Eruption at Kilauea

/ 07/06/2023

Update: An eruption has started already. Visible in the webcams. The initial outbreak is beautiful and is a must watch:

There is a very odd magma intrusion happening at Kilauea right now. How do we know it’s an intrusion? There is very rapid deformation in the tiltmeter at the summit of Kilauea, far beyond what is normal, and comparable to levels typical of magmatic intrusions. We have earthquakes, a lot of tiny earthquakes and tremor-like signals. The located earthquakes are all in the summit caldera area. The swarm includes a M 3.4 earthquake, in the 2018 caldera ring fault, that started the main sequence. There was a bit of inflation before the M 3.4, probably related to cyclical deflations-inflations of Kilauea, this inflation triggered the M 3.4, and then, since the earthquake all sorts of crazy seismic and deformation signals have been visible in the tiltmeters and seismometers of Kilauea.

The two seismometers UWB and HAT located in the north side of the caldera seem to be best capturing the seismic sequence. They show multiple earthquakes every minute, and a background tremor like signal. Below is the UWB seismogram at the time of publishing:

But the deformation is the strangest thing. At first there was deflation following the M 3.4. Deflation of the caldera rim floor as seen from Uwekahuna Bluff, in the Uwekahuna tiltmeter, on the western side. This deflation was strange and, combined with the seismic signal, I knew this was an intrusion. Then a rapid 5 micro radian drop started, which is substantial, and I knew things could get serious. Then the tiltmeter switched to inflation, faster and faster. As of writing it has jumped up 25 mircroradians and is accelerating, which is massive, more than usual summit dike intrusions that have erupted in the past. But it is the pattern of deformation that is strange. A normal summit intrusion produces only uplift fastest at first and then decelerating. Now we have accelerating deflation, and then accelerating inflation of enormous scale:

Uwekahuna tiltmeter for the past two days. The deformation sequence is puzzlingly complex. It starts after a M 3.4 ring fault earthquake which is the small downward spike that then leaves the tilt at a higher level.

I believe some of the unusual aspects of this sequence could be related to a magma intrusion in the ring fault. The reason for this is that there have been 3 similar intrusions before: two in 2020, and one three months ago in March. And I interpreted these intrusions as ring fault intrusions. This one has the same patterns. Why ring fault? There is a very complicated succession of deflations and inflations in the western side of the caldera tiltmeter instrument Uwekahuna that is unlike the simple inflation of a dike. The two events of 2020 also produced unusually vigorous and intense seismicity on the northern ring fault of the 2018 caldera fault of Kilauea, which led me to infer the intrusion happened on the northern side of the ring fault.

A dike pushes the ground up and out as it intrudes, which is relatively simple. But ring fault stuff can be more complicated. If the ring fault is intruded by magma, it will start shifting. If the caldera floor drops, this will create subsidence in portions of the caldera. But the opposite side of the caldera might rise because pressure increases on the magma chamber and pushes that side of the caldera floor up. When a fault shift one side goes down and one up. If the caldera floor subsides on one side, the immediately adjacent caldera rim will rise up. Leading to a potentially much more complicated pattern of deformation. Which is what we might be seeing now, with first deflation, then inflation, and a very unusual acceleration that could mean gradual opening of the ring fault.

Schematic drawing of magma intrusions around an uplifting or collapsing block.

The following are examples of normal dike intrusions in the Uwekahuna tiltmeter, the kind that have produced summit fissure eruptions. They are gradually decelerating inflations, although one of them has two pulses, a big one, then a small one:

This is actually more dangerous than a typical intrusion. Because the ring fault is a delicate region that prevents a large block of solid rock from crushing down into the magma chamber and collapsing, Magma intruding the ring fault can have dangerous consequences. One of them could be an explosive eruption since. Kilauea has produced several explosive eruptions in the past, of small volumes (VEI 3 mostly), but in some cases substantial intensity. One of them, around 1510, clearly took place along the northern ring fault of a caldera that formed around that time. The other explosive eruptions are less clear. Will that happen? I don’t know, but I can see the possibility. This kind of intrusion has happened three times before since 2018 and nothing happened, but this time the deformation is so much bigger, which means it could be different. We could have an explosive eruption, or a magmatic eruption, or nothing. It might go to sleep again. I will update the post to add more information:

Update

Despite the complex deformation sequence, the result has been the same as more normal intrusions. A fissure has opened across the floor of Kilauea. In 25 minutes, much of the caldera floor is already covered in lava.

The outbreak involved a sudden surge of lava to considerable height, a bit reminiscent of the previous eruption. It is possible that rising magma built up under the lava lake crust and inflated it like a balloon, then suddenly gave way in a magnificent blast of fluid lava.

Deformation has stabilized, and it looks like the intrusion is over now that magma is erupting.

https://www.usgs.gov/volcanoes/kilauea/monitoring-data

 

Course of events

Earlier eruption, January 5-March 7: The previous eruption of Kilauea started on January 5, 2023. It was a short-lived eruption. The official date of the eruption ending is March 7. But the eruption was dead before that, just playing with the remnant lava in the lake. A large deflation of Kilauea that started around February 17 is probably what killed the eruption, by reducing pressure and starving the conduit. This deflation was of a kind of cyclic pressure reductions of Kilauea’s magma system, known as DI events. Pressure did not recover from this event until March 9. this long deflated state probably ended the active conduit.

-Long-term inflation, March 7-June 7: During the large February-March deflation, magma had probably been flowing into Kilauea. And when it rebounded from it, on March 9, it did so to a much higher pressure level than before. The following three months, March, April, and May, were characterized by a near continuous inflation, due to incoming magma supply. Inflation rate in March was low, barely 2-3 microradians during that month (as recorded in the Uwekahuna Bluff tiltmeter). A faster rise happened in early April, and then a very sharp, important acceleration happened in late April. A magma surge hit at some point during April 23-24. This surge coincides in time with a flurry of 35-40 km deep earthquakes under Mauna Loa that started on April 23, and lasted a few days. Over a month following April 24, Kilauea inflated by 15-16 microradians, a very high rate. In fact, most of the precursory inflation to the present eruption happened during this 1-month-long period. Normally, it would take 2-3 months for the Uwekahuna tiltmeter to go up this much. Inflation rates slowed down towards the end of May.

-Sudden return of inflation, June 6-7: Less than 1 day before the eruption. On June 6, inflation increased slightly. Uwekahuna started to ramp upwards rapidly and earthquakes happened across the summit. I speculated this was part of a DI event that had started 24 days before but had not yet rebounded. A very delayed inflation phase of the DI event. I think this is likely, but I won’t get to confirm this due to the eruption. Two important earthquakes associated with this inflation happened inside the caldera at 11 UTC on June 7, a M 2.6 and a M 2.7, as well as many other smaller located and non-located events.

