It is a narrow but passable road, or at least it used to be. It begins at the Saddle Road which crosses Hawai’i between Mauna Kea and Mauna Loa. Both mountains have observatories at or near the summit, but while Mauna Kea is busy day and night, the Mauna Loa observatory is a much quieter affair. Observatory Road runs to the Mauna Loa Observatory. It begins on top of a lava flow and continues like that for 17 miles, while climbing from 2 km to 3.4 km altitude while the colourful lava of the start turns grey and dark. At first it runs up the slope towards the northeast ridge of Mauna Loa, before turning sharply right and continuing parallel to the ridge, ever climbing. The vviews are one-sided but spectacular. The road consists of only a single lane – in the unlucky case of meeting another vehicle, you may need to move over onto to lava. And if there is fog, there is only a white line to guide you – best to turn around. Continue, and you’ll find the end of the road at the Observatory, 5 kilometers from and 800 meters below the summit.
The road is now cut in three places, showing one of the disadvantages of routing it parallel to the eruption-prone ridge. The rifts follow the same direction, and as their lava finds the fastest way downhill, it crosses the road at right angles, for each eruption point in turn. The lava took out not only the access, but also the power to the observatory. There are actually three different observatories which share the site, but all have now paused. Best known is the atmospheric observatory where the famous Keeling curve of CO2 is measured. There is also a solar observatory here, and a radio telescope called the Yuan-Tseh Lee Array which is operated by Taiwan.
The eruption came in the night. On Sunday 27 November, 22:40 local time, the shaking started. It was already the morning of Monday 28 November in the UK. The first shake was a brief snap. Just over a minute later, a much larger shake followed and after that it became continuous. There was strong tremor for perhaps 20 minutes which became weaker. Around 23:30, lava reached the surface and the eruption began. After midnight it started to pulsate, with pulses lasting a minute and spaced 2 minutes apart. By half past midnight, the quaking calmed down. By this time, the lava was flowing freely.
The eruption started in 2004. After the 1984 eruption, Mauna Loa had shown little activity, and even slight deflation from 1990 to 2002. In 2004, an earthquake swarm , 50 km deep heralded awakening. A new magma batch had arrived and began its slow move up. It took 10 years for this to reach the upper magma chamber, some 4 km below the southwestern rim of the summit crater. In 2015 this caused a phase of rapid inflation. That stopped again There was more but slower inflation after 2018. In late September 2022, the earthquake swarm and inflation began in earnest. It very quickly became apparent that this was more like it and that an eruption was becoming possible.
The inflation had been centred underneath the southwestern side of the summit crater. This crater is called, in typical Hawai’ian fashion Mokuʻāweoweo, roughly meaning ‘burning island’. The association of a bone-dry crater on top of a 4-km tall mountain with an island sounds surprising, However, remember that the original inhabitants came acros a wide ocean where the first sign of land would be a towering cloud, caused by the sun warming the land and setting off air convection and cloud formation – and rain. They had become familiar with the smoke rising from the crater in its frequent eruptions. It is a nested crater, elongated along the main rift axis. Along this axis it is some 5 kilometers long.
As the inflation had shown, the main shallow magma is not underneath the centre of the summit but is offset to the southwest. It hides about 4 kilometers below the summit, more or less at sea level. This magma chamber is fairly small: it continuously receives new magma, but this magma does not spend long here. We know this from the lack of crystallization of the erupted lava. Perhaps this is the secret behind the frequent eruptions: a small magma chamber that quickly overflows, upward. This magma chamber had been depleted in the 1984 eruption but was now slowly growing. The earlier earthquakes swarms may mainly have come from the magma entering the chamber. But when the inflation resumed in October, the motion placed the magma closer to the centre of the crater. A dike was growing out of the magma chamber, along the line of least resistance which was angled towards the centre of the crater. This put stress on the rift zone and it began to open up. The lava baby was getting ready to arrive.
In most cases, though, events like this do not lead to an eruption. The dikes end before they reach the surface. Magma is pushed out from the chamber and is on the move, but the pressure may be insufficient to break the tough rock (basalt, of course, and unfaulted). At some point the magma pressure equals the strength of the overlying rocks and the dike stops in its tracks. This time, though, there was help. A larger earthquake cracked the rift running through the centre of the crater. Now the broken rock failed the stress test. Magma saw its chance and in less than an hour, it broke through to the surface.
There was no pre-eruptive activity at Mokuʻāweoweo: gas measurements showed a constant temperature. There is no shallow magma chamber. The opening of the dike on Sunday night created the connection. The pulsing could have been the flow from the magma chamber establishing itself through the connection.
