Keilir

/ 01/03/2021

Mount Keilir, on the Reykjanes Peninsula

When a year ago Thorbjorn was inflating and seemed at risk of erupting, we put out a post to describe the volcanics of the Reykjanes peninsula. The front picture of the post was of a small cone no one had ever heard of. And now, a year later, that cone is at the centre of attention. Keilir.

Reykjanes is the dark horse of Icelandic volcanism. It is far from the hot spot, and has not erupted since the middle ages. It has been 800 years since the last eruption. It seemed safe enough to build both Iceland’s capital and its major airport here. But there is power hiding here. 3 km3 of holocenic lava is located in between Reykjavik and its airport, Keflavik. I should say that neither of these two are in danger from the current activity. But Reyjavikonians may now find themselves with a front seat to an eruption – and hope that the wind blows the sulfur away from the capital. The prevailing wind here is easterly – putting Reykjavik downwind of Reykjanes.

Faults

EÁ = Eyjafjörður Deep. TFZ = Tjörnes Fracture Zone. SISZ = South Iceland Seismic Zone. A = Arnarvatn fault zone. NVZ, EVZ, WVZ = Northern, Eastern and Western Volcanic Zones. H = Hofsjökull volcanic system. SH = South Iceland flank zone. GK = Grímsvötn–Kverkfjöll volcanic systems. RR = Reykjanes Ridge. ÖS = Öræfajökull–Snæfell flank zone. RPTZ = Reykjanes Peninsula trans-tensional zone. Source: Geology and structure of the Reykjanes volcanic system, Iceland: Kristján Sæmundsson et al., 2018, Journal of Volcanology and Geothermal Research.

The Reykjanes Peninsula contains a short section of the main fault/spreading rift that affects Iceland. (This section is called RPTZ on the map above.) It is an unusual section though: it is the only transtensional fault found on land in Iceland. ‘Transtensional’ means that it is a combination of a transform fault and a rift. The spreading rate here is about 8 mm/yr. Many of the quakes of the current series are associated with a section of this fault.

North-south strike-slip faults at Reykjanes

But the Reykjanes peninsula contains many more faults here, which are attached to the main fault but act independently. Some of these have left us fissures, which run to the NNE. The fissures are mostly halyoclasts, which erupted during the ice age. The icecap contained the lava, and the lava formed a ridge rather than a flow.

The fissures indicate three main areas of activity, from west to east Reykjanes, Krísuvík, and Brennisteinsfjöll. (Hengill is part of the wester volcanic zone.) Brennisteinsfjall and Krisuvik are the most productive. Reykjanes contains several sub-centres, including Fragadalsfjall, Svartsengi and Reykjanes.

But there is more. Many small fractures run north-south from the main Reykjanes fault. These NS faults become very long south of Reykjavik, where they can extend as fas as 10 km. An example is the Kongsfell fault, south of Reykjavik (‘K’ on the image above). They are much shorter in the Fagradalsfjall and Krisuvik regions. They are strike-slip faults, and become activated when the main fault moves.

A lot of the current activity is happening at these north-south faults. When one gives, the next one comes under stress and is likely to give as well. Like books on a bookshelf, they topple one after the other.

The largest earthquake of the current series reached M5.7 . That suggests a rupture length of order 3-5 km, based on scaling from quakes in South Iceland, down to a depth of 8 km. A series of parallel NS faults have failed, with a combination of large events and small ones that break a small section/depth of the fault.

the Kóngsfell Fault, seen towards the north. The east side is pushed up by 1 meter.

The faults are described in Páll Einarsson, et al,
The structure of seismogenic strike-slip faults in the eastern part of the Reykjanes Peninsula Oblique Rift, SW Iceland, Journal of Volcanology and Geothermal Research,
Volume 391, 2020, 106372, https://doi.org/10.1016/j.jvolgeores.2018.04.029. The images above are from that paper.

Volcanicity

The faults can provide pathways for magma to come up. The Kongsfell fault is a good example. It is the source of a lava flow that has been dated to the 10th century. It happened shortly after the Settlement ash layer, and occurred on the northern tip of the fault. A number of segments erupted, but only one generated a significant amount of lava. That one was quite significant though, with an 8-km long flow.

