or mostly a slight increase in earthquake intensity? I remember feeling a big earthquake before the Fagradalsfjall eruptions.
Since we could either get an earthquake swarm as the pressure builds up, or a more silent runup, I would say that tremor is the best thing to go for.
Problem is that if you do not have access to direct-feed data you will miss it since the official tremor plot updates every 48 minutes (if memory serves).
The other way to look at it is that we have gotten the needed signals, and now we just need to have a 1000-liter tank of popcorn nearby and chill the drinks of choice and wait a bit for the show to start.
Yes, the tremor chart is terribly slow to update so we need to study each new line carefully haha. Thanks for the answer, I just hope there will be at least a few minute’s notice so people can get out in time. Energy drinks and popcorn are on standby.
How can we see the difference between wind (it’s a bit windy now) and volcanic induced tremor?
Wind is high frequency (Blue)
Waves are low frequency (purple)
Best thing is to know your station, at GRV-station waves are normally stronger than green and blue, but during a storm it is switching to blue.
It is also good to know the baseline of the station where the average normal noise level is.
And volcanic tremor ramps up extremely fast compared to storms and waves.
Here you can see what I mean, prior to, during, and after the tremor-crisis during the magma-breakout and foaming as the magma rushed into the newly formed dyke.
This dyke rifitng snapped the crust quickly as was seen how it rushed under Grindavik just ago, but that crust rifitng also released alot of pressure and the opened rift devoured the magma dyke like a hungry fish, alot of stuff goes underground and now with reduced magma inflow any expected eruption will be smaller, the crust really swallowed up there underground..
Carl is there any data on Fagradalsfjall s inflation rates? if its still inflating then I see no problem that the magma maybe comming in there for rest of our lives as Chad says, 2021 almost made a shield but it was little too fast
Jesper
Remember that it started during Thorbjörns inflation, that stopped and even reversed a bit during Fagradalsfjall eruptions.
Magma from the top of the mantle goes where there is the least resistance, and back then it was Thorbjörn, then Fagra, and one would assume now it is Thorbjörn again.
If Thorbjörn erupts there will most likely not be another Fagra eruption for the next 800 years since the strain is spent and there is not enough to open a new fissure/dyke with Thorbjörn nicking all the magma.
Currently Thorbjörn is causing way to much noise on the GPSes to see what is happening as near as Fagra, but I would suspect it is deflating and not inflating.
Then volcanism is jumping between systems thats probaly fairly common during reykjanes eruptions
On the grv highpass drumplot, would the lines get a little thicker/fuzzy?
Yes, but that also happens during storms, tractors, and other stuff.
The best is to look at the totality of the signal, and use common sense.
But, if you see a very quick rampup like on the picture, and it is visible over a large portion of Iceland on other sensors, then you have something.
There is a caveat and that is that these drumplots are autoscaling. If there is a really big quake, then the scaling might be turned down so much that the fuzziness is difficult to spot, if not completely invisible.
The drumplots and tremor plots are frustratingly low on detail for someone who specialises in signal processing.
As Tomas mentioned below the drumplots autoscale, and I have had the unfortunate experience to try to cite a plot, only to return and find that the autoscale totally removed the “fuzziness” of the seismic trace so my attempt to make a point was useless.
Next high tide is 5.43pm, so the tide is currently on its way in. 4hrs to next high tide so tide is currently about one third(ish) of the way in (assuming even rise over time which isn’t always the case I believe). The tide change is about 3m, so another 2m to go.
https://www.tidetime.org/europe/iceland/grindavik.htm
If the port is designed to deal with a normal 3m change from low to high tide then the wave breakers are probably about 6 meters above low tide in my totally inexperienced opinion. Drop the wave breakers by 1.5m and high tide likely gets quite close to over topping from waves even on a calm day.
When we look at the port wave breaks they already look like the tide is high – there isn’t much clearance not long after low tide. As Carl says the difference from a couple of days ago is noticeable.
And if the tide is going to go up another couple of meters from where it is now at 13h30 it does look like it could be very close to the top of the wave breakers. The risk of sea flooding looks to be quite significant.
We will have to wait another week for a high tide during daylight to be able to really see the impact although it might be possible to see something around twilight today.