Initially the eruption was from a short fissure within the summit crater. The crater began to fill with lava, and perhaps slightly overflowed towards the southwest. This was exactly as expected: eruptions at the summit tend to start as lava fountains from short fissures with lava flows covering the floor of the caldera. It is not always like this: there are several fans of explosive debris on and beyond the rim. The crater itself has no record of these: the entire surface is from recent lava flows, looking like a solidified black lake. Dating has shows evidence for 5 explosive events which ejected blocks over a meter in size across the rim, requiring ejection velocity of 200-300 m/s. The explosions were comparable to the explosion which started Kilauea’s activation in 2008. One explosion was much larger, and may have deposited ash over much of the southern flank. The two eastern fans are 150 and 200 years old. The western fan is about 850 years old. The large explosion is older. But this time Mauna Loa limited itself to fountaining.
Mauna Loa eruptions can quickly begin to migrate down one of the two rift zones, a behaviour that is very similar to that of Hekla, also a rifted shield with very short warnings before eruptions. This eruption mirrored this common behaviour. Within 7 hours the eruption moved to the upper northeast rift zone and the summit ceased erupting. There was a brief excursion to the southwest, probably because the short fissure extended in this direction. But the magma supply itself did not move in this direction: the flow from the centre of the crater. Instead the dike extended towards the northeast. There had been earthquakes at the northeastern end of the summit crater in the week before the eruption. These were likely related to the growing dike putting pressure on the rift. The widening of the rift had reduced the stress and allowed the dike to grow further in this direction. Think magma tube with a hole in the top at one place, underneath Mokuʻāweoweo. When the tube is blocked further down the line, the magma spurts out through the hole. But as a new opening formed further down (the fissures), the first hole lost its feed and magma flowed through the tube to the more distant and lower altitude hole.
The northeast rift was a good choice. The southwest rift zone is potentially more damaging, as lava can reach populated areas near the coast within a day. Northeastern lava flows tend to remain in areas already well covered by previous lava flows. They are not entirely without risk: in principal both coasts, including Hilo, are within reach. Since 1850, lava has reached near Hilo five times, but they always stopped before reaching the town. Half of Hawai’i is covered by lava flows from Mauna Loa: it is best not to underestimate its eruptions.
Over the next few days, four short fissures formed at different distances from the summit. The eruptions from each fissure did not last long. Again, imaging the magma tube. You need a lot of pressure to feed more than one hole simultaneously. The final fissure, fissure 4, was a step too far. Fissure 3 extinguished the other three and is now the only active one. The last active fissure is at the end of the earthquakes distribution of the past week. This was indeed the weakest link.
The radar image shows the roughness of the ground, as measured by the reflected radar signal. Blue is mostly fresh (smooth) lava. (Some of the pit craters have a blue rim on the right, due to shadowing of the radar signal.) There are flows on the southwest, a bit below the ridge. The original summit fissure possibly extended into this direction, aided by overflow from the summit crater. This was only a brief phase which ended when the northeastern rift opened. The main flows are from the northeaster rift, and are now purely from fissure 3.
A good view of the fissure come from a newly installed webcam. I don’t know exactly where this webcam is, but installing (and powering) is may have been an adventure!
The northeast rift has a series of cinder cones and the current eruption is likely to add to these. The presence of the cinder cones shows that eruptions tend to focus on a single point. The current eruption has created four separate fissures, but currently only one remains active. If the eruption continues long enough, the remaining fissure may leave such a lasting cone. In fact the webcam shows that it is already well on the way to do so.
The lava lobe has reached the saddle region where the land is almost flat. This has stopped significant expansion – for now. At the current rate, it could be weeks before the saddle road itself is reached and the eruption may not last that long. The main road seems safe. But things can change. The eruption could stop, only to resume on a lower fissure a week later. It is unpredictable. Keep an eye on the Saddle Road flow. If the pressure at the fissure decreases, the lava flow will slow down and the lava will no longer reach the end of the flow and instead there will be smaller break-outs further up stream. If that happens, it is a first sign that the eruption is running out of steam.
Mauna Loa eruptions can last anywhere from a day to a year. Volcanologists probably hope it will last long, so they get proper data with modern instruments – for the first time for Mauna Loa. The rulers of the land probably hope it will end before it destroys the Saddle Road, although a nice viewing area next to the road would be god for the economy. Astronomers and atmospheric scientists want their observatory back. Some will want them not to do so so that CO2 emission can continue without checks and balances. VC, on the other hand, just wants to get good views from a safe eruption – let it continue for as long as it is safe to do so. Cheers!