-M 3.44 earthquake, 12:35 UTC June 7: A magnitude 3.44 event hit near the northeast corner of the 2018 caldera. This earthquake pushed up the UWE tiltmeter by 2-3 microradians. An upward effect on the tiltmeter is typical of ring fault earthquakes that collapse slightly a part of the caldera floor, and produce a corresponding rebound in the rim. This rebound presumably affected the UWE tiltmeter, despite being located some distance away.

-First tremor sequence, 12:52-12:55 UTC: Immediately following the 3.4 earthquake, a vigorous swarm of earthquakes starts. Earthquakes make a flurry along the fault between the downdropped block and the deeper part of the caldera that contains the lava lake. A number of earthquakes happen here between 12:40-12:56 UTC. This overlaps with a tremor sequence at 12:52-12:55 visible in HAT and UWB seismometers. The tilt started to go down immediately after the M 3.4 earthquake, to a total of 1 microradian. This deflation lasts about half an hour after the earthquake and then flat-lines. This suggests a magma intrusion along the ring fault between the down-dropped block and the deeper portion of the caldera, or somewhere near it.

-Second tremor sequence, 13:40-13:46 UTC: The Uwekahuna tiltmeter shows that about 1 hour after the M 3.4 earthquake, around 13:35, rapid deflation kicks in. The Uwekahuna tiltmeter rapidly drops 5 microradians. This coincides with a second distinctive episode of tremor in HAT and UWB, 13:40-13.46 UTC. Very few earthquakes are located during this time, and there is no distinctive cluster. The seismograms clearly show how large earthquakes paused around the time of the tremor event. Presumably another intrusion pulse hit at this time, which again subsided the Uwekahuna Bluff. Possibly due to a reduction in pressure of the magma chamber.

-Intense inflation starts, ~13:52 UTC: Around 13:52 UTC, the rapid deflation switches to rapid inflation. Over a little less than an hour, the Uwekahuna tiltmeter rises ~26 microradians above the preceding deflation, which is ~20 microradians above the level reached immediately after the M 3.4 earthquake. This is a more typical intrusion that pushes up Uwekahuna. Earthquakes intensify over an area around the caldera and some slight tremor may have gradually built towards the later part.

-M 3.3 earthquake, eruption starts, earthquakes stop, continuous tremor starts, 14:43 UTC: Multiple things happen at 14:43 UTC. A M 3.3 hits along the north ring fault of the caldera, which pushes Uwekahuna another ~6 microradians up, due to rebound of the caldera rim. Simultaneously with the earthquake, a giant ball of lava blasts through the floor of the crusted lava lake. Many other openings start to pop up over the floor over the next hour in a chaotic pattern. Continuous tremor sets in. Earthquakes mostly stop. It seems the intrusion is over and now the tiltmeter deflates due to lava effusion.

 

Interpretation of the intrusion/eruption event

My initial interpretation was rushed. Volcanoes don’t give you much time to think! Now I will look a little more closely at what has happened and why. Is there a need for this? Didn’t pressure just build up, punched through with a bunch of earthquakes/deformation, and then erupt? Yes. So am I overthinking things? Maybe. But there are many ways for magma to intrude, and many reasons for it to do so. First, the trigger is unconventional, a M 3 earthquake, which is as far as I can recall the first time a large earthquake kick-starts a Kilauea magma intrusion since 2018. And second, the deformation sequence is odd. There are three different phases of deformation that require three different modes of intrusion.

It is good to start with a map. the following map shows some of the things I have talked about earlier:

Caption from the USGS monitoring map of Kilauea showing the earthquakes during the swarm, a satellite view of the caldera, and some additions of mine.

One of my biggest questions is what happened during the intrusion. The intrusion had basically three phases. First, 12:35-13:35 UTC, when there is a slow but distinctive deflation in the Uwekahuna tiltmeter starting in the immediate aftermath of the first M 3 earthquake. This first phase involved a very distinct flurry of earthquakes between the down-dropped block and the deeper caldera area. Second is between 13:35-13:52, involving a much faster Uwekahuna deflation, and no clear earthquake cluster. And last is the one between 13:52 and 14:43, which involves large scale rapid Uwekahuna uplift, no clear earthquake cluster, with seismic events happening all over the caldera area.

Dikes in this area tend to follow the Halema’uma’u fissure/dike swarm. Dikes are near-vertical. This is a historical pattern. Uwekahuna is only 1.5 km away from the Halema’uma’u swarm, and adjacent to the area where dikes start to form (immediately east of Halema’uma’u, in the green part, in fact). So a dike will always push up and away Uwekahuna. This is in part an elastic rebound from the extension of the summit area, the south flank moves south pushed away by deep magmatic spreading, and this stretches out the summit. The caldera stretches and subsides. The dike is in part just an elastic rebound of this deformation.

However, the present intrusion induced deflation and not inflation in the tiltmeter. It was not a dike, at least not until 13:52. It initially also produced the flurry in the area marked green, which is, coincidentally or not, the centre of Kilauea. An option is a outward dipping ring fault intrusion along the green area, concentric to the inner collapse. An intrusion here, because of its geometry, would push the area to the east, the down-dropped block, upwards. To the west it would make subsidence, due to a trapdoor-like sinking of the Halema’uma’u crater area, creating subsidence into the caldera of the Uwekahuna portion, which is to the west of the green area. I think this option is fairly good. The second phase may indicate a fast aseismic widening of the area intruded in the first phase. But I cannot be sure either. Other geometries could potentially work too.

At 13:52, the intrusion changed into your typical Halema’uma’u dike. Halema’uma’u dikes take about an hour to erupt, which is a historical pattern too, and that is how long this one took too. It erupted at 14:43. Apart from that there are the more obvious signs, opening of fissures along the floor of Halema’uma’u, beneath the lava lake, and also near the SW corner, where the Southwest Rift Zone starts, outside the lake (a small fissure opened there much later than the others). And also the rapid uplift of Uwekahuna, maybe a little bigger than usual.

 

The March 11 intrusion

There was an event that happened 3 months earlier which caught my attention, because I didn’t quite understand it, and I still don’t. It had some similarities to the initial phases of the recent eruptive intrusion. The March 11 intrusion.

The March 11 intrusion happened after a tilt/pressure rebound from a deep, long DI event that lasted a little over 20 days and contained several smaller Di events inside. Tilt jumped 3-4 microradians (Uwekahuna tiltmeter) above the previous high stand, before the DI started. This large rebound, between March 9 and March 11, immediately resulted in an intrusion.

The intrusion commenced at 20:33 UTC with a very strong 1-minute-long pulse of tremor. There is no clear precursor before that. The main intrusion lasts some 33 minutes until 21:06 UTC. During these 33 minutes, there are probably over a hundred micro-earthquakes seen in the UWB seismometer, while the RIMD seismometer shows a low continuous tremor. The Uwekahuna tiltmeter shows deflation starting a little after 20:30 UTC, and continuing to roughly 21:00 UTC, so coincident with the seismic signal, although there is more complication to the total deformation sequence. The USGS catalogue shows only 4 located earthquakes during the main seismic sequence, which is underwhelmingly little to reconstruct what happened, but at least all four earthquakes cluster in the same area, the northern ring fault of the down-dropped block 2018, a few hundred meters north of the 12:40-12:56 swarm during the last intrusion. Then follows a period with no tremor and very reduced earthquake levels until 21:50. At 21:50 UTC, a M 3.1 earthquake happens.

