The Sundhnukur Fires. Summary, precedents, and future.

We are still learning. There is much we humans don’t know about volcanoes or about how they behave. The past few years have been enlightening. It all started in January 2020, the Svartsengi region started rising, and an elliptical area of inflation appeared that encompassed Mount Thorbjörn, the Svartsengi Power Plant, and the 800 years Eldvörp fissures. It became apparent that magma was building up under the area, the elliptical shape implied that there was a sill inflating below the ground, a flat body of magma. At this point, this was merely some unrest, but it would escalate into the once-a-millennium cycle of Reykjanes eruptions. This would become clear a year later.

On 24 February 2021, a dike intrusion started growing under the northern part of Fagradalsfjall, a cluster of subglacial volcanoes formed during the ice age, which is located 10 km NE of Grindavik. The dike continued to grow slowly in a remarkably long-lived and complex intrusion, spurts of magma made their way into the rock cutting open the plate boundary to eventually erupt a month later, making a series of surface fissures that effused magma to construct a small shield volcano. This eruption was complex, at first it shifted in between different fissures, then stabilized into a single cone that featured episodic fountaining, sometimes the eruption would stop for a while and then resume. The chemistry of the magma also shifted over time. This may be considered to have been the start of the Fagradalsfjall Fires. Over the next three years, this volcanic system would continue to experience activity, which consisted of dike intrusions that originated from the same spot, under the northern part of Fagradalsfjall. Dikes are expanding blades of magma that intrude from a volcano, and in mid-ocean ridges, they are the ones that generate oceanic crust, by filling the plate boundary and then solidifying into rock. These Fagradalsfjall dikes took place on 21 December 2021, 30 July 2022, and 4 July 2023. The first did not erupt, the last two erupted. All Fagradalsfjall eruptions were of a low intensity and moderately long duration. It’s unclear to me if Fagradalsfjall will continue to do dikes and eruptions or not.

2023 was an important year for the volcanic cycle. If 2020 was the first magmatic activity below the surface, and 2021 was the first eruption onto the surface, then 2023 was the year the activity went crazy. July had two dike intrusions, the eruptive event of Fagradalsfjall, and another simultaneous dike in the Eldey volcano, just offshore the Reykjanes Peninsula. The seismic swarm of Eldey had all the characteristics of a dike intrusion and was most certainly one. Another event took place on August 13 a few tens of kilometers down the submarine Reykjanes Ridge, it featured many characteristics of a dike intrusion, although due to the distance, the earthquakes were poorly located and it’s hard to know for sure, but my feeling is that it was a dike. During late October the Svartsengi area resumed inflation, but faster than on previous occasions.

On 10 November 2023, the plate boundary snapped into a massive dike, some 18 km long. The sides of the dike rebounded, unleashing their pent-up strain from the plates pulling apart over two millennia and at the same time the ground above the dike sunk, undermined by the extension of the earth, Grindavik was to be found in this unlucky graben, this linear depression along the dike intrusion that experienced deflation and formation of large fractures. The intrusion had commenced under the Sundhnukur fissure swarm. This is a polygenetic system of fissures that last erupted 2000 years ago. This fissure system is along the east end of the Svartsengi magma sill that has experienced episodes of inflation since 2020. The dike did not erupt, but the area did not fall quiet either. Inflation seemed to be underway again and seismic activity was continuous all along the Sundhnukur fissure swarm.

The red line is the Sundhunukur fissure swarm of 2000 years ago. Circles are earthquakes from IMO. Red earthquakes belong to a swarm that was ongoing during the hours preceding the November 10 dike. During the dike intrusion, that area was aseismic, as it was during the following 2. Yellow are early intrusion quakes, blue are the last events. I made this map back then while it was going on. The dike continued to lengthen afterward and grew offshore as well as northwards.

This situation of constant inflation and seismic activity continued until December 18 when the system ruptured again and in just over an hour magma made its way from the 5 km deep area of magma accumulation to the surface, it blew into a huge fountain over 100 meters tall and the ground started to rip open in both directions, up and down the fissure swarm, cracks opened up and lava gushed out of them. Soon a continuous curtain of fire some few kilometres long was born. This eruption was far more intense than those of Fagradalsfjall, which some of us had warned they would be in the comment section beforehand. In my Reykjanes Fires article that was released again just after the eruption, I talked about two types of eruptions that occur in the Reykjanes Peninsula, slow and fast. The eruptions of Fagradalsfjall were slow. The eruptions of Sundhnukur 2000 years ago were fast, and the eruption of December 2023 was fast too, although not as large as some of the earlier eruptions in the area that managed to send flows to greater distances. The eruption was over in under a day. Again continuous earthquakes and deformation resumed, and a line of earthquakes also became active under the western part of Fagradalsfjall, more than 6 km deep, probably a deep perpetual dike.

Map showing earthquakes of the December 18 dike intrusion, from IMO. Blue circles are the earliest earthquakes, while orange are last. It shows propagation both up and down the swarm. A relatively aseismic area in between the blue earthquakes, towards the middle of the dike is the spot that seems to be supplying the intrusions. This spot flared with earthquakes for several hours before the first November dike, which itself was aseismic there, it is also where the largest Sundhnukur craters are located and where the tallest fountain of the December 2023 eruption formed, The first fountain of the eruption which towered well above 100 meters in height above its base.

As I write this article Sundhnukur rages into life again. It erupted after a 5-hour-long dike intrusion that started around 3 AM on January 14. The intrusion made its way southwards and reached under Grindavik, eruptive fissures then opened around the central part of the intrusion, north of Grindavik. One of the fissures opened inside the protective wall, constructed to keep away the lava, and thus is heading towards town. Luckily this is only the output of one single fissure, the walls have deflected the rest of the flow away.

Unfortunately, just after publishing this article, I’ve seen in the comment section from Quinauberon and Chad that a new fissure has just opened up within Grindavik, right next to some houses, although it’s really weak and unclear whether this vent will do much damage. The main flow is right now outside the wall, following its perimeter, and seems to have protected the town thus far.

Earthquakes of the last, 14 January, dike intrusion shown on a map. Green events are earliest, pink events are last. The sequence started just south of the aseismic area and advanced towards Grindavik. Fissures opened towards the middle of the earthquake line.

A dike in November, another in December, and now one in January. We are going at one event per month right now. The once-in-a-millenium Reykjanes cycle seems to be escalating and has entered a new chapter, that of the Sundhnukur Fires. Meanwhile, Eldey, Fagradalsfjall, might want to repeat at some point. Krysuvik swarms, and who knows what else awaits. The broader Reykjanes activity is unprecedented in modern observation times, but the Sundhnukur Fires do have precedent, the Krafla Fires and the Afar episode of 2005-2011.


The Krafla Fires

The Krafla Fires were a series of 18-20 dike intrusions of varying size between 1975 and 1984 from Krafla volcano in northern Iceland. 9 of the Krafla Fires dikes erupted. The eruptions totaled some 0.3 cubic kilometers.  However the intrusive volume must have been much larger. The first dike was the largest and generally the dike size decreased through the sequence. The first 3 eruptions alternated with non-eruptive dikes and were minuscule. The six last dikes, from March 1980 onwards, were all eruptive and of increasing eruption size. Eruptions focused towards the end of the episode and were all close to the center of the fissure swarm, whilst the distal ends of the swarm were more affected by the early dikes and did not erupt. Eruptions happened as little as one hour after the dikes started growing, and up to several hours afterward. By the end of the Krafla Fires the central parts of the fissure swarm had opened by as much much as 9 meters. The logical interpretation is that magma started to fill the plate boundary, at first most of the magma stayed underground, but in the last few years, more magma started overflowing, probably due to magma taking up the available space. These eruptions happened as dikes intersected the surface, and sometimes must have been simultaneous with continued dike growth. The Krafla Fires demonstrated the creation of oceanic crust and the way that mid-ocean ridges work, the most important type of magmatism/volcanism on Earth.

The last event, in September 1984, was the largest eruption and happened after a long dormancy of 3 years. This eruption formed an 8.5 km long curtain of fire, a continuous line of fissures meters to tens of meters high. A flood of lava engulfed the area around the vents, up to 3 km downslope of the fissures, the whole landscape becoming a mass of flowing incandescent lava for kilometers. The eruption stabilized into a single vent that fed lava at high rates for two weeks into a vast channel that traveled 9 km north, covering a swath hundreds of meters wide with aa lava.

This whole place is the Krafla volcanic system, normal faults visible in the image form when dikes intrude below the surface and open up the ground. Source USGS.


The “Afar Fires”

The other location with a subaerial mid-ocean ridge is the Afar Depression in Ethiopia. This location featured a similar volcanic episode to the Krafla Fires, from 2005 to 2010. This event is interesting and worth looking into in more detail. It started in September 2005 with a gigantic dike intrusion that rifted an area 80 km long of the plate boundary with up to 8 meters of opening, this dike is estimated to have had 1.5-2 cubic kilometers of magma. This dike also involved three different volcanoes. It started near Dabbahu and Gabho, two central rhyolite volcanoes. This phase included a small rhyolite fissure eruption in between the two. Both these volcanoes experienced circular areas of deflation followed by rapid reinflation afterward. The largest portion of the dike, however, formed around Ado’Ale basaltic shield volcano, a day after the Dabbahu dike. Most of the magma is modeled to have come from a deep reservoir under Ado’Ale, with a smaller contribution from shallow magma storage of Dabbahu and Gabho. Over the next years, 14 additional dike intrusions took place which started from under the summit of the Ado’Ale shield volcano and propagated in both directions along the plate boundary. These smaller dikes may have intruded nearly 2 cubic kilometers of magma into the crust, which added to the earlier dike made this one of the largest volcanic events of recent history. Two small but intense basaltic fissure eruptions took place from dikes that did not extend far from the central reservoir. These eruptions came from a dike roughly towards the middle of the dike sequence, and another that was the penultimate intrusion.

Topographic map of the area affected by the 2005-2010 activity.

At the same time as the Ado’Ale dikes, activity started to spread across the Afar Depression, the Red Sea, and even Arabia. In 2007, Jebel at Tair volcano in the Red Sea erupted. Next year, Alu-Dalafilla, a neighbor of Erta Ale, produced an intense fissure eruption. Harrat Lunayyir, in the Arabian Peninsula and close to the Red Sea, followed with a major non-eruptive dike in 2009. Activity resumed in 2011 when Nabro volcano of the Afar Depression erupted explosively. And finally, the Zubair volcanic field birthed new Red Sea islands in 2011 and 2013.