Albert, 4 December 2022
135 thoughts on “The Mauna Loa eruption of 2022”
USGS youtube live stream of the fissure.
With estimates of around 100m3 per second it should now have done 100 million cubic meters in 6 days, so fagradals eruption in a few days. althrough Mauna Loa can be much much faster than this. The 1950 eruption did most of 1950 s volume in a few hours. Who knows this coud become a large and long lasting eruption, been 38 years of magma input from depth.
Lava looks more fluid now om the live feed, the vent canal is getting wider and fountains becomes lower and a bit denser. The color on the day in the camera is very poor, but addictive to watch. The output seems steady at over 100m3 per second.
I wants to walk the channel edge, being the Krafft s for a day, photobombing the lava fountain as well as they did at Krafla 1984 and at Mauna Loa s lava channels in 1984
It was always this fluid I think, based on pictures of the early fissures. Only thing is the lava was erupted very fast and with strong fountaining, so turns into a’a as it flowed any distance away. But this happened in the other eruptions too.
If this does keep going it could well move vents again eventually. 1980 vent was a strong fountaining vent that then opened an effusive fissure a few km downrift later in the eruption. 1935 did the same thing, an effusive vent opened on the north flank after 6 days of fountaining on the rift zone.
The 1843 eruption has a cone on the rift, which was formed by high fountaining suggesting it was active quite some time at that location, but the majority of the lava erupted out of a fissure on the north flank which can only have erupted later, maybe even several weeks, although reports of this eruption only concern later activity so this is an unknown. This might be particularly applicable given that eruption was preceded by many years of inactivity, like today.
Question is if there has been a swap in dominance of the volcanoes. That might be something that we can only tell after this eruption ends and the rate of refilling for Mauna Loa can be watched for at least a year I think. But I wouldnt expect it, not with how fast Kilauea has reactivated after 2018, keeping in mind both of them began inflating together that year.
They are showing a 3.0 northeast of the observatory, but I do not see an signature on the webicorders??
Yes, that seems mistaken. The nearest seismograph is HSSD and it shows a very small excursion at that time. The reported depth puts it perhaps 1 km below the surface. The automatic system got this one wrong.
Mauna Loa has been downgraded to ‘orange’, I guess because of the low risk of any explosive action
Il Mondo dei Terremoti
BREAKING NEWS STROMBOLI: Tsunami warning after two major landslides occurred on the Sciara of Fire!
Between 15:28 and 16:18 this afternoon, two important landslides occurred on the Stromboli Fire Sciara, in the Aeolian Islands. According to the statement from LGS – Laboratorio Geofisica Sperimentale , the second of the two landslides was the most voluminous and impacting the sea caused the formation of a tsunami whose maximum height reached 1.5 meters triggering a tsunami warning throughout island and turning on the emergency sirens. Such a change in sea level was recorded by both sea bays present off the Fire Axe and managed by LGS, which are useful to trigger a tsunami warning in time. As far as we currently know there has been no news of particular criticalities, we will see if further announcements will be issued to clarify the situation.
Today’s activity started at 3:10 PM with a small lava flowing from the crater area north of the volcano causing a small portion to collapse. In conjunction with this frantic movement, along the Sciara del Fuoco a series of pyroclastic flows have formed that are still ongoing and that have impacted at a great speed against the surface of the sea. The crater area has also generated explosive activity that at times proved intense.
Taken from facebook post
2019 … chilling flashbacks
Video of a pyroclastic flow in Stromboli, presumably from this eruption:
Thermal and visual video of the PF from the summit:
I wants to be at the vent now, standing at the edge of the fast flowing channels, watching the standing waves clad in thermal suit, walking towards the camera I set up. In a way repeating the Kraffts footage from 1984 eruption.
live of the flow front
must be what some Ionian flows are like as well from the faster fissures. Hi Albert woud I feel the heat from lava flows there in same way as Earth without an atmosphere? well there is always radiation, but no hot air
It is the radiation that heats you, in my limited experience
Eruption in Java as well
“Volcanic ash mixed with monsoon rain was falling on nearby villages and 1,969 people, including children and seniors, had been evacuated, the National Disaster Mitigation Agency (BNPB) said.”
Mount Semuru again, btw.
No deaths, 2000 ppl evacuated.
Last week about 300 deaths caused by an earthquake in West Java.
