Each volcano is an expression of a magma architectural construction, a great sculpture of chambers, pipes and sills, as intricate as an ant colony, or rather like the roots of a plant. This is all hidden away from our view, under kilometres or tens of kilometres of rock that makes it impossible for us to know what lies down there, or perhaps not? To me a volcano is a puzzle of many aspects, geochemistry, earthquakes, structure and eruption behaviour, among others. A puzzle can only be completed by taking all the pieces and putting them together. Not an easy task. I will attempt to assemble the puzzle, or at least part of it, of my favourite volcano. Kilauea. And it all starts with a caldera collapse in 2018.
As I write this, three years ago the summit of Kilauea volcano in Hawaii was collapsing into a caldera. Its shallow magma chamber emptied laterally through fissures in its rift. It might seem like this was a while ago and is now over, but is it? The collapse set off a series of cascading consequences that are still rippling through the molten structures of Hawaii Island. The deflations of Mauna Loa, a swarm of tremor and earthquakes under the town of Pahala, the recent eruption of Kilauea, all might be connected and it has just barely started, I will argue how this all happened and how all the events would be related.
We should first know a little about the connections of Kilauea with Mauna Loa and Pahala.
Kilauea and Mauna Loa
These two volcanoes have quite an interesting relationship. When one volcano is more active the other is less so. In particular each takes over for a period of 100-250 years, during which it gets most of the magma supply in Hawaii, then this activity goes to the other. They share the same magma supply. A far as I know this has been going non-stop for at least 2000 years. On a future article I will talk more about this aspect.
Volcanoes of Hawaii Island. From USGS.
Kilauea was dominant throughout the 18th century and until 1840. 1840-50 was a transition decade. Mauna Loa was dominant from 1850 to 1950. And Kilauea from 1960 to present. We are currently in an era of Kilauea and there is still more than forty years to go.
This relationship is best seen in the supply and the chemistry of the magmas. While Mauna Loa was dominant it erupted every ~3-4 years at an average rate of 1.2 m3/second. The total supply would also include dyke intrusions and slow spreading which could increase the total number by a factor of two or so. After the 1950 eruption its eruption frequency plummeted spectacularly. Dormancy periods have been 25, 9 and 37+ years. The output was reduced to 0.11 m3/second, a difference of a whole order of magnitude!
Kilauea mirrors Mauna Loa but in the inverse way. When Kilauea erupted continuously in the 1840-1920 period it did so at a rate of 1 m3/second and there were practically no large dyke intrusions. In contrast when Kilauea erupted continuously after 1960, during the Mauna Ulu and Pu’u’o’o eruptions, it did so at a rate of 4.1 m3/second, four times greater than in the subdued state. Ever since 1960 Kilauea has been rapidly inflating, spreading, and erupting. It has produced over 6 km3 in this time. The most productive volcano in the world. Overall Kilauea seems to erupt more, but it is clearly impacted negatively when Mauna Loa is more active.
From USGS.
Both volcanoes must feed from the same magma reservoir at depth, and through some mechanism the supply to this reservoir goes to either one or the other. But where? And how? All will be answered, but will have to wait for future articles, lets first take a look at the Pahala Swarm.
Kilauea and Pahala
A swarm of earthquakes has been raging under the town of Pahala since 2019. Actually the swarm has always been there, but its earthquake rates have skyrocketed starting in January 2019 and rising to unprecedented levels. The earthquakes are 30-40 km deep. And there is the tremor. The area just offshore Pahala is an extraordinary source of volcanic tremors. Almost all deep tremors of Hawaii originate from this location and are thought to be caused by magma rising up from the depths. Pahala would be a magma conduit then. The swarm has two parts the southern, deep, offshore swarm of of tremors, and the northern, shallower swarm of fracturing earthquakes. These two distinct parts are important when looking at the post-2018 series of events.
Deep earthquakes August-October 2019, when the Pahala Swarm was starting to ramp up. From USGS.
The Pahala Swarm is thought to be the magma feeder to Kilauea. How could we know this? When looking at a map the connection shows up quite clear, the Southwest Rift of Kilauea, which runs straight from its summit to the swarm, providing a useful connection. However the Pahala earthquakes are very deep, 30 km, does the rift really extend down to here?
Hawaii has a peculiar tectonic system powered by the magma supply. The rifts and the decollement faults. A rift is like a fracture system that is opening up and filling with magma, when simplifying things down a lot. The rift pushes away the flank of the volcano to open up space for the magma. The flank creeps on top of a nearly horizontal fault that is slightly upslope, a reverse fault, this fault is know as the basal fault, the basal detachment, or basal decollement. Why basal? Because it runs through the base of the giant lava pile that is Hawaii. Here the volcano rests on top of the depressed ocean floor 8-10 km below sea level.
The flanks of Hawaii Island are moving like a series of blocks away from certain rift zones. Crustal decollement refers to the basal fault. Created in Google Earth.
Because Kilauea is the volcano getting most of the magma now, then it is in front of Kilauea’s main rift, the East Rift, where we see these processes in action. The East Rift is continuously spreading very slowly, pushing against the south flank which swells upward and contracts, being squeezed by the lateral pressure. This can be seen in action if one visits the data of the GPS stations that the Hawaiian Volcano Observatory is monitoring on the south flank. When the basal fault can hold no more it breaks. The fault can rupture in earthquakes reaching M 7.9, some of the most powerful volcano-tectonic earthquakes in the Planet.
With all the mightiness of the basal fault a second, more modest system is often forgotten. Which is this unfortunate fault? The Mantle Fault Zone. It is called this way because it runs at a depth of 30 kilometres, in the lithospheric mantle. It happens to be a nearly horizontal fault similar in many ways to its shallower, larger relative, it can produce earthquakes reaching up to M 5.2, but most importantly has a very particular slip direction, 137º clockwise from the north, exactly perpendicular to Kilauea’s southwest rift, and positioned is such a way that it would open up the line from Pahala to Kilauea’s summit, and at the perfect depth. To put it simple, the southwest rift extends down to the Pahala Swarm and could provide an effective pathway towards Kilauea. More evidence for a Pahala-Kilauea connection is seen in the events following 2018.
I should also say that the magma chambers of Kilauea are most of them aligned with the southwest rift. This shows when there are deep sources or deflation or inflation, one of the most common sources of deformation that shows up is an egg-shaped pattern that is centred just southwest of Kilauea’s summit, is aligned with the southwest rift, and has the long end pointing towards Pahala. The main caldera of Kilauea formed in 1500-1790, has its outer scarps rectangle shaped with its long sides running parallel to the strike of the southwest rift. Currently the main axis of the Southwest Rift runs more or less coincident with the southeast margin of Kilauea Caldera, making a nearly perfect N 47º E direction line, that is perpendicular to the Mantle Fault Zone slip, and connects the most primitive magma eruptions of Kilauea, at Kilauea Iki, and Keanakako’i Craters, and the December 1974 dyke which marks the main rifting axis of the rift zone. This is seemingly a little detached from what must have been its original position.
The “egg pattern”. From USGS.
There is yet another structure that links Pahala to the summit of Kilauea. The Kaoiki Pali. I think this pali, which means cliff, is none other than the rim of an large ancient caldera of Kilauea. Why? you may think. Because it hasn’t ruptured in over 9000 years. Fault-related scarps like those linked to the slumping or to the rifts rupture frequently over and over. Kaoiki Pali also wraps around the summit of Kilauea like other caldera faults do.
The formation of this structure happened at a very particular time. Kaoiki breaks the Pahala Ash layers that formed until 11,000 years ago, but is covered by 9000 years old flows of Mauna Loa. It formed at 11,000-9000 years. This marks the most important transition in the recent volcanism at Hawaii, where Kilauea ended a lengthy period of powerful explosive eruptions known as the Pahala Ash, and resumed summit overflowing. Mauna Loa went from a period of low activity to a period of very high activity, maybe even almost uninterrupted dominance lasting a few thousands of years. It was a big change. Kaoiki Pali could have formed if the whole complex of magma chambers and sills placed along the Southwest Rift of Kilauea collapsed. Which I think is the best, although perhaps not only, explanation.