This eruption was the start of a 400-year long era of Reykjanes eruptions, from about 940 to 1340. The series began in the east, in the Brennisteinsfjöll volcanic system, with a series of eruptions, a few decades apart and ending before 1200. After 1150 eruptions began further west, in Krisuvik, also lasting until about 1200. Now the Svartsengi and Reykjanes systems joined in with a series of eruptions, from 1211 to 1240.

The most famous eruption of these was in 1226, perhaps starting a few years earlier. It left the tip of the peninsula a volcanic waste land. Icelandic sagas mention ‘fires in the sea’ at the Reykjanes Peninsula for 1223 and again 1225-1227. A violent explosion in 1226, spread 0.1 km3 of tephra across the area, as far as Reykjavik. The sagas mention that it caused ‘darkness in the middle of the day’. The winter of 1226/1227 was called a ‘sand winter’. This word is normally used for the year after an eruption, and indicates the effect of the volcanic ash rather than the ash fall itself. It causes mortality in the farm animals, and famine. Fluorine may be to blame, but there are other possibilities. Ash and tephra are unhealthy for cattle when digested with the gras they cover. Sulfur emissions may also have killed vegetation, leaving insufficient fodder to last the winter. Farming and volcanoes make for an uneasy partnership.

This behaviour of progressive eruptions turned out to be typical. There had been a similar series of eruption 1000 years earlier – and the same another 1000 years before that, and again before that one. In this region, eruptions move from the east to the west over several hundred years, terminate, followed by 700 years of volcanic sleep before it restarts.

But why do the fissures tend to run at a different angle than the NS faults? Strike-slip faults may allow magma to come up, they are not ideal for magma to flow sideways. Magma likes to form dikes. These dikes push themselves along the direction of least stress. The faults carry stress. Least stress is perpendicular to the direction of plate spreading, and the fissures take approximately that direction. The dikes cause eruption within a few kilometers of the main Reykjanes fault. The dikes can actually extend much further, up to 50 km, but those dikes stay underground and do not cause eruptions.

The earliest eruptions, shortly after the ice went, were larger than they are now. As the land rebounded from the ice age 14000 years ago, it may have generated more magma. Large shields formed: the largest one covers over 20 km2. Over time, the eruptions became smaller. But they did not fade quietly into the volcanic night: The thickest tephra layer dates from 6100 BP, up to 1.5 meters thick.


Keilir

Keilir

The current earthquake activity has focussed on a surprising area: Keilir. In spite of its anonymity, it is actually a well-known landmark, an easily recognized and widely visible, 378-meter tall cone.

The northwestern part of Reykjanes Peninsula has three main lava shields, from east to west, Hrútagjá, Thráinskjöldur and Sandfellshaed. They are half-shields where the lava flowed (as pahoehoe) north but not south. They summits are some 200 meters above sea level and the slopes are very shallow. Thráinskjöldur covers 20 km2. It is dissected by many faults, including those currently active. Keilir sits on the lava field of Thráinskjöldur.

Lava fields of Reykjanes. The green areas are the large shields. The pinks and purples are the flows of the 940-1300 era.

The three shields formed about 9,000-10,000 years ago. Together they contain 15 km3, which is 75% of all magma erupted in Reykjanes in the past 10,000 years. The magma production was associated with decompression when the icecap melted.

Keilir is sitting on this shield. It is however older than the shield. The cone formed from an eruption underneath the ice cap, which melted through the ice only at the very end. It must have been taller than it is now, when it formed between 10,000 and 100,000 years ago. The shield came later and covered some of it up.

Volcanoes here are monogenetic. It is very unlikely that Keilir will erupt again. But the current activity may result in an eruption in its environment. As shown by Kongsfell, eruptions tend to go for the end point of the fault, and the fault is currently ending just 1-2 kilometers east of Keilir.

Will it erupt? This is the million dollar kroner question. It is trying hard. But that is never a guarantee. As Carl said, get the popcorn ready. You may need it.

Albert, March 2021

Keilir:
https://goo.gl/maps/bcrMNS9CsShuFEeL7

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119 thoughts on “Keilir”

  2. Looks like all the recent eruptions produced Aa flows .. since they had fast eruptive rates. The next eruption may produce impressive curtains of lava fountains and later focusing into a few spatter and perhaps tall fountain cinder cones. Grindavik and Blue Lagoon coud be in trouble.