 

Seismic sequence of the March 11 intrusion.

The deformation is funny and strange. It goes down and up three times, eventually leaving the Uwekahuna tiltmeter the same as it started. Deformation is small. The three downward excursions are more easy to explain. The first two are part of the same deflation, only that a short upward jolt interrupts in the midst of it. This deflation coincides in time with the main intrusion, ~20:30-21:00, and must be related to it. Presumably magma removal from the Halema’uma’u storage deflated the caldera area. If not interrupted by the upward jolt, the intrusion would have sent down the tiltmeter by 0.75 microradians.

Deformation of the March 11 intrusion in the Uwekahuna tiltmeter.

The third subsidence clearly correlates with the M 3.1 earthquake of 21:50 UTC. Normally ring fault earthquakes produce a rebound of the Uwekahuna tiltmeter, but not this time, and the reason is not too difficult to guess. The M 3.1 happened near the eastern end of the down-dropped block, a good way from the northwest side of Halema’uma’u where Uwekahuna is. The magnitude is small, which means the rupture must not have extended a long distance. So most likely the tiltmeter was caught in the weak subsidence induced across the caldera floor by the small eastern rupture, while rebound must have been centred on the eastern rim of the 2018 caldera.

The three uplift events of the sequence are more difficult to explain. The latter two are gradual, and together last around 100 minutes, with the M 3.1 barging in the middle, they seem to undo the subsidence from the intrusion deflation. The first uplift is more sudden, like a jolt, but there is no located earthquake that could have done it, so it’s strange. I don’t understand what caused the uplifts. One possibility is caldera rim rebound due to slow-slip of the ring fault following the intrusion.

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120 thoughts on “Eruption at Kilauea”

  1. Is the lava fountains going through 400 meters of pooled lava right? As it erupted right inside the rootless lake as well

  2. What a beautiful mess! Good luck finding a traditional fissure. Agree, Jesper–that’s what happens when Pele doesn’t have to cut a new dike through that last 400m.

  3. Posted this before, I think the B1 cam wont have long left in this world now.

    • Excited! Burning plastic and fumes, only the steel parts will surivive it

  4. Wow. that live stream, scroll back and watch the eruption start, then the other little vents open up 1 by 1. So we reckon this intrusion hit the bottom of that old lava lake and just pushed its way through the thin crust in a bunch of places? Or has this actually popped up at different spots on the ring fault?

    • It probably broke out from the bottom of the lake, as you say, then blew multiple holes through the lake’s crust.

  5. The downdropped block will be flooded within the day, it has already filled in the southwest bay which is at the same elevation, the southwest edge is at least 3000 ft elevation, so once the surface settles it will flood the downdropped block.

    Also a whole new vent opened 10 min ago with a huge surge through the lake, and there are at least 3 vents on the north side very close to the downdropped block. I think multiple dikes were involved here.

    • Looking at the live webcam, looks like another vent opened up in the side of the crater.

  6. Hector, the email notification arrived in my inbox and by the time I had clicked on it, 8 minutes after you posted the “Intrusion” post, you’d edited to “Erupting”.
    I’m very sorry to say that I did not read your article but headed straight to the live webcams and goggled in astonishment; unfortunately then real life intruded (hur hur); taxi and plant watering service was urgently required.

    I will now get the webcam up on my tv and take some time to catch up.

    Real life has a habit of interfering with my volcano viewing recently; the whole StarsDie estate has been blitzed and remodelled, with new summerhouse and shed, future-proofed low maintenance designs and relaid driveway. Only the formal garden path and bark beds remain to be completed, then the planting can begin in earnest.
    I just hope I can stay awake long enough to see all the news reports and videos. I think i need a holiday, the first in over 5 years…

    • Well, I barely finished the post now. What you missed were only my initial misplaced speculations.

      • Surely it can’t keep erupting through over 1000 feet of new lava for much longer!

  7. 08:56:37 on the V1 webcam, the camera moves to the right to see a new fissure emerge part way up the side wall of the caldera. There’s now a pretty cataract of lavafalls there. I’m not sure which compass direction that is.

    • It looks as if Pele really blew a few gaskets, so many fountains all over the floor.

  9. There is a minor vent outside the lava lake on the KW webcam, high on the southwest wall.

    • I think that’s the one caught at its emergence on the V1 camera.

      Also, has the B1 downdropped block camera been relocated or zoomed? The rocks in the foreground change.

    • Tim Clarke on FB Volcanocafe group have a video with the start up, insane stuff with a few 100 s of meters tall lava fountain!

    • Yeah, I saw that on the livesream, too. I think that means Kīlauea still, to the least, have some pressure left. There might be more vents appearing in the future, although that’ll become more and more unlikely as time goes on.

    • It’s easier for lava to come up outside the lake on the wall due to density differences between the lava lake and the dike. Most vents have opened under the lake, which is degassed and denser, but the dike contains frothy buoyant magma that can rise higher through the walls outside the lake.

        • The laser points at only one place, which I believe is located at the west end of the old lake basin from 2021, which was filled in very fast. The crust of the lake seems to be getting buoyed up again so is rising out of the lava and the lava in turn is also starting to flow back down under the crust. I am only guessing but I think the laser happens to be pointing at a spot where the lava is flowing back, probably right in the middle of the area that the livestream has zoomed into, where it looks like a drain might be forming.

          This area also was very elevated before the eruption, the january eruption saw inflatio of the crust but it stopped before the lake could equalize in height and fill in the low areas with ooze up flows, so there was just this big cliff that was basically right in direct view of the webcam so was hard to actually see for what it was. I think maybe with all of the new activity things could move around and the crust could level out, with the laser pointing at a spot that sank down in doing so.

          A third option might also be that such a large fissure opened below the lake that it was able to basically drain out as much lava as was visibly erupting, all of the degassed dense lake lava flowing back while hot gassy lava floated to the top. It isnt quite equal as there is net deflation on the tiltmeter but far less than I would have expected given the level of activity we have seen.

          HVO has said the lake has risen by 10 meters at the time of their update which was now almost 9 hours ago.

  10. Just when I thought yesterday that Kilauea does a longer volcanic break, it escalated today.
    The first eruption of 2023 in January was in the eastern part of Halme’uma’u. Now the eruption is pretty much along the “Halema’uma’u fissure/dike swarm” you mention. The first 15 minutes of the eruption show how the new hot magma melts through the partially melted cooled lava lake and from time to time finds new spots for fountains.
    Is this eruption a continuation of the 2021-2023 Halma’uma’u eruptions or something new? Can it initiate something towards the SWRZ?