I seem to remember GeologyHub mentioning that a bigger eruption may occur at Semeru back in October.
It looks like some people weren’t convinced at the time as seen in the conversation that Tallis started on this page near the top of the comment thread…
Breath-taking footage of Semeru’s pyroclastic flow as it engulfs the camera:
That camera was in the right location! I hope the camera operator was not
Thankfully, there doesn’t seem to be any reports of casualties so far. That’s some scary footage.
I once had a very vivid nightmare that looked just like this. Only difference was that in the dream there was a small hill between me and the volcano. The main road went over the hill and there were houses on both sides. As we saw the pyroclastic flow come down the mountain I immediately realized there was no point in running. Eventually, the flow went behind the hill and disappeared for a long while. Just as I started to think that maybe it had stopped on the other side, it came rushing over the hill at great speed. The final moments looked exactly like in this video. I woke up with a huge gasp for air, absolutely soaking in sweat. I usually never remember my dreams, but this was so different, so intensely real, that it stuck in my mind forever and every time I see a video like this it sends shivers down my spine.
Echoes of the Krafts on Unzen.
Is this what they saw in St Pierre on Martinique in 1902?
If those on sure had time to look. The captain of the steamship Roddam, which was tied up off the waterfront, likely saw that, as well as those on the Roraima. Personal accounts of individuals aboard those two vessels have been recorded for prosperity. I would expect that the people of Pompeii would have witnessed the same horror show
An additional thought. On seeing this the first time I was immediately taken back to the video of the event and the tragedy on Unzen when the Krafts and their crew were killed.
The lava lake in Halema’uma’u looks super super sluggish now, circulation is very slow and the crust floating on top is as thick as it ever been. Most of magma supply is going into ERZ and deeper summit storage as seen with the low So2 outputs, never seen it this stale before
I think possibly Mauna Loa erupting has had some impact too, the lake dropped during several 20th century Mauna Loa eruptions. This isnt any sort of connection just pressure. This deflation and sluggish lake activity began at the same time as Mauna Loa had its first had its shallow earthquake swarms in September. That event probably was the result of a lot of magma ascending from the deeper system to the shallow system and its pretty obvious what has happened next. If the deeper system of Mauna Loa has effectively lost pressure then that will also take pressure off Kilauea. The same thing in reverse probably gappened in 2018, Kilauea draining out removing pressure from Mauna Loa, which stopped inflating in that time too.
The effect need not be huge, Kilauea is still erupting after all, and Mauna Loa resumed inflating again after the 2018 eruption. But there definitely seems to be a link in thus manner. I guess in 1984 Kilauea was still deflating, it did so from when Pu’u O’o began until the 2000s, so there was ample magma for Pu’u O’o to erupt on time. The 1983 kaoiki quake also shoved into Kilauea, probably had an effect…
The stress inside Mauna Loa changed with slipping of the slopes. That is the reason that the southwestern and northeastern rifts are so different: the slip to the west and to the south differ in nature. The most obvious way Kilauea can affect Mauna Loa is by braking or pushing the slip to the south
Given that the magma system of Kilauea is at least as large as that of Mauna Loa, possibly larger, if it is inflated or inflating then it shoudl have an affect. The thing is Mauna Loas summit storage is 3 km deep below the summit, which is at the same elevation above sea level as Kilauea, so Kilauea cant really directly impact that part of Mauna Loa, but Mauna Loa can push on all of Kilauea. In practice though, it seems that maybe Mauna Loa doesnt currently have continuous direct feed to its upper magma chamber, or at least didnt before September, it was inflating deeper down, where Kilauea could get at it.
But what I hypothesize is that because both of them had pressure, removing it from one (Mauna Loa magma moving up to shallow depth) also removed pressure at Kilauea, which has temporarily caused its activity to decrease. This might well last for some time, maybe even as long as it takes to recover the volume that Mauna Loa erupts if Mauna Loa itself doesnt begin to recharge on its own. That number is impossible to know, however some of the numbers I have been seeing for the magma volume potentially at hand is that there is more available now than there was in 1984, this eruption could end up being very big. I wasnt sure before but now after a week with no evidence of significant decline it is pretty clear this is the main event and not just a precursor, it is a 1984 not a 1975.
Going on the above senario, one can hypothesize this eruption might get a similar size to 1984, or even to something liek 1859, 0.2-0.4 km3. In turn, it could last months, and potentially take enough pressure off of Kilauea to make it sleepy as it is now for 2-3 years as its magma supply is diverted underground. This though, will probably have a positive effect on eruptions at Kilauea after this, with all the extra magma stored things coudl get interesting. It will be fun to find out as this decade goes on.