  3. I just repost my comment, Let us be mindful of 4 different scenarios:

    1– EQ swarm continues for at least one more week. Eventually an eruption happens, as it reaches the point of no return. We are progressing in this scenario
    2– EQ stops. An intrusion stays in place, as it did in 2019-2020 further west. Another EQ is likely to start further east, probably in Blafjoll, and it could be a big one (and nothing necessarily volcanic). This is the expected eastwards unfolding of tectonic tension. This is the most likely scenario.
    3– Activity might shift eastwards and a swarm starts at Krusuvik. It could lead to an intrusion there (if it then stops), or an eruption.
    4– Grey swan. Grimsvotn erupts in the meantime and this swarm continues too. It’s not unlikely to have two eruptions at the same time. Its Covid time, and airplanes are mostly not flying. Volcanoes chose wisely this time.

    • That seems to cover it. The eastward progression could be slow. It could be years before the main fault fails there. The way things are going is suggesting an eruption somewhere. But it could be from days to decades from now.

    • I also want to remark that the Reykjanes cycle (750 years) seems to indicate next eruption will be in the 21st century, and it might be quite about now. Starting most likely in the Krusuvik or Brennisteinfjoll. Activity in Reykjanes and near the Blue Lagoon is more likely about a few several decades from now.

  4. Thank you, Albert. A good and very much appreciated overview of the geology of Reykjanes projected on the current activity.

  5. AN HYPOTHESIS
    Let’s examine a possible correlation between large rifting events in Vatnajokull triggering the start of a cycle of activity at Reykanes. Let’s take a 4000 year period.

    The major Vantajokull (and dead zone) rifting events happened in 2015, 1783, 1477, 1250, 934, 870, 150, 1200 BC, 1950 BC. I do not go further back in time, because eruption dating becomes more dubious. I choose flood basalt events bigger than 1 km3.

    DATA:

    It is a remarkable coincidence that the cycle of Reykjanes eruptions started in 940 (date uncertain), right after Eldgja eruption, a very big event. That is within a few years of Eldgja. The settlement ash (from Vatnaöldur, Bardarbunga), another very big event, happened a few decades earlier, in 870. So far, this might be just a coincidence, you might say.

    Interestingly enough, a few months after Laki (another very big event), a large rifting event happened at Hengill (but no eruption took place) in 1784. But in 1783, an explosive eruption happened at Reykjanes, out in the sea. These are literally within months of Laki.

    After these two coincidences, I started looking further back in time.

    The other cycle before, at Reykjanes peninsula, happened around 200-500BC (eruption in Reykjanes, Krisuvik). No major rifting seems to have happened elsewhere in Iceland at this time.

    But before then, there were eruptions in Krusivik and Brennisteinsfjöllum around 1050 BC (and a Veidivotn eruption is dated 1200 BC – which was the previous before the event of 870).

    In 1800BC, a larger eruption happened at Reykjanes. Interestingly enough, Grimsvotn had a significant lava flood (about half the size of Laki) around 1950 BC, which was the last eruption there before Laki.

    CONCLUSION:
    Overall, we found that following the last 8 large rifting events in east Iceland, 4 were followed by eruptive activity in the Reykjanes peninsula. Judging that both type of events are relatively rare, this is a remarkable association. But it can still be a simple coincidence.

    It might well be that Reykjanes cycles are triggered right after a major rifting event at Vatnajokull, as tectonic across Iceland suffer a major shifting. Or perhaps the Icelandic plume also affects the Reykjanes peninsula and triggers activity there.

    We had a major event in 2015 and following 4-6 years (2019-2021), we see magmatic intrusions taking place in Thorbjorn and near Krisuvik. My hypothesis can be tested now. If an eruption happens this year in the Reykjanes peninsula, it is difficult to reject a possible causality link between both regions of Iceland.

    • Holuhraun was north of Vatnajokull though, all the other examples you include are southwest of Vatnajokull, which is probably connected better tectonically with Reykjanes. The southwest rift of Vatnajokull is due to rift some time in the future, probably at Veidivotn because that has not seen a big event for over 500 years.