    • New eruption officially because it comes after a break of at least 90 days, though you could say it is really just Episode 4 of an eruption that started in 2020 i.e. filling the 2018 collapse.

      • HVO would consider it a new eruption regardless because it was a new intrusion. I believe that was a result of 2018, whether to consider the eruption in Puna as part of Pu’u O’o, in the end it was ruled as its own thing. That does also mean the new vents that formed in 1997, 2007 and 2011, as well as the 2008-2018 lava lake, those were all new eruptions too as they had sources that were independant of Pu’u O’o. Not sure of Kupaianaha or TEB vent, they were some distance from Pu’u O’o down the ERZ but fed directly from it and had no associated seismicity associated with a deeper intrusion.

        So there has been 4 eruptions since 2018. I think this eruption will last a while, but not for more than a year, the fact a vent opened on the wall adjacent to the SWRZ, some 930 meters elevation, probably means other parts of the summit are in play, and intrusions might begin towards the southwest if the lake gets any higher. There were lots of SWRZ eruptions after 1790 up to 1823, and then Mauna Iki in 1919, most of them passive intrusions from Halemaumau itself. Kamakaia hills was probably a real SWRZ intrusion with more primitive magma not already in the summit, which pushed out some resudent evolved stuff. Was somewhat faster making a tall cone and a’a flow field before becoming tube fed pahoehoe.

        Probably this all happened when the lake was at around 950-1000 meters elevation, so about 50 meters to go, maybe a year or two. But a SWRZ intrusion from the connector might happen before that potentially.

        • It’s easier for lava to break through the caldera wall rocks than re-bore a route through recently solidified magma-blocked vents. So, as long as there’s enough pressure, there’s going to be vents around the caldera rim. Fill and collapse, rinse and repeat with variations, rather like classical music.

        • Yes, I agree; Kupainaha and the TEB were just extensions of the Pu’u’o’o conduit dowrift and are part of the Pu’u’o’o eruption, while 1997, 2007, 2011, and 2018 effusions fed from dike intrusions independent of Pu’u’o’o and would be separate eruptions. The 1997, 2011, and 2018 eruptions, in fact, initially erupted evolved basalts different from the primitive basalts of Pu’u’o’o and the summit lava lake. HVO also treats the 2008-2018 summit lava lake as a separate eruption, too.

      • The table of historical eruptions shows that there were eruptions of “gradual filling” which lasted over many years. F.e. 1906-1916. Can we compare those periods of “gradual filling” with the process of “gradual filling” since 2020?

        • Way slower and more continuous, the activity of the late 19th to early 20th century was more liek the 2008-18 lake, only that there was no flank vent the take lava away to prevent an overflow. eruption rates were also less than half that of present per year back then. 1919-1924 supply was probably a surge and comparable to present but was temporary and died off after 1924, Mauna Loa was very active in the two decades after.

          The eruptions now are maybe most close to what was going on way back in the dawn of history in Hawaii, in the early 19th century, when the caldera was filing with a lake like the present one but a lot bigger. But even this isnt really satisfactory, because that was waning activity after a major caldera collapse, 2018 was a big event but was nowhere near as big as the collapses that created Kaluapele. So the present activity is probably a bit of its own thing.

          Clearly, too, Kilauea is still in charge. Mauna Loa erupted only 8 months ago, which was expected to mark a shift of power betwee nthe two, but it was not to be, and that did nothing to blunt Kilauea. If anything it only accelerated the rate of melting at the source now that two volcanoes are drawing from it… Hawaii is already the most productive lava source on the planet but it coudl get pretty crazy in th enext few years.

          • Chad I knew Kilauea has done explosive and phreatomagmatic eruptions in the past, but I never sat down and really read into its known recent history. I just spent time learning about the Aila’au eruption at over 5km^3 and the massive lava tubes it created (which started from vents east of Kilauea Iki), and then I learned that the first millennium CE contained many explosive eruptions and tephra falls, and that according to what I read ‘explosive’ may have even been Kilauea’s main eruptive mode throughout this time. Wild! Then it switched back to predominantly effusive, I think, around the time it formed the monster Powers caldera.

            Which eruption formed the Powers Caldera (I can’t believe how large that’s presumed to be!), I think I either missed it or we don’t know exactly? Figured I’d ask the resident Kilauea expert.

            Such a fascinating volcano, I really did myself a massive disservice not fully reading into Hawaiian volcanism sooner, thinking its history was that of mostly gentle effusive events. Maybe it is/was, but some of those effusive eruptions were monstrous and fast…

            I’m turning into a Hawaiian fan, largely thanks to you, Hector, and some others here.

    • It’s not like the term eruption is perfectly defined, as far as I know. This is a new dike erupting, which means it’s a new magma conduit, different from the one that erupted January 5-March 7. In fact, we have had four different dikes that have erupted since 2020. So as far as conduits go, this would be the fourth Halema’uma’u eruption.

      But it also seems that Kilauea is intent on filling up the 2018 caldera, to an elevation of at least ~950 meters I think, so until then lava will keep coming up though Halema’uma’u. It might hit 950 meter elevation somewhere around late 2023-early 2024, assuming continuous filling, when it might start alternating with rift activity. ~950 meters is the elevation the Halema’uma’u floor had when rift activity started in 1961, after the 1960 collapse. it is also the elevation it had in the 1832 and 1840 major rifting events that followed infilling of the 1790 caldera, as well as maybe 1823 although I’m not sure. When the Kamakaia Waena eruption happened in the Southwest Rift Zone at some point between 1790 and 1823, the floor can’t have been any higher than the 950 masl height the “black-ledge” had in 1823-1832.

      • The eruptions since 2020 all remained inside Halme’uma’u. They were all effusive. They added layer after layer of lava on the 2018 collapse hole.
        I’m thinking about whether the present eruption remains the same or whether it opens towards something else: either an expansion to the down-dropped block or towards the SW.

        • It was lapping perilously close to the edge of the down-dropped block on the first day, when HVO flew a helicopter in to obtain lava samples. The chap just wanderd over to the degassing edge and scooped his samples, then retreated and left. Awaiting the analysis with impatience.
          The level has subsequently dropped leaving a bit of a bath-ring around the edge of the caldera, as degassing has occurred and the effusion rate has slowed.I didn’t realise just how close the B1 camera is to the edge, I’m hping it can be retrieved and resited before the lava breaches the block.

          • There isn’t much to go vertically until the lava lake floods the down-dropped block. But the area has become so large, that a lot of volume is needed to spread the area.
            The “Stromboli” on the southern wall shows nice spatter activity now: https://www.youtube.com/watch?v=Q5M-5XFplo0
            It sits on a place where there was no lava activity since … 1971? It is outside Halema’um’u. It is the first time since 1982 that lava erupts on the summit outside Halema’uma’u.

    • The first moment it looks like a atomic explosion, because the camera is not used to the sudden light flash. Only after the camera has adapted to the light, the initial fountain becomes visible.