Future of the Reykjanes and Sundhnukur Fires

From earlier historical events we can conclude that mid-ocean ridge rifting occurs in tight sequences of dike intrusions and accompanying eruptions, where the events occur at intervals of months and go on for years as a whole. The Sundhnukur activity is likely to produce a series of repetitive dike intrusions. So far from what we’ve seen from Fagradalsfjall and Sundhunukur, it seems that most dikes erupt. Unlike Krafla where only half erupted, or Ado’Ale where only a small fraction did so. It could be because the fissure swarms are much shorter. Sundhnukur rifted nearly 20 km, but that is far from the 80 km of Dabbahu-Ado’Ale.  Drawing from the Krafla Fires, Ado’Ale, and Reykjanes events thus far, I expect that dike intrusions will continue to grow from a seemingly aseismic spot under the Sundhunukur craters 3 km NE of the Svartsengi power plant and 6 NNE of Grindavik. These dikes will propagate NNE and SSW as underground blades of magma that may reach Grindavik to one side, and a similar distance in the other direction. These dikes will, most of them, erupt within hours, maybe in as little as an hour after the intrusion starts, so will have very little warning. Geodetic data may perhaps help given that these eruptions seem to be happening when the Svartsengi area inflates back to the level of the last event, or shortly after surpassing this level, the deflates during the dike. I expect over time there will be less space underground and the dikes will start to overflow more abundantly. As the eruptions go on, they might get bigger and more long-lived and I wouldn’t rule out an eruption of this volcano to last for 1 or 2 weeks, which is something that has happened nearby in similar systems during the Ogmundarhraun and Arnarseturhraun eruptions 800-900 years ago. Some of these bigger later eruptions may unzip the Sundhnukur fissure swarm for kilometers. It’s hard to know how long this will go on or how many dikes will it form.

As for the Reykjanes Fires, I expect a rough repeat of what happened 800-1100 years ago, however not a perfect one since it’s already different. During the previous Reykjanes Fires, activity advanced westwards, starting in Langjökull with the Hallmundarhraun shield volcano around 900 AD, then the Brennisteinsfjöll eruptions around 1000 AD, the Krysuvik eruptions a century later, and the Stampar (Reykjanes power station area) and Eldey eruptions around 1210-1240. So far activity has been focused in the Fagradalsfjall-Svarsengi area, and the volcanoes that have erupted did not do so during the previous cycle. If activity moves west it may jump over Edvörp and Stampar which were active 800 years ago and go into the submarine volcanoes offshore. There are some hints of activity already starting offshore with the swarms in July and August this year. But it’s hard to know. One area that as far as I know did not erupt 1000-800 years ago comprises the fissures west of Trölladyngja, so that is one possible area to watch if activity does not shift westward but eastward, another is Hengill. It’s hard to know since there is not very clear information on how the previous cycles developed in the area. Perhaps a paleomagnetic and radiocarbon study of the lava flows could be carried out and help establish the chronology of the past eruptions in better detail. Otherwise, all we can do is watch how this cycle develops and what surprises it may throw at us.

513 thoughts on “The Sundhnukur Fires. Summary, precedents, and future.

  1. There’s been a small but definite increase in inflation at Svartsengi since Grindavik South stopped producing lava. Although Icelands experts placed their guesses on an eruption East of there very early on, I remember others picking an eruption point close to the “crossroads” South of Blue Lagoon in those early days of November. While Grindavik North provided some deflation to Svartsengi, Grindavik South did nothing of the sort.

    Is there something besides the lack of seismic activity in the immediate Svartsengi area that causes us to continue to place it further down the list of candidates for the next eruption?

    • “There’s been a small but definite increase in inflation at Svartsengi since Grindavik South stopped producing lava.”

      I meant to say an increase in the RATE of inflation.

    • Interesting, the main rift of this eruption is on the east edge of the first graben, and the rift at the edge of town on the west edge of the new one.

    • I think that explains the location of the smaller fissure. They seem to be associated with each other and there must be some underground splitting of the magma.

  2. Over the holiday period, I was playing around with placement of the sill (along with the other features). At the time it was mainly to get things straight in my head and to check whether my visualisations had merit. I didn’t rewally intend to go any further with it, but then last week, an Insar image was posted on Facebook, showing the inflation, which seemed to validate my thoughts. That coupled with some comments about struggles to visualise the sill had made me think that there could be some more general use, even though it probably isn’t entirely accurate.

    The image shows my approximation of the sill. I started off by looking at the relative locations of the GPS stations shown on the image, based on the map on the IMO pages. I then looked for features on Google Earth that were in approximately the correct positions that could be locations for the stations (this may or may not be correct, but is close. I then looked at the lateral movement of those stations on the IMO GPS page, ignoring the sudden shifts that were likely due to the intrusions into the dike. I then used these to triangulate the lateral movement, which I then transferred onto the IMO map, extending the lines to triangulate the area of the sill, by triangulation, seeing where they crossed. This wasn’t exact and created a rough circle in the area of crossing. I then visualised the relative inflation at each station to try to estimate the shape (yellow). The size is probably the least accurate part, as it is part guesswork and is more to show what I thought was the most likely shape. However, I think I saw some figures for the extent of the sill, published by IMO, which are pretty similar to the area of the shape I have created. I then looked at an area for a possible feed (orange) to the dike that might account for the data not matching the shape of the sill. I have also marked the approximate locations of the dike and fissures during December 18th. As can be seen, it is roughly an ovoid area, with a flattening on the south-east side. It’s possible that the weight of Thørbjorn is causing this.
    The Insar image on Facebook indicated a similar shape, but the inflation seems to be rotated a little more clockwise relative to my image.
    I avoided the periods of sudden changes, because the lateral movement is likely to be contaminated by movement as a result of the dike inflation.
    Looking at the GPS data since Sunday’s eruption, some of the stations didn’t show any deflation, namely THOB and SENG. Conversely, SKSH and HS02 did show some deflation, if much less than previously. I think we have to ignore GRIV, as it is too close to the eruptive fissure to give a representative picture. The question is, why is there a diffrerence between the stations this time, when previously all of them showed deflation at the point intrusion into the dike? I can immediately think of two possibilities and the third is something that has been suggested. However, I haven’t seen any evidence that a second feed, directly into the dike is occuring.

    1. The sill only emptied towards the southwest part. This would likely be due to the northern portion emptying into the feeder to intrude into the dike and then being replaced by the magma in the southern end. However, this doesn’t really make sense if the sill is a single structure.
    2. The sill partially emptied into the feeder, but didn’t full intrude all of the magma into the dike, with the remainder staying in the feeder. This would seem more likely from my visualisation, as it is closer to both Svartsengi and Thorbjorn, so could still cause the two GPS stations to still show inflation.
    3. There is a second feed, aside from into the sill, this time directly into the dike. As I mentioned though, I haven’t seen any evidence of that yet and it isn’t something that IMO has mentioned.

    Obviously, these are just my musings and should be taken with a pinch of salt, but if it helps to visualise the sill, then it still has some benefit.

    • I concur with the idea of the ‘Svartsengi gap’. Thorbjorn is old and it’s roots deep, if the magma was going to travel through the chain and into the dike it makes most sense to come through north of Thorbjorn.

      As for the sill, the dyke was gradually filled, but at some point the feeder closed, and then reopened which caused the initial eruption. In other words, November 11th would have been a failed eruption. Of course since then, much of that magma has since been remelted/erupted out.

      I view the pathway from the sill to the dyke sort of like a valve – sometimes it’s open, sometimes it’s shut. This is probably dependent on a pressure gradient. Either way, any time some of it empties out it creates a vacuum and forces refill from the mantle/lower crust sill network, which is why it is constantly inflating and under pressure. Whatever it’s ’emptying out’ that isn’t erupting is going into the dyke/the crust.

      • Your description matches the mechanism rattling around in my head, although, I hadn’t really matched it to a valve as such.

    • The other station to keep an eye on is BLAL. It isn’t marked on the IMO map, but it must be close to SENG, as it is The Blue Lagoon (Blaa Lonid, sorry for using the approximation of Icelandic letters). It’s possible that the structure I’ve indicated as being SENG, is in fact BLAL.

    • ” I think we have to ignore GRIV, as it is too close to the eruptive fissure to give a representative picture”
      But I still don’t understand why the sharp 1meter subsidence occurred in Grindavik on November 10-11, 2023r. explained by IMO as a “initial dike propagation”. To me it looks like ice floes floating on the sea, and any disturbances that are difficult to predict may result in the flow of lava under these floes. Last eruptions are short times, so it means, that they are like result of ground movement rather than a continuous feeding from a deep magma source feeding the sill.

    • Thank-you for your Analysis Richard!

      At what depth would you localize the sill? This would help to get a three-dimensional imagination.

    • Nice visualization, and I generally agree that the sill is NW of Þorbjörn, although I do wonder if it might not be subdivided into linked ‘rooms’ akin to the voids in Carlsbad Caverns.

      Some of the GPS stations on your image appear to be misplaced, though. SKSH, for example, is considerably to the east and in fact is within the area you have shaded as the likely location of the sill; I’ve been there numerous times. You may want to look at the dropdown for GPS stations here:

  3. What is the situation in Fagradalsfjall? inflation or deflation.

    • On the 8 hr plots:

      Inflation at FEFC. FEFC dropped followed by uplift pretty much the same as SUDV.

      KEIC had been drifting downwards since the end of October but is now rising again.

      No data points on GONH since the end of November.


    Back when it was only Fagradalsfjall that had erupted, I proposed that all of Reykjanes from Eldey to Hengill could be functionally like a single volcano with many vents. It was unclear if Fagradalsfjall was really part of the next sequence as it had not participated in the regular cycles before, so whether it was getting magma from a different source than fed earlier series, as was determined to be the case with the magma composition.

    Well, basically, the magma erupted by Svartsengi now has a common origin with the Fagradalsfjall magma, and different from the magma of the Reykjanes fires in the 1200s. So it is possible that all of the Reykjanes volcanic zone will have this composition and erupt in the near future. It also might mean things move a lot faster than before, given we are at 2 volcanoes and 5 eruptions in less than 3 years, compared to in the middle ages where decades went between eruptions even at the same volcano…

    • Having a look at recent papers, in 2020 the entire peninsula west of Kleifarvatn was affected by deep magma intrusion. Looks like at least half of the peninsula could be considered as one large system. It’s maybe sort of like how volcanoes surrounding calderas can have common sources (e.g. Lokon and Soputan, Katmai region), they appear to act independently but are really “siblings” with the deep source being the “mother”.

      Probably not important/just coincidence, but the distance between the tip of the peninsula and Kleifarvatn is the same as that between Kleifarvatn and Hengill, so (speculation) perhaps you could split the peninsula into two volcanic fields, East and West?

      Anyway this has just been published, could’ve done with it sooner! –

    • Volcanoes on Iceland often act in families like Grimsvötn with Bardarbunga and Thordarhyrna; Katla with Eyyafjallajökull; so also the Reykjanes peninsula. Maybe also WVZ has some examples.