      Another thing I noticed which is related but different, 3200 years ago Bardarbunga erupted in Veidivotn and created the Drekahraun and Burfellshraun lava field, it is probably the biggest eruption there since Thjorsahraun, and likely the eruption responsible for creating the existing caldera of Bardarbunga. 3200 years ago there was also a big basalt eruption south of Hekla, which created the lava field of Langviuhraun and was at least about as big as Holuhraun, which is way bigger than most of the basalt eruptions in this area.
      It is my hypothesis that rifting events in Veidivotn extended into the Hekla area and triggered eruptions there, at least they did before about 1000 years ago. This only applies to the basalt vents though, not Hekla itself, the basalt vents are monogenetic and fed direct from the mantle which is probably quite shallow in this area. I dont know where Hekla itself gets its magma from but possibly if the crust is thinner it might be secondary decompression melting of the Veidivotn deep rift, with what we know of how the deep plumbing of volcanoes works there is no way Hekla is physically separate from the basalt vents at depth, but the different magmas might not be miscible which would keep them separate. There needs to be more study on the basalt vents around Hekla, they happen about every hundred years so maybe we will get to see one soon but there is so little information about them.

      • I am not a geologist of any kind but I believe that, although the rifting events Irpsit was referring to as belonging to Vatnajokull took place beyond the confines of the glacier, they have their origins within and belong to the fissure swarms of volcanoes that are located within Vatnajokull.

        Also, I believe that Reykjanes belongs to a different tectonic system from Vatnajokull (as in the first diagram Albert posted above).

        But perhaps I have misunderstood all of you!

        • Yes the lava erupting from Veidivotn is fed from Bardarbunga, or at least from somewhere near Bardarbunga, it is very much the same as Holuhraun. But the rifting event could have an indirect impact further beyond the active eruption, for if you follow Veidivotn southwest you get to Hekla. The basalts around Hekla are all very similar to Etna basalts, so cant be part of Bardarbunga, but tectonically the two areas could interact.

          • Ah, OK. Such technicalities as potential influence are way beyond my pay grade, but the’ve been discussed a fair bit on here in the past, I think. The interaction between Torfajokull and the Bardarbunga system at (Landmannalaugar’s) Brennisteinsalda, and the eruption of basic and acidic lavas in the same area is important, I think. (I have recently emerged from a period of lurking since the last Icelandic excitements, so I’ve not followed all the posts or discussions. And as I said, I am not a geologist.)

        • Also yes Reykjanes is definifely not a part of this, its just a bit of normal mid ocean ridge that is above water really.

      • A possible correlation of large rifting events around Vatnajokull (like Laki, Veidivotn, Edlgja, and even Holuhraun) and the start of eruptive activity at Reykjanes cannot be explained by a simple volcanic link. The regions are separated by abut 200-300km.

        If rifting at Vatnajokull triggers considerable tectonic strain in the rest of Iceland, then it is possible that this explains the start of activity in Reykjanes, within a few months or years.

        Another hypothesis is that a hotspot plume pulse, feeds new magma into both Vatnajokull volcanoes (causing the rifting there) and also elsewhere in Iceland (feeding Reykjanes). A recent paper shown that the plume extends at depth across most of Iceland, dividing in plume branches, as it reaches the upper mantle, one towards north, and one towards southwest, extending quite a way away from Vatnajokull.

        It is remarkable that out of 8 major rifting events in Vatnajokull, 4 were followed by eruptions in Reykjanes peninsula (and within a very short timeframe).

        If my theory holds true, then we should see the magma coming the first eruptions of a Reykjanes cycle (whether it is from Krusuvik, Reykjanes or Brennisteinfjoll), this magma would be similar to the same primitive magma found at Holuhraun or Veidivotn. And then subsequent eruptions at Reykjanes peninsula, would show progressively more evolved magmas.

        – – –

        I like your theory chad. I also had this idea before, that Veidivotn magma reaches not only Torfajokull (this is a well established fact), but also occasionally it reaches towards Hekla.

        This would happen quite deeply, beneath the upper crust, and we wouldn’t know about it.

        However I could not find any historical evidence of an eruptive link between the two regions. It is a question of finding out whether the basalts south and east of Hekla are similar to the ones at Veidivotn.