    • USGS says initial fountains reached 200 feet (60m) and consistent fountain height is 50 feet (15m).

      • That was when they first saw it, not the actual very first fountain when it burst out. Their numbers are sensible for the fountains that stuck around for the first few hours but the first burst of several vents was clearly much larger.

        • I think they are just as capable as we are to rewind their webcams to have a look at the exact first moment 😉

          From the 9AM bulletin:
          “Halemaʻumaʻu Lava Lake Observations: Multiple minor fountains are active in the central eastern portion of Halema‘uma‘u crater floor and one vent is open on the west wall of the caldera, within the closed area of Hawai’i Volcanoes National Park. The largest lava fountain is consistently about 15 meters (50 feet) high; during the early phase of the eruption, fountain bursts reach at least approximately 60 meters (200 feet) high.”

          • It says at least, preliminary measurement. If a lot of people are coming up with 100+ numbers from fall calculations then either we get a feed with a different speed or they have some other definition of fountain height. I know they didnt consider the tall fountains from fissure 17 in 2018 to be true fountains rather than continuous strong spattering. They said ‘fountains at 50m with bursts over 100m’. I can see the same applying here.

          • Well, there is wind resistance… Lava crust can sometimes fly up into “dust devils”, it’s often frothy, so wind resistance might be factor to consider. Chances are the height using the simple formula is overestimated.

            Although it is true HVO tends to be conservative about fountain heights. They might not refer to the largest burst, but to one they were able to measure better.

      • Not sure whose feet were used for measuring the fountains, but I know I’m not going to put my feet anywhere near that:)

  13. 15 million m3 of lava erupted in the first couple hours, eruption rate of over 1000 m3/s at the onset 🙂

    • Can we estimate the mass/weight of the new lava? How well can the volcanic structure cope with the increasing weight of molten rock?

  14. Alert level at Mayon raised to 3, effusive eruption is on and lava dome formation is increasing, tremor and vog is back at Taal.

    • The wall fissure is on the southeastern side of the bay. Can it be a sign for a future expansion of volcanic activity towards SW? It could interrupt the Crater Rim Drive above the southwestern end of the caldera like in September 1974.

      • Yes I think there is a possibility of eruptions trending southwest as the lake gets higher and vents open at higher elevations. This vent is apparently 30 meters above the lake, which is probably around 895-900 meters elevation, so the vent is at 930 meters elevation.

        If this vent does evolve into the new center of activity and turns into a conduit, then a SWRZ eruption is a very likely case given the proximity. In fact it would probably spawn many such eruptions, the area is very fractured, if the lake gets high enough as it is I wouldnt be surprised if it just quietly flows into the cracks on the wall and starts oozing out of cracks down on the SWRZ without any sort of traditional signal. Most of the vents there have no pyroclastics, and are quite small in scale, basically tiny pahoehoe breakouts in the desert, so probably no gas in the magma.

        • With “SW” I wanted to apply to “Summit Southwest eruptions”, not SWRZ eruptions. The summit caldera is large enough to host eruptions to the southwest or west of Halema’uma’u which still can be judged as “Summit eruptions” but are different to SWRZ.

          There is a broad variety of eruption places and eruption styles which are possible on Kilauea, and this makes this volcano exciting to watch.

          • But a “southwest leaning” eruption inside the Caldera may be a bridge towards a future eruption period on SWRZ … 1919-1920 both erupted on the southwestern corner of the Caldera and on the SWRZ.

          • I think that would only happen if the caldera was mostly filled, it is clear now that eruptions can actually happen above the lake leven even with vents in the lake itself but I think if there was enough pressure to erupt on the rim then it would have done that last night, its only a couple hundred meters away. If a dike went into the SWRZ cracks now it would probably erupt in the walls of Halemaumau and then some distance to the southwest and skip the bit inbetween until the floor gets higher. Only my assumption though.

            1919 and the eruptions in the 1970s happened in Halemaumau first then went down the SWRZ from there, with that area under crater rim drive being about where the rift starts. But at the time Halemaumau was only a few tens of meters deep or actually overflowing in 1919 where now there is still 150 meters to go before it might be close enough.

            1970s eruptions also had advantage of being gas rich magma, so could rise up, where now that might be difficult.

          • The present Halema’uma’u is larger than the old crater which collapsed 2018. Some lava springs now would be classified as “Caldera eruptions” outside Halema’uma’u if the structure of 2018 still existed. The old Halema’uma’u was around 1 km², now it is at least 1,5 km² and is going to flood the downdropped block which is another 1,5 km² large.

    • Southwest wall vent visually reminds me a lot of Bob at Fagradalsfjall in 2021, before the eruption got bigger. Perhaps if all of the other vents in the lake close up then this wall vent will get a lot bigger too, fountainign and turning into a lava geyser 🙂

    • The closest to Io s volcanoes on Earth is Kilauea as well with its power.. the bigger the volcanoes are the better : )
      Looks like a whole network of dykes breached the caldera

      • I liken it to a dike rising through a gravel pit. 🙂

      • These boulders from the original collapse have probaly long melted 🙂 at least the smaller ones, with the walls now being melted glass thats encases the lava lake itself, lava have very poor heat conductivity, so I guess the submerged walls have not melted that much, althrough they are incredibley hot. This whole rootless lake is freaking the biggest shallow magma body on the planet now

  17. The lava is now forming their pools yet lava keeps flowing out, probaly the heavy lava have broken through the crust on the rootless lake. With many overflows on the crust we may get some perched lava lakes, perhaps even lava shields with luck. The Wall vent is fun, flowing like water and probaly will make a nice spatter cone.

    Andrew Hara on FB haves some nice photos of the eruption as well the lava is very shiney and fluid so basicaly almost crystal free.

    • Sometimes a thermal camera is best way to view it as it can see through all gunk and reflections, givning a more clear view of where the lava is active

      • The thermal maps shows the distribution of lava springs inside the lava lake. There are three lava springs which are in the northern part of the lava lake. They are more close to Uekahuna outlook on the northwestern border of Kilauea Caldera:
        https://www.usgs.gov/maps/june-7-2023-kilauea-summit-thermal-maps
        Are the northern springs related to earthquake swarms on the saddle area to the northwest side of Kilauea?

    • The lava pond in the middle is Re – activated! It first formed in 2021 s and often circulated too .. as its doing now

  18. This was said in todays HVO update.

    “The very earliest phases of this eruption appears to have an effusion rate that was significantly higher than the previous three Kīlauea summit eruptions based upon the rapid coverage of the entire crater floor. ”

    The lava lake was 1.5 km2 in area at its largest, and probably some 5-15 meters deep depending on location.

  20. The flow from the side of wall is still going. It is probably fed by lava from the collapse pit, push out by the high pressure underneath the lid. Once the pressure goes down, this may be the first flow to cease

    • The area of the lava lake is now larger than the Halema’uma’u area before 2018. Some of the present lava springs would have happened outside the pre-2018 Halema’uma’u. The area may even double if/when the lava lake floods the down dropped block. Now it has 1,5 km²; with the expansion on the down dropped block it would become 3 km².
      Interesting are the three lava springs in the northern part of the lava lake. They are outside the line of Halema’uma’u fissure/dike swarm.