Yes this is going to be large Mauna Loa eruption in volume and long lived.
It have now erupted the whole volume of the 2020 – 2022 Kilauea eruption. I see probaly No problem of reaching 0,5 km3.
Mauna Loa is monsterious The base Supply of Mauna Loa is something likeX 5 times Piton De La Fournasie s yearly input, so aftet 38 years there should be plenty to tap from. ( Piton is monsterious compared to most other volcanoes)
I see plenty of potential for this eruption because of that, we are talking about a volcano of huge scale. And chemicaly Mauna Loa sits closer to the Hotspot than what Kilaūea does with Mauna Loa being even further into the Thoelitic area, But they are so close to eachother so They share the magma source.
Chad how large coud this eruption become? There is No caldera collapse But there is plenty of stored magma in depth
HVO has said for a while now that there is more magma than there was in 1984. But they dont say if that means more than the volume erupted in 1984 bas been supplied, or if there is more magma in total in the volcano than there was before the eruption in 1984. If it is the former, then the eruption might end soon as the dike has a volume about 0.1 km3, and then a similar amount erupted.
If it is the latter, then this eruption is not even half way done yet… In the extreme end of this I do expect it will either slow down int oa very long eruption, or at some point there will be another intrusion and lava will break out further downslope. The 1843 eruption has got a cinder cone on the rift that looks liek the current one but is mantled in fien tephra. meanwhile most of the lava of that eruption erupted on the north flank from a separate fissure that is radial to the rift (called an ‘orthagonal’ vent in some papers, rather than a true radial vent). I think that as the second fissure opened the upper vent became a gas vent and sprayed out a jet-like fountain before it became inactive. All of the documentation of the eruption, by Titus Coan and others, is of this second stage which lasted for a few months I believe.
I do use 1843 as a comparison, because it was not preceded by any other eruptions within at least a few decades. There was probably no 1832 eruption and if there was it was very small, and the youngest eruption otherwise is the Manuka flow on the SWRZ that is from about 1809 although not observed so its age is not known to an exact year.
So there was probably decades of inactivity at Mauna Loa before 1843, about as much as the recent gap. I have seen some suggestion in various papers it would take high supply to get a long eruption or a radial vent but the supply was probably not high in 1843 either, maybe not until the end of that decade, so it should be very comparable to now and yet the eruption was several months long and did manage to erupt outside of the rift too. And it was a NERZ eruption like the ongoing one too.
Only thing is the current eruption might already be more than half of the 1843 total if it has got to 0.1 km3 but without an official number from USGS it might be best not to assume a volume at all yet. I got my voluem by comparing to 2018, but the 2018 lava at Kilauea was partly degassed, where the lava now on Mauna Loa is not, so probably has a higher load of SO2 for the effusion rate. As in, the effusion rate is probably a lot less than the 2018 eruption although it is still very considerable. Again USGS numbers are needed, but those might not come for a while, not until they can get a better idea of the volume erupted so far.
Here are the 1843 vents, in comparison to the 2022 fissures. Only two areas of that eruption are still visible, there was probably originally a more continuous fissure coming from the summit but that has been buried extensively so that only the lowest section and the tall cone mentioned above are still visible.
As is clear, the lower vent is strongly angled away from the rift and directly downhill, but not radial to the caldera as was the case in 1859.
There is definitely a bit of a lava pond forming within the cone now, compared with a few days ago. The eastern side of the fissure has also stopped fountaining much in the M5 cam, probably drowned in the lava. Maybe soon the vent will become singular and with a tall jet fountain, although not all eruptions produce these.
Looking at GPS signals in and around the summit area of Mauna Loa, there’s (not surprisingly) a very obvious ongoing deformation signal. The summit is clearly deflating as magma is drained and flows to the eruption. Do you guys think we will see another sequence of collapse induced M5+ quakes, just like at Kilauea and Bardarbunga? I assume the initial deformation is elastic, but after a while (soon?) I guess it should start to show up as earthquakes.
I dont think the vent is low enough for that. Eruptions that have formed calderas at Mauna Loa are all down at about 1500-1600 meters elevation or less, both on the SWRZ (Hapaimanu, Pu’u Ohohia, probably 1868) and on the NERZ (Pana’ewa/ Kulani cone). Maybe this is why there was no collapse in 1850 too, that eruption was enormous and extremely fast, but also not at especially low elevation and well above that 1500m mark.