        • The problem with extending the rift beyond Torfajokull is that that it takes it out of the eastern rifting zone. Up to Torfajokul it is within the area associated with the eastern rift zone. Beyond that is a region that is not rifting but is (currently) a stable crust. It will be hard for the magma to push into this area, because of a combination of increasing stress and low pressure after traveling this far.

        • The basalts around hekla are transitional alkali basalts and very similar to lava erupted from Etna, both in composition and physical characteristics from what I can see. Veidivotn is exactly the same as Holuhraun. I have seen the basalt vents around Hekla attributed to Vatnafjoll, but Vatnafjoll looks like just a mountain that happens to be there.

          • Vatnafjoll sounds like a volcanic field to me, similar to Vestmannaeyjar. The major Icelandic volcanoes are caldera systems, both basaltic and bimodal. Hekla is probably in the process of evolving from a volcanic field to a caldera system.

          • The thing is Hekla erupts magma that isnt directly evolved from the Vatnafjoll basalt, and it actually began silicic and has become generally less so over time. The basalt volcanism of the area seem old, Vatnafjoll is probably a subglacial eruption while Hekla is a new Holocene feature. There are also Vatnafjoll basalts that actually erupted directly from the northern extension of Heklugja as recently as 1300 years ago, as well as the massive eruptions of Krokahraun and Axahraun in the mid Holocene which probably erupted from the area Hekla occupies now, so the Hekla source was initially either very weak or was very episodic. Since about 1000 years ago, and especially since 1970, the Hekla source appears to have become permanent, and basalt eruptions have only been on the east side of the Hekla fissure, unless the flank eruption in 1970 was a part of Vatnafjoll and not a lateral eruption of Hekla.

  7. There is an insar picture of the area available now, there is definitely magma involved in this. At the time the magma was about 6 km deep but I would expect it has moved around a bit so could be shallower now. There was also a livestream set up at one point to look at Keilir, it isnt going now but people are watching 🙂

  9. Let’s not forget laguna del maule, “Two earthquake swarms were recorded during 15-16 February; the largest events were local magnitude 3.1, and were located 9.1 and 8.8 km SW of the lake at a depth of 1.9 km. The epicenters were near the area producing anomalous carbon dioxide emissions. Swarms were recorded in June and December 2020, and January and February 2021, with the largest events occurring during the most recent swarm.”
    Inflation has also gotten faster.

  10. What is the Icelandic name for a small hill or a volcanic cone? Hawaii has Pu’u for this type of labdform, and I know that crater rows and spatter ramparts are called gigar(gigur?) In Iceland, but from looking at maps it looks like most eruptions on Reykjanes dont last long as fissures, they isolate to a single cone.

      • Chadseldkeila

        Doesnt really combine well… 🙁
        Maybe I should have used my other common username, would fit much better, but too late for that.

        • turtlebirdman or cryptodome-guy´s nick? (;

          Sorry, couldn´t resist!

        • Ummm perhaps .. both live in Australia anyway : )

          Anyway he= chad keeps well to the VC rules now.

          But I think They are diffrent persons

        • Yes I am not either of those people, anyway those dont play into eldkeila either, maybe that is why in Iceland they name the lava field instead of the vent… 🙂

      • It is funny that albeit German languages have ever since diverged, the common origin can still be traced back. Keila… The Dutch verb ‘Keilen’ means throwing over pins (as in bowling pins or what ever needs to be thrown over). De Dutch word for such a pin is ‘kegel’ which incidentally is also the translation for, you might have guessed it: Cone.

  11. Activity continued overnight. I am counting 4 M4+ earthquakes since (UT) midnight, along the same fault to Keilir. The small earthquakes have become less focussed but are more distributed along the fault.

    • It is good to remember that IMO doesn’t recalc anything below M3 due to workload. So, the small’uns can be all over the place.

      • If it erupts it may look very similar to Kilauea 2011 and 1970 s and 80s Krafla Fires….
        I dont expect it to grow very large … that far out on the penninsula. Reykjanes Penninsula is slowly dying as an active ridge segment. The MAR is migrating to the more domiant Katla – Grimsvötn line. Vatnajökull – Katla line will only get more active as the plume establish itself in the future.