      • The crater is like a magma bathtub right now. True vents are on the bottom of the lake and on the SW wall of the crater. The vents that we see are just weak spots in the lake’s crust that lava/magma bursted through.

        • Would you guess that the vents on the bottom of the lava lake are in line with the main Halema’uma’u fissure? It is hard to imagine how streams of new magma go inside the 2020-2023 lava lake before they reach the surface.

          Unlike the lava lake 2008-2018 and Puu Oo’s lava lake this lava lake has only had upward transport of magma/lava. It has never lost magma down back towards the magma chamber(s). 2008-2018 the lava lake had a circulation which was openly linked to the magma chamber. That’s different to the lava lake sind 2020. The new lava lake only knows growth, no shrinkage. It still behaves like a rootless lava lake, while the 2008-2018 lava lake was a rooted lava lake.
          Another thing has so far not happened: Collapses. How close are we to next collapse in crater/caldera? In the 19th century there were many cycles of growing and collapsing.

          • Ahhh,, the old proverbial, ‘stay tuned to this station for further news’. I’ve alerted those participating in the ‘bubbleheaded’ conversations on the ‘Two Pineapples’ Youtube channel to log in here and learn something. The same kind of yada yada went down on one of the major channels covering Iceland at the time. Everything but the girl.

        • Given how previous eruptions in Halemaumau have often reoccupied or erupted very close to slightly older fissures, it isnt unrealistic that the same locations that first erupted in 2020 might have kept reopening, perhaps with a greater length of fissure each time. If you curve that dike around then it goes to the southwest wall vent pretty neatly, and it also goes the other way towards the singular vent next to the downdropped block. Maybe not surprisingly this general trend and these locations are also the only places now that actually have active surface vents anymore, the big fountains in the center are probably easy weak spots (some are still active ponds) but not directly over the fissure, rather over the deepest part of the lake. At least the area to the east of the tephra island dates back to the start of the September 2021 eruption, which broke out there first.

          The geometry of the crater walls and all of the fractures the 2018 collapse must have made surely affect the surface orientation of the vents, the wall cone and its fissure are at near right angles to the SWRZ only a couple hundred meters away for example, but generally speaking they still form the same trends as before. Seems that the deep pit of Halemaumau was a caved in conduit style of collapse that was occuring alongside the ring fault collapse to the east at the downdropped block, so sort of like 1924 and also a smaller example of a real caldera.

          I would hesitate to call that as the lake gets deeper, successive intrusions under it will get longer along this line or close to it, probably opening vents on the downdropepd block (maybe only after it is submerged though) but possibly also pushing into the SWRZ, and maybe in the slightly longer term feeding most of the lava to the SWRZ if this takes place, making a lot of small shields and flows. The wall vent is probably some pretty good evience that intrusions are at least trying to go that way even if the lake needs to rise a lot more to get beyond the walls.

          This might also explain why the January eruption didnt last so long, it was over on the east side of the crater, all of the visible vents were probably just rootless and the fissure that opened under the lake was maybe quite short so was subdued by the weight of the lake quite fast and drowned out completely after a month, the other eruptions all had a vent open outside of the lake somwehere at least initially. Will be interesting to see how this eruption goes, wall cone is pretty weak but it is also some 30+ meters above the lake, which will take probably several years to reach. A lot can change in 3 years…

          • With every layer of lava put on the existing lava lake new magma needs more Newtons (force) to do an eruption. This could explain the spectacular onset of the eruptions in January and in June. The more force Kilauea’s magma system need, the more will supposedly rise the likelihood for expansion of the eruption over the borders of Halema’uma’u and Kilauea Summit. I’d expect that future “lava shows” will become more spectacular than previous ones.

            Google Maps shows that there are several cracks in the southwest of Halema’uma’u. The most southern crack appears to be in line with the vent on the southwestern wall. Is magma already intruding into this area? Maybe they should better observe the cracks there.

          • I do think that the height of the lake is probably making it harder to erupt, eventually it will become easier to erupt elsewhere. Those cracks to the southwest are where the 1919 and 1971 eruptions were, and yes I think as the lake gets higher it could start flowing into the cracks, or an intrusion might one day start out of the wall cone, a lot if things could happen but this is almost an inevitability if the lake gets high enough, it happened in the 1810s to 20s, it happened in 1868, in 1919, and in the 1970s, all of which were when the lava level was very high over 950 meters. Only twice have high lava levels set off LERZ eruptions actually, in 1840 and in 2018, maybe in 1960. But high levels do seem to set off SWRZ activity more readily than a LERZ eruption. But long term summit filling activity is not familiar to most people there today, because most activity on Kilauea was on the ERZ from the 50s until 2018.

          • Obviously the magma will take the easiest path. If the only consideration is the pressure form the weight above, then it will tend to go through (into) the lava pond but the density of the lava is less than that of the surrounding solid rock, so less weight. This will funnel the magma towards the bottom of the lava lake. Close to the surface, the strength of the rock also becomes a deterrent: it has to be broken to let magma pass. But if there is a crack already then magma will take it.

          • Until now the Halema’uma’u crater only gets input, now output. That’s different to rooted classical lava lakes like 2008-2018, the ones of Nyrogongo and Mount Erebus. Those lava lakes are openly convecting from magma chamber to the lava lake. They have a balance between input and output. The idealtype of a rooted lava lake usually neither growths above the ceiling nor falls down below the surface.
            The present lava lake in contrast to those idealtypes only knows growth like big business. It has no balance. It knows no shrinking.

            Previously (before June 2023) the vents in the lava lake were more distributed towards Kilauea Iki (Summit’s ERZ). Now they’re getting in a line which continiues the cracks and faults of SWRZ. Do we already see an early first sign for shift of power from ERZ to SWRZ? Google Maps shows the easily visible cracks in the southwest of Halema’uma’u. They’re not far away from the present vent on the wall. 1971 had eruptions close to this area.

          • A lava lake that doesn’t receive new input will grow a solid lid. That is the dangerous phase. Over time, degassing will still occur but the gas becomes trapped underneath the lid. Eventually the gas pressure exceeds the strength of the lid and the thing suddenly explodes. These can be significant and very unexpected explosions. I thin k the start of the current episode was like this. New magma inflow brought new gas, the gas rapidly rose to the surface (the sudden sharp tilt changes in the hours before the eruption), an earthquake tried to give release but failed, and eventually the lid exploded. The gas came out but the pressure reduction cause more degassing in the lava below. Now we had a real eruption which will continue until the gas runs out!

          • Interesting is (as I wrote in another post) that the spatter cone on the wall/cliff sits outside Halema’uma’u. It should be judged as a “Kilauea summit caldera” vent. It is the first time since 1982 that an eruption actually has left Halema’uma’u. What is going to follow that way?