After the 2018 eruption
Back to the big eruption. In 2018 Kilauea erupted 1.2 km3 of lava and its summit caldera underwent a nested collapse. An event on this scale had not shaken the island since at least the 1868 eruption of Mauna Loa, if not since 1790. If there was any eruption that could disturb the hellish furnaces deep under the mountains of Hawaii it would be now. What do I mean by this?
An eruption drops the pressure of a magma chamber by extracting magma from it, which may increase the resupply from the magma source to restore the pressure. It just happens that 5 months after the 2018 eruption ended the seismicity of the Pahala Swarm started ramping up towards record levels. The seismicity of the previously suspected feeder to Kilauea Volcano. So presumably it did react to Kilauea’s pressure drop.
First came the tremors. As I’ve said the Pahala Swarm has two parts, the tremor swarm at ~40 kilometres deep, and the fracturing swarm at ~35-30 km. The Pahala tremors tend to always start with a sudden jolt and then a series of later spikes, these can be located much more easily, like they were earthquakes, than other types of tremor.
The tremor came much stronger than usual in 2019. There were 4 pulses. The first pulse had its main phase in January 11-January 23. The second pulse peaked March 14-April 2. The third May 12-June 3. The last pulse came more dispersed in a series of peaks and could be considered more like a bunch of small pulses lasting from June 26 to July 27.
After the 4 big pulses the tremor activity dropped to the typical low levels until mid-2020 or so when a second series of strong tremor pulses started. I will focus only on the first series though. I do know however that there was at least one pulse in the second series, in January 2021, that does rival the 4 big pulses of 2019.
Characteristic Pahala tremor episode.
The fracturing swarm exploded into existence in August 2019. I remember being really impressed by this strong activity and yet this was nothing compared to what was to come. The rock fracturing of this type is thought to be volcano-tectonic, caused by an increase in magma pressure which shatters the rock around the magma. The Pahala Swarm started almost above the location of tremors. If the tremors were related to magma flow, then the fracturing may have been due to this same magma pulse pushing against the rocks on its way up.
The swarming initially exploded near Palima Point, and then propagated 10 km northeast, towards Kilauea, until it reached the opposite end of the Pahala Swarm, where I suppose the magma must have dived into the southwest rift of Kilauea. This happened around the time of peak earthquake activity on February 2020, when HVO was locating 80 earthquakes per day here. Unprecedented for Pahala. The levels then gradually dropped through the remainder of 2020. In 2021 earthquakes rates have started rising again and have nearly reached the levels of February 2020. The first rise August 2019-February 2020 seems to correlate with the first series of strong tremors, the second rise in 2021 seems to correlate with the second series of tremors.
Magma waves?
I was eagerly waiting the magma pulse to hit Kilauea. Perhaps a bit too impatient. It took more than a year for the pulse to move just 10 km up and 10 km sideways from the tremor area to the closest end of the swarm to Kilauea, it was obviously going to be a long wait! But finally something happened, not in the way or the place I would have expected however.
Mauna Loa got weird. Weird means that the volcano started deflating quite markedly with no apparent reason to do so. This was around October 20, 2020. Hawaiian volcanoes, and volcanoes in general, deflate when magma is removed from their magma chambers to feed intrusions or eruptions. There was certainly no eruption. I didn’t notice any intrusion either, and I think I would have noticed, or at least HVO would have. If magma wasn’t removed by the conventional ways, where did it go?
Mauna Loa deflates twice. Modified from USGS.
2nd deflation event. From USGS.
The next thing did happen where I was expecting the way I was expecting. On the morning of December 2 a sudden surge of magma hit the summit of Kilauea. It was quite dramatic. I had been following Kilauea since the 2018 eruption and not much had happened. But all of a sudden there was the fastest inflation I had seen, within a matter of hours the summit “broke”, a dike rose towards the surface but failed to erupt. Kilauea kept inflating, on December 20 it snapped again this time the dike intersected the crater of Halema’uma’u and started an eruption.
History then repeated again, Mauna Loa started deflating abruptly on March 23, 2021. Then on June 1 Kilauea set off in another episode of rapid inflation. It was time to write down the hypothesis.
Kilauea getting two magma surges. The first was responsible for the December 2020 eruption. The pause in supply that ended the eruption could be correlative with the pause in tremor activity seen in Pahala before the 2nd tremor pulse started. Modified from USGS.
Timing of events
What do we know? First, Mauna Loa and Kilauea share the same supply and must be connected at some depth somewhere. Second, a large amount of magma rose through the Pahala Swarm in a series of 4 pulses in 2019. Third, Mauna Loa and Kilauea each have been hit by two rare magma waves, producing inverse effects on them.
Here is what I think. There was a magma chamber which reacted to the 2018 eruption, this chamber is where Mauna Loa and Kilauea are connected. A series of magma pulses rose, each pulse sent two waves, a positive wave towards Pahala and then Kilauea, and a negative wave towards Mauna Loa. Why negative? With each pulse the magma chamber pressure would have dropped pressure, remember that pressure drops when it feeds an eruption or an intrusion. This is an intrusion. The pressure drops would have manifested eventually at the summit of Mauna Loa, which is apparently closer to the source because it was hit by the changes earlier. Basically it would have lost magma due to the 2018 draining of Kilauea needing urgent resupply.
Presumably each volcano has been hit by the first and second pulses of tremor that took place in 2019. There is one problem though, the distance between them seems to have changed. The first and the second came 62 days apart in the tremor region, 154 days apart as they hit Mauna Loa, and at 181 days as they hit Kilauea. This would suggest the second pulse is travelling slower than the first. It is possible that the speed at which the waves move could be slowing down. The depressurization wave created by Kilauea was the fastest to reach Pahala in 8 months, the first pulse took 23 months to travel the same route up, the second 25 months.
This makes predicting the arrival of the third pulse complicated. Assuming that the interval between the second and the third changes by the same factor as the first interval, the arrival of the wave can be estimated, though how accurate it may it be remains to be seen. It may arrive at Mauna Loa on August 17, and at Kilauea on November 20. The third could be the strongest if the number of tremors are a good indicator.
Conclusion
The 2018 eruption of Kilauea keeps giving new surprises 3 years later. It seems that it set off a series of waves that are rippling right now through the magma system under Hawaii, and might continue to do so for years to come. There could be a lot to learn from this. The third pulse could provide the final confirmation that Kilauea and Mauna Loa are connected through a magma chamber that feeds into Pahala, and it may also provide data regarding the properties of this connection.
Kilauea is likely to keep erupting from Halema’uma’u Crater episodically and fill up the caldera or part of it. Seeing how the pulses interact with the filling of the caldera will be most interesting.
I plan to continue this article with some others about Kilauea too. See you in the next one!.
Great article Héctor, thanks.
As a scientist I do like testable hypotheses. Do I read this correctly “It may arrive at Mauna Loa on August 17, and at Kilauea on November 20” that we could expect the next eruption for Kilauea to happen around November 20th?
Since most everyone was surprised by the last eruption at Kilauea, this time we would have an expected date for it to break the ground, if the speed of the depressurization wave behaves as you predict…
Thanks Holguer_Alberta.
Not exactly. The waves would affect the amount of magma entering the volcanoes, which means that somewhere around November 20th Kilauea should start inflating rapidly as a higher magma flux reaches the magma chambers under the summit.
Mauna Loa would get it first. If my theory is right then I expect that Mauna Loa will start inflating soon as it is hit by the “calm” before the third wave. The third wave would perhaps hit somewhere around August 17, but I don’t know how accurate the predicted timing is, and this will cause the volcano to deflate rapidly.
Kilauea right now is receiving the second wave and a lot of magma is entering the volcano, this may continue for a few months. The inflation could slow down gradually as the pulse dies down. When the third wave enters, around November 20, it would be expected to increase inflation due to more magma entering the volcano.
The next eruption will happen whenever the pressure of Kilauea exceeds a certain threshold, and that might happen at any given time. Maybe sooner than November 20 I would guess. Kilauea is currently getting the second wave of magma so it is inflating and could eventually erupt, but I don’t know where the threshold is so I can’t make any predictions about that.
Alright “somewhere around November 20th Kilauea should start inflating rapidly” is a testable hypothesis by itself. Together with “I expect that Mauna Loa will start inflating soon as it is hit by the “calm” before the third wave” we now have things to measure your predictions by.