        In the future.. melting under Reykjanes will diminish and perhaps Reykjanes will change from larger ammounts of partial melting ( thoelite ) to small ammounts of partial melting that forms Alkaline…magmas. Snæfellsnes Penninsula maybe the future of Reykjanes Penninsula. In Snæfellsnes thats been left behind by the mar and hotspot.. you finds the most alkaline and dying magamtism in Iceland

      • If this potential reykajnes eruption… erupts… alkalines instead of thoelities, then the theory is correct. But historical flows been thoelitic MAR basalts, and change to alkalines are very slow and not instant.

      • Its going to take millions of years to completely switch, in the mean time there can be two parallel rifts. Katla is also still an alkaline intraplate volcano, there is no rifting associated with it yet. There was Eldgja but that seems to have been a one off for the Holocene, Katla does have other large lava eruptions on its flanks but all within 20 km of the caldera and more in a radial distribution. Eldgja could be a sign of what is to come but its a very early one if that is the case.

        • Eldgja was a massive eruption which could only have happened with a well-established pathway. The rifts can be used by any volcano within reach. Eldgja erupted through an existing graben. All it needed was an initial connection from Katla to that graben.

          • Is it rifting that makes the dyke or is it the dyke that makes the rifting? This is not a simple question of course, however I would say the later is more accurate. In my knowledge the typical order of things is the following:

            Extension > volcanoes > rifting.

            Widespread tectonic extensional forces first create melt that moves up to form volcanoes. The volcanoes intrude dykes in the least stress direction created by the extension. These dykes literally split the ground in two and focus extension into a rift so that the plates can be pulled away from each other.

            At least that’s how the Gulf of California and the Red Sea happened, and similar to how magma manages to drive spreading in Hawaii, though with no tectonic extensional forces in the later.

            In this sense Katla is able to open up its own new rift/fissure swarm.

          • Maybe I should write a post on this. It is not a simple problem. The basic issue is that a single volcano is no match for an entire tectonic plate. It can only make a local difference.

          • I agree the effect is only local, you do need a lot volcanoes acting together, each with its own fissure and dike swarm, and it still takes millions or tens of millions of years for a plate boundary to develop, only if both tectonic and magmatic conditions are favourable.

            One has to take this with a geologic timescale perception in mind… so I’m not saying Katla will show up with a rift from one day to the other, but rather that over its lengthy lifetime if will steal some of the rifting away from the the Western Volcanic Zone and extend the Eastern Volcanic Zone rift system to the southwest, and it will be all thanks to the magma.

          • Think that here it is plate motion (transform margin) causing localised fissures, which may or may not erupt lava.

        • It is something to wonder what Katla actually looked like before Eldgja. There is no other eruption in the Holocene big enough to explain its caldera, and also unlike Bardarbunga there has not been multiple collapses, so the caldera of Katla probably is entirely because of Eldgja.

          Perhaps Katla was once a massive mountain, a big basaltic stratovolcano and an icy cousin of Etna, not a steep cone but much more prominent than it is now. Katla isnt big enough to have gigantic shallow magma storage so to have big effusive eruptions it would need some considerable height to it. The same could have been true of Grimsvotn before 1783, that was in the Little Ice Age so Vatnajokull was probably a lot thicker than it is now, and a lot more dangerous to explore, so a 2-3 km tall volcano would be surprisingly hidden. Bardarbunga caldera edge is 2 km tall but still nearly invisible.

          Theres not anything like that today in Iceland so another Eldgja is probably impossible, the tallest volcano in Vatnajokull that doesnt have a caldera is Thordarhyna or Hamarinn, they are both only 1.5 km tall. Hamarinn is though next to Veidivotn which is about due for a rifting event this century, so it might get some time to shine. Something similar to the last 3 rifts there, 2-5 km3 magma eruption, which is a VEI 5+ if theres water involved like there was in 1477. If not then we get another big lava eruption, which might last over a year at that sort of volume.

          • Don’t forget that the Eastern Volcanic Zone is on the plate boundary where the plates are pulling apart.