          • Albert that happens in more sticky lava but not on these rootless lakes, the roof is porous and most of the gas comes out pretty easily. So no explosions although maybe the crust did act to contain the pressure and give a bigver fountain when it did break.

            What you described happens at volcanoes that make pancake domes, like at fissure 17. So Kilauea did do this once but it wont do it in Halemaumau. Lava lakes and pancake domes are analogous structures but lakes are free flowing which matters I thibk.

          • It happened at Agung sometime after the eruption had ended. The explosion in Kilauea the other day was rather minor so the pressure containment was limited, but the rapid change in tilt is in my opinion pointing at gas pressure as a driving force for the eruption start.

          • It is pressure driven but pressure in the magma chamber not under the lake crust. Agung isnt a good analogy for this, the lava is too sticky, it doesnt have a liquid lake, it is a ponded blocky a’a flow. Rootless lakes have formed many times at Kilauea in the past 70 years and never exploded, they tend to be degassed already, unlike rooted lava lakes which are in conduits.

            If the wall cone grows and forms its own conduit then that could start doing episodic fountaining like Pu’u O’o did, or like Fagradalsfjall, but while this is violent degassing it is really not explosive. Wall cone has grown a lot overnight, so this is possible, but who knows.

          • Is there a way to localize the magma channel which feeds the cliff volcano? If it comes up vertically, it could be a future door opener to the southwest. If it comes more flat from the bottom of the lava lake, it’s rather a side vent.

  21. Looks like the lava is almost soaking into the crust on the rootless lava lake as Chad says.
    Perhaps its flowing into cracks on it?

  22. Just a rough guess on the area where active vents are probably showing up. I would expect this to get longer as the lake gets deeper and other parts of the caldera and surroundings become easier to intrude.

    • The vents are on the surface of the lava lake, as Hector has explained. This could mean that the northern lava spots have a channel through the lava lake to a vent on the bottom of the lava lake where we don’t know the position.
      The northern vents may otherwise be related to the swarm on the saddle towards Mauna Loa, that we noticed some weeks ago.

      • Yes that red line is my guess on where the true vents mostly are, the actual image of the lake isnt taken from vertical but that line is all under the lake if you overlay a USGS update picture over it, except the southwest end where wall cone is 🙂

        • This is the newest thermal map of the Summit: https://www.usgs.gov/media/images/june-8-2023-kilauea-summit-thermal-map-0
          The fissure is already going to concentrate on three main vents: The one in the north close to Uekuhanu outlook, a second in the central southern part of the lava lake and the third one in the cliff. The appear indeed to follow your red line which is parallel to the northwestern wall of Kilauea’s caldera. The red line which is parallel to the northwestern wall, follows the direction of SWRZ. Past eruptions since 2020 were rather on an eastern line in Halema’uma’u towards Kilauea Iki.

  24. The lava superfluid now, the Wall vent looks like liquid aluminium, the lava haves to be at least 1160 C and nearly crystal free to have souch apparence. Andrew Haras photos have it bright orange in daylight so perhaps 1170 C, the viscosity is very low.. defentivly as low as Nyiragongo I guess.. and the massive magma body overall have probaly not cooled at all since 2020

  25. Aniakchak is still inflating and if it is has maintained it’s speed since April, it would’ve risen 65 cm by now. Unfortunately bad weather and equipment issues are making it hard to discern how the situation is evolving.
    The swarm at Chiles-Cerro negro is still going and VT quakes are now taking place just 300 m below sea level, LP earthquakes exploded last month easily beating last years record. Some of these LPs appear to have a similar signature to the Deep LP quakes that took place last year and in 2020 which could mean that another batch of magma from down deep could be making it’s way upwards, historically this process can take anywhere to almost a year to just a month.
    The Katmai Complex has gotten my attention with it’s deep quakes, the swarm has shallowed and waned a little but it’s likely that this just the result of the magma rising from the deeper reservoir towards one of the shallow one(likely at Trident) so escalations in the future is a solid possibility
    1 study suggests that Campi flegrei could be close to erupting and while I am not sure about the accuracy of the model the study is interesting. Unrest at Campi flegrei has been on a steady upwards trend for more than a decade now so I wouldn’t be surprised to see an eruption in the next few years (No VEI 7 confirmed) ):
    https://www.nature.com/articles/s43247-023-00842-1

    • Great research. Interesting, esp. the tracing back to other episodes back to 1950. Thanks Tallis.

      • Campi flegrei is one dangerous volcano but it’s been pretty active over the past 4000 years so I doubt it’s going to go anything higher than a VEI 5. Chiles-Cerro Negro is the one that I am thinking will erupt big if it does.(Large magma chamber, 1000s of years of dormancy, felsic system, and a persistent plug)
        Trident and Aniakchak are this year’s wildcards, both have the history and size but we don’t know about the specifics of the current situation so the future is up in the air.
        Lameailuea’s eruption won’t satiate my volcanic thirst, but deciphering which of the volcanoes will erupt if any of them is an interesting challenge. Katla and Grimsvotn could erupt soon too so that makes this year even more interesting!
        Which volcano’s stocks will you invest in? You can only buy 3! I’ve got CCN, Trident, and Katla stocks. High risk but High reward!

        • All of those volcanoes are mostly effusive though Tallis. Probably the one with the best chance of a VEI 4 or more is Aniakchak, but it would probably max at the low 5s. Katla might go for a 4-5 but Grimsvotn is unlikely to get to a 4.

          Might be a long time before CCN goes, we dont have much to compare but inactive volcanoes becoming active again is not a well observed thing so could take decades of obvious change, but it is likely to be quite the major event. Santa Maria in 1902 might be the closest I can think of, so CCN might do a VEI 5-6 followed by effusive activity for decades or centuries after.

          • Concerning CCN, I don’t think it’ll take decades for it to erupt. Last years swarm was likely the result of magma breaking out of lower crustal reservoir and the current swarm is likely the result of either magma or volcanic fluids or gas making it’s way to the surface. The cause of this swarm has risen 2 km over the past 3 months and there’s always the risk of more magma rising from the chamber.
            Trident is more of a wildcard, I can definitely see it producing an effusive eruption but Novarupta’s eruption could’ve marked a transition towards more explosive behavior.
            I think a VEI 4+ eruption at Grimsvotn is likely, the volcano has completely recovered from the Laki eruption along with more magma, more pressure, more inflation, and a higher cumulative seismic energy compared to the 2011 eruption. I’d be surprised if it produced anything smaller than a VEI 3

          • Laki was a once in 5000 year event, the last eruption like it was half as big and 5-6000 years ago, and another about the same size 3000 years before that, off of memory though so might be a bit off. 2011 was the biggest explosive eruption from Grimsvotn since the start of the Holocene too. It isnt impossible but the chances are not likely that an eruption of that scale happens again so soon.