“I don’t know how accurate the predicted timing is”. No worries, I have made and published predictions (in other corners of the scientific world), some of which were proven to be wrong. That’s how progress is made, that’s science in action!
Now, I only have to remember where to look when we hear about new action (inflation, deflation, or otherwise) in Kilauea and Mauna Loa.
It is a hypothesis that will be tested within half a year, and therefore it is brillant.
The deformation pages of HVO have the most relevant data:
https://www.usgs.gov/volcanoes/kilauea/deformation-data
https://www.usgs.gov/volcanoes/mauna-loa/tilt-and-gps-deformation-data
Courtesy of the HVO Volcano Watch: https://www.usgs.gov/center-news/volcano-watch-new-research-sheds-light-recent-p-hala-earthquake-swarms
Fabulous article! Thank you!
I rather get the feeling it is time for MBL to move the Natthagi webcam….
Bums of Iceland:
Very interesting, Hector. There have bene several similar episodes at Mauna Loa before, but very much smaller than the last two. They are visible on the 5-year plot. One was in July 2020 and is clearly visible. The earlier ones are not as obvious, but I would place at April/May 2020 and September 2019 (that one coincided with an outage on the GPS instruments but seems visible just before and after the outage). I had been wondering about their cause. It seemed an increasing instability. I attributed it to slippage of the Mauna Loa lava pile underneath the overlying Kilauea lava leaving the top layer in place. You give another possibility.
It seems sort of obvious that active and also dormant volcanoes are connected, also Nyaragongo and Nyamuragira. So, this look underneath is very interesting and the pics and graphs brillant, thanks.
One who thought they are all somehow connected was obviously Jules Verne as plate tectonics and other things weren’t known.
Basically I was wondering whether Lo’ihi should be mentioned in this context. Anyway, there will be more.
Héctor, I always wondered about those deep quakes and your article is a fascinating look at this. Thank you for taking the time to write to us. I appreciate it.
A bit old… but still out there. Basically the view down to the plume head. Don’t sweat the audio, there is none. (I’m not a DJ) Hum your own tune. 😀
“Totally awesome dude”!!
The lava inside the Iceland vent has spent the whole day tossing like a storm-wracked sea and producing 40m radius bubbles and 60m splashes and splatters every few seconds, with the lava channels in front of it running nonstop branching every which way and probably sending lava to both Nátthagi and Meradalir.
There’s no way it’s not near or at its highest effusion rate yet.
It has been very impressive in recent days. Lava bubble bath
An oozy jacuzzi
Interesting article about Pahala. The area has intrigued me since before the 2018 event. It certainly appears to be the focal punch thru point of the hotspot. From there it gets muddy with overlapping flows from Mauna Loa, Kīlauea, and baby Lō‘ihi intersecting. The best guess I’ve seen is that magma moving towards Kīlauea moves laterally from depth roughly in line with the SW rift zone with a slight upward component until coming in line with the summit where it goes near vertical.
How and where this system connects to Mauna Loa is a real mystery. There is a lot of seismic activity north and west of Kīlauea, but that seems out of the way and would contradict the authors pulse arrival times. Logic would try to convince one that magma would take the shortest distance between Pahala and Mauna Loa, but I don’t see the requisite activity that might point that out. Perhaps the conduit is so mature it flows with little to no telltales of its existence?
It certainly appears the volcanoes share Pahala as a common source, where and how is a big ??. Looking forward to more articles on this topic!
I will look at the Pahala-Mauna Loa connection in future articles. It is seismically silent but I’d say that there are some other clues pointing at the conduit location. It’s an almost direct connection I think.
One question for Hector:
There appears to be two trains of tracks for volcanoes, see https://www.ibtimes.com/worlds-biggest-most-active-volcanoes-hawaii-formed-3-million-years-ago-due-pacific-2534465
The map shows this best:
Haleakala is still active on Maui.
So is the feeder tube at Pahala just a transient structure now, feeding Kilauea?
There seems to be some justification for 2 tracks as shown in the map
There *are* two tracks, and they erupt different magma chemistries. Héctor’s paper seems to discount this, and that’s fine–knowledge is power and I await his next posts eagerly.
Re: The above-posted map. The tracks are obvious to spot and I suppose the macro question is this: Why did the track split? Is it rejoining? Is the process that Héctor posits a step in the rejoining of the tracks?
In the next article I will look at the different chemistries, and the reasons for this difference.
Jon Steiner posts a 10 min 17 sec video made June 17th 2021 on the active lava pool, seen from a drone, while playing Richard Wagner’s Ride of the Valkeries. See https://www.youtube.com/watch?v=lTiOZeMQTcw
Another drone film of the active cone, May 30th – June 3rd. See https://www.youtube.com/watch?v=D4-uFnP7wKE
GutnTog today. I love people doing dangerous BBQ. Crazy.
I’m not so sure that cooking marshmallows with a PLASTIC rake over lava is such a good idea 😀
Yesss finally 😀
Does though look like there is a slight change at Kilauea, the summit isnt going to the moon anymore but it looks instead like the rift conduit might be going a bit more east, to Pu’u O’o or even a bit further, theres some quakes in the area on occasion now where there were none before. Pu’u O’o GPS is also possibly beginning to rise, at least it is definitely not sinking anymore.
Beautiful sunset. Main flow building toward the walls. Natthagi and Meradalir quiet last hours.
A bit young to visit a lava field? Camera is far more interesting than the geology ….
Source: https://www.youtube.com/watch?v=XwN-u4Ccygs
Lava may be going over the western wall (or where it was).
Or light is reflecting off something …
Lava. Link as above
At 00:35:15 video zooms to bright spot in question, definitely lava.
Yes….a rather large wall moving towards the drop-off.
Well that big surface flow is cascading down into natthagi now, very strong flow. Ocean entry in a few days now.
Would the flow from Geldingadalir have built up a bit of a ‘berm’ itself, thus keeping some of the new flow as a lake with a lot cascading over the ‘berm’ and continuing downwards and outwards? (eventually building up on itself?)
Maybe but more likely is it will just merge, lava lake crust isnt that strong and lava is very heavy.
looking at the flow now I can say 100% it will break through and the lake is going to overflow in the next day, probably be in the ocean by the 22nd.
No, that is not the spot, a hill in-between. Look at the map.
There is still some filling needing to be done before the lava spills out of Natthagi. After that it has around 1,300 meters to get to car park 2 next to the 427, the most likely crossing point before it heads to the ocean another 600 meters away.
So 1,900 meters to go to the sea which is roughly the distance from the cone to the most southerly point of the lava in Natthagi at the moment.
So for me if it even reaches the road by the end of the month I’d be surprised especially as the flow at any moment could switch North again to Meradalir.
The big river that has just flowed into natthagi is 2300 meters long, and it only began about a day ago, it is rather a lot more than a dispersed pahoehoe flow most likely it will be quite narrow and very fast when it first escapes the valley. It might take some days to move into the ocean as it is very flat there but it also might not.
Same thing happened in 2014 when the lava was going to Pahoa, it was slow but then fount a natural channel (or actually it might have been unnatural, it was never that clear) and once that happened it flowed something like 3 km in a few days almost into the middle of the town way faster than was expected from the week prior behavior.
And of course it stops now 🙁
Murphy’s law…
😎
I didnt realise there was such a big difference between the output of Kilauea and Mauna Loa, I mean I have always thought and proposed it but never backed it up and was by this point just under the assumption they switched over on equal grounds and Mauna Loa was bigger simply because it is a lot older.
But it is really incredible that Kilauea at its slowest is within the margin of error of Mauna Loa at its peak, and when Kilauea is at its peak it is pretty much uncomparable to anything else, no wonder a few of its more notable eruptions (1840, 1960) have been revised to higher volumes in recent times after being studied again. I do wonder if the great height of Mauna Loa has something to do with it, being it is 4x as tall as Kilauea and seems to be roughly 4x less productive. Or if maybe Loihi is also more active when Mauna Loa is too, which is something we just dont know.
Largely agree with Chad about how fast it will move toward sea. Red area on image shows where it will flow: https://imgur.com/a/quqy4aP. A valley funnels straight toward road/sea. A somewhat larger area will need covered than in Natthagi, but it will be downhill, so far less volume. It is 3700m from Nar to the Natthagi exit, but only 1900m to the sea. Assuming the new flow maintains the rate of the old and does not get diverted to Meradalir, Natthagi will overflow in 36 hours and lava should reach sea within a week.