  12. @krjonsdottir
    The new InSAR data indicates a dike is forming roughly where the seismicity is lined south of Keilir. Rough sleeping -stress plus earthquakes felt in Reykjavik throughout the night

    Replying to @GeirssonHalldor
    It should be added, in light of new InSAR data, that it now looks like a dike intrusion is the most likely source of the ongoing deformation !
    https://twitter.com/krjonsdottir/status/1366660348690989057

  15. Ok, random question now… How much can volcanic ash clouds effect internet signals?

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  17. A lot of ash and lapili falling from Etna eruption now…

  19. “It is in itself an unchanged position. This signal that appeared on the radar image of the dynamic movement continues to be confirmed in seismic movements and GPS measurements,” said Deputy Commissioner Víður Reynisson after a meeting of the Scientific Advisory Council at lunchtime.

    “Today’s big task is to cover what it means and look at the models that have been made of eruptions and lava flows in this location south of Keili and at Mount Fagradals,” says Vienna further.

    Experts believe it would be most likely that a volcanic eruption would be low, if it were to happen, and that would not threaten settlements.

    “The eruption of the Reykjanes peninsula will not be very large. The biggest lava there is nothing huge. The probability of a large eruption is not high, but we look at everything in this and exclude nothing,” said Wire.
    https://www.mbl.is/frettir/innlent/2021/03/02/gasmengun_yrdi_mun_minni_en_fra_holuhrauni/

    • The link you need is the second one. Nice overview.

      Seismic activity has become very low since noon today. The end, or a breather?

      • Hi! Yes but i want to provide the source of the link…

  21. There is no shallow magma chambers in the Reykjanes Penninsula, If that was the case then you woud have collapse craters, and even shallow evolved melts. Reykjanes is almost purely feed by dike intrusions from the deep litosphere I think. The central volcanoes on Reykjanes are poorly developed. Perhaps Brennsteinsfjöll may resemble a long lava shield, and Hengil haves a subglacial hydroclastic lava pile construct near thingvallavatn. But mostly eruptions in Reykjanes are short lived fissure eruptions. Some eruptions at Reykjanes Penninsula have made lava shields, but historical ones been fast short fissures.
    Eruptions on Reykjanes have produced alot of pahoehoe lava before, so some eruptions may last months – years. Reykjanes basalts coud be quite hot since they are not cooling in chambers. The pahoehoe near Brennsteinsfjöll are very fluid and thin, reminded me of molten stearine thats been poured. In Google Earth the white mossy Reykjanes flows are the Aa lava, and the green humocky flows are the pahoehoes

  22. There seems to be a slowing down of the seismic activity today, what are the likely scenarios here?

    • Pent up strain thats been released through the swarm mayhem.. its more relaxed now

      But most quakes been at 5 kilometers depth.. and thats certainly not magmatic depths even If the sourrounding enviroment is very hot.

      Magmatic stuff woud be a swarm at 15 kilometers or more I think.
      But the maps clearly shows that magma been intruded, perhaps Reykjanes is hot and ductile enough to not give away alot of deep earthquakes.

  23. The earthquake between Keilis and Mount Fagradals in Reykjanes has continued today with over 2,000 tremors throughout the day.

    Unlike previous days, there have been no major tremors after lunch, which naturalization expert Einar Bessi Gestsson says in a conversation with mbl.is is not necessary to indicate that the devastation is under control.

    It’s known that calmer cycles come in between, but that the devastation can then take off again.

    Two things in the position if dynamic insertion is expected
    Since there are expected to be dynamic intersections in tectonic plates in the area, there are two things that can happen in the second:

    That the mercury stops and coalesces or it eventually breaks its way to the surface, thereby ending up in a volcanic eruption. It is impossible to tell if that happens, but it is more common for the mercury to coalesce and not become an eruption, including Einar.

    New details on further land changes due to the dynamic are not obtained until new satellite imagery taken tomorrow night, but the results from them probably won’t be until the morning after. Until then, the big picture is unlikely to change, but the tremors remain a good indication of the situation.
    https://www.mbl.is/frettir/innlent/2021/03/02/rumlega_2_000_skjalftar_i_dag/

    • Good to know, I thought first, that if a cycling release of tectonic force every 24 hours which stops suddendly would end up in a larger and/or stronger EQ…

  25. Since last week (24-February) around 80cm ground inflation occured in Krýsuvík GPS station.. clear signs of a magmatic sill intrusion.