            Higher seismic energy also doesnt mean a huge eruption, nor inflation. Both of those were happening at Kilauea until it just erupted now but apart from a strong start the eruption isnt really remarkable. And the level of deformation at Kilauea recently is much stronger than at Grimsvotn, with a similar sized magma system. The magma supply to Grimsvotn is about 0.02 km3 a decade, around 1/5 of Kilauea, so after 12+ years there might be something decent but not another 2011, maybe a low VEI 4, about 1/5 as big as 2011, we can see who is right when it decides to go 🙂

          • It looks like Grimsvötn has lost much to Bardarbunga 2014 and may have entered a more weak era of several decades. But it can still do a local ash plume with VEI2. I’d rather expect bigger eruptions on Katla and Hekla.

            Campi Flegrei last did a “viscous Surtseyan” eruption with “New Mountain” (Monte Nuovo) 16th century. It doesn’t look like it’s going to do something big, but small eruptions can already be dangerous in a dense populated neighbourhood. Imagine f.e. a Maar eruption (VEI3) which may easily kill thousand people.

          • Piton de la Fournaise, Fernandina, and Kliuchevskoy (which has so far not erupted this year according to GVP).

          • Grimsvotn has magmatically recovered from Laki but it’s not likely that it will produce a similar eruption because it’ll take time to build back that level of stress. Kilauea and Grimsvotn are two completely different volcanoes with very different behaviors. Pinatubo didn’t produce the same levels of uplift that other volcanoes have done before producing the biggest eruption in the past century. Grimsvotn may be Mafic system but it’s caldera volcano first and foremost and as far as caldera volcanoes go, this unrest is impressive and far more impressive than the build up to the 2011 eruption.
            The 2011 eruption was strong but the volcano has produced much larger explosive eruption before

          • Actually Kilauea is a very similar volcano to Grimsvotn, it is also a caldera volcano as well as a shield, the calderas of the two are comparably sized, with evidence of very large explosive eruptions in the past (Pahala ash) and Grimsvotn would also be effusive mostly without being subglacial. Kilauea also has done Laki sized eruptions just out in the deep sea, and 2018 did at times approach peak values of effusion that were comparable to Laki. But Kilauea also has a much larger magma supply and faster rifting, which tends to result in frequent and usually smaller eruptions, Grimsvotn builds a bit more pressure.

            It is also very unlikely it has recovered from Laki, as we can see from Kilauea now volcanoes that have recently made calderas dont necessarily just stop erupting until refilled back to the original levels, that is a resurgent caldera which Grimsvotn isnt really and neither is Kilauea. Bardarbunga is though.

          • The Pahala Ash is ~20 meters thick across the area of the slump scarps, 10 km south of Kilauea. It is a pyroclastic layer uninterrupted by lava with a chemistry similar to Kilauea lavas and different from Mauna Loa. Whichever eruption/eruptions formed this ash, must have reached at least VEI 5. There are some earlier pyroclastic layers that are very substantial too, the Moo, Pohakaa, Kahele, Halape, members. A lot of these were probably gas driven eruptions with little to no fresh magma, since the layers contain a large amount of lithics and fine ash, and are almost always yellow coloured rather than black. Like the Saksunarvatn tephra, very little is known about the Pahala Ash and earlier explosive eruptions.

            The Saksunarvatn tephras, on the other hand, probably came from magmatic plinian eruptions since they are black coloured, probably fresh glass.

          • I once have read that Kilauea does Plinians as often as Mount St. Helens …

            On Iceland we should also have an eye for the Ryholitic systems, f.e. Torfajökull and Örafajökull. There is a lack of historical scientific experience with this kind of eruptions in Iceland.

          • Torfajokull is active when rifting happens at Veidivotn but is not very big, 1477 eruption was a VEI 3-4, compared to a 5 almost 6 from Bardarbunga, along with 1 km3 of lava from the latter.

            Oraefajokull though is a monster, it is like Pinatubo in that pretty much all of its eruptions are on the larger size but are very violent and powerful. Actually it is the volcabo I would think Tallis finds most interesting in Iceland, given it is mostly rhyolitic and actually does do VEI 5 plinian eruptions, most Icelandic VEI 5s are really 3-4s that last for months, but Oraefajokull is the real deal.

    • Interesting Article about Phreatic and hydrothermal eruptions at Campi Flegrei: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020TC006227
      It shows in my opinion that the danger for sudden phreatic or hydrothermal explosions/eruptions is the largest realistic volcanic threat. “Phreatic eruptions are generated at very shallow volcanic levels and consist of short-lived and impulsive explosions”. They don’t need a large magmatic caldera eruption.
      They reveal that the “Pisciarelli fumarole field” on the northeastern part of Campi Flegrei has since 15 years shown most volcanic unrest. During 2000-2020 earthquake activity moved there. Fumaroles had an escalation of temperature. CO2 flux has increased. Mud volcanism has increased.
      “These phenomena and their ongoing variations are the most significant phenomena recorded in the caldera since the current unrest started in 2005. As discussed before, this sector of the caldera is also affected by the largest number of shallow high-frequency volcano-tectonic earthquakes (0.5–2.5 km b.s.l.) and seismic swarms recorded in recent years at the Campi Flegrei caldera (La Rocca & Galluzzo, 2019).”

    • I wanted to cite this:
      “Friday, September 24, at 7:12 p.m., a swarm of small, shallow earthquakes, accompanied by continuous volcanic tremor beneath Kīlauea’s summit caldera, triggered HVO’s monitoring alarms. Less than 10 minutes later, observers saw a red glow from the caldera floor just west of Halema‘uma‘u Crater. By 7:30 p.m., they could also hear the roar of lava fountains. Kīlauea’s summit was erupting for the second time in six weeks!
      The initial fissures broke out between Halema‘uma‘u and Kīlauea’s southwestern caldera wall, erupting lava fountains as high as 50 m (165 ft). Lava flows spread south and east, spilling into Halema‘uma‘u in a dramatic cascade that soon covered the crater floor.
      Minutes later, a fissure opened on the southwest caldera rim, erupting lava fountains that soon moved into Kīlauea’s southwest rift zone (SWRZ)”

  27. On the USGS live stream there was a partial collapse of the cone at 2:49.

    Mac

  28. Note that Pahala has gone dead quiet (“relatively” speaking) since the start of Kīlauea’s eruption…as evidenced by just a single M2.9 within the last week, with 27 shocks >M2.5 ( which is typical for Pahala) in the previous 3 week period.
    IMHO, this strongly suggests there’s a well confined, direct hydraulic linkage present between Pahala and Kilauea’s central magma source.
    Based on a report we discussed here a few months back that detailed how Pahala’a seismic zone was riddled with sills, I wonder if it’s a sill that has surfaced under the floor of Kilauea? This might explain the rather unusual location of some of the vents along the crater wall, the hotter temperatures and higher effusion rates as compared to the smaller dikes/conduit’s that have periodically broken through per the last several eruptions?

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