In the 24 hours up until the new flow from Nameless Valley arrived, Natthagi rose maybe a few tenths of a meter for an average rate of 1m^3/s (most of that in first few hours of that period).
I think the active cone must read VC too, as it abruptly changed its manner and now the very brightly light lava flows have all suddenly disappeared. I am guessing that this volcano does not want anyone to predict its behavior.
I’m not sure its just dawn making the flow less obvious. Clearly something a bit dramatic happened.
Really enjoyed the Kilauea article Hector- esp it’s relationship to Mauna Loa.If you ever get the chance I would like to hear your thoughts on Haleakala(1750) and Mauna Kea(2460 BC) -is their any interconnection with Kilauea magma source- and likelihood of them erupting again?
Thanks David. Haleakala and Mauna Kea will erupt again at some point. However they can be dormant for centuries or thousands of years, so they are not very active and the likelihood is rather low. There could be some connection between all of them, but I don’t think as good as Kilauea-Mauna Loa, and I’m not aware of any signs of its existence.
Cheers Hector-that was helpful- looks like I’ll miss those eruptions-oh well!
In case they are dormant for thousands of years doesn’t the north-west movement of the Pacific plate play a certain role concerning the prognosis? Most active and with most volume is Kilauea which fits also perfectly with plate tectonics. Also Lo’ihi.
https://www.volcanocafe.org/hawaii-and-the-story-of-the-pacific-ocean
Actually Loihi is kind of small for its age, while Kilauea is probably pretty big for its age. They are both a lot closer in age than Kilauea is to Mauna Loa. Loihi is apparently entering its shield stage as it has both tholeiitic and alkaline basalts erupting today. Kilauea did that transition only around 50,000 years ago, it has grown into the mountain it is today in the geological blink of an eye. Thing is most of this information is in the deep sea, so it is largely unknown.
There is actually quite a frightening list of things we dont know about Kilauea really, 200 years isnt long enough, especially when 3/4 of that it was giving Mauna Loa the limelight. Hector hasnt replied to my other comment so I expect it is going to get answered in the next article 🙂 but I would not feel confident ruling out any possibility of eruption entirely. An eruption in Puna can potentially be a Laki scale event, it might have even done this in the 1600s in the Kahawali eruption. I know Hector will talk about that 🙂
The Kahawali eruption was big, maybe bigger than 2018, but saying Laki scale would be a little too much… I guess you mean those huge eruptions from the tip of the Puna Ridge, I will certainly mention them, although not much is known of course. If Kahawali had been on the same scale as those Puna Ridge events we would currently have a caldera running from Pahala to the summit and Napau Crater 🙂 .
By Laki scale I mean the intensity, not volume of course 🙂
Still, some of the vents in the Kahawali eruption, including Kaholua o Kahawali itself, are cones born of high fountaining, and the fissure seems to be continuous, it would have been quite a sight to see. It also looks to me that the eruption could have involved at least 3 fissure swarms being active simultaneously, not too different to 1955 but way bigger in every regard.
Im not Hector but I can answer the question is yes and yes. They are not connected so much today though, but both are Kea trend volcanoes, maybe rather obviously 🙂
Haleakala seems to go in episodes about every 1000 years, and Mauna Kea maybe every 5000 years. Mauna Kea though has much bigger eruptions, think Etna, but it lasts a few months…
Hualalai is probably quite fundamentally different from the others, it has no shallow magma system but probably has a very large deep complex, so it has no evolved magma today and erupts in large volume.
Speak of the devil 🙂
Cheers too Chad ,there’s no boredom in learning about volcanoes.
Man I’m sick and tied of these so called adults gooning in front of the cam!
At about 08:24 on the Langihryggir camera, a figure appears on top of the earthworks. Yes, you’ve guessed it, he/she goes for a wander across the lava crust.
High-vis jacket and gaiters, he wanders off screen, then just before the camera switch to Nattagi he’s back on the lava, the other side of the channel.
When the camera next returns to the berm, there he is, on top of the barrier and the digger is working away in the background, while he fiddles about over to the right.
Mister Supervisor Engineer got caught literally surveying on the ground… Oopsie
Hey good police work there!
I aim to please 😉
Attention to detail, and I’m a nosey b****r
This may shed more light on the “walking on lava” ….
Curious as to why the ground is steaming to the right of the earth dam (towards Nattaghi).
Yah, me too. i wondered about that… and i don’t believe he mentioned it in the clip. looks ominous… but there were professional smart people around the steaming and it looked like they were considering what to do.
Don’t know. I would guess that the earth used for the dam was damp from recent rain which would contribute to steaming but would not explain why it consistently comes from the same spots.
Hey, whaddaya want for free? I’m serious–if this had occurred in Leilani or anywhere in lower Puna, with the totalitarian HI Civil Defense…one live cam, with a CD watermark that took up 1/4 of the screen, sightseers would be shot on sight, Ikaika Marzo would be arrested for incitement. And don’t get me started on what a Mauna Loa SWRZ eruption would look like.
More for a thesis in human behavior rather than volcano science.
Surely there must come a point when it is not wise to continue to raise the earthworks? i.e. They are on a hill and, if they fail, more lava and debris would go over in one go, causing more damage?
Wouldn’t it be better to focus on how to divert the lava away from Grindavik when it goes over?
Source for image: https://www.youtube.com/watch?v=BA-9QzIcr3c
The lava isn’t going to pool here, it’s just being held away from going over the edge, and directed to take the established way downslope.
One of Gutn Tog’s videos looks down at Nátthagakriki, and it looks like a roadway is constructed to take materials up the hill. They’ve had a lot of time to consider the lessons learned from the early experiments. This time, they’re not playing games.
Were they ever playing games? It won’t be cheap to construct earthworks, even if they did use local material.
Note that the original earthworks did not fail, they where over-run. Under the lava they are still there.
If the same hold through here there would be now huge spill, just a flow going over at the regular rate.
The lava isn’t going to pool here, it’s just being held away from going over the edge, and directed to take the established way downslope.
One of Gutn Tog’s videos looks down at Nátthagakriki, and it looks like a roadway is constructed to take materials up the hill. They’ve had a lot of time to consider the lessons learned from the early experiments. This time, they’re not playing games.
Caspar David Friedrich is back (the ‘Rückenfigur’). There was also just another episode of ‘bums of iceland’ (<- borrowed this from Stars Die).
Yes, its most odd that with a whole mountainside to see the view from, people congregate in front of the camera.
One imagines that iceland is backwards and nobody know what it is and who is watching.
Going by the youtube its between 300 and 400 people, typically.
15 minutes of fame.
And I just realize that ‘bums of Iceland’ came from Clive, sorry. Had to laugh loud there.
“”its most odd that with a whole mountainside to see the view from, people congregate in front of the camera.””
Probably because the mbl cameramen put the camera in the best place.
Based on past history, though, it may not be wise to hang around MBL cams for too long.
Jokes aside, the RUV camera suffers as much from this as the MBL one.
Today we have new lava covering half meradalir.
Any reason not to put a berm right where the emergency vehicle is parked
at the very beginning of this video ??
Because if it fails and dumps a tidal wave of fast lava onto the road, people could get killed, etc.
True. a dam at the top of a slope is a life-long danger. Villages in our area had to be evacuated a few yers ago when a dam threatened to fail.
Mostly, the long term effectiveness of said berm would be null. Eventually the lava would overtop the berm and still flow towards the road, the farm, and finally the sea. Since they can’t prevent lava from flowing into Nátthagi they have to opt for a path of that valley that minimizes infrastructure damages.
It so happens that that particular path would cause the least damage to the road, which they might cut a channel for the lava to follow through to reduce the damage even further. Unfortunately, the farm (which has only been used as a vacation home for the family in the last few decades) would succumb while known archeological curiosities might prevail {atm I do not recall if the article mentioned if the archeological site was in danger, nor could I find the older article which talked about the archeological parts and where they were in relation to the main farm}
There’s a helicopter on Theatre Hill, and I’m wondering if the crew is fixing the defunct webcam? They are clustered about something.