I am concerned that the small quake activity at Grindavik and into the ocean went quiet, last night, while the northern part of the projected dike fissure kept up with the small quakes. One, does that mean the magma stopped intruding into this section of the dike, or that two, magma may have arisen here, quieting the quake activity. We have seen how quiet things go just before the fissure opens.
I’m getting the impression that this volcanology business is a teensy weensy bit complicated. I think I’ll stick to looking for puffs of smoke on webcams.
😉 🙂 🙂
You sound like i think.
Evidence of magma moving closer to the surface
At the expert status meeting earlier, it was revealed that land deformation has slowed down in connection with the magma tunnel, or dyke, that formed on Friday.
This trend suggests that magma is moving closer to the surface. However, it should be noted that no new models have been run to determine the depth of the magma at this time.
Seismic activity has remained fairly constant since yesterday morning. About a thousand earthquakes have been recorded since midnight, most of them at a depth of three to five kilometers. The most seismic activity has been in the middle of the corridor north and south of Grindavík.
mbl.is cam: What could be more safe now than climbing on a ladder on Þorbjörn?
https://www.youtube.com/watch?v=hvcP4kVVOnk
(15 minutes of fame)
From what I’ve heard it’s the Norwegian TV installing a new webcam.
I’ve noticed this a couple of times in the past couple of days: Google translate seems to think that RUV is Norvegian TV. It’s not. 🙂
You’re right, I based that on someone else’s comment online but just saw RUV’s update about it.
Google also translates vedurstofan to “Norwegian weather service” all the time.
They are fixing the RUV cameras.
It looks like they’ve switched to a much longer lens and remote zoom capability.
To be honest, being on Thorbjorn might be the safest place to be, its high ground.
I agree, it is fairly sturdy piece of real estate.
(Maybe not with a >5.0 quake right below? But, yes, the ladder might be of the Thule type, i.e. approved for magnitudes beyond imagination.)
It would be interesting to see a camera set up looking at the port of Grindavik or somewhere in town with a long view over the places the land has broken to see what happens as the eruption occurs. For example at Golfagraben. A timelapse of that, or the port sea levels changing would be fascinating.
I wonder if there are any security cameras out there that could be used? Not that that is on anyones mind at the moment!!
Is this real?
https://twitter.com/NewXPosterity/status/1723571593614360613
A real as it gets, but it is not the sound of the magma.
It is instead the sound of having an earthquake swarm propagating right under your house at shallow depth.
Yes, it’s their sliding doors vibrating from the eq’s … a sound i know well. but i have no sliding doors…. just an old house that rattles well.
That was shared here back during the first hours of the dike intrusion.
https://twitter.com/Icevolcanx/status/1723654516862496853
…Interesting post by ÍSOR about historical submarine lava flows near Grindavik..
Depth measurements reveal an underwater lava field west of Grindavík that most likely formed when Eldvarpar lava flowed in Reykjaneseld in the 13th century.
That’s amazing. You can see Ogmundarhraun’s lava delta too.
Yes really amazing!
This time the dyke is between Grindavik and the next vik (“vik” = “bay” in english). Somewhere between the bays an eruption may occur:
A possible Surtseyan eruption would occur close to the Bay (=”vik”) of Arfadalsvik. Grindavik would be protected against volcanic waves/tsunamis. But the golf course of Arfadalsvik may get hurt.
An onshore eruption on the peninsula of Stekkarholl would do quick ocean entry and fill various lagunes with lava.
Volcanophil, what makes you think that the eruption might occur here? The 20% rule of where lava erupts once a dike is formed to about its full length? Just curious .. as I have had some thoughts about an underwater eruption too.
I don’t think this map has been posted here yet. As a layperson I find it to be very informative so I would like to share it with the other laypersons here. I hope the experts don’t mind.
https://imgur.com/a/ABAVjUa
This is great!
If these are exxagerated “trails” then there is, besides the obvious central one, a second divergence zone to the NW of Grindavik? Could coinside with the quakes off the main axis?
(exaggerated, coincide … I’m going to wear my paper bag soon.)
Of course I’ve totally no idea whats going on, but this secondery “divergence” area could well be were the yellow/red quakes appear on the animation for today’s quakes.
If you drag the gif to your desktop you can let it run indefinitely.