  5. Question: there were two different historical eruptions in Iceland happening in the same moment?


    Ragnar Heiðar Þrastarson

    Elevation difference map (vertical displacement) based on two different acquisitions by our remote sensing team. These area base on two DEMs spanning 1 Dec. to 15 Jan. covering the latest eruption in #Grindavík

    – New lava fields
    – Lava barriers

    – Quarry for barriers
    – Barrier entrenchment
    – Graben formation

    • Well, I asked here about DEM scanning on Nov. 14, and they did it shortly thereafter. Does that mean the IMO is taking cues from the VC comment section? (Just like the volcano is taking cues from the blue lagoon I suppose?) Just kidding, I am not the megalomaniac I am pretending to be… 🙂

      At any rate, this is outright brilliant data quality. Not sure how they did it (photogrammetry or LIDAR; aircraft or drone), which would strongly change how expensive it is to do one of these scans. But imagine doing one of these every 2-3 days with that kind of resolution, you would be able to see the relaxation motions of the various sections, and the “breathing” of the surface from the magma pressure changing and shifting as an actual animation in real time!

      But anyway this one difference image is already amazing. I find it very interesting that the small crack opened at the edge of the graben structure, whereas the main one actually formed in the center. I thought these would basically always be at the edge of the graben area? Or is that not such a clear thing?
      It is also interesting that the ejected lava volume is much larger than the volume displacement from the sinking of the graben area even when extending it to quite far outside of the picture.

      • I wonder if the small southern vent was maybe magma erupted secondarily from one of the earlier intrusions, possibly fron November 14. It was described as being a little more evolved than the lava of the main fissure but originating from the same source, which would make sense. So it was technically a very delayed November eruption and separate to the main fissure.
        I guess having the new graben cut across the 14/11/23 graben and dike gave enough of a weak spot to allow a bit to escape, and would explain why the southern vent didnt open with the main fissure at the start and only quite long time afterwards.

        • My impression of the southern eruption was that it reminded me of the first Leilani fissures!

      • ” I find it very interesting that the small crack opened at the edge of the graben structure, whereas the main one actually formed in the center.”

        The main eruption opened along the edge of the November graben though, which maybe makes it even more interesting.

        • Yes, you are right. The main graben formed in November is west of Gindavik.

          • I saw it posted somewhere else with the edges of both grabens marked as well as the eruptive fissures. I can’t take credit for the observation.

        • If we compare the graben with a caldera, the edge of the graben would remind to the behaviour of a ring fault.

        • The November graben has a bit of a wedge shape, i.e.e there was some rotation involved. It makes sense that the fissure happen along the edge as there is a line of weakness here. Magma moves ion the direction of least resistance. A break in the rock has less resistance! As for the point of eruption: magma will move forward of the pressure needed to move ahead is less than that to move up. The latter is set by the weight of the rock above and the tensile strength, minus the buoyancy force. In a graben, the magma will tend to come up quite quickly. That saved Grindavik. (Well – in fact the wall was what saved the town!)

    • Is there any pictures like this one for the first eruption? Trying to map it but I dont trust google earth to update before the next eruption in that location… 🙂

  7. Picture with new graben on eastside of Grindavik:

    The new graben is slightly more towards Fagradalsfjall and could be a first sign that both systems are going to interact with their lava fields. Maybe we also have to think about that the current Fires choose different locations for their fissures than the previous Grindavik Fires 2000 years ago.

    • If the picture is correct, the new graben has formed just on the east side of the previous (November 2023) one. The graben takes a direction to the harbour/port of Grindavik. This increases the danger that the next eruption is going to destruct both populated areas of Grindavik and infrastructure of the port with a potential explosive interaction with sea water.

      • I was already thinking before the last eruption that it would shift south, rather than north, as was the case with Fagradalsfjall. I don’t think there is much space to shift northwards. The MAR is generally shown towards the southern shores of the peninsula or as the whole peninsula, but from the images of faults, I suspect the centre of the MAR runs just to the north of the two dikes. Fagradalsfjall had more room to travel northwards.

      • Looking at the outline of the lava field makes me wonder if Grindavik is now far better protected against lava flows from the north than it was before?

        Assuming future flows originate from further north than this one did, wouldn’t the lave field essentially serve the same function as the berm, but better? Or is this just wishful thinking on my part?

        • Ah. Good point, Merlot.

          Those grabens, especially the associated fissuring, are IMHO an even worse risk than the lava. They’re not going to go away even if the eruption locus shifts to a safe distance and no further intrusions occur.

      • If we look on the new graben/sill (orange), the port of Grindavik and settlement close to it is in worst risk for an eruption. This includes the risk for an ocean entry or other types of phreatic/phreatomagmatic eruptions close to human infrastructure.

  8. I can only now see this latest eruption as a humanitarian crisis that has finally made the people of Grindavik realise that their town may no longer have much future in the short term. Obviously they, as well as the government, hope to save the port beause of the tremendous revenue it has brought to the country throughout the many years of it’s very lucrative fishing industry. But for the people of Grindavik now, they need to be able to look for future stability for their families and especially for their children. They can no longer look at Grindavik as a stable place to bring up their children, which is a very sad fact indeed. I know many on here are looking at all this from a totally geologic and volcanologic standpoint, and I have no issue with that at all, as while this begining of unrest was not affecting the population I also found it so very interesting. However I beg of you now to see the crisis behind this upheaval, which is just as crushing for the people of Grindavik as for any other poor people displaced around the world by geologic or volcanic disturbances. It is easy to forget that whilst Iceland was formerly a rich country, that no longer applies because of the raging inflation throughout Europe. I know that some Youtubers have set up a link to help the people of Grindavik through Red Cross donations. If anyone is in a position to donate to this then could I please request that they may remember these poor people at their time of need. Iceland is a very small country and although I know Icelanders are very generous towards their own, there is only so much than can be done for these displaced people. If you have read this far then thank you.

    • Once the fractures occurred in Grindavik, I pretty much thought there was no going back. Iceland is a country that is much more socially aware than many. While it won’t be easy, I am pretty confident that the people will be looked after as well as is possible.

    • Yes. The town cannot be reasonably occupied for a few decades. A new site needs to be selected, possibly towards the east but it might be a valuable topic of discussion, following the usual erudite article, to consider suitable sites. Somewhere with lower likelihood of a disruptive eruption and with the makings of a decent harbour.
      That might help the (ex) residents.

      • I don’t see that happening. There is really no spot along the southern side of the Reykjanes peninsula that is “safe” from potential volcanic disruption and carving out a new harbor would be very expensive. Despite all that has happened, Grindavík remains the most liveable spot in the area.

        The people of Grindavík are already dispersed all over southwestern Iceland with all sorts of temporary housing arrangements that will eventually turn into something more permanent. As sad as it is, I don’t see this community being wholly relocated to a new site.

        • Maybe, but Grindavik is a non-starter, so someone needs to go looking for an alternative.
          1) Significantly lower risk area.
          2) Perhaps consider removable housing this still allows 5m widths in two sections)
          3) A reasonable harbour that can be improved.

          Not cheap, it depends on whether a replacement for Grindavik is worthwhile.

  9. Latest MET update again hints that Grindavik hasn’t seen the worst yet:
    “According to computational models, the magma lies shallowly at the southern end of the magma tunnel, where the land appears to be highly fractured and the magma can therefore easily reach the surface. There is a chance that new fissures will open without warning.”

    • They also mentioned that a GPS north of Grindavik went under lava. Judging by the data points, this was probably GRIC.

      • That’s interesting, because the MEH seismometer stopped showing data on Jan 14, around 10 AM, right after the start of the latest eruption. However, MEH appears to be slightly outside of the lava flow.

      • I see that GRIC is now showing current data; so, it can’t be the station that went under. It’s location is also pretty far from the mapped lava flow.

  10. Do we know if there are more than one sill which should be factored into all of this? Eldvorp gps station had the biggest drop during the recent eruption. Svartsengi didn’t even register a drop.

    With this in mind is it possible that there are two separate sills each feeding magma in an easterly direction. Svartsengi was responsible for the first two events, Eldvorp or nearby the cause of the 3rd. Is it therefore plausible to suggest that Svartsengi is now due and this time affect things nearer to the original eruption location away from Grindavik.

    • I mean, Eldvorp and Sundhnjukurgigar are both part of the same fissure swarm, probably getting magma fed from sills that form under Þorbjorn. I imagine that it is the existence of these mountains in what is an otherwise almost dead flat landscape that is why sills form instead of slow eruptions like at Fagradalsfjall. Maybe Fagradalsfjall will become like this too if its activity increases but who knows.

      Of course it is likely multiple sills exist too rather than one, so what you say could well be the case too in which case things just got way more complicated.

  11. The Blue Lagoon website is saying they plan on reopening Jan 20th.

    So far, Blue Lagoon reopenings have outperformed inflation measurements and seismic activity as predictive factors for eruptions, so I’m thinking that there’s going to be an eruption next week.

    • It will be hard to run the Blue Lagoon if most of the people who work there live in Grindavik which is now apparently indefinitely abandoned or at least no one lives there until it is all stable again.

      Really it seems asilly idea to even let anyone near the active rift. The land the Blue Lagoon is built on is made of lava from Sundhnjukurgigar… and if it breaks open at Eldvorp then Grindavik might be safe but it is much closer to the Blue Lagoon and Svartsengi. The walls helped in this eruption but a major eruption, something that might erupt as much lava as the 2021 eruption of Fagradalsfjall in a matter of days, even the 10 meter walls arent going to be enough.

      • I do wonder (and hope I’m wrong) if eruptions aren’t the only threat to the Blue Lagoon. As we saw in Grindavik, fissures can open without warning, and were one to open under the lagoons while in use (they even swim in the winter…) a lot of people could be lost. If the original grabben had extended a bit more to the north, I think Blue Lagoon would have been in a fissure area.

        I also wonder if an eruption could occur closer to it than assumed. Or worse, in it. I rewound one of the camera feeds from the Grindivik eruption to watch the start of the fissure right at the edge of Grindavik; there was a warning sign, a steam cloud, but that warning was maybe a minute.

        The lava seems to move rather fast right at the start of these fissure eruptions, and these are small eruptions. I agree the Blue Lagoon shouldn’t be open under present circumstances.

        There’s also the issue that their track record for deciding when its safe to reopen has a 100% success rate as a negative indicator. 🙂

        • The warning to Grindavík was an earthquake swarm. Because the authorities were expecting this to be a precursor and the elapsed time between the onset of the swarm and the eruption, itself, to be short, they got people out in time.

          If there were to be an eruption nearer to or at Svartsengi, it would be a new fissure or an old fissure reactivated. Both would produce earthquake swarms. But how much time there is between the onset of the swarm and eruption is anyone’s guess right now. To be safe, you’d have to assume that the period is short.

          • I chose my words poorly. I didn’t mean the start of the eruption, but of the start of the southernmost fissure eruption, the one that opened a few hours later, right by the houses.