Sure, close cam working again. Good point of view!
Magnitude M 4.0
Region ICELAND REGION
Date time 2021-06-20 17:59:19.0 UTC
Location 63.92 N ; 22.22 W
Depth 1 km
Distances 29 km SSW of Reykjavík, Iceland / pop: 118,000 / local time: 17:59:19.0 2021-06-20
14 km NE of Grindavík, Iceland / pop: 2,800 / local time: 17:59:19.0 2021-06-20
https://www.emsc-csem.org/#2
Not showing on the Icelandic eq site…
It was but is downgraded now…
I think this timelapse cam its new from a few days. Named meradalir vestari varnargardur, i dont know the location.
http://brunnur.vedur.is/myndir/webcam/2021/06/20/webcam_meradalir_vestari_varnargardur_A.html
That name would translate as Maresdales Western Berm, they put it up the day before the lava started flowing over/around the western defensive wall (that’s the flow that crashed the 2nd floor down into Nátthagi).
Thanks for an interesting article Hector!
We are going to have a massive influx of family members over the summer, so I’ve pretty much decided that when they leave I’m going to need a holiday of sorts, which means that I’m quite likely going to jump on a plane to Iceland in august/september to get a volcano fix or something.
Can we ask for a report of the trip? We’d love posts like that
That should be possible
https://www.youtube.com/watch?v=nSnp5GeSu7c is an airplane flight over the cone, taken yesterday June 19th. Shows the current lava lake quite well, it is quite large.
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Interesting to see the changes in the crater – a week ago, the exit channel was quite narrow and its lip was quite high up, so there’d be a few minutes delay before each eruptive episode, when the lava level would be at or near the top of the crater.
Now, the exit channel is much wider (I think the eastern wall has gone), the lip is much lower, and lava is pouring out non-stop. Some is going west round Theatre Hill, some straight towards the Langihryggur camera. Both those streams will end up in Natthagi. Not sure how much is going to Meradalur but some lava definitely is.
There was about half an hour or so today that the pulsing came back, around 12:30 to 1pm. The time was much faster than before, a couple of minutes and the lava lake was notably low in between the pulses with the lava bubbles reaching near the top of the come during the pulses. After that it went back to continuous activity
Publicly available information about Gutn Tog
Gutn Tog (Good Day) is an Icelandic citizen called Roman (Kristmundur Roman Zach). formerly from west Ukraine; hence the unusual accent. He has lived in Iceland for 15 years, currently in Thorlakshofn. You can contact him via his Youtube channel. I assume the language his blonde-haired travelling companion Nina Nx speaks, which Roman translates to English; is Ukrainian..
https://www.youtube.com/c/Zakharii2/about
WOW! anyone else watching the high lava lake empty? Anyone? Anyone?
over now went on for an hour… You missed it… maybe You can scroll back.
what time did it start emptying?
20:27
Randall did You find it????
What webcam?
I was watching it but assumed it had been like that for some time. It’s still pouring out this morning. Exit channel much wider and lip of channel much lower than this time last week.
https://www.ruv.is/sjonvarp/beint/ruv2
(Langyhriggur camera – occasionally swivels to look at the Route A dam and then Natthagi.)
Every one of those cams needs to come with an air horn, and a button on the YouTube page wired up so that if enough people click the button during a one-second interval, the camera lets out a 200-decibel AAAHOOOOOGAAA!
Extra bonus: we’ll get to see the looks on their faces as they jump six feet in the air and then run off.
Another Jon Steiner drone video https://www.youtube.com/watch?v=UdsK6tuq9m8 for June 20th, today
New Lava over the western Wall…..
Just to be the contrarian here.
Seems like everyone has forgotten to look at the bottom of the volcano again, even other volcanologists.
While everyone else is going “oh” and “ah” about what is going on at the surface, I steadfastly and boringly look at the bottom of the volcano where the future is shown.
The general meme that the eruption at Fagradalsfjall will continue for a long time seems to be about to be refuted by reality, science, and in general the GPS-network.
I have always found that the statement that the eruption will continue for years or decades to be a bit farfetched.
Yes, initially during the time we had 5 cubic meters per second the dyke continued to dilate (not inflate), and there seems to be increased amounts of magma sitting under the crust. This was evidenced by the GPS-network.
At this point it was reasonable to assume that the eruption would be ongoing for a relatively long time, well at least for a few months.
As the lava outflow jumped up to 8-10 cubic meters per second the dilation abruptly stopped, and the pooling of sub-crustal magma ended. This then held steady for roughly 45 days.
From this we can surmise that the magma produced in the mantle, and that is arriving under the central part of the Reykjanes Peninsula, is about 8-10 cubic meters per second and not 20 as was initially stated.
This magma first went into Torbjörn, and later into Fagradalsfjall, and this magma pooling might continue for quite some time. But, I am not so sure that it will continue into Fagradalsfjall for much longer.
Now that the outflow has increased yet again (about 3 weeks ago), there is a net deficit between outflow and inflow.
This has caused crustal deflation, something that is clearly seen on the GPS-network. There is also evidence that the dyke is mydriating (nice word for the opposite of dilation, mydriasis is greek for closing the eye).
This obviously means that the pressure is decreasing, the only reason the flow is continuing, for the time being, to be high is that the dyke has widened due to crustal melt.
In the end the dyke will though shut down, and it is not that far away. I give it between a week and 3 months.
This would then give 3 scenarios.
1. The vent closes, pressure starts to build up, and a new vent opens up after some time nearer to Keilir.
2. The dyke closes, pressure starts to build up under Reykjanes over a couple of years, and then something else goes off, probably Thorbjörn or Krysuvik.
3. The dyke closes, the magma pools for a time (long or short), but there is not enough pent up strain left to open a new rift in Reykjanes. This leads to decades of rest until the next eruption in the neighbourhood.
My bet would be 3, you need both a heck of a lot of pent up strain ripping a rift apart, and available magma below. With only one you get a cancelled show, and the Reykjanes Tour has not that many tour dates to begin with.
Anyway, I will know beforehand which of the options will be true, the GPS-network will tell us.
Here is the link to the collected GPS-stations complete with map of their location:
http://brunnur.vedur.is/gps/reykjanes.html
And on a different note… I hate being faceless… 🙁
And mysteriously I have a face again. 🙂
Not the regular one with Bozoo the Atomic Clown, instead it seems that my real ugly mug arrived for all to behold.
I even have a profile blurb all of a sudden. Nice!
Oooh, we like contrarian…
Always dangerous when an urban myth starts up with very little real actual evidence and general acceptance.
Apart from a long article here about “The Hell Machine”.
I’ll let you two argue it out …
I did say at the very start of that article that it was a hypothesis, not a fact. Just pointing that out here. I am obviously not a main writer so I think a bit of speculation is allowed, and everyone was speculating a great deal back in those early days too 🙂
Quite correct.
It is easy to be the contrarian in hind-sight. 🙂
And I enjoyed the article a lot!
Yes, was fun to write too 🙂
I have also been looking for deformation graphs or insar data on the eruption too for a while, but couldnt find them, so I generally assumed the eruption was stable and accelerating because of increased melting or a growing conduit. I do think it will go on maybe a bit longer than a few weeks more though, maybe reach at least 0.3 km3 like some of the old estimates, it is maybe 1/3 of the way there now.
Of course if it makes it to 1 km3, or 10 km3 and lasts for a decade or two I will also be happy, but the area is going to be pretty active in that sort of timeline anyway so we all win, except maybe for those in Grindavik if an eruption happens near it…
I do hope that the next one will be Krysuvik and not Thorbjörn for the sake of the Grindavik residents.
It all depends on how much pent up strain there is at a particular spot. So, there is actually quite a good chance that some other place will go next since both Thorbjörn and Krysuvik has had a far bit of seismic activity in the last few years.
Krysuvik is also dangerous though, if it rifts towards Reykjavik it could do a lot of damage, even just the rift itself let alone the eruption going with it. Best case really is if the current eruption system stays active, out of harms way and nice and slow, if it goes to Svartsengi or Krysuvik it might be a while before an eruption but it will be a lava flood when it happens, the sort that you can never hope to outrun. It will be like Kilauea in 2018 but if fissure 8 opened full force immediately.