So no caldera right now although it is never impossible the intrusion restarts and ends up somewhere down a lot lower. But I wouldnt expect that now, eruptions at that elevation on the NERZ are 1/1000 year events, and the eruption is already in that rift so a new intrusion southwest is very unlikely and not considered a reasonable possibility by HVO.
I also woudl have expected some of these quakes in 1984 too before we get them now, and there werent any to my knowledge.
1950 not 1850 🙂
What was the volumes of the Pana’ewa and Hapaimanu eruptions? They must have been leathaly fast, truely my stuff, Hapaimanu overunned villages
But the ultimate dream is a Line.. a wall of Calbuco andesite / Masaya like basalt plinian columns 100 s of km long.. But Thats something No volcano on Earth can do.. so stuff for my imagination:)
Ask Hector, but both Hapaimanu and Pana’ewa were multiple km3.
Hapaimamu was 2.6 km3, I measured the lava delta and lava flow of that eruption with the help bathymetry and topography elevation contours. Panaewa would be more complicated to estimate, although I expect its size is similar to Hapaimamu.
Jesper, you may be able to get a line of fountains more powerful than Calbuco several kilometres to a few tens of kilometres long during major caldera-forming eruptions of large calderas. Unlikely to happen in Hawaii, but large silicic calderas, or basaltic calderas in volcanic arcs, are capable of this.
This with volcanoes are becomming a serious addiction for me, but for me Iceland and Hawaii is the only thing thats tastey now, as they are Earths two most migthy magma sources ( and specialy Hawaii )
I really only wants enormous volcanoes .. and Kilauea and Mauna Loa are dam huge and Hawaii seamount trail is incredible mass and productivity compared to any volcano.
Yellowstone is tastey too Althrough infrequent
I really Hopes Iceland also does something soon as well..
Watching the Mauna Loa eruption with excitment and IO 2024
The bigger and more silly the volcanoes are the better .:..
Hopes we gets to see more of IO soon .. sadely Nasa most intrested in Europa now and the space – fish there
Yes, I agree. Probably this is not low enough to start a caldera collapse.
Deflation is about 30 cm or so which is quite large. But the volume is perhaps 10% of Bardarbunga’s magma loss and the crater is large. I expect some sinking of the crater floor but not as collapse events. Pit craters could form though if this continues.
Webcam: and yes I think this will be a large eruption, been decades without… and being as formidable as Mauna Loa is in magma supply its probaly will be an extraodinary event. I see all chances of reaching 1 km3 just feels like that. So thats 8 weeks more of eruption at 100m3 per second
Of note is that this eruption debunks two long-standing assumptions of ML eruptions:
One is that this vent, well down the RZ, was not preceded by a summit-only one. 1984 had 1975, 1950 had 1949, 1942 had 1940, 1935 had 1933, etc. There was at least a hint that 1975 ‘wanted’ to erupt further down the NERZ, but didn’t.
Dating back to at least 1852, NERZ eruption sites progressively were sited further south with time. It could be argued that this held only if the fissures were below ~10000 ft, and that’s worth considering.
Kilaueas summit lava lake have now stopped circulating, and is only overturning its crust.
There is No cracks in the skinn that indicates movement of the surface
Episodic resurfacing now
Seems to be some convection into the Halema’uma’u lake again
The bottommost video embed in the article isn’t loading correctly.
looks like Taupo has kinda gone quiet. I am sure with me typing this it will resume again. Ha ha
The lava flow is creeping forward somewhat below snail’s pace. At this rate it will reach the Saddle Road not before January. But in fact the creep is now in a direction that would make it more likely to go left, towards the west coast – it cold even miss the road. Of course at this rate, it will be 2025 before we know for sure! Not quite a Jesperian event
But the lava channels arr as addictive as morphine to watch, flowing like water as USGS say.. the close to vent channels are perhaps flowing at 40 km an hour or so.
10 m/s or 36 km/hr as measured on December 5th. So a similar speed to the 1984 flows, and a little bit slower than the fast channel next to fissure 8 in 2018. So I think maybe my earlier asumption the effusion rate was similar to 2018 was rather optimistic, it seems to be a lot less than that although still high.
USGS say 100m3 per second at vent
About 1/3 of 2018 then 🙂
Or… 1/10, if they are talking bulk during surges. Those surges were enormous, bulk rates of well over 1000 m3/s were standard and one gor over 1500 or even 2000 I think although will need to confirm. DRE is in the range of 500-700 m3/s. Average was 250 m3/s DRE for fissure 8, so gaps between surges were probably similar to what we see on Mauna Loa now.