          • I tried to jump on top of this eruption, thinking it was about 1 hour out from the earthquake swarm start around 3:31 am, but the fissure eruption was over 4 hours later, so getting on top of such things after a swarm occurs is a bit dicey.

    • Stubborn Icelanders. Hot tub > lava eruptions. You gotta set priorities. 🙂

      • the Blue Lagoon is almost solely used by tourists. All those British and American travellers coming over in the dead of winter to swim in the Blue Lagoon while watching the Northern Lights. I can’t tell you how many times I’ve heard “Oh no, Blue Lagoon is closed, I hope they open it again when I come over” during the past few months, without ay regard for the reason why it was rightfully closed.

        • There are plenty of geothermal areas on Reykjanes. They could quite easily make another blue lagoon. Less so another Grindavik.

          • But the Blue Lagoon is a waste water lake, they don’t have many of those around 🙂

        • Blue Lagoon has a restaurant named “Lava”. I don’t know if lava is also an occasional menu item, though I’m starting to wonder….

          • Been there.

            The main restaurant window lets one see a cut out lava Aa flow.

            Was served the worste cocktail I have ever had, called the lava.

            It was redcapsicum based with vodka and it was ghastly in concept and taste.

            The food was good.

          • Stew, if I ever get to The Blue Lagoon, and it’s still there, I’ll avoid that drink.

            So, a restaurant named “Lava”, looking out over a lava flow, put an item called “Lava” on the menu. And now it’s at risk of having significantly fresher lava, and just reopened.

            Perhaps they’re just changing their menu a bit, and decided that instead of basing that cocktail on vodka, they’d base it on fresh basalt?

    • The Port of Grindavik is in bad danger now … in my view. Either the infrastructure or the whole port is in risk to be buried by next eruption(s)

      • Also at risk from fissures and ground sinkage. If the ground drops below sea level, there will be flooding.

          • You get a bigger harbour and less land round it ….

            & if you are really unlucky, you get a phreatic eruption.

      • Volcanophil:

        I share the same feelings, which is that when the next fissure eruption occurs, it will be in the middle of Grindavik, and possibly extend into the ocean leading to a Surtseyan eruption.

        This whole thing is very agonizing to me, as thousands of people have been pushed into a state of uncertainty. I listened to the man who owned the home which was burned by the lava, and it was very pulling on my heart.

        These are real people, living real lives, and yet the volcanic forces of nature will overrule anything which we human beings have accomplished. It is tragic to see the loss of these (3 or 4) homes in Grindavik, but more things lie ahead.

  12. Ármann Höskuldsson, discussing the threat to the Reykjanes as far as Hafnarfjörður and Hengill: “we definitely have to start thinking about the future and start connecting this threat to our entire organization. This is here to stay and will be here for the next 150 to 200 years.”

    Historically, when the Reykjanes wakes up, the whole peninsula remains intermittently active for centuries. We’ve discussed that at VC, but I don’t recall much mention of it in the Icelandic media until now.

    • I appreciate that Ármann Höskuldsson is thinking ahead, and asking Icelanders (and all people, really) to think ahead. Too often we are just thinking in the short term, then wonder why we got bit in the butt.

    • That the Reykjanes peninsula is covered with active volcanic systems is of course not new knowledge. It has been well studied by experts and occasionally covered by media before 2020*. But there is of course a huge pyschological difference between a theoretical risk (pre-2020) and seeing a volcanic system actually wake up on the peninsula.

      * from 2018
      * from 2012

      There is however one aspect of potential volcanic activity in the area that I don’t remember being given a lot of attention until the crisis with Grindavík and that is the potential for formation of dikes that may not cause eruptions but could very well reach the outskirts of the Reykjavík urban area and cause huge disruption with graben formations and large movements in existing fissures. That seems to be a much greater risk than lava flows.

      • These grabens seem to be a particular aspect of this particular region. I am not aware of any mountain in Iceland dissected like Thorbjorn is. It almost looks as if the western part of the peninsula wants to be its own little plate, with a bit of rotation away from the east. A dike into the Reykjavik area could be a major earthquake hazard, of course.

  13. Got a fun paper for you all!

    “Magma supply rates from the mantle to Hawaiian volcanoes serve as an important control on eruptive behavior at the surface. The Pa ̄hala Sill Complex, a collection of magma-bearing, seismogenic structures at 40 km depth beneath Hawai‘i, presents an opportunity to elucidate interactions between stress and magma transport processes in the mantle. We invert for full moment tensors of sill earthquakes and identify predominantly shear mechanisms with persistent tensile faulting components. Slip occurs in-plane with the sill structures. Pressure axes are radially oriented about a point near Mauna Loa, consistent with a stress field generated by a flexural load. Together, these observations suggest that magma flux through the sill structures generates seismicity by increasing pore pressure and promoting slip. Our results suggest that stress changes in mantle structures may enable fluctuations in magma supply rates to the surface over short timescales.”

    • It’s interesting if other horizontal planes of intense seismicity in Hawaii also contain magma or interact with sills, like the seismogenic portions of the ~7 km deep decollements of Kilauea and Mauna Loa, the Mantle Fault Zone of Kilauea, and the other regions of 20-50 km deep seismicity in Hawaii; in front of the ERZ of Kilauea and the SWRZ of Mauna Loa, and around Hualalai and Mauna Kea. A new kind magma storage in the form of shear magma planes.

    • “Our results suggest that stress changes in mantle structures may enable fluctuations in magma supply rates to the surface over short timescales.”

      Sounds alot like the sort of stuff that has come up in discussions on here in recent years… 🙂

      I do wonder if anyone at HVO actually goes on here on occasion. Maybe they read all those long comments by me and Hector and others, all the speculation about how the volcanoes work.
      Not to try and come across as knowing better but I dont recall seeing anything ever discussing the deep quakes at Pahala in the literature before it was mentioned on here. The first suggestion they could be sills was on here too, I think just after the 2018 eruption before the swarm took off.

    • Mike:

      WOW! I am impressed by your paper. This is a lot of very technical work. I have always wondered about the feedpoint of the Hawaii Island volcanics, but you have focussed in on the critical details.

      One question, do you think that the 19.25 deg N – 155.45 deg W is the actual mantle hotspot?

      What about Loihi Seamount? I see that the HVO has applied a new name for that volcano – Kama’ehuakanaloa
      Is the Loihi seamount feeding from the hotspot more directly than Kilauea?

  14. Found myself staring at The Grindavik Greenhouse. Surrounded by lava, yet untouched. This doesn’t surprise me. The greenhouse doesn’t have anything the volcano wants. It is obviously growing something other than corn.

    • I read they grow barley in there. Doesn’t pop, but maybe they can brew a decent volcano whisky from it.

      • I wasn’t too fussed about that awful glowy thing. But if it destroys the beer barley then it’s the worst disaster in volcanic history.

    • They were growing GMO barley to get the human Epidermal Grouth Factor protein. Bioeffect is the brand, they have a e-shop to sell their skincare products based EGF and also Iceland geothermal extract and lava powder. Prices are not for everyone.

  15. CJ 17/01/2024 at 20:49:
    >Looking at the outline of the lava field makes me wonder if Grindavik is now far better protected against lava flows from the north than it was before?

    >Assuming future flows originate from further north than this one did, wouldn’t the lave field essentially serve the same function as the berm, but better? Or is this just wishful thinking on my part?

    I would say in itself it could help a bit if the flow comes from further north, yes. But once the new flow tops the layer anywhere, it can run straight over the wall.

    ut If this layer of 2-4 meters cools fast enough so that they can basically extend the existing wall on top of the lava to add another barrier, then that would do a lot, even more than the old one, as the new surface is less inclined. Therefore the capacity of the “basin” that is formed by the barrier is much bigger than before, so it could handle a much bigger flow before overtopping.

    But I am not sure how long one would have to wait to start earth work that extends on top of a fresh lava layer… (And if they want to just increase the existing barrier it would need far more material, probably too much).

    • If I’m remembering right (always a big if), in La Palma and Hawaii they were able to put roads in and on top of lava flows at around 6 months old, so my guess is they were pretty much cool enough by then. Rock is an excellent insulator, so working at the flow surface might be safe enough. Maybe. I wouldn’t want to try it without getting expert opinions, though. 🙂

  16. How close are the sills and the eruptive fissures around Grindavik to previous ones 2000 years ago? The Catalogue of Icelandic Volcanoes shows some old eruptive fissures and craters close to Grindavik, but it’s difficult for me to compare it with the position of the current ones.

    • The blue is the older fissures and the red is the new fissures. So pretty close although not in exactly the same place.

      • I remember after the first eruption, a comment about the dog leg and how it did ‘the follow previous fissures. It now lines up quite nicely with the second set of fissures. The old a and new seem to be on opposite sides if the grabens, if I’ve got my bearings right.

        • Im not 100% about the locations of the December fissures. Plotting the official map didnt line up very well with where the eruption actually started, which was conveniently on an old cone that is easy to find on maps. There are a bunch of maps in high detail about the lava field shape but nothing like the DEM of the last flow which shows the elevation change and lava thickness, and shows the vents.

          The older rift probably goes way further north, there is a small fissure and lots of faulted terrain out in the lava field of Þrainsskjoldur, the small fissure might be a part of the Sundhnjukur eruptions or maybe older, it isnt really very obvious.

          But what is obvious is that this area is going to look very different in 2025. I dont want to see Grindavik getting flooded by lava but the data doesnt lie and geological history

          • It’s difficult to see properly on my phone, but they seem quite close to where I placed them, although that wasn’t my main aim when I was doing it. I was trying to work out the pattern of inflation.

      • By the looks of the older fissures, I noticed that so.e of them run parallel to each other. I have no idea if they are different ages, but if they are the same age, that might indicate that the fissures don’t erupt twice from the same crack. I have no idea, maybe they could reactivate, though.

        • That is how old the Sundhnjukur lava is, 2000 years is a bit of a rounding error.

          The November dike seems to have followed the old vents at least in the southern segment although not as much in the north. But the new eruption has deviated more east, which might support the idea it is fed by a slightly different source within the sill complex.

      • This graphic strongly suggests that weakness in the crust will persist, even across thousands of years, and be the point where fissure eruption activity occurs.

      • Thank-you Chad! The fissures are more close than I thought. Only the most southern part around Grindavik begins to differ more. We will see if the new graben/sill also follows the old geography or chooses new locations for eruptive fissures.

  17. How big is the risk for Maar eruptions in/around Grindavik? Krysuvik hosts some maars, and the new sill of Grindavik is getting closer to the water shore. So there could be groundwater (partially sea/sweet water) which can be hit by a potential dike. Historical eruptions on the Reykjanes Peninsula included phreatomagmatic/phreatic eruptions.