I looked at this too, but what’s to say that pressure further to the northeast where most of the quakes (pink circles) are located, indicating maximum stress change? To my eye, it looks like both are possible.
https://twitter.com/Icevolcanx/status/1723699063785173034
Crack through Grindavík
A large and long crack has opened in several places in and by Grindavík due to the magma inflow
Crack opens in Grindavík
A large and long fissure has opened in several places in and around Grindavík due to the magma intrusion that started early on Friday.
This is stated on the Facebook page Eldfjalla-og naturvárhópor Suðurland (South Iceland volcano and natural hazard group.)
The group received images from a town resident, Ingibergur (who posts more images, not related to the current activity, on Instagram here).
The most recent pictures taken by Ingibergur, on Friday afternoon, before the town was evacuated, shows a crack, which seems to have slipped significantly with soil fallen into it.
The group says that the slippage of the crack is a direct result of the ongoing magma intrusion.
“Looking toward the town you can see how the crack is heading straight through the centre of town. There, marks of the crack disappear under structures, but from the little footage that has been obtained from the town this weekend it is clear that much damage has been done by these movements.”
(Anybody else going to change pants?)
Looks like some sort of depression was already there when you look on google earth, just not the holes. Collapsed trench/pipeline? 63 50′ 05” N 22 26′ 31” W
According to the original post there was already a known crack there, but now it’s widened.
Ah I see, thanks
I think Carl wrote about this in an article during one of the previous upheavals. Possibly the first eruption. If I recall correctly, apparently the crack ends (or…once ended) close to a house basement – in the line of houses nearest.
Interesting that they use the Icelandic word of “quicksilver”/”mercury” for magma. Does this label apply well for magma?
Does the graben follow the dyke in the map? If so, it would spare most of Grindavik.
It’s not the same word, only similar enough that automatic translation gets confused.
I think that’s a Google feature again. Icelandic for maga is kviku. Mercury is kvikasilfur, where kvik is old norse for quick.
In German there is not much left of the “quick”. We have “keck” (meaning “cheeky”) and, interestingly a pleonasm, “quicklebendig” (“very vital, alive” or, again with possible relation to quicksilver, “mercurial”).
The Icelandic word “kvikur” translates to “quick” or “alive” in English. It can refer to something that is fast-moving or to the concept of being lively or animated.
These pictures do not show a new crack? They show the edge of a field, so that edge was there already?
Yes, according to Faceborg the crack even had a name.
Eruptive activity is increasing once more at #Etna’s Southeast Crater; cloud cover renders observations difficult. Video was taken while visibility was still decent, view is from home in Tremestieri Etneo, using my 3000 mm zoom. 12 November 2023
https://twitter.com/etnaboris/status/1723712818073989122
Grindavik cam is jumping…
new cams:
https://www.youtube.com/watch?v=Qvw5qh5K4wI
This is exactly the cam I have been waiting for. One that follows as far as possible along that crater row. Well done RUV
https://www.youtube.com/watch?v=Qvw5qh5K4wI
This one I mean.
The last Fires Series of Svatsengi was 1210-1240. But the whole eruptive period on the peninsula lasted from 900 (Afstapahraun) to 1340 (Brinnisteinsfjöll).
If we look on the whole Middle Age period, 900 the first eruption was indeed close to Fagradalsfjall with Krysuvik’s Afstapahraun. So it’s possible that the systems of Fagradalsfjall/Krysuvik are prone for the inital eruptions of the RVZ cycle. They sit in the central part of RVZ with Reykjanes End to the west and Brennisteinsfjöll to the east.
After the eruption 900 the next one at RVZ was 920 with a tuff layer of Reykjanes system. So it’s possible that we currently follow the same pattern with central RVZ eruptions first and western RVZ eruptions next.
This means, if same pattern repeats, that after Reykjanes, later it would involve eruptions at the volcanoes further to the east, such as Krisuvik, Brennisteinfjoll located near Reykjavik, and even Langjokull (which also erupted last time around year 1000)
New one (and best one I think) from RÚV: https://www.youtube.com/watch?v=PasUycyE96o
I like that one too Lobster. You can see a lot of new cracks and scars from rockfalls in the last days.
You can see a coast guard ship waiting at a safe distance just outside of Grindavík.
I this that is the Thor that the requested a few days ago. Sorry cannot use the Icelandic symbol I cant get it on my keyboard.
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