Kilauea eruption – lavabergs, fountains and drainbacks | VolcanoCafe

Kilauea eruption – lavabergs, fountains and drainbacks
Kilauea is back erupting since December 20! The eruption style is typical of Kilauea, yet it’s been decades since it last showed it and many aspects have not been explained properly. The most important unanswered question being the difference between a rootless lava lake (this eruption) and a “true” lava lake.
The eruption came as a surprise, the Hawaiian Volcano Observatory (HVO) was apparently planning to raise the alert level but Kilauea was faster than that. HVO had noticed the higher state of unrest the volcano was undergoing. However as it usually happens with volcanoes you can tell its preparing something but don’t know how, when, or even where the volcano is going to erupt. Since I was watching all the signals closely I can give a summary of the situation before the eruption took place.
Prelude to eruption
If you enter the deformation data page of HVO the first thing that shows up is the UWE tiltmeter. UWE stands for Uwekahuna Bluff which was the former location of HVO (before the 2018 caldera collapse that damaged the building). For decades the Uwekahuna tiltmeter has been used to record the ups and downs of pressure at Kilauea, it measures changes in slope away from Halema’uma’u Crater. Two kilometres below sea level under Halema’uma’u are located the shallowest magma chambers of Kilauea its pressure changes is what the tiltmeter shows.
Around September this year an unusually fast inflation was registered by GPS stations located south of the summit caldera, the inflation was accelerating and also changing its centre. At this time the Uwekahuna tiltmeter was not picking any inflation and the levels of earthquakes in the UERZ (Upper East Rift Zone) were very low, they fell down since the start of October, around the time when Pu’u’o’o stopped inflating too. All of these signals show that little magma was reaching the shallow storage of Kilauea but was entering at increasing speeds into the deep storage south of the summit area.
Slight unremarkable inflation resumed into the shallow chambers of Kilauea in mid-November. On November 30 an intrusion took place under the summit that had a similar seismic signal to later intrusions of December, at the time I thought it may have been a sill, but this remains unclear. The intrusion reduced the pressure of Kilauea by a very small amount and the volcano was re-inflated in a few hours.
November 30 intrusion, The first swarm visible is composed of long-period earthquakes. It is followed by two intrusion sequences, each one 15-20 minutes long. Fracturing earthquakes merge into tremor. From HVO/USGS
The surge of magma supply affecting the deeper portion of Kilauea’s storage since September might have well reached the shallow magma chambers on the morning of December 2. The tiltmeter at Uwekahuna recorded rapid inflation while a swarm of earthquakes lit up the East Rift down to Pu’u’o’o. These swarms have been called inflationary swarms by some seismologists, they often happen when the volcano inflates rapidly. A molten conduit connects the summit chambers of Kilauea to chambers within the East Rift Zone, if pressure is high and increases further the conduit pushes against its roof and fractures it producing a linear swarm of tiny earthquakes that is most pronounced along the Upper East Rift. Many eruptions, including 2018, have had precursory swarms along the East Rift Conduit, regardless of where they erupt from (East Rift, Southwest Rift or Summit). A short conduit running south of the Summit into the Southwest Rift also shows sometimes.
Earthquakes throughout the past month at Kilauea explained. Modified from the Hawaiian Volcano Observatory.
On the evening of December 2 the summit snapped to produce a dike. HVO has modelled it as an inclined dike intrusion below the south rim of the caldera, dipping 60-40º north-westward. The tilted intrusion caused the caldera to lift like a trapdoor which produced positive tilting in the Uwekahuna tiltmeter, and shows as an impressive upward jump in the graphs. Like any sill or dike intrusion would do it reduced the magma pressure within the volcano, the volume intruded was very small, 0.4–0.7 million cubic meters, and probably recovered fast.
December 2 dike intrusion at Kilauea (the green rectangle). From Hawaiian Volcano Observatory.
Rapid inflation in the shallow and deep magma storage of Kilauea continued until the eruption. Another swarm of small earthquakes extended along the UERZ on December 17, however Pu’u’o’o did not show any inflation which could be due to magma flow stopping somewhere uprift from it.
At around 20:30 HST on December 20 a new dike intrusion started at the summit, an hour later it breached the surface and the eruption had started. This dike was also inclined, and while HVO hasn’t spoken about it, it is apparent from the short lived uplift signal picked by stations on the south caldera rim that the intrusion dipped southeast, the opposite of the December 2 dike. A large deflation kicked in afterwards due to the eruption.
Intrusion and eruption sequence of December 20. Modified from Hawaiian Volcano Observatory to indicate the timing of events.