    • I share this concern. At the bottom of the crack the guy fell in, there was flowing water.

    • To my knowledge, there aren’t any maars in the area. The Stampar fissures near the tip of the Reykjanes Peninsula exploded in shallow water where the fissures went submarine, but the onshore fissures and even those right by the coast are normal. Still, it can’t be ruled out that a phreatomagmatic explosion would occur in Grindavik.

      • Krysuvik had some maar eruptions, but it’s maybe a different geological situation than Grindavik. Anyway we should look at the potential for preatomagmatic eruptions. The new graben gets very close to the coast of Grindavik.

    • A maar is a volcanic vent/crater (and not a small one) that collapses and subsequently fills with water. I don‘t think there is something like a „maar eruption“, even if a volcano that formed a maar reactivates it would be called a phreatic explosion.

      • No, a maar is not formed from collapse, but from phreatomagmatic explosions. The resulting crater is usually later filled with water to form a lake. A maar explosion is caused by magma interacting with groundwater. Now, there are abundant aquifers at Reykjanes, but it seems like dykes usually cut right through them without problems.

        • I feel the ground has enough fissures – and maybe that doesn’t allow the steam pressure to build up in this area even when magma interacts with ground water? And so you just get outgassing rather than a ‘bubble on the surface going pop’ (which is how I think of Maar eruption).

          is that the right way of thinking about Maar ?

  18. Bit of a swarm around Kleifarvatn today. One place on the peninsula they wouldn’t want an eruption – it’s about 5km3. Not sure if the water is used locally also.

        • Thanks Diana, I found that information really interesting.
          If I was younger I would by now definitely be making an effort to learn Icelandic! However being an older lady with somewhat dodgy health, I decided the effort was not worth it. Google translate may have it’s faults but is way better than nothing. With Reyjanes having childish tantrums despite it’s very old age I do feel cheated a little that I have come in at the start of an experience that will definitely outlive me. So I am determined to read all I can and watch all I can in the time I have left.. I think you may find the article I linked to below to be as interesting as I found it. Keep fighting Diana and much love.

          • Oh I’m not THE Diana, I’m just Diane. I have a bunch of Icelandic horses and sheep in Oregon and I like learning about volcanoes.

          • Oops so sorry Diane. I should have noticed the spelling of you name and didn’t! I am developing cataracts that impede my vision without glasses, so please forgive me for the mistake! Also many thanks as I really did enjoy reading that article and if Diana is reading then apologies to you also.

          • By the way Diane, I love the sound of the Icelandic horses in Oregon! I have always loved those Icelandic horses that appear compact but incredibly strong. Reminds me of the Icelanders themselves. Not compact of course but they appear to me to be a very strong and resilient people.

    • The swarms are tectonic but the area the current rift through Grindavik opened up in was also where a lot of induced quakes happened during the Fagradalsfjall intrusions too. So maybe the induced quakes are indicative of where future rifts will open.

      If that is the case then future eruptions will occur on the east side of Trolladyngja and through Kleifarvatn (Krysuvik), at the north end of Brennisteinsfjoll, on the west side of Hengill and up at Tindaskagi next to Skjaldbreidur. Probably not all soon but within this cycle.

      • The past Fires lasted from around 900 to 1300. So the Reykjanes Peninsula has a lot of time to play its whole Fires. The majority of the eruptions will happen after our lives. That’s also possible concerning Krysuvik’s or Brennisteinsfjöll’s eruptions.

    • I saw plenty of people here at VC saying the area was waking up for a long-term eruptive sequence, and that was well before Fagra 1.

      Saying the same thing after 5 eruptions? Even I could manage that. 🙂

    • Needs to get his facts correct (or perhaps the reporter got it wrong). Grindavik is build in the only region of Reyjanes which did not have an eruption in the fires 1000 years ago. 2000 years of safety is not bad. People still happily build houses on the sea front which will be under water in 100 years time, and developers love flood plains for new houses which will be flooded once a decade. Let’s not blame Iceland. In the 1250 years since the settlement, eruptions have destroyed quite a few farm homesteads in the south of the country, but only one town has been lost: Heimaey. That is a very decent record for a nation as volcanically active as this. And the number of direct fatalities is very small. Laki was a humanitarian disaster because of the secondary eruption impacts, but more people died of it in the rest of the world than in Iceland! No, Iceland is doing very well, and Grindavik was a good a location for a fishing town as any on the south coast.

      • Before the latest cycle, I would probably have felt safer in Grindavik than Vik, with Katla just up the road.

        • Vik isnt at risk from Katla actually, even a full plinian VEI 5 wouldnt do too much. Katla is dangerous and has such a reputation because of the massive flooding it causes during eruptions or just randomly, which made crossing the area very dangerous until the ring road was finished. Vik is probably where it is to avoid the floods actually.

          Probably before the last 5 years the most precarious place to live in Iceland was Husavik, which sits on a major fault that can do mag 7+ quakes. Second place might be Hofn, next to Oraefajokull, which looked like it was going to erupt in the 2010s. Oraefajokull is basically what think Katla is like but actually living up to its reputation 🙂

          • Höfn isn’t really all that close to Öræfajökull – the town is about 75 km away to the northeast. There are a bunch of small farm communities (including one called Hof) at the foot of the mountain, and a hotel and community store/grill/gas station nearby. I would not want to be there when things get hot.

      • Albert, for info.
        In reality in the UK building happens where local councils allow building. Building is NOT controlled by developers, and has not been for decades. Government local and national of all parties set down building criteria. These often insist on ‘sustainable’ sites (‘sustainability’ is undefined) effectively to pass the first hurdle this means adjacent to existing medium sized settlements. These are frequently on good farmland on low lying sites, because that’s where settlements formed.
        In recent years building on flood risk sites has been contra-indicated (see environment agency) which usually means building on higher, more visible farmland not adjacent to settlements (so ‘not sustainable’) unless large enough to have new schools etc as part of the plan. Its not simple, councils hold much of the blame for this.
        I feel that untrue urban myths should be countered by the truth so that, as citizens, we can be better equipped for social views. Sorry about that. Please carry on vulcanising ….

        • Large developments are indicated by the councils but the developers still have to put in for the planning permission. Small developments tend to be proposed by others. The UK government has rules where development is possible. Actual flood plains (which flood regularly, say around Tewkesbury) are banned. Otherwise it depends ion frequency of flooding. But planning may still be allowed if mitigation is planned, e.g. a proposed dike can change a classification as flood plain to the next level. And the classification is based on past events. It does not take global warming or sea level rise into account. At least, this is my understanding!

          I saw one flood caused by a bridge which wasn’t letting enough water through. After several events, the river was dredged underneath the bridge, so action was taken.

          Clearly, farmers will be well aware of the state of their land!

      • Nearly every US city has more risks by natural and human disasters than Grindavik. Look at the threat for tornados, thunderstorms, blizzards, droughts, hurricanes and earthquakes. Additionally to this Iceland since Middle Age has had a long peaceful history without (civil) wars. Iceland has learned to make love & volcanoes instead of wars.

      • First, Italians must be asked, why they build 2mln metropolitan city around the one of deadliest volcano in the world ?

        • Naples is different. I love the city but the people are completely mad. And great fun

        • Along the same vein, ask the 18.5 million residents of the greater Los Angeles area why they build their houses on possibly one of the worst quake areas in the US? I tried to chuckle when I saw a map of the area around Riverside, where new houses were put right on top of active faults.. Duh !!!! developer monies take precedent over life, I guess. Amusing then not so amusing. The Northridge Quake was one of the scariest for us Californians, when a quake thrusting upwards exceeds the force of gravity, and this one did, then everything, including your body, gets tossed up in the air. (and believe me people got throw up into the air) This unusual quake brought much concern and fear into the public in the LA area. But their thrust quakes haven’t stopped and will sooner, or later, hit again. So why build in an area, when things get tossed up into the air?

        • The oldest trace of humans in the area of Naples are from the Neolithic,in the second millenium BC later there was a mycenean town and 2800 year ago a greek colony town was found with the name Parthenope and later it became Neapolis. A strategic geografical position, with a large bay in the center of theTyrrenian sea, and the productive vulcanic soil of the Campanian region are the main factors driving the destiny of the area in the last four millennia.

  19. It comes across as a summary piece for a scientific evidence summarising what is already known. The statement that the existence of Grindavik is beyond logic as it is on a lava flow, is a little bizarre, considering the whole of Iceland is lava and the number of settlements across the globe built in the shadow of volcanoes.

    • Sooner or later more parts of the Reykjanes Peninsula – even the Keflavik Airport – will likely get impacts by eruptions. The last eruption cycle included several Tephra eruptions offshore the westend of the peninsula. We’ve had some recent earthquake swarms around Eldey and Geirfuglasker. There Surtseyan eruptions are possible that can send ash to the airport and in worst case even to Reykjavik.

      • Keflavik is a bit outside MAR. South of Reykjavik can be indeed at risk.

        • The map shows lava layers, but not prehistorical tephra. Surtseyan eruptions in the sea west of Reykjanes can be big enough to cause ash fall around Keflavik.

  20. HVO website was down for a few days but is back now. Seems that in that time Kilauea has had continuous quake swarming at intermediate depth under the summit, and nothing much shallower

    • It seems as if the floor of the ongoing DI events slopes upwards. I think that we have 4 Ds but no I, and that a strong inflation of 1.5 microradians per day is happening in the background. Possibly parts of the magma storage wall are starting to detach with magma rushing into expanding fractures and deforming rock into a more compressed form, but the detachment is completed. When the two biggest ongoing DI events are completed the tilt might go up some 4 microradians or more, going above the previous highstand quite a bit.

      But, for the most part, it seems Kilauea has calmed down somewhat over the past 2 months.

      • There was this signal at SDH, not sure what it is but it looks like a quake swarm signal. Probably the same signal that was discussed the other day, which looked like tremor but left no other signal.


      • Cams are looking at other stuff now. Oh well. Must have been wishful thinking.

    • Don’t think so. Looks like vehicles on the svartsengi cam. The light is too white.

      (Mind you; I said that about Holuhraun 🙂 )

      • Definitely vehicles in a convoy I think. I saw it on the cam overlooking Grindavik. A slow moving convoy of vehicles that at first made me think a new eruption because the lights from the rear were orange. It looked exactly like an eruption fissure until I noticed it was cars moving forward. Perhaps a convoy of workers for the fish processing plant being led by an escort vehicle because of the danger of some roads in Grindavik. Or else ones coming in to map and examine any new fissures in the town.

          • Thanks for that info Talla. Good to know they are continuing to maintain as many services as possible. It may turn out to be a futile gesture, conversely Grindavik may escape destruction. I think unless the harbour is destroyed they will put all best efforts to keep the town viable.