But then, this is also a pretty standard Mauna Loa eruption, eruptions here are not continuous so go big when they do happen 🙂
The flow front below is slow Aa as the channels are not insulated and loose heat. At the vent its as fluid as Nyiragongo
At the flow front its even more viscous than Paricutin was close to its vent. Distal front basaltic Aa lava have viscosity that spanns into some near vent andesite flows I think
Even slower than Arion Vulgaris?
( these invasive turd slugs ) Europes worst garden pest.
You have them in UK too If I remebers correctly
My grandparents kills many thousands each summer, and yet there is even more of them.
Luckly these beasts dont grow to the size of houses.. or trains
You can kill garden slugs by leaving a pan of beer in the garden.
Doesn’t work for fire ants.
Do fire ants work against slugs?
Don’t use budweiser. It will get ignored
A well respected UK research group examined slug baits to remove them from gardens.
Most were no more effective than beer BUT
bread dough (pre baking) attracted 1000x more than anything else. Apparently filled the container.
Not for nothing, perhaps, that durum wheat is used for commercial slug bait (poison).
That was a good laugh. I am now imaging your grandparents fighting off an invasion of lava slugs crawling over the lettuces and feasting on sauteed sprouts
And I often have strange dreams of my homecity being invaded by Arion Vulgaris slugs thats are the large as the QM2 ship. 345 m long
They eat whole trees like nothing
These monsters are Impossible for the military to kill by hand weapons, and haves to be bombed by aircraft. They produce copius ammounts of slime do cars and pepole gets stuck and die. Just a whole mess.
I guess a slug that size woud collapse under its own weight
Its a horrible mess these Giants leave behind : D
Speaking of dreams, I have a few of my own and some volcano-related.
Where to start? In this one, there was what seems to be future Hawaii (???), where it zooms into the two rift zones that are somewhat parallel to each other and it zooms to in between them for some reason. There was a shot of what seems to be a cowboy (for some odd reason), but then cuts to a normal town (i.e. streetlights and a hotel, of which I was in the hotel and dirt roads). The area in question has a valley with very steep slopes in between in the distance (assuming that this is the rift zone) and a savannah forest.
At the night, there are cracks spitting under the buildings and beyond and began pouring lava and I was jumping between cracks. I somehow exited the building safely (along with a few others) but there was lava still coming, now in a sort of fast flood (kinda like the summit eruption Maunaloa had). We were running away but there was lava at every street, flowing in a sheet. We somehow grabbed quads and went through a sort of arid landscape. That is where my dream stops.
My second one is a bit shorter. I was in a desolate landscape (i.e. pahoehoe with ash on top) while observing what seems to be a big egg. It then cuts to us flying in a helicopter over a chasm, of which a large river of lava flows. I then fell off the heli and that is where it ends.
News article out that Villarrica in Chile is starting to erupt. Last eruption was 1984, coincidence? Not sure what their definition of Lava Balls are.
“About 28,000 people live less than ten miles from the peak in a city called Pucon. Officials have placed a yellow alert for the volcano, which means imminent eruption. “
Last big eruption there was in 2015 not 1984, I remember seeing the massive fountain on the news 🙂
Thanks for the news. The SERNAGEOMIN page on Villarica has some data:
A clear escalation of activity can be seen. It looks like LP earthquakes were nearly uninterrupted yesterday, possibly representing small strombolian explosions. Major eruptions of Villarica are often spectacular subplinian eruptions of fluid mafic lavas, and lahars are a hazard. Without data for earlier years, and from before the last eruption it seems difficult to judge whether the volcano will blow or not, but it looks very unstable.
Cotopaxi is also escalating. A thermal anomaly has appeared in the crater. But Cotopaxi has a long history of becoming restless and then making just a few small puffs of ash (although it also has an earlier history of producing dangerous eruptions):
Coud be violent dukono like strombolian activity in the crater, or vulcanian style violent degassing
Just noticed some new instruments on the Big Island. Does not appear to have any data from them yet. I think I got them all?? It was also nice to see them publishing data for some of the Seismometers that usually do not show data.
Instrument Icon Infrasound Monitoring Station
Instrument Icon Infrasound Monitoring Station
Instrument Icon Infrasound Monitoring Station
Instrument Icon Infrasound Monitoring Station
Instrument Icon Infrasound Monitoring Station
The name of the first one has to be a hommage to Volcanocafe, right? Either that or a misplaced Icelandic one…
Was looking around and found this under monitoring earthquakes on the HVO website, https://www.usgs.gov/observatories/hvo/monitoring-earthquakes-hawaii.