Brennisteinsfjoll would be a safer option, it will probably behave a lot like the current eruption, if not for the fact it will set off a major earthquake when it does erupt… Its really looking to be pretty precarious, this cycle started in about the only place it could do so without an immediate problem.
If you really want nightmares…’
Raudholar. The actual vents are by now removed by industrious Icelanders looking for building material, but the lava that flowed out of them went through the suburbs of Reykjavik. I have forgotten the volcano-fissure swarm it is on, but it is east of Reykjavik with a nice downhill slope into the city center.
http://jardfraedikort.is/?coordinate=64.09%2C-21.72&zoom=8
Says those are pseudocraters, not vents, so maybe not likely an eruption will happen at this location. Still, as we saw at Pahoa in 2014 even a small slow flow is pretty alarming inside an environment like that.
Being somewhat lazy I haven’t examined this in detail but this area should be close to the MAR. So it doesn’t seem that unreasonable that the MAR did the opening rather than pressure from beneath, which just welled into the inevitable (in time) gap. I know the faults are complex but ultimately something has to give somewhere.
The question then is whether the gas supply, which seems to be powering the flow of lava, will wane or whether the ejected lava itself is responsible for the gas that powers it.
How big a reservoir of magma with the appropriate properties to produce this lava is, nobody seems to know, although the article on crystal mush separation does attempt to address the issue.
As always it needs someone to put some figures down, real figures based on decent estimates, to make a prognosis. Postulates are two a penny….
How about some quantitative sums, guys?
Absolutely correct Chad, I mistok the name of the rootless former cones for the volcanic feature of Gvendarbrunnar/Holmshraun.
Problem is still that nobody really knows where that came from, likely culprit is a radial fissure of Hengill, and that would be poop indeed, because that one is on a completely other order of magnitude than the Reykjanes volcanoes.
For the rest, Hengill is one of the Icelandic big boys that have produced plus 5km3 eruptions after the last ice age. One gotta love triple-junction volcanoes…
Where is the source of Hengill doing eruptions that big? I have found in my research that it has done eruptions around 0.5 km3 (nesjahraun), theres nothing around it that is 5 km3. To me it seems not too different in scale to any of the Reykjanes volcanoes, the volcanoes with 5 km3 eruptions are all on the Vatnajokull rift, unless you count shields which are a bit different.
I would be interested if you have other information though.
Farmeroz
It was a bimodal thing between pent up strain and lava from below. The lava came pushing first, but that might be an effect of the MAR over time. It is a coin with two sides…
The same bimodal function was probably what got the Icelandic plume going 14.2 million years ago.
The gas powers squat, it just makes it more lively on the top. It comes with the magma from depth, but is suspended happily in the magma due to pressure and ads no power to the equation down below where the volcano starts.
It nucleates at the upper parts of the dyke, so it has no effect on the formation of the volcano, nor as a driving force for the magma moving upwards (untill the last kilometre or so).
Now over to the size of the reservoir.
There are two answers to that. The simple answer is that there is as much potentially available as there is upper mantle under Reykjanes. But this is not what you really asked about. 🙂
The dyke reservoir contains between 250 – 350 million cubic metres of magma and reconstituted crust at any given time. It is replenished from the upper mantle at a probable rate of 8-10 cubic metres per second as evidenced by geodesic data from the GPS-network.
I always base what I write on quantative figures. If I don’t I always clearly state that.
Carl,
Now might be as good a time as any to tease out the mechanisms that power an eruption. It seems to me there are two mechanisms (typically happening together to various degrees). If we exclude gas for the moment they will be :
1) Faults allowing a low resistance path to the surface.
2) Hydrostatic pressure.
I assume most lava is relatively low density, comparable to the crust in (solid) density and since in general I would expect the earth to be essentially in hydrostatic equilibrium then we ought to be able to make some estimates.
I cannot find figures for the density of lava, but I found (to my surprise) that silica has several high temperature allomorphs complicating things but essentially there is a 20% difference between liquid and solid forms (at atmospheric pressure). Surprisingly high.
OK That would give an immense overpressure because a 20km tube with density (order of magnitude figures here) difference of 20% on 3000kg/m^3 or say 10x600x20,000 Pa = 120MPa or 1.2kBar. That would be enough to break rock if it was in a sill. However that’s still only 0.06bar per meter or about 1psi/m which is quite modest for pumping a quite viscous lava.
I ought to guestimate the effect of gas in the last km, but it looks like a second order effect.
OK That explains how a relatively viscous liquid can travel so far through tubes of such small dimensions. The flow is essentially regulated by the cross-section of the conduit (which may be complex).
Just for fun using an online calculator for water and a 1m bore with 0.06bar/m gives about 3m^3/s which is (amazingly straight off, no tweaks) in the right ballpark!
That’ll do for now.
The ‘official’ equation for flow rate through a pipe (conduit) of radius is below. Below the bar is the viscosity. Above is the difference between to rock and magma density (buoyancy), and g is the gravitational acceleration. This assumes a stable situation, and it does not include over pressure, for instance (mainly) from the difference in surface height.
Chad, I have it in a paper somewhere in one of my boxes of papers…
I got it from a reference in the GVP back when they had eruption size figures in it.
I also do think that you have a lot of volcanoes in Iceland that has opinions about the Vatnajökull line. I am not familiar with that term, I assume that you are talking about the Eastern Volcanic Zone (EVZ).
Only clearcut ones on that one is Bardarbunga, Grimsvötn and Thordharhyrna.
Katla is clearly debatable if it is on the EVZ or the VVZ. Same goes for Hekla and Vatnajökull that normally are grouped into end members of SISZ.
But just for humours sake, let us say that they also are on the EVZ, and move on to more clearcut 5km3 plus volcanoes.
ÖVB – Öraefajökull
NVZ – Askja, Fremrinamur, Heidarspordar, Krafla and Theistareykir all have opinions. 😉
WVZ – Hengill, Eiriksjökull and Prestahnukur has definite opinions.
I have probably forgotten a couple.
Do note that the gas-pressure is effectively nill untill it nucleates… If memory serves the nucleation zone is depending on the density of the overburden and the gas at hand between 2.1 km and 1.2 km. Below that the pressure of the crusts will always be higher than the potential pressure of the gas.as it transitions from solid/liquid in suspension to gas.
Below the nucleation zone there is literally no gas at all, just chemistry giving the potential for a gas to form as the pressure drops.
I do not know how to put it any clearer than that.
Gas is not a driving force, we are not talking about bean-stew here. 🙂
Vatnajokull rift is to mean the zone extending from Tjornes south through Vatnajokull and to Vestmanneyjar, as opposed to the Langjokull rift which is the zone from Langjokull going southwest through to the Reykjanes ridge. Its not very formal though more my own way of categorising, which can be confusing here… I would assume the formal defijnition is North Iceland volcanic zone + South Iceland volcanic zone, and West Iceland volcanic zone + Reykjanes volcanic zone, respectively, but I probably missed some 🙂
Still, it seems all eruptions of really large scale in the ‘Langjokull rift’ are shields, flood lavas are all under 1 km3. I would be happy to be proven wrong but to me a shield isnt technically a big eruption, it is a small eruption that lasts a really long time. Pu’u O’o vs Ahu’aila’au for a more recent comparison if you will, intensity is the factor I judge the most, rather than total volume. Same goes for the northern areas of Iceland, biggest flood lavas are maybe 5 km3, everything bigger is shields.
I guessed that you meant something like that. 🙂
I a more prosaic, I just go with the amount of erupted lava. Time is relative, and either a flood basalt or a shield is just a brief instant on a geological timescale. Albert is the obvious winner of discussions like this, he operates on the timescale of the Universe (Multiverse).
I forgot, I in general think that the “hell-machine” idea has a bit of merrit.
I do think that the magma production at depth will continue for quite some time, what I do not think is that it will come up for much longer at Fagradalsfjall.
Carl one of the best post I’ve came across to date on the future of the Reykjanes 2021 eruption! Thanks for putting your neck out too!
I like your thinking, Carl and thanks for reminding us of the GPS measurements. I have noticed that the cone is losing impetus and the gas pressures becoming less and less. I am torn between #2 and #3 of your possible scenarios. Maybe we will drop back to increased swarming again but in another location. Time will tell. Thank you for being a contrarian 😃
Thank you Carl. I must admit to hoping to be able to see this for years (and fascinated to see how the recourceful Icelanders deal with it, channeling lava to the sea and a road bridge over a lava river would be a sight to see).