Eruption
I was personally surprised by how there was practically no explosive interaction with the water inside the caldera. Kilauea has produced many prehistoric explosive eruptions, some of them very dangerous with pyroclastic surges or lava bombs and blocks bombarding the summit area. A couple of them are probably dry and wet caldera collapses, others may result from open conduits interacting with shallow groundwater. I also suspected some of them had been the result of dikes cutting through shallow groundwater or water lakes, particularly given that this happens at other basaltic volcanoes. This time however the dike must have cut through groundwater near the surface yet it erupted in an effusive style.
The most remarkable feature of the eruption is the formation of a huge “lava lake”. But should we really call it a lava lake? It is actually completely different from those sitting within Erta Ale, Masaya, Nyiragongo or the 2008-2018 Overlook lake at Kilauea, the ones typically called lava lakes.
The lava lake has kept rising to more than 177 meters. By Joe Bard from the USGS.
What sets them apart is the conduit, the Overlook lava lake was a wide cylinder, around 200 meters in diameter and going down to the nearest magma chamber, deep-rooted. The molten cylinder allows magma to freely circulate up and down which keeps it hot and gas filled, the gas forms small bubbles suspended in the magma, if a rockfall pours into the lake then an amount of gas is suddenly released and explodes.
Overlook lava lake draining down its cylinder conduit in 2018. From USGS.
On the other hand, the lava lake currently active at the summit is rootless, it has formed from lava collecting within the funnel-shaped Halema’uma’u crater. Had the dike erupted in the slopes of the volcano the lava would have simply spilled all over the place, due to the number pit craters at the summit and east rift zones of Kilauea many rootless lakes have been recorded historically at Kilauea, the last one in 1979 as far as I remember.
Since a rootless lake is fed from a dike, it erupts from a narrow crack, unlike the Overlook case, the crack only allows magma to move either up (a fountain) or down (drainback), if you have several cracks/vents active then you can have some of them acting as fountains and others draining the lake. A rootless lake depends on the amount of magma coming up to keep it molten, it doesn’t have the smooth circulation of a broad cylinder of magma, so they are short-lived. If magma input stops or slows too much the lake’s surface rapidly solidifies, this insulates the interior which remains molten, some smaller molten openings can remain open for a long time.
More differences are that rootless lava lakes make lava fountains, whereas deep-rooted lava lakes do not. The way the level changes is also different, a deep-rooted lake is connected to the magma chamber pressure (it reflects magmastatic pressure), it rises and falls with the pressure changes in the volcano. The level of a rootless lake instead depends on the fountain and drainback processes taking place within the feeder cracks so it can change independently of the volcano’s pressure, it should still reflect somewhat where the magmastatic pressure of Kilauea stands though.
Some of you may be struggling with the idea of drainback, after all it’s not every day that you see a volcano reabsorb its own eruption. Note that lava in the lake is colder, degassed and therefore denser, lava that erupts from the fountains is hot, gas-rich and lighter. This contrast in density is what creates an struggle between the rising fresh magma and the lake lava flowing down. If there was just one vent it would alternate between a lava fountain and drainback like it happened during the 1959 Kilauea Iki eruption. However there are multiple vents in the current eruption, when lava drowned the north vent on December 26 it simply switched to the west vents and kept erupting from them.
There has only been minimal drainback in December 25, when the lake seems to have fallen 2 meters, I find it unclear which of the vents was responsible. This is really a very small amount, in the past entire lakes have disappeared down the sinkhole, this shows there is magmastatic pressure supporting the current lake.
Lava drains into Kilauea Iki in 1959. The wall of rock and pumice in more than 100 meters tall to show the scale. From USGS.
The lavaberg
There is an enormous floating island of solid lava inside the lava lake, part of the island is under the lava so it’s like a lavaberg, there are also a few smaller floating pieces. The lavaberg is 260 x 115 meters across, it seems to have formed early in the eruption from the lava which first ran into the water lake and solidified. But how does rock float in lava? The explanation could be that the material forming the island is spongy, vesicular, like pumice floats in water the lavaberg could be porous enough to be buoyant on the lava.
It also rises and falls, in the past few days it seems to have been rising above the lake and a lot of it that was previously concealed by the lava is now emerged.
The great lavaberg. Note steam or gas is coming out from it, any water still there? USGS photo by N. Deligne.
Future of the eruption
At 2:40 AM of December 26 the eruption came to a turning point. The west vents reactivated and erupted together with the north vent for 20 minutes, then the north vent became quiet. The west vents have kept erupting while the lava lake rises very slowly and the volcano inflates, in other words the eruption reached equilibrium, there is no reason for it to stop now, has it become sustained? and if so, for how long?