  30. 1 M4 and 3 M3 quakes since midnight. Definitely still active

    Edit: corrected from the original number which included yesterday

    • I’m only seeing one M4.1 and 4 other M3 quakes since midnight. Still pretty active, but not as active as earlier.
      But of course this can change again.

  31. Not volcano related but…

    M 6.9 – GREECE – 2021-03-03 10:16:07 UTC

    • Basic EQ questions (Wikipedia didn’t help):

      Location/Magnitude/Seismic:

      We know how deep and how much N/E/S/W but is this the start of the crack, the end or the middle?
      (my guess: middle)

      Is a M7 possible in a fault of 1 km (guillotine vs. sword – is not the same)?
      (my guess: yes)

      A M3 is a M3 – it does not matter how long it was (duration)?
      (my guess: yes)

      The M is just the longest spike (top/bottom) on the seismometer?
      (my guess: yes)

      The shape (triangle) of EQ in a seismogram is because smaller and smaller echos from “the crack” or every spike in this triangle was actually EQ with lower energy?
      (don’t have an idea)

  33. The entire Etna coud easly be placed on Reaykjanes Pennisula… just now I realises how large this seemingly small arera in Iceland is! And Iceland itself is 8 times bigger than Hawaii

    • Yes the lava would have to actually flow a long way to reach the road, something like 15-20 km if it erupts in the mountains, maybe 10 if it erupts next to Keilir. To get an a’a flow to go that far on flat ground you need sustained high eruption rates. Holuhraun was able to flow almost 20 km before stopping but that was wet sand, it probably could have reached at least 40 km if it was anywhere else. Fissure 8 was erupted at higher rates with a lower viscosity, it likely could have flowed even further still. But at Reykjanes the eruption will only be that intense for a day maybe, and as a fissure not 1 vent. It would have to be a big eruption to flood the road.

      • Holuhraun was very hot up to 1190 C
        (40 C hotter than Fissure 8 ) But USGS never measured close to the vent at Fissure 8 so perhaps they erupted both at same temperatures, F8 certainly did to explain its low viscosity. Did USGS measure the highest temps of F8 near the vent?

        The somewhat higher viscosity at Baugur haves to do with Holuhraun carrying alot of microlites.. tiny olivine crystals.
        But close to the vents, Holuhraun was fluid and falls into the ”Hawaiian Style” category of eruptions. Holuhraun had fast open rivers and wide smooth sometimes shiney skinned lava ponds.

        Its when lava flowed outside the channels that Holuhraun lacked close vent smooth pahoehoe channel overflows. Spiney and shark skinned pahoehoe are the only pahoehoe that exist at Holuhraun close to the vents.

        Holuhraun woud be terrfying If it erupted at Northen Brennsteinsfjölls steeper slopes, then massive As flows woud be free to flow into Reykjaviks city center

  34. The #Reykjanes peninsula newspaper
    @Vikurfrettir
    has set up a live webcam pointing towards the area of #earthquakes and #magma movement near #Keilir mountain

  36. It looks like earthquake activity is picking up steam again. Lots of quakes in the Reykjanes area right now.

  37. From IMO: “A tremor pulse was detected at 14:20 and is measured at most seismic stations in Iceland. The pulse is located south of Keilir by Litli Hrútur. Similar signals have been observed leading up to eruptions, but no eruption has been confirmed. The IMO is working on further analysis of the pulse. An intense earthquake swarm started on the Reykjanes Peninsula on February 24th with an earthquake M5.7 followed by an M5.0. “

    • Here is the tremor. This looks like a good attempt at erupting

        • Those are the strong quakes. It is hard to measure depth of tremor

      • That does look like a magma intrusion signal. Dykes can propagate very fast towards the surface so it wouldn’t be unlikely for an eruption to have started or start soon.

    • IMO says it is likely that an eruption has started! Visibility is poor in the area right now with low clouds. Coast guard helicopter on its way to confirm.

      • Possible steaming at ground level on the webcam, but not rising very much. Wind appears to be blowing from right to left in image. Hopefully the weather clears and we get a better look.

  38. IMO has people in the area that are being evacuated. No confirmed signs of eruption on the surface yet.

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