          • Icelanders really display the most admirable part of humanity. How many of us live in a cold freezing environment and put up with volanoes and fissure eruptions on very short notice? They love their place. They have been very innovative and turned the geothermal heat into an advantage. I say more power to them!

    • Theres no smoke, if it was an eruption there would be cloud coming from the light source.

  21. How many of you share the same apprehension as mine? I have 2 or 3 things which still keep nagging me. #1 The new grabens in the Grinkavik area are because of magma intrusion, so when is that magma going to come up? #2 The continued upward movement of most GPS stations in that region are still rising. This means that all that magma, sooner or later IS going to escape in a fissure eruption. #3, the longer that the inflation period continues, the possiblity of a larger eruption grows.

    Early morning a couple of days ago, I wondered if things are shaping up to a large fissure eruption, most likely at Grindavik?


    • Regards point 2, the uplift, combined with lateral ground movments, at quite a few stations indicates to me (IMHO) that inflation is not only continuing, but the recent eruption didn’t do much to relieve it. This worries me, a lot, because IMHO it’s going to come up somewhere in the region, and the Grindavik area looks like a likely spot.

      As for point 1, I’m worried, but less so than on point 2; if those intrusions remain static for a while, they’ll solidify, so no long-term danger. Right now though… short term, they worry me.

      On point 3, I agree.

    • Chances are that the whole rift that formed in November, except maybe the last few km on each end, is going to erupt. The largest eruptions are probably going to be inland of Hagafell, but it is unlikely the area at Grindavik will escape seeing as the dike went offshore.

      The eruptions so far have been intense but small, one only needs to look a few km away at Eldvorp to see what a large eruption is like. Eldvorp has got parallel lines of fissures so likely formed in many eruptions, but the entire fissure line opened in the final eruption of the sequence. And then, the last and largest of the Svartsengi eruptions, at Arnaseturshraun, was on a different fissure line so even a mature rift may not prevent the sill complex rupturing in other locations or even in two at the same time.

      Eldvorp is also the source of one of the largest of the Reykjanes fires tephra layers, a VEI 4 I believe, originating from the ocean just beyond the fissure on land, and presumably predating the final lava flow. If one goes over to Krysuvik some of its eruptions have flowed into the ocean on both sides of Reykjanes, and with long fissures and sheet flows devoid of any proper flow features. The eruptions would have been of an enormous intensity. Hengill is like this too but it is even bigger again, its last flow was a 20 km long curtain of fire that erupted a similar volume to Holuhraun. A repeat of that eruption but a bit further northwest could send a lava flood down into part of Reykjavik, or potentially into Hveragerði, and both scenarios would probably destroy Hellishielði. Hengill is the least active of the Reykjanes volcanoes though so the risk is a lot lower, but still.

      I dont want to see Grindavik buried in lava but a lot of unusual and unlikely events would have to occur to avoid that outcome unfortunately.

      • No offence, Chad, but I hope you’re wrong. I suspect you’re right, though.

        I’ve had concerns about the Reykjavik southern suburbs ever since Fagra 1 began.

        Do you happen to know if the last Reykjanes fires started with small eruptions (Like Fagra, and the current set near Grindavik) with the big eruptions occurring later in the sequence, or did it start big?

        The big question on my mind is when and where will the next one be? I can only note that what’s been the best warning sign of imminent eruptions is flashing red: the Blue Lagoon reopened today, so I’m still betting on an eruption this coming week. 🙂


    • #1 In MAR the magma is mainly filling spreading dike and cooling inside. Only little, if any, of this magma comes to the surface
      #2 It not means. The sill is like a buffer tank in dike spreadig process.

      • The proportion of dikes that erupt is not the same as the amount of magma that erupts or doesnt erupt. Every eruption is also an intrusion, but some intrusions dont erupt too. For rifts that are fed by a central volcano (Bardarbunga, Kilauea, etc) you can even get eruptions that are significantly larger than the volume of magma that intruded into the crust to reach that location beforehand. The intrusion that fed Holuhraun was about 1 km3, while the erupted lava volume was about 1.7 km3. For Kilauea in 2018 the original dike that intruded on the ERZ was only about 0.1 km3 and yet it resulted in an eruption of 1.5 km3 of lava. These rifts also typically go as singular long and usually intense eruptions rather than episodic short lived eruptions.

        Rifts that happen on flat ground without elevated central volcanoes usually have bigger intrusions than eruptions but it isnt really so clear as that either. Krafla, as it says in the article, had 18 intrusions, and 9 eruptions, which sounds like 50% rate. But the first 12 intrusions only had 3 eruptions while the last 6 all erupted. The first intrusion also had only a tiny eruption and was gigantic, probably multiple km3. The last 6 intrusions were all a lot smaller but went directly up and fed powerful fissure eruptions. The intrusion to eruption ratio of the first big intrusion in 1975 was probably like 1000:1, while the intrusion to eruption ratio was probably more like 1:2, if not more favored to an eruption.

        Same is probably at play now at Svartsengi. The November dike opened up a long rift and failed to erupt. But the dike in December went right up and erupted almost immediately and didnt go nearly as far lateraly. This recent eruption was kind of inbetween. As the space underground is filled up by future intrusions the size of eruptions will increase and possibly so will their frequency as nowhere else is left to go.

  22. Alice – today’s video from Shawn was indeed excellent! Answered all my questions about the tectonic movement, cleared up my hazy knowlege on grabens. That guy is a treasure, to me!

    (Link to his vid: )

    Thanks for that link, the submarine lava flow maybe struck you, (as it did me) as possibly an additional ominous sign for Grindavik? But there’s no crystal ball …. so despite everything, the Icelanders just keep, “keeping on”, it’s inspirational.

    • The small purple spot to the southwest of Grindavik bothers me. We can also see them between the recent eruption and the Dec eruption. Again, I wonder about a major fissure eruption in the making.

        • I think it’s the lake too, with the Blue Lagoon off to the left.

          The spots between the two eruptions look the most interesting to me as they aren’t in a north to south line with the other fissures, but look a little more broken and east to west to my eye.

  23. A must watch from Just Icelandic

    Reality Bites – Housing Crisis and the Computer who Says No

    This is a big update that even covers a residents’ meeting with a few clips that you will find interesting in order to understand the unfolding story of the worst natural disaster to hit Iceland in historic times. This is also a major economical disaster and the biggest issue now are the abandoned houses in Grindavik, the house that the insurance system won’t cover.

    • I noticed that about an hour or so ago and it’s looking roughly the same now but with a bit more smoke/steam. I assumed it was a slight reopening or maybe lava crust collapsed?

      • That area has been smoking for the best part of all day. I assume either magma leakage or a small collapse. Certainly nothing significant.

      • I would also assume crust breaking. Quakes have been rather quiet. It’s not visible on Husafell camera, and the RUV Thorbjörn camera only shows it very faintly. If it were an eruptive event I would also expect mbl’s Thorbjörn Austur camera to show glow on the nearby rocks and the sky.

        • I rewound the stream, the same spot was glowing before dawn, but during the day is only visible as steam. It is hard to tell much without a zoom. Its only a very small spot, but the brightness does fluctuate and at times brightens considerably, and there is a little bit of twinkling in the nearby flow. It might just be some material being forced out of the dike by the weight of the overlying flow, with no gas pressure behind it.

          • Wasn’t there a rubbish dump somewhere in that area that produced lots of dark smoke? I’m sure I saw something in one of the drone videos. Maybe it is the rest of the dump slowly smoldering / burning?

      • I was watching on Live from Iceland. The mbl feed has LFI on its time stamp so it is probably a shared feed.

    • We will soon find out how regularly the Grindavik system is going to erupt. Fagradalsfjall confirmed twice a regular recurrence time. It’s possible that Grindavik’s volcano is going to erupt more irregularely. Sometimes with eruptions quick after each other, sometimes with longer dormant periods. The Grindavik system looks more complex than Fagradalsfjall.

      The approximate recurrence time between the First and Second eruption of Grindavik’s system was four weeks.

    • Its apparently a burning waste pile from the greenhouse or something like that. Its not an eruption or a crack with a shallow dike.

    • The cameras I have found by experience the past 2 years, can often give misleading information. The sudden brightening can actually be an image artifact from both the camera and the image compression algorithms. It is best to have two independent confirmations when something appears on the camera as an eruption event.

      • Well, it is still there this morning, and still varying in brightness. if it is a pile of waste, it is a big one.

        • I know, I have been watching for several days too, wondering exactly what is going on. But the vagaries of the cameras have caused me to be cautious, as I misinterpreted one camera as indicating a renewal or resurgance of volcanic activity, which no such thing occurred.

  24. One volcano that does many volcanic quakes is the Clear Lake Volcanic Field in California. It was last active until 9,000 years ago. GVP says that ” A large silicic magma body provides the heat source for the Geysers, a geothermal field with a complex of electrical power plants.”

    Does this mean that we should expect the volcano to stay dormant for longer time or should we expect that the dormant period can finish? The lot of hydrothermal activity makes it difficult to distinguish between normal and above normal activity.

    The CVO (California Volcanic Observatory) judges Clear Lage Volcanic Field as having “high” threat potential. In October they published a Hazards Summary:
    They say that it’s uncertain in which stage the volcano is now. “Intermittent seismic activity and the presence of heat at depth indicate that the system is still active and eruptions are likely.”

    • Clear Lake is probably a future supervolcano, 9 millennia is not necessarily a very long time for a system like this. Probably also means the risk is very low of an eruption actually happening but should it occur a lot of damage would result.

      • The Hazard Summary doesn’t mention this risk. But an eruption in the lake of Clear Lake poses a hazard for phreatomagmatic eruptions with tephra/ash fall over parts of California. During the past period, there mainly happened Maar eruptions and cinder cones along Clear Lake.

        Clear Lake Volcanic Field is linked to the San Andrew Fault and by this different to other Californian Volcanoes (f.e. Cascades volcanoes like Mount Lassen). The largest volcanic feature of the Field is Mount Konocti, a large Dacitic Dome cone. Dacite Dome building can be a bit boring … like St. Helens’ effusive and slow Dome building activity during the 1980s. But the opening phase for such a Dome building can be explosive.

      • As a nascent potential supervolcano the system certainly deserves more study even if it might not be a threat in the short-term. I can’t really think of any other system where there is an oppurtunity to study what a potential supervolcano in its infancy is like

    • Volcanophil:
      I have not heard one explanation which satisfactorily explains why quakes keep occurring in this area. Clearly from the Berkeley quake monitoring center, we can see how active this region is. But as to the driver or reason for the quakes, to my own reasoning, I have not heard a satisfactory explanation.

      • The main reason for quakes there are likely hydrothermal quakes like we often see at Yellowstone or Myrdalsjökull (Katla). But it’s possible that these quakes mix with magmatic quakes that would show an awakening of the volcano.