The west vents erupting in parallel with the volcano inflating suggests Kilauea will keep erupting until something changes in the volcano. I believe the situation is similar to summit activity in the 1823-40 years which was interrupted only by rift eruptions and small caldera collapses in 1832 and 1840. As such we might expect the eruption to continue until a dike intrusion or eruption takes place in the rift that drains the summit and destroys the active conduits. There could of course always be some unforeseen factor that ends the eruption, but I don’t see any reason.
In the meantime the surface of the lava lake is likely to solidify. This is already happening on one side of the lake where a solid ledge has formed. An elevated levee of solidified lava encloses the lake on this side and frequent flows overtop it and spill onto the ledge. While so far most of the surface seems to remain molten, the eruption rates have lowered significantly since the first days, and all it takes is one deflation-inflation event (cyclic overturnings of Kilauea’s magma system that generate pressure changes) to temporarily pause the eruption and a portion of the lake to go solid. So most likely over the next several days/weeks the lava lake will shrink in area.
Rootless lava lake of Kilauea on December 26, note how a solid ledge has formed around it. Lavaberg swimming around, while the west vents dominate now. USGS thermal image by M. Patrick.
The interior does remain molten, for as long as decades if it doesn’t drain away! So it can become like near-surface magma chamber. As of 2020 there are still new publications coming up based on data collected from the Kilauea Iki rootless lava lake of 1959. Kilauea Iki was drilled repeatedly to study how magmatic differentiation took place in magma chambers and the interaction between magma and hydrothermal systems, it turned out to be the perfect natural experiment!
However the Kilauea Iki eruption was different in many ways, this time the eruption is most likely to become sustained. A small molten lake will probably remain next to the west vents even if the rest crusts over, additionally the drowned vents (there are at least 3 submerged openings) might inject gas-rich magma from below, which, if it comes to be the case, would be interesting. It is likely that the crater will keep filling slowly until the next rift event happens. Filling may take place both from lava flows as well as piston uplift of the crust.
Back in the 1823-1840 people seldom visited the summit of Kilauea however when they did they would describe multiple cones and lava lakes erupting through the caldera floor, often they were witnesses to how the surface suddenly cracked and a new vent formed. Rootless lava lakes were presumably molten but crusted over at those times and as magma was injected into the melt below it created new openings. The vents often got covered with sticky lava and released gas in episodic bursts, strombolian eruptions. It’s hard to tell, but we might see a similar activity show up in the future.
Kilauea Caldera in 1838 by Captains Chase and Parker. 8 cones were erupting lava or ash. 6 small lava lakes were active (C). The largest lake had a floating island (I) that heaved up and down. Streams of sulphur cascade down the caldera walls at (B). Kilauea was essentially erupting during the entire 19th century, but the activity in 1823-32 and 1837-40 was simply spectacular. Large rootless lakes formed in 1823 and 1830, another rootless lake may have formed before 1837 to explain the high activity in 1838, but if this is true no one witnessed its formation.
The East Rift
Most of Kilauea’s volcanic edifice is formed by lava flows and intrusions in the East Rift Zone. This rift is 130 km long, 55 km of which is subaerial, the rest goes on underwater. Since 2018 much of the subaerial portion has been actively spreading and inflating (up to half a meter of uplift in areas of the Middle ERZ). Spreading takes place both from slow expansion of a crystal mush at 3-8 km deep and intrusion of dikes above 3 km deep (none since 2018), fissure eruptions and satellite shields cover the flanks in lava. The internal growth is accommodated by seaward movement of the southern side of Hawaii Island over a system of reverse faults that Kilauea shares with Mauna Loa, capable of generating magnitude 8 earthquakes (great Kau earthquake of 1868).
Almost every dike intrusion from 1955 to 1975 in Kilauea shown as translucent red bars. The white circles are starting points of the intrusions, note how they delineate the conduit of the East Rift Zone. Created in Google Earth.
Activity in the ERZ has been highly variable and cyclic. The 18th century saw high activity, then following the enormous summit collapse of 1790 activity dropped to almost none throughout the 19th century, and finally the 20th century was a gradual return to ERZ activity. The events of 2018 have if anything prepared the scenario for more rift activity, the M7 earthquake accelerated spreading rates (the flank keeps moving faster than during Pu’u’o’o) while the eruption improved magma transport to Middle ERZ. So if we are looking into the future of Kilauea we have to consider what the East Rift will do.