Infrasound – Earthquakes, eruptions, explosions, and other phenomena emit sounds into the air as well as into the solid earth. An infrasound sensor is a special type of microphone that measures sound waves in the air. This offers a unique way to monitor explosive volcanic activity and has great promise to aid in rapid eruption detection.
Jump! Just watch that landing!
Jump! Just watch the landing!
Past week of earthquakes at Kilauea. All of this is well after Mauna Loa did anything, so seems to be unrelated.
I wonder if maybe another intrusion happened to the southwest this week. That would explain the sudden loss of the lake, it was low for a long time but Mauna Loa didnt really affect it for a few days nor did anything change there either in the past week. I guess possibly the affect of a dike intruding into the NERZ of Mauna Loa could have pushed at Kilauea enough to disrupt its delicate equilibrium, but the 1984 dike was bigger and did nothing, and I am not aware there was any affect during the 19th century eruptions either, there is even the famous painting of the lake full to overflowing with Mauna Loa erupting in the background, in 1880 I believe. There was also an affect in 1919, which was a SWRZ eruption that would not have interacted with Kilauea much at all.
The data still suggests Kilauea has a robust supply the same as before just that it isnt reaching the surface. If it is pressure from Mauna Loa then Kilauea could erupt strongly soon after Mauna Loa stops.
Kilauea is inflating as fast at times as other times when it does not erupt. I don’t think Mauna Loa has anything to do with it. Maybe the conduit has become clogged somehow, although I find it puzzling that it still reacts to DI events. The idea you proposed that dense magma had settled over the vent could be happening, maybe dense crystalline magma is drowning the vent. In any case, the magma supply has shifted to producing deep inflation under the caldera, with an strong horizontal-dominated displacement of the area south of the caldera towards the sea, and reaching as far as Hilina Pali or beyond.
Couple of 3.6 magnitude quakes, one south east of WOOD, the other at the caldera of Kilauea.
The magnitude 3.6 at Kilauea has produced an increase in radial tilt at the nearby Uwekahuna Bluff tiltmeter. This suggests that maybe a caldera ring fault has had a small rupture, collapsing slightly the floor and sending up the rim of the caldera where the tiltmeter is. Perhaps it released some enduring strain from the 2018 collapse, although the trigger was probably the rapid spreading and inflation that is occurring at Kilauea.
Looks like high fountains are Maybe building up at the Mauna Loa vent, fountains been higher now than anytime since the cone started to form
Will only further increase Aa formation If the fountains gets taller
Between 200 and 500 ft, or 60 to 160 m. Not the biggest but a lot bigger than 1984.
Might be correlation / causation, but that might explain why the channel got blocked and the main flow got cut off yesterday and overnight. Those 1600-footers at Maunaulu and Puʻu ʻŌʻō looked badass but they weren’t really massive lava flow producers. They were essentially ‘A’ā as they left the vent.
Generally yes, but not always though. If the cone is still big enough to trap the fallout then you still get a long fluid flow. One of the Mauna Ulu flows advanced 13 km to the ocean in a few hours, was fed by a 300+ meter fountain, almost as fast as the SWRZ eruptions on Mauna Loa, never really gets mentioned much for some reason…
Pu’u O’o made its longest flow of the whole eruption up to 2014 back in April 1984, episode 18 I think, where the lava flowed a total of over 14 km to about 1 km from the ocean west of Kalapana. There were 4 other big flows of that episode, which had 200+ meter fountains and lasted for 3 days compared to the 1-2 that was standard at that time. If all the flows focused into one it would have reached the ocean easily.
Episode 18, it should be noted, was the first episode after Mauna Loa stopped erupting, only 10 days after or something like that. And episode 17, which happened at the same time as Mauna Loa erupted, was no different to the other episodes. So seems maybe Mauna Loa did have some affect, although it was not a negative correlation.
And then of course we also have the flows from Laki and Eldgja, which were fed by fountains 400-700 meters high (not 1500).
A video as to why the fountains are taller but the lava effusion is slower (because it is becoming more gas rich and nearing the end of the eruption).
HVO says the channels are all blocked, while effusion rate has probably gone down, lava flows dont go more than 4 km from the vent. But the fountain is much higher, maybe because it doesnt need to blast through a pond anymore.
The volume seems unlikely to be close to