So on a more touristic and less geological note – GET THERE WHILE YOU CAN!
https://www.youtube.com/watch?v=T7vzMmTtUyE
Superb drone footage of the vent, its sorronds and the interconnecting flows and bridges. If you look carefully, a little pimple of Fissure 1 is still sticking up out of the lava plain.
If I were to place a reckless bet, I would choose your (2) scenario, Carl.
I base this on my spurious evidence of watching the drumplots at Krysuvik.
There have been ongoing and quite large tornillos in the plots for quite some time now. I think magma may already be well emplaced. So once our current vent ceases, give it some time and the next rip will the there.
(hands over ten UK pence to the bookies…)
“will the there” of course should read: will be there. My scientific and carefully research hypothesis ruined by the inability to type before coffee.
RESEARCHED Aaaargh!!! (boils kettle)…
There’s a possible addition to option 2, the Reykjanes volcanic system, itself, could erupt. Seismic activity moved westward from Krýsuvík; could volcanic activity follow at a much slower pace?
There’s option 4. the eruption was enabled by the crustal moving to accommodate activity to the east; one of Fagradalsfjall’s older and bigger cousins could be next.
That is the option 3… 😉
Off to clean my specs!
Data is data. Interpretations are many. It is true that the deflation could be interpreted as some sort of pressure loss in a reservoir or dyke that could eventually put an end to the eruption.
But alternatively the deflation could be modelled as the magma mush under Fagradalsfjall losing volume, it could simply have to do with the natural process of squeezing melt out from a mush and may not be related to the pressure in the volcanic conduit.
The squeezing of the tooth paste would be visible on the GPS-network, and it is not really showing.
Instead there is widespread deflation.
Remember that several stations is quite near the dyke and would be picking it up if there was a lot of squeezing.
Instead there is the more gentle effect that is often associated with a mydriating dyke.
I meant squeezing in a different sense. What I mean is that there are, 20 km was it? of rock on top of the melt, pushing down. If the melt can escape then the ground will subside and this will press the magma into the conduit. The “squeezing” shows as widespread subsidence.
Using the sponge comparison once again, then your hand would be applying pressure on a sponge so that it started dripping water. We are talking rock here so this is obviously something that would happen on a very long timescale. The shrinking sponge under the pressure of the crust, as it leaks through Fagradalsfjall, is the deflation I meant.
Ah, seems like I am very bad at understanding people today.
As with Albert above we meant the same thing.
Sigh, I guess I am to excited about the soon to begin Jarre concert.
The deflation, and horizontal motion towards the eruption site, is indeed quite notable. The original dike is closing. The conduit is not. The flow rate is set by the cross section of the conduit, the density of the magma compared to the rock, and the viscosity. There is an additional term from the pressure from the dike but I think it is minor. The sudden jump in May I think was because the magma changed (as seen in chemical analysis), not because of a change in conduit. The pulsing came from a bottle neck in the conduit, which may have been a kilometer down. This may have been a narrowing, but it can also be a mixing between two magma components of different density and viscosity. It stopped because the obstruction resolved itself, when one of the magma components (I guess) lost part of its pressure. Magma squeezed out of the dike may be one of the components.
The eruption will end but I am hesitant to put a time scale on it. There is no evidence for a large magma chamber at the moho. If we assume that the feeder area measure 5 by 5 km, is 500 meter thick and has a melt fraction of 50% (the first and the last number are probably ok, the second and third number are guesses), then the available amount is around 5km3. The eruptible fraction is perhaps 10%, so we could have a 0.5km3 eruption – in theory. The flow rate is limited by two effects. One is the conduit which can handle 15 m3/s, apparently. The second is the rate at which magma percolates through the lower crust, between 5 and 15 km depth. Carl shows that this rate may be around 10 m3/s but not higher. I think that is the rate at the top of the lower crust – deeper down it may be lower. Since early May, the eruption has been feeding of this. (Before that, it used magma which had collected at the base of the upper crust, 5 km deep. It had collected here in early February.) The change-over in May was when the viscosity became lower and the eruption rate higher. Putting the numbers in, this eruption could last a few years in ideal circumstances. But it could also end rather soon if the loss of pressure at the bottom of the lower crust collapses the conduit. The deflation suggests there is a real chance of a sudden change.
It seems to me that the eruption is related to Krysuvik. Any events there could affect what happens next.
The volcano-tectonic episode started in the vicinity of Krýsuvík.
Always been puzzled by the seismic gap between the dyke and Krýsuvík. Is eruptable magma there too?
I talked about readily available magma below the MOHO, not in it. Sorry if I was unclear.
Over to the magma reservoir. Or rather the lack of one. There is only a happy sheet-dyke hanging there. And a sheet-dyke is easy to count on 🙂
It is 7000 by 5000 meters in length and height, it was initially 1.2 meters in pure dyke, but due to melting of the adjacent crust it has widened to around 10 meters.
We do know the amount of melt inclusions to be below 30% thanks to that AGU meeting, this and the temperature points towards 85 percent melt and a 15 percent solid fraction. The dyke is both hot and wet.
It is good to remember that the initial link was a movement in activity from Thorbjörn to Fagradalsfjall, I think that Krysuvik is mostly just having indigestion on the 2010ish intrusive period.
There doesn’t seem to be a lot of evidence for crustal melt in the erupted lava. Any crustal melt stays below – not sure why. The width of the dike changes with depth. At the bottom, the width is purely determined by the excess pressure of the magma, and is typically around 1 meter. If the magma pressure increases, it pushes the sides further apart and vice versa. Closer to the surface the dike can widen, as you say. The melt fraction at the top of the moho (~16 km here) is around 50%. It becomes lower when you go deeper into the mantle. Of course only the melted fraction rises up so this doesn’t apply to the dike. I calculated what is available at the top of the mantle where the magma seems to be coming from. You used what has collected in the crust – two sides of the same coin. The dike magma reservoir has a volume of order 0.1km3 using your numbers for the size. The mush at the top of the mantle has a larger volume but is slow to replenish what is in the crust. That replenishment is the weak spot and with the numbers you found, is already falling below what is being erupted, as the GPS movements show. There is in principle enough magma to continue the eruption for many months but it would become increasingly fragile and more easily disrupted.
I think (but do not know) that Thorbjorn was a separate intrusion and that the connection from there to Fagradalsfjall was a tectonic one. But the distances are not large and the magma flow to Fagradalsfjall cannot be entirely independent from its two neighbours. I think any eruption at Krysuvik would affect the magma supply enough to end the current eruption.
Today most of the lava seems to go into Meradalir. Natthagi has a day off.
It seems that we are completely in agreement as soon as we do not talk past each other. 🙂
Yes, Thorbjörn was definitely not related as an intra-crustal movement. I meant what happened below the MOHO as magma moved along sub-crustally.
I guess I am a tad to bottoms up sometimes in how I think, but not sufficiently so in my explanations. 🙂
I do not think any of them will erupt prior to the end of Fagradalsfjall, it is not enough sub-crustal magma production to feed two of them at the same time.
Also, we would see a very large swarm first.
Gutn Tog lamenting the blocking of Trail A by lava:
https://www.youtube.com/watch?v=Mc6PyW5bbNM
He does show a point on the Trail where lava could overspill into the other valley.
The rain has made Natthagi particularly steamy today!
Skin Care by Natthagi 🙂
Not just skin care, I also have a range of aftershaves too.😎
Old thread was confused. Lava flow through a pipe.
Assume viscosity ~ that of water or 1mPa.s, pipe diameter of 1m, flow of 10m^3/s ~ velocity 3m/s, density 3000kg/m^3 gives a reynolds number of10^7. so NOT laminar flow (transition at approx 2000-3000). So (unless I have made a mistake) Albert’s equation should not be used.
Means using Colebrook-White equ. I used to have a neat circular slipstick for this. Anyway if the relative roughness is 2% (optimistic?) the friction factor is 0.07 we get a loss of about 1000Pa/m and we have ~6000 so the roughness can be very considerably more than 2%.