It seems that most likely the summit will go on erupting until the next time the East Rift erupts or produces a non-eruptive dike intrusion, it could also be in the Southwest Rift but this is less likely because it’s much less active and not spreading much right now anyway. However I still find uncertain where or when the rift will snap next, it could take a few years but I wouldn’t be surprised if it happens in 2021 either, a dike intrusion in the Upper ERZ is unlikely to breach the surface while an intrusion in the Lower ERZ is likely to produce a voluminous eruption.
For the time being looks like we are going to have a nice show from the summit of Kilauea, however the future points back to the East Rift, to eruptions that might not be so pleasant.
I really like how you’ve made the mechanisms understandable – good article.
The eastern dikes look a long way off – does east of the caldera slope downwards gradually? Just thinking that it’s a fair bit of energy to expend to push magma out so far away from the source.
White Island just had a minor burp & Soufriere is growing a dome – a couple of months back we were complaining about the lack of excitement!
They were captains of 2 ships, but I don’t know any other details. I have read their observations in the American Journal of Science.
Fun fact: They walked on a lava lake! The area termed A in their picture they didn’t know was a lava lake. Probably suspected something because they could see lava through cracks. When the got outside the caldera they saw the surface where they had walked on, fall in, together with spatter cones, and turn into molten lava (a thickly crusted overturning lava lake).
Very nice article, Héctor, many thanks, it answers some of the questions I had.
Some left though…. 😁
About the shape of Helema’uma’u’s (former?) conduit. It is like a cylinder, all the way down? How does such cylinder shape grow? Was it starting as ‘just’ a fissure/crack and was the constant movement of uprising magma shaping the conduit?
The cilinder has been filled by rubble in 2018. I would have expected that this rubble lid would not resist the newly pressurized magma chamber. Is there a chance the old conduit will be reactivated in some way?
Sure, part of it will be compact, I think so too. But it has not merged with the solid rock surrounding, so because it hasn’t merged that is perhaps the weak spot.
Maybe a fissure or crack excisting (more open conduit) is an easier for presurized magma to escape the chamber..
Probaly grew since 2008 s start by eating away the bedrock and collapses into the lava lake conduit, the 2008 – 2018 lavas where also very hot
Overlook lava lake started with gas blasts blasting a hole, then the magma column just carved out and existence for itself. The force of pressure perhaps.
The overlook lake grew by collapses that widened the lava lake, when it drained in 2018 it did not get much narrower deeper down. Yes very much a pipe into the magma chamber.
Exactly how the overlook lava lake formed, I dont know.. Hector will give a better description with his commentary soon
I don’t really know how the initial conduit formed in 2008, only that it was not a dike, a dike forces its way to the surface by quickly opening fractures. Instead the Overlook Crater lava lake had been warning with gas emissions and tremors for months, eventually an explosion made an opening and there it was, the lava that being. Over the next ~10 years it grew in width gradually.
Did it simply melt through? If so, why through a single spot? What are the conditions required? Those would be my unanswered questions…
At some point this conduit will probably come back, there was a conduit of similar size and location at Halema’uma’u before 1924, the collapse destroyed it. But how long will it take I have no idea.
The old lava lake formed by rising magma melting through the roof. It came from the lava flowing through to Pu’u’O’o. As that connection to Pu’u’O’o narrowed over time, higher pressure was need to push the lava through and the lava rose to the level needed to create that pressure. It acted as a pressure valve on the lower dike. Because the lava kept flowing through, the lake did not solidify. The current situation is not identical. I think the current lava comes from a different conduit and it is a stand-alone dike, not a through-flow.
Lurker here, I was looking at the google earth images of Kīlauea and the crater, it appears that the fissure this eruption came through could have already been forming in late 2019 and early 2020. There is an apparent crack in the wall of the crater that looks to be about where the eruption started. The image was taken January 2, 2020. I’d love to hear what the more knowledgeable volcano aficionados think of that feature.
If you mean the line that crosses the lowest ledge, that is a fissure from 1974, so predates the collapse. The picture from Jan 3 2020 is actually not very well aligned, the picture was not a direct overhead.
Hector what about the possibility of the first eruption outside the caldera being on the southwest rift? I gried writing my own article on the matter but I dont think im a very good writer. Anyway after 1790 the first flank eruptions were on the southwest rift. The east rift is likely to become more active as you say but the southwest rift eruptions seem to actually come from lava that is within the caldera, and we know that from Mauna Iki. Something like that will happen next year I think.