        Clear Lake Volcanic Field can in largest/worst case eruptions threaten the Central Valley and San Francisco. I wouldn’t expect a Supereruption, but a Plinian VEI4 should be possible. A Maar eruption would be around VEI3, interesting and aesthetical, but with limited damage.
        This Volcanic Field is linked to the San Andreas strike-slip transform Fault. Therefore it is different to usual subduction zone or extension zone volcanoes.

  25. Nice little swarm right at North Grindavik. There’s some electric line work going on there right now, but the depths match the swarm before the last eruption. I understand those depths can be inaccurate in some instances. A couple of the quakes are near that little patch of lava and smoke though. I’m not going to guess… because there’s no need to. If the nice little swarm becomes a less nice big swarm, there’ll be no guessing about that.

    • Some quakes near Grindavík with 0.0 magnitude and 99.0 quality. Not sure how that works.

      • The magnitude numbers are logarithmic, so a zero-energy “quake” would have magnitude minus infinity. Magnitude 0 is just a fixed factor less energetic than magnitude 1, which is the same factor less energetic than magnitude 2, etc.

  26. So I was looking at Iceland in Google earth as one does, and came to think that what if the unthinkable happends, and all of reykanes starts erupting off and on for 200 years, where would the Icelanders move their capital?

    Icleland is a Biiig island, but where would the climate and topography, not to say the geology be beneficial?

    • I think it was on one of Just Icelandics videos, but he said he was kind of confused why Reykjavik was where it is and why it isnt built around Borgarfjordur to the north, which apparently has a better climate and is geologically stable. I cabt remember which video now though, or if the location is the correct one.

      I guess now though with how sea ice is a rare thing anywhere in Iceland it might be possible to make Akureri the capital, but unless an eruption happens at Borgarfjall or in the Blafjoll area and flows into the city directly I think moving most of the population would be more risky than the eruption. But maybe someone actually from Iceland would know a lot better 🙂

    • Iceland is warmed alot by the Gulf Stream so pretty much is the warmest coastal location of any at that northen latitude, rarely gets very cold near the coasts, unless arctic airflow is present. The sea never freezes as its in warm temperate water currents rather than cold arctic water, huge moderation in winter, at least in the coastal areas. Akureyri have the same warm waters, but gets air from the interior in winter so is usualy much colder. During polar waves Akureyri is one of the coldest cities in entire Iceland with below – 20 c is possible, westfjords can also get quite chilly if polar windflow is present. Woud be fun to have the capital in the fjords, coasts lined by bulldings and roads and apartment blocks, overlooked by incredible mountains, then Reykjavik woud be stretched all along westfjords coasts, woud be insane, minus the rockfalls and potential landslides. But not alot of space in the most epic parts of that place in Iceland.

      Most of Icelands weather problems woud be solved if it was at latitude 50

      • Had Iceland been around polar currents, it woud have probaly never had forests even in holocene, it woud depress the summer temperatures so much, parts of Québec is cooled so much by the labrador current that they have tundra at latitude 53

    • It would take something a lot more destructive than anything that has happened since the last ice age to cause Reykjavík to be abandoned as a capital. The worst case scenarios I can imagine involve heavy damage to the suburban outskirts in the south and east of the urban area (which are mostly not Reykjavík proper) and damage to vital infrastructure such as the Hellisheiði and Nesjavellir geothermal plants. Maybe a huge dike finding its way directly underneath central Reykjavík on the peninsula? Doesn’t seem likely.

      If there is a need to relocate the capital or a significant part of the population, then I think there are plenty of suitable locations in the west, north and far east that are geologically stable in the very long term and are not space constrained by close mountains. See Akranes, Borgarnes, Stykkishólmur, Búðardalur, Blönduós, Sauðárkrókur, Akureyri and Egilsstaðir.

      • I agree with you except that most of the places in the north and the east with good harbors do not also have enough flat land to allow the construction of an airport with runways in two directions. Also, the winter in those places is so much more brutal than in the southwest. Borgarfjörður is really the only viable year-round alternative. Of course, why worry about bad weather when we have already chosen our new winter capital – it is called Tenerife! (Ignoring the fact that there is a volcano there too…)

  27. Hard to imagine this whole thing glowing like a nuclear test, it woud be a sight beyond any capacity of mental imagination, and this was from an simulation of an asteorid impact just a kilometer wide or so. Even larger impacts like Chicxulub can envelop the entire planet in hot ejecta causing global destruction by reentering ejecta heating. But the simulated stuff woud take out Iceland instantly and destroy most life on a small subcontinent

    Image replaced with smaller version on faster site – admin

    • And Chicxulub orders of magnitude worse of course, recepie for atmospheric grillning, large parts of the planet woud be like being in an oven

      • Thanks Jesper!
        In case anyone is wondering how ejecta from one impact point could cause fire in the sky globally, that I can weigh in on; it very much can. A lot of the ejecta would recondense, into spherules (such as have been found at places like the Tanis site). These spherules, and other ejecta, would vary in velocity and trajectory. Even at orbital velocity, orbital mechanics would place the perigee at ground level near the point of origin (that’s why, to raise a spacecraft’s orbital perigee, you have to do a prograde burn at apogee).

      • hmm, lesseee…
        Mas of air per sq m of surface earth: ~10T/m^2
        Mass per sq km thus 10^7T/km^2 = E8 T/km^2
        Earth radius ~6.4E3 km
        Earth surface area 4 pi r^2 = ~ 500 E6 km^2 = 5E8
        Mass of atmosphere ~ E8 x 5E8 = 5E16.T
        Volume of r-1km asteroid ~ 12 cu km
        Density 8gm/cc = 8T/m*3 = 8E9 T/km^3
        Mass asteroid 100E9 = E11 T
        So atmosphere ~ 5E5 size of asteroid.
        Assume asteroid collides at a leisurely 33km/s
        Energy 1/2 mv^2. ~ 5E8 joules/kg
        If all energy deposited into atmosphere (just to get a handle)
        that’s approx 1kJ/kg.
        New interesting factoid, specific heat air at STP approx 1kJ/kgK
        In reality more complex due expansion etc
        BUT to my amazement only 1C!!
        Please check the sums as I am very dyslexic and likely to be out by many orders of magnitude…

        • farmeroz do not forget the reentry of the impact plume, it will fall back on the atmosphere causing the atmosphere to heat up, can be imagined as millions of shooting stars filling the skies. The real damage from larger impacts than this simulation are the plume and its reentering materials heating things up and dust that blocks the sun.

        • You are pretty close. The asteroid volume is 4km3, not 12, its density should be 2.5gm/cc (8gm would require iron – exceedingly rare at that size), and an steroid will typically enter the atmosphere at 15-20 km.s, not 33. But the uncertainties cancel and your final number is almost correct: I found 0.2kJ/kg. Clearly your dyslexia does not extend to numbers. So yes, the Earth’s atmosphere would not heat up from the explosion energy. A 1 km asteroid (radius) would create a crater of about 40 km across. The KT asteroid was 10 times larger, so 10^3 more energy. That would give a decent temperature spike of ~10C, however most of the energy went into the ground rather than the air.

          • Well I was assuming a nickel iron asteroid and its possible you omitted a pi on the volume. As you say, order of magnitude: who cares.
            The KT max ave air temp of ~+10C with 100% efficiency would be quite nasty in the open air in many places but as you say, significant energy loss to ground melting and deformation as well as a proportion exceeding escape velocity or having a longish period extraterrestrially would reduce the net energy deposition. We discount burning vegetation.
            All the same, quite fun to do these sums, because it suggests the more extreme scenarios are likely wrong (globally). I wonder how long an orbiting dust cloud could survive to block the sunlight?

          • Here’s a thought.
            Assuming the KT boundary is asteroidal.
            You suggest its not nickle-iron but presumably more like Tunguska(?) then a 40km large asteroid (possibly starting very much larger) is perhaps more likely to break up, possibly on preceding close encounters resulting in one big explosive impact but proceeded/followed by multiple secondary impacts, perhaps more-or-less annually as earth crosses the debris field. That would certainly put life under strain for perhaps decades or more and show little evidence. Indeed we may still cross that debris field today, although the impacts would be hugely attenuated. We would be looking for a meteor shower perhaps with few large bits of meteor remaining.

      • Chicxulub woud have ejected perhaps 100 yellowstone volumes or more, all that ejecta was sent on reentering trajectories, and scary enough most of that materials woud already be hotter than the sun

        Every glass droplet that reenters the atmosphere forms a hot plasma stream like a meteor, now imagine 100 0000 s km3 of this stuff counting on the crater cavity, this woud heat up the entire atmosphere flash point, you woud be grilled over most of the planet, there is plenty pf soot and spherules from KT all over the world

        • Jesper. I have just done a back of an envelope estimate giving worst case. If you are to be scientific its good to bracket “could have” to more than this but less than that, based on physics. I just illustrated the worst case (and Albert expanded it) for the atmosphere, I could probably refine it somewhat but basically worst possible (and improbably high) case is all the energy heats the atmosphere for an ave 10C temp increase (KT asteroid).
          So many wrong/implausible statements can be checked using this idea.

          • Farmeroz, I think you did great regarding the calculation, but if I’m understanding you right, that’s for a net warming of the atmosphere, not a brief (two minutes or so,) radiative infrared heat pulse.

            My own personal theory is this heat pulse would have been lethal (due to imparting significant skin burns) to large land animals (without major heating of the atmosphere as a whole). Nuclear detonation at altitude effects are similar (though obviously briefer); a heat pulse at distance, often enough to cause flash fires, though without major heating of the atmosphere (which is largely IR transparent) Burrowing animals, on the other hand, could have survived (such as the ground dwelling avian dinosaur species that did survive). The “global winter” that followed IMHO probably finished off any large survivors, and IMHO it’s no coincidence that, so far as we know, only omnivores survived on land.

            BTW, I’m talking Chicxulub, estimated to be 10 to 14 km across, giving us a low-end volume of around 500 km3. Estimates vary, but the consensus (I haven’t checked these numbers) of an energy yield around 75 teratonnes of TNT (based on an assumption of an impact velocity of 12kps, which I think is a tad low… even free-fall from the edge of Earth’s Hill Sphere would give a velocity at impact of over 11kps.).

          • CJ.
            Yes, quite correct.
            You can get a handle on that easily from the figures I presented, no need to guess. I stick with my r=1km iron meteorite entering a very high velocity (thank you Albert).
            Energy was 1kJ/kg atmosphere and we have 10,000kg/m^2 of atmosphere so that’s 10MJ/m^2 of planet ave BUT this isn’t a very useful bound. If this was just radiation it would leave tangentially and almost all will exit into space and vanish. Ejecta will of course also cool by radiation into space, probably at quite a rapid rate given the large area. Yes there will be a significant shock wave but how much energy goes into this and how well it persists I have no idea, but it will be a tiny fraction of the total energy. We need a big explosive volcanic eruption to get a handle on % energy into shock waves…….