I have to say that despite using several calculators and getting the same result, I am not convinced this result is right. That may be because I am not used to flowrates in big diameter pipes.
https://www.engineeringtoolbox.com/darcy-weisbach-equation-d_646.html
Yes, my equation is for laminar flow. There is one for turbulent flow but it is a lot more complicated. I have it somewhere in my office.
Otto Aviation!
I love laminar flow, hard to achieve though. And yes, I want a Celera…
It isn’t quite a foregone conclusion, but close: the southern road on the Reykjanes is awaiting its demise along with the historic farmstead at Ísólfsskáli. Focus is now on devising long-range plans for protecting Grindavík and the Svartsengi power station.
https://www.ruv.is/frett/2021/06/21/lawa-przetnie-droge-sudurstandarvegur (in Polish).
It would take quite something for Grindavik to be at risk.
Svartsengi is years away.
As noted above, I do not think that the eruption will go on for long enough for the farm, road, old farm and the Seismometer to be at any risk.
chad 20/06/2021 at 01:38
looking at the flow now I can say 100% it will break through and the lake is going to overflow in the next day, probably be in the ocean by the 22nd.
Don’t tell Chad, he thinks the farmhouse will be gone by tomorrow.
If you look under that comment you will see I already know, that was back when the big open channel flowed down but it didnt last as it turns out. Had that formed a tube it probably would have filled the valley by now.
I wouldn’t disagree.
I was shocked when I got out of bed and checked the MBL Nattagi webcam the next day and there was almost nothing happening.
I doubt Grindavik or Svartsengi would be threatened even if the eruption lasted a decade. However, whenever the bulk of the flow decides to go to Natthagi again as opposed to Meradalir, that will doom the road given the funneling terrain. The last time lasted 6 days at ~10m^3/s, doing that again would reach the sea. Similarly the farm is placed right where the flow will reach the sea if I have correctly identified it on Google Maps. If the eruption continues a few more weeks, that will likely do the job.
Since the eruption started over 2/3rds of the lava has gone N into Meradalir
Volume erupted 63m3
Flow South
Geldingadalir full 7m3
S Meradalir full 5m3
Natthagi almost full 5m3
Total 17m3
Flow North
Meradalir 46m3 the balance
Conclusion based on the historic evidence 6 days at a flow of 10m3s south is highly unlikely
Also the lava to the South has twice as much time to cool meaning the chance of a lava crust forming is increases forcing the lava to flow on the surface reducing the distance it can travel.
As I said before, if it makes the car park on the 427 by the end of the month I’ll be very surprised.
I’m pretty sure that the volcano has erupted more than 63 cubic meters, 63 hm^3 (63 cubic hectometers) sounds more like it lol
But on a serious note, I wonder what the breakdown between N Meradalur and E Meradalur is
It may well be several weeks before it escapes Natthagi if the flow settles on Meradalir. However, once it does escape, it will be very fast. My estimate is three days once out of Natthagi, assuming 10m^3/s: 1st to fill depression near exit, 2nd to road, 3rd to sea.
There was very little volume in Natthagi before the new flow started, only half the area and a few meters thick, compared to 15m. 10m^3/s for 6 days is about 5 million m^3, so sounds about right.
Given Nar puts out about 1million m^3 per day, it should be a total of about 73 m by now for the eruption as a whole. You are forgetting accumulation in the nameless valley, which is up to 35 meters in places. I wouldn’t be surprised if that is 10 million m^3. Still Meradalir has probably gotten a majority of the eruption’s flows.
The flow rate is more than sufficient to send lava to Grindavik, or to Svartsengi. It seems what is actually the problem is the flows change too much, its not like Pu’u O’o where you get it flowing sable for months or years, here it is apparently days. Seems many Icelandic shields are this way, the shield itself is made of short flows, there could be longer flows but early on. Seems shields in Hawaii flow further for whatever reason.
Thanks to Carl for exploring the potential future options for this eruption both on Facebook and here – and to other commenters for adding their wisdom.
My question is probably a rookie one: if this eruption ceases due to a lack of pressure but pressure then builds up again, why should it not erupt at this point again due to it being the most recent closed point, therefore surely the easiest fractured? Is erupting through a recently closed fissure not easier for the magma in energy terms more than making a new fracture through cold areas such as Krysuvik?
It is the one point with the least pent up strain in all of Iceland.
Also, the residual melt will work like glue on the conduit leading up from the dyke.
Volcanoes like brittle rock, it fractures more easily, ductile hot rock works more like a rubberband.
So, if option 2 is at play (Fagradalshraun closes, dike keeps building pressure, and breaks again), would that mean a likely new breakpoint is just west of Kistufell? If I remember correctly, there were quite a few shallow EQs there in the initial swarm. Or is it less likely because of this initial very shallow EQs?
Kistufell would surprise me quite a bit. I think you mean Keilir and not Kistufell.
Kistufell is near Bardarbunga.
https://volcano.si.edu/volcano.cfm?vn=373801
Nope, I do mean Kistufell, but the other one. 😀
Kistufell is also home to the hottest lava ever erupted in Iceland its rocks are primitive picrite basalts and estimated to have been erupted at 1280 C
Bloody hell, they had to reuse the name on a defunct old volcanic ridge.
Now I get you, thanks.
I still go for just south of Keilir as the most logical place.
People are actually walking on the lava – seen from MBL cam Nátthagi camera from 4:05 cam time
gives a nice idea of size. The camera is not that high up on the hill side. Probably why so many people walk past it.
Hi All,
A timelapse with lava rivers meandering, overflowing and finding new pathways from yesterday 20h45 to 7h45 this morning from the MBL ‘close-up’ camera (it’s not that close anymore however).
I kept it long (slow). It’s flowing fast enough already.
https://youtu.be/x4K42LFJ2zs
Catches all the overflows i watched live… Great catch! A+++ Eye Candy.
Over the last hour a bit of pulsing has returned to the vent. Completely invisible in the fog, of course, so no idea what it actually did.
It’s good to have contrarians when they base their claim on data. So I enjoyed your idea Carl, despite wishing that the eruption lasts a long time.
I checked the GPS data after reading your post, to see what is happening. Yes there is some deflation but it is minor.
In Holuhraun the deflation caused by the caldera sinking, followed an exponential decay function and it would have hit zero by March 2016, and it did so, as the eruption finished.
This eruption is caused by a very different mechanism and so far the linear deflation seems to indicate a gradual movement of the crust rather than a sudden one, which would reposition itself at the original levels pre-eruption in an estimated 1.5 to 2 years in the future (when looking at the GPS graphs, and extrapolating such deflation into the future).
The eruption has poured perhaps a figure slightly under 0.1km3 so far in 3 months. Let’s assume a volume of 0.4km3 for a maximum eruption (this figure is based in another assumption, and that of a 10% figure of magma that could be erupted out of a 4km3 in the dike). This means that the eruption could potencially last 9months more based in this figure.
Anyways, both these calculations give us an end date for the Fagradalsfjall eruption between March 2022 and March 2023.
If melting from deep would sustain and continue, then we could approach a shield volume of 4km3
(assuming the average shield size in the Reykjanes region) and this would mean an end date around the year 2031 or 10 years of eruption (roughly estimated). We have no evidence for, or against this.
Take my estimated with a grain of salt.
I favours a small shield .. and a small shield in Iceland is 5 km3
The lava is really primitive and the dyke have formed a conduit pipe.
So far the hottest active lava ever seen on camera in Iceland.. 1220 C in the vent
Bardarbunga was a piston driven caldera drop.
The function here is completely different. Do note that the maximum uplift was only 40mm for this eruption, and we have 20mm of deflation in 3 weeks. Another 3 and we are at base level.
On a dilating/mydriating dyke you do not get a lot of uplift, nor will rhw EW-component return to zero since the bulk of the magma will stay in situ to fill in the void created as the rift ripped apart.
https://m.youtube.com/watch?v=UpfMDW7-rqA
View into the crater interior of Nyiragongo
Totaly drained out and is very deep.. when the lava lake will return is hard to say.. but coud be many years like the absence of open conduit vent lava lake in 1977 – 2003
Thank you, impressive.
The scale of that ‘crater’ is awesome! It really brings home the power of Nyiragongo.
Thanks for the link, Jesper!