Filling the caldera to about the 800 meter elevation was not trivial after 1790, probably taking at least a decade even with elevated supply. But when the current eruption was going at full strength before Christmas the Hawaii Tracker team presented a case for the lake to reach 800 meters elevation on the 4th January through extrapolation of lava lake rise rates. That obviously wont happen now, but 60 m3/s for 15 days is just under 80 million m3, a number achievable with the base supply in about 8 months, or some time about August next year. By that point the bottom of the lava lake will be almost 300 meters deep.
Because of the density of lava, the pressure at the bottom would be nearly as high as being 1 km deep under the ocean, and faults from the southwest rift directly enter the caldera, it shouldnt take much pressure to inject into such a fractured environment. There have also been a number of recent intrusions into the rift, many before Pu’u O’o but there was one in 2015 and possibly in 2006, and just this week a flurry of quakes near the 1982 vents right above the start of the southwest rift conduit, actually the only quakes at Kilaueas summit since the eruption started have been in this area…
I suppose it’s possible for the lake to push into fractures of the southwest rift and drain through it. However the fissures of the Kealaalea and Keaiwa flows are not in line with the central part of the caldera, seem more in line with the part south of the caldera, and the same is true for the Kamakaia Hills eruptions which were probably fed from the tip of the southwest rift conduit. 1832 would be the only occasion that a rootless lake may have drained directly into the Kilauea Iki-southwest rift line, so it’s not something so common but does remain a possibility
1868 was also like that I think, as well as an east rift intrusion. It would seem that all of these southwest rift eruptions were actually from what USGS has called the ‘seismic southwest rift’ as opposed to the ‘volcanic southwest rift’ that Mauna Iki is on. It looks like that the current lack of eruptions there is just part of a phase, sort of like how the east rift was largely inactive from 1790 to 1955. It looks like the last round was from 1800 to 1823, in the Kamakaia hills it looks like there have been several rounds of eruptions, there was one about 400 years ago, possibly Pu’u Koae and Cone Crater were also formed in this phase. At this rate it would also not be surprising to begin a new phase.
If Puu Oo never existed then its likley that the summit overlook lava lake woud constantly overflow for 10 years, forming something similar ( but much bigger ) like Kupaianaha at Kilaueas summit. Puu Oo constantly robbed the summit and stopped frequent lava lake overflows. Kilauea had shields before at the summit 🙂
But like Kupaianaha had Puu Oo, Puu Oo had Overlook to remove most of the gas, leaving hot degassed magma, perfect for long tube-fed pahoehoe. A few more years of high fountain/Aa episodes and who knows if any of those flows would have made it to the coast. One could make the case that it was Overlook that did the robbing…
Overlook crater was caused by increased supply between 2003 and 2008, it probably would have happened anyway. The average supply rate to Pu’u O’o in its high fountain days also was the same as the base rate, only all of that months worth of lava erupted in a day and on repeat instead of slow continuous flow. Kupaianaha was just when there was too much pressure to fountain as opposed to breaking the rift again. Probably Kupaianaha, which means strange, would also not have been named that, or at all, had we known of the future, it is almost buried in 2007 lava regardless, I would just call the 1983-2018 structure Pu’u O’o now.
Two events showing up in seismometer recordings around Kilauea and the ERZ. Both are connected with small negative changes in the tilt measurements. Couldn’t find matching eathquakes in the monitoring system though.
Looks like swarms of long-period earthquakes. Interesting that they are linked to deformation. DI events and long-period earthquakes often take place together, so perhaps the small drops in pressure are small DI-events
HVO reports the lake to be 186 meter deep and 33 hectares in area (I think this is considerably larger than the 2017 lava lake!). It seems to get deeper by 2-3 meters per day, or 10m3/sec. Looking at the videos, that flow rate seems to agree with the speed and size of the flow from the vent. (Which means not much drain-down is going on at the moment.) The GPS and tilt show no change, apart from small DI-like events. The seismographs seen very noisy at the moment. That may include wind noise?
This lake is way bigger than the Overlook lava, and apparently also bigger than the Kilauea Iki lava lake too. USGS has also said they measured the supply rate to be 10 m3/s. At this rate it will flow onto the downdropped block in the middle of the caldera by the end of this year, if this supply is sustained and there is no deformation then that would also mean the base supply rate has doubled from Pu’u O’o at least for the near future. I would expect something breaks before it actually gets that high though, so some point this year, maybe when it goes above the vent.
The lava lake is crusting up forming crust thats thick enough to sink into the lakes interior. Crustal overturns started on december 29. The vent channels have now tubed over too. These crust overturns been seen alot in the Kupaianaha lava pond. The 2020 lava lake remains rootless
Still a rootless lava lake ..