        • When ejecta reenters the atmosphere it causes millions of fireballs to blaze across the skies like meteors, that will make thermal radiation to be cast on the ground below.

          But only very large impacts causes any atmosphere firestorms

      • Albert you forgets the ejecta reentering, that will defentivly cause radiation heat towards the ground when it comes back as countless meteors, but 4km3 is not a very large asteorid. Small impacts will not cause any atmosphere firestorm

        Chicxulub was much bigger so had global effects, there is plenty of spherules and charcoal dust in many KT deposits.

        • The ejecta still get their energy from the asteroid. Farmeroz’ calculation was based on the total energy that is available. Some of it will have gone into the ejecta. Some goes into radiation which for a very large impact may cause everything with a line of sight to the asteroid (perhaps out to 600 km) to ignite. Tunguska ignited moss out to several kilometers. The shockwave itself also causes a major heat pulse. But averaged over the entire atmosphere of the Earth, even Chicxulub had limited impact from the direct effects.


        And really large impacts results in a rock vapour atmosphere, here is one infamous animation, what woud happen if a protoplanet woud hit Earth today. Will not happen again, as souch large impacts happened only in the hadean era. But I still call this animation pure art

        This is 50 times larger than Chicxulub for comparsion and makes Hunga Tonga look like a pweff

      • Count in the reentering ejecta causing billions billions of fireball bolidies in the sky, the ejecta curtains woud be like a wall of fire when they comes back. Well the air itself may not always gotten to flash point, but there will be thermal radiation from a sky that goes from blue into something thats like hot lava in color with countless white streaks. That may cause bark and vegitation to dry and burst into flames

        There is plenty of soot and spherules from the KT boundary globaly, even in New Zealand so large parts of the world burned, forests fires all over. But if the fires where global is hard to say, but probaly was the case.

        Chicxulub woud bring glass rain over the entire planet if if happened again, but in Europe and Asia spherules deposits are just centimeters milimeters thick from KT. But woud be bad for surface life with all ejecta comming in and lots of it burning up releasing radiation

    • Oh, somehow I must have been redirected to AsteroidCafe. 😀

      Impressive and almost unimaginable. Even Supervolcanoes are petty against an asteroid impact.

      PS: Don’t look up! 😉

      • Effects are not that diffrent on climate as it is with supervolcanoes, Chicxulub caused a severe impact winter, and the 1 km wide example woud also mess up the climate

        But really really large Impacts like the simulation just turns Earth into a fireball leaving only bacteria alive kilometers underground

  28. Based on the Eldvorp station which actually showed deformation in the last eruption, the next eruption is probably going to be in about 10 days or on about the 1st February.

    • Let’s hope that the fissure vents do NOT open up in the middle of Grindavik.

      • The biggest vents are most likely to erupt inland of Hagafell where the dikes seem to originate from. These vebts will feed huge fast moving lava flows but Grindavik will be mostly protected by topography. The Blue Lagoon would be in huge danger from these eruptions though.

        The risk to Grindavik probably comes from from more distal fissures like we saw recently. This might include submarine activity.

        One can hope but our thoughts cant control geology, the only thing I hope for is that it all happens soon so whatever necessary rebuilding and relocation can begin, and not have this drag out for years. Grindavik as it is already is probably too dangerous to live in regardless of eruptions, too many cracks and certainly far more sinkholes that have yet to form too.

        • I read somewhere about one of the plumbers going into Grindavik to check and pulling into a driveway with the van. He went to step out and thankfully saw the small sink hole that had opened next to the vehicle. Probably it formed by the weight of the vehicle. His fellow worker who was driving managed to manouver the van and drive out again avoiding the hole. That was when they could see the cracks in the driveway. A scary experience I am sure! I was surprised anyone at all had been allowed in without full checks, especially on a day with snow cover.

      • Richard, today, when checking the quakes, I see another trail of quakes at about the 355 deg compass setting north of Grindavik (on the IMO map) I think these quakes are happening due to stress release from the inflation in the Mt Torbjorn region. This is the 2nd time that this string of quakes has occurred and this time they are more dense.

    • Why is it accelerating? Is this a trend or will it likely turn back to longer recurrence periods?

      • Its not necessarily doing anything, just that Eldvorp will get back to the baseline before the last eruption around the end of the month. There are too many variables to completely rely on this but it has been pretty consistent so far.

    • It easy to forget that SKSH, the most centrally located station above the sill is rising up at almost exactly 1 cm per day. At this rate the station would rise 3.5 meters in a year if uninterrupted by eruptions/intrusions and maybe the exact center of sill would rise even more!

      • HS02 is currently rising at about 1.3 cm per day. SENG, GRIV and SKSH all at about 1 cm, as you say. I think HS02 is closer to the centre, but there isn’t much in it.

      • We need someone to carefully sort out all the GPS stations elevation changes. Some stations are now static, while others are going up, just as mentioned. I wonder if making a polygon net map for a time period for all the GPS stations elevation and creating a few dozen of these for the past 3 months might suggest what is going on.

        • I posted an image back a page or two based on me drawing vectors for the closest staions and looking at relative inflation

    • I’d have said 31 January but then I’m impatient 🙂

      But given that Svartsengi has just carried on inflating, not sure how reliable a predictor it is for the graben area.

  29. Looking at Kilauea’s past week map of automatic earthquake locations of HVO and comparing it to captures I have of it from a few months ago it looks as if south flank seismicity all along the East Rift Zone has increased substantially, the increase is noticeable as far as Leilani. The past two days of increased inflation at the summit have included increased seismicity along probably both the south flank and Halema’uma’u. In fact 3 out of 8 M 2+ earthquakes of the past 2 weeks, in the south flank, have been during the last two days. South flank seismicity had been very low in the past two years or so.

    The ERZ connector is quiet, but it is unclear how exactly connector seismicity happens, maybe there can be magma accumulation in the rift that doesn’t show in the connector because pressure is low.

    • I dont recall south flank quakes ever really going away, maybe their magnitude was reduced outside of the Hilina pali area, but almost always something.

      Maybe there is some deep rift filling going on, not necessarily a proper intrusion but a diversion of most of the supply away from Halemaumau and the SWRZ. The degree of inflation seen at those two places without resulting in a dike forming is a lot more than I expected. It also means most likely any intrusion or eruption out there is going to be a lot more powerful than was expected before too. Not necessarily very voluminous, but highly intense.

      If there is a deep rift filling event going on then there is also probably going to be another round of voluminous ERZ activity in the future too. Probably still after more summit filling and a few SWRZ intrusions and eruptions, but that was also true of the years before Pu’u O’o too.

      • This is the last capture I have, it’s from the first week of November 2023:

        The first week of November had 2 M 2 earthquakes and 12 M 1 earthquakes. The past week had 5 M 2 earthquakes and 23 M 1 earthquakes, but most of them seem clustered in the past 2 or 3 days where the summit has also seen increased inflation and earthquake rates due to the rebound of a few ongoing DI events. We will have to wait and see if this continues or not, but it looks like the may be some increase of earthquake rates along the south flank of the ERZ.

        • Other captures I have for four weeks of August, April, and March 2023 also show much less activity over the south flank than now. Although in 2020 it was higher than now, when the ERZ was active.

    • The current earthquake map looks like the Summit is going to erupt next. The recent deformation there also has accelerated. Either close to Halema’uma’u or like 9/1982 above the southern cliff of the Caldera.

      The current supply rate for Kilauea is 0.1km³/year.
      Hamakua Volcanics (Mauna Kea) during early Weichsel Ice Age had 5% of current Kilauea.
      After this Mauna Kea during Laupahoehoe Volcanics decreased even much more its activity to 0.0004 km³/year = 400,000m³/year. So it’s nearly out of the race, but is it comparable to some subduction zone volcanoes?

      • Hualalai is probably nore comparable to an active subduction volcano in output. Its hard to tell though because many stratovolcanoes can stay open and technically ‘erupting’ but have basically 0 lava output.

        Supply rate long term to Hualalai is something like 0.2 km3/century so around 50x less than Kilauea but it is about as productive as Katla has been in the past 1000 years on average to put things into perspective about how active Hawaii actually is…

        • Hualalai is around 50 times less productive than Kilauea, and if I calculate correctly, Mauna Kea is around 50 times less than Hualalai. There is a huge difference in their postshield stage. Hualalai is in the early postshield stage, while Mauna Kea in the late stage some millenias before extinction. Also the magma chemistry is a lot different.

          • Mauna Kea is actually younger than Hualalai 🙂

            It also has much larger eruptions wen it does erupt, going up to multiple km3 for single events. Though still it is less productive than Hualalai it might not be by 50x less,

            Magma is also intermediate composition,

    • I am hoping that they release this as public information. All the quakes still occurring on the dike means that another eruption IS coming.

  30. Magnitude 7 at 10 km depth in Xinjiang, more data to come.

    • OH, that does NOT sound good. Please update us Tallis when you have news.

    • Thank you, saw it on the Lastquake app.
      Some heavy aftershocks as well….
      Not good.

  31. Recently there was a switch in the relationship between the tilt at UWE and SDH. They had been out of step, with UWE rising while SDH was falling or steady. Then SDH would rise while UWE was steady or falling. Now UWE, and SDH both 326 and 316 are moving in the same direction at the same time. Does this give us any in-site to changes in the system, even as it has been pretty quiet for a bit? I know the UWE and SDH look in near the same direction so that could be a lot of the similarities.


    • Hadn’t realised that SENG is knocking on 22cm uplift since November with a few downturns in between.

      • Guess the key question is how much of that is tectonic and how much is volcanic 😉

        Net uplift is 22cm. The total uplift is over 70cm with a nearly 50cm drop.

      • The other stations next to it are showing similar uplift, with the exception of THOB, which has a big mountain pushing down.

        • Elevation map after all, november, december and january subsidences by MBL.IS

          First november subsidence was 1km wide.
          Relying on the article: for dyke-induced fault agle 30˚ estimated top of the dike can be at 1,75km deep, for fault agle 20˚ 2,75km deep. But I don’t have any data for reykjanes grabens dyke-induced fault agles, Edges of Porbjorn graben look sharp, with small angle.
          General with all subsidences, Grindavik graben now is 2km wide, so I mean that in january the top of the dike was deeper as a result of eruprion of the upper part of the magma.

      • The stations with net uplift are close to the dikes and are being pushed up by them. Dikes have a central area of subsidence and two uplift areas to the sides, in InSAR known as butterfly pattern. That is also the reason why some stations uplifted during the past eruption because the dike intrusion pushed up those areas more than the deflating sill set them down. That’s why I think SKSH and the Eldvorp station are better at judging pressure in the system because deformation comes more from the sill and less from the intruding dikes.

  32. Pingback: Volcanic eruption in Grindavík vicinity, Iceland

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