No open large conduit shaft under it. The lava lake will soon approach 200 meters deep! The lake have stopped draining into previous small dykes. Advice is to NOT walk over it : )
Was just reading up about the 1902 eruption. Perhaps eerily, that coincided with an eruption at Mt Pelee which is also starting to rumble…
From the ‘Christmas Pudding’ photo, it seems to be in something of a dome-building phase. The 79 eruption seems to have come after a dome build that lasted several years?
I must admit to being something of a part-timer, but the last time I remember watching a volcano building a dome in that manner was Chaiten (2009 I think?) – which then produced a rather big explosion!
Sustained supply rate of 10 m3/s, over twice the rate of Pu’u O’o. There has been no net inflation or deflation recently, just some little dips that recover and are maybe related to eruption changes. If this rate is actually real then the entire 2018 caldera will fill within 3 years…
This eruption looks to be progressing, magma now oozing out the sides of the dome and a small amount of ash. Found a video on ewetewb of someone far too close to the volcano filming it from this morning and it looks like it’s coming out of cracks in the sides of the dome.
This was the open conduited Kilauea Halemaumau lava lake two years ago. The lava lake is almost 300 meters wide and somewhat elongated.The summit lava lake was basically a 300 meters wide pipe down to the summit magma chamber.The lava lake is the top of the magma chamber system, like the water of the top of a bottle. I seen it many times from Jaggar overlook as a child.
The lava wells up at the south end of the lake and then moves across the surface where it sank down at the northern halemaumau caldera wall.
Its a circulation convection that kept going for 11 years. This connection in the conduit is why lava lakes can live so very long and don’t stop. Lava Lakes can be very very very long lived and earlier Kilauea lakes have lasted more than 10 times longer. The lakes hot surface cools as it contacts the air forming that grey lava lake skin.
The skin is only a few milometers thick and is broken into numerous crustal plates that rides and move across the lakes molten interior. That’s called “lava lake crust tectonics” Lava Lakes are best seen at night… where the full glow and colour and glowing cracks in the crust. In daylight lava lakes can appear very grey and reflective like molten metal due to the silica glass in the lava lakes skin. This photo was taken in overcast daylight in full daylight its very reflective. The bubbling is gases that escapes at the down welling site.
Two years ago this was the very largest lava lake on the entire planet.
A surge in magma supply caused it to overflow spring 2018 and 2015.
Had the Kilaueas flank slide and intrusion not happened the lava lake would still be here today.
1-2 km depth underneath Kilauea Iki, interesting. Tilt shows nothing, but since the tilt leveled off there has been more seismic activity at the summit, first in the southwest corner, then a scattered swarm 2 days ago, and now a 3rd swarm at Kilauea Iki. This eruption is far from over, it looks like there could be a lot more to this than we all thought…
It will be interesting to see what happens when the active vent is submerged now, theres no more to go. I would expect if the current eruption shut down it would be no more than a few weeks before eruptions resumed. Last time the supply was this high it lasted at least a few years, so far this eruption has been going for under 2 weeks.
Its interesting that the cone is a more strombolian cone than a spatter cone now. It shows the spattering is actually a lot bigger than it looks, probably being ejected 50+ meters above the vent so it cant weld to itself when it lands. The cone looks small but its probably 50 meters tall above the lake at this point, HVO measures the lake relative to the elevation of the original vent, not the new cone, and even that is somewhere at 30 meters still.
The strombolian eruptions show this is also very gas rich magma if it is able to behave that way in such a fluid magma as this.
Assuming that the vent is 3-4 meter wide (as HVO found earlier), the spatter cone would be some 10 meter tall. There is nothing to give a scale (do you think we could get a HVO volcanologist to stand on the top for that?). The lava lake is currently about 80 meters below the lowest part of the rim. Judging from the elevation contours on HVO maps, the vent is about 60 meters below the rim (20 meters above the lake) but it is hard to read the contours accurately. That would put the tip of the cone 50 meters below the lower edge of the down-dropped block. At 1 meter rise per day, the vent may flood towards the end of the month.
4 meters wide was referring to the spot where the lava flowed into the lake at the bottom of the cone, not the actual vents at the top. A few days ago they said the drop from the vent was 40 meters, it is less now, maybe about 30 meters, but the cone has also grown a lot since, so it is probably at least around 40 meters tall on the lake side.
Wait and see. HVO called it a ‘small cone’ today. That does not suggest 40 meters tall to me. Part of the vent is said to be already submerged. Interestingly, the lake is now perched. The sides are solidifying.
They could be measuring its height on the side next to the crater wall, that is probably only 10 meters. Its sort of arbitrary really, its not very big next to most east rift cones, or next to Pu’u Puai, but it is still pretty substantial next to the lake which is over 500 meters wide on its short axis.
I used to watch that episode religiously when I was about 10, then I discovered that Kilauea was erupting all the time which got me hooked 🙂
I hope this eruption lasts long enough to replace Pu’u O’o, overflow the caldera. HVO says its very unlikely but that is only the case if the east rift takes over again, the caldera will last maybe 10 years tops if that doesnt happen. We will have to wait and see.
Eruptive vigour have increased at halemaumau since January 2 .. 2021
A dome fountain blaster pours out superfluid lava at tremedous rates. Just spewing into the filling Kilauea lava lake. Its acossiated with a bit faster deflation now of the system.
I dont think the deflation has increased, in fact the tilt is only showing any vertical change because the scale is so small, all of the change since the 26th has been within 2 microradians. On the main graph the tilt is basically flat since the deflation at the beginning of the eruption ended.
I dont know why this dome fountain has appeared, it might be higher supply but that would probably cause inflation, maybe the vent redirected. The supply was already very high to begin with, the eruption has stabilised at 10 m3/s which is twice the deep supply of Pu’u O’o era, and similar to the rates in the early 19th century when similar filling was going on. I would guess it will keep rising, but even if it doesnt I doubt the eruption will actually end unless a flank eruption happens, it could at this rate be flowing into the down-dropped block this year which is easily visible from the legal vantages 🙂
1790-1823 saw a lot of SWRZ activity, and 1823-1840 saw a lot of rapid filling and collapse events at very hig hrates of supply, so probably this sort of stuff will happen now only the 2018 caldera is a lot smaller than the 1790 caldera so the timescales are shorter.
Well if the supply is really sustained at 10 m3/s, that is just over 0.3 km3 a year. This cant be sustained forever because it is higher even than the hotspot rate, this is decompression melting after a collapse. It will, however, probably last for at least 5 years possibly several decades, easily long enough to fill the caldera, which in total is about 1 km3 before it can overflow to the southwest.
I think if this eruption transitions to a shield then the eruption could stay at the summit and overflow the caldera, but if it rises as a single massive lake then it is just a matter of time before it drains down into a rift eruption. If the lake can reach 300 meters deep then the pressure at the bottom would be the same as being 1 km underwater, and the top will be at about 830 meters altitude, in the early 19th century rift eruptions started to happen in the Kau desert by this point.
Keep in mind though that the collapse of 1790 was seemingly bigger and had a destructive effect on Kilauea’s plumbing that 2018 did not. 4 pit craters formed along the East Rift Zone, from the collapse of the conduit’s magma chambers, which shows the summit storage must have been destroyed to the depth of the East Rift Conduit and thus the summit would have no way of sending magma into the rift zone, which feeds eruptions and intrusions from its own storage.
The concentration of activity at the summit and Southwest Rift was more likely a consequence of the East Rift losing its means for magma supply than anything else. A return to Mauna Loa dominance was soon underway and the East Rift took a whole century to become just feebly active and another one to be back to high levels of activity. So this is not the same situation as a post-1790 activity, I would rather compare it to the late 18th century although there is little information to know what was exactly happening back then.
There is a deep conduit in the southwest rift though, not very long but it seems at least to go about a third of its length. Historical eruptions there have been slow effusive except for in the 1970s, but Pu’u Koae was a high fountaining eruption like those which happen on the east rift, I dont know how old it is but it is probably from the 18th century activity.
The Mauna Iki line needs a high summit but the conduit south of the caldera is probably much the same as the east rift one, though less active it is unlikely to be directly caused by summit activity. It is possibly only the elevation that prevents eruptions there during east rift activity, the open east rift conduit goes to a lower elevation.
I found a webcam image with the cone and the island both in it. That gives me a scale, as I know that the lava island is perched 6 meters above the lake. The cone has an angular height 2.5 times that of the island. The camera is about 700 meters from the cone, and the lava island is about 150 meters further. Correcting for the difference in distance, this gives me a height of the cone of 12 meter.
This is in projection from the rim of the crater. The lava island is seen on a slightly different angle. Correcting for this increases the height of the cone by 10%, so 13 meters. To be clear, this is the height from the tip to the surface immediately below it. There are some uncertainties on this estimate: my distance estimates may be wrong, the tip may be wrongly identified (there was a lot of smoke), but I would hope I am not off by more than 50%.
The 6 meters is for the ledge on the island, not the whole thing. That ledge formed when it was near the north vent and since then the island has risen up a bit. So 6 meters is literally just that tiny little drop off the side, the actual summit of the island is a lot higher. Shows the scale well, this thing is massive.
It woud be the Shield for me because it means lava always acessible when I haves time to visit Iceland.
Icelandic state woud quickly open up souch an eruption for spectators and tourist hike groups woud go daily. As example Puu Oo became a massive tourist phenomena. Something bigger and more long lived woud be too.
Flood basalt wont happen, theres only 2 places I can find capable to do one now and neither are near that scale.
70x Pu’u O’o is nearly 300 km3, biggest actual eruption is 1/10 that big. Still lava for a century but you are more likely to find a shield eruption long enough to reach that volume in Hawaii not Iceland.
I just want something happen.. It has foold us to many times. First katla for a couple of year. Then øafjall then grimsey and now grimsvotn is teasing. And grimsnes and the fracture zone. But nothing has happened…… Maybe they all are going to erupt all at the same time… We need something. I have been following the ice island for 5 years now. It has been building up…. And I think this is going to be good but no, it has calm down again. I am thinking there is no more volcanos in iceland. 🤔
I think a lot of the problem is that we are all expecting a big eruption next, when most eruptions in Iceland are small, and under the glacier at Vatnajokull. Holuhraun was a very big eruption, not an average eruption. There have probably been a few eruptions that have not escaped the glacier, 2 at Katla in 2011 and 2017, one near Bardarbunga (Hamarinn) in 2011, these would probably have been small eruptions without the ice but we wont know. The next eruption could be like this but not under ice.
I did a while ago research the output of Icelandic volcanoes, Grimsvotn is about 1 km3 a century maybe a bit more, so 2011 was 1/5 of its supply this century in 1 go. Bardarbunga is a bit better, just over 2 km3 a century, but of course Holuhraun was from here so that is basically 3/4 of this century already, it wont be doign much for a long time.
In case you are wondering, Kilauea is on average more like 12-15 km3 a century, about half of that erupting. Mauna Loa seems to be at least 5 km3 a century if it also erupts half of its supply.
Back to Iceland, Hekla is more intriguing to me. It is also in the 1-2 km3 a century range and has not erupted since the 3rd month of this century and though very intense it was not a particularly big eruption. That is the place I would be watching if you want a big effusive eruption, for a big explosive eruption you are better for Oraefajokull 🙂
Remember that 3 years average is every eruption, even small ones, not 3 years between big eruptions. We just had a big eruption, those are more like every 50 years. The last eruption of similar volume to Holuhraun was Hekla in 1947. In the last 500 years the only eruptions bigger than Holuhraun was Laki, and also Askja in the 1870s if you include that whole rifting event as a single eruption which is somewhat debatable.
It might be predictable for me to say this but chances are the next big effusive eruption will be in Hawaii again, at either volcano.
December 28 the cone was 40 meters tall over the lava lake, which on that date was 179 meters deep. Now the lake is 192 meters deep, and the cone is probably a few meters taller, so it is probably just over 30 meters tall above the lake, more or less.
HVO also have both said that the dome fountain is from a tube within the cone, and an actual vent that has diverted, it isnt clear which. Lava also has broken out of the cone above the lake too, in addition to the dome fountain, and the vents on the cone are bright incandescent in the day, it looks like the eruption is getting stronger again.
Dome fountains are amazing.. requires the perfect rate of flow and gas pressure.
Its only the most fluid and low visocisty magmas that can do them..
Dome fountains been seen in 1910 s 1970 s 1980 s 1990 s 2000 s and 2010 s and 2018 in Hawaii before. Dome fountains was also brifely seen at Holhuraun eruption
The Kilauea eruption continues at great speeds going constant and erupting at supply rates..
The magma supply for any hawaiian volcano thats dominant over the Hotspot is asthonishing.
If the perspective is the same, and the fountain is 5 meters tall, then the summit of the cone is 40 meters above the lake (measured at 8 times the fountain size). (The height of the cone above the vent is obviously much less. I previously estimated that at 13 meters but it may have grown a bit since). It appears like the vent is building a lava tube reaching into the lake. I hadn’t realized it would do that.
Hey Albert, let’s keep what happened with my proposition a secret. It would ruin interblogging prestige. 🙁
Anyways, do you have an idea on what’s keeping grimsvotn from erupting? For a volcano that’s close to erupting it sure looks boring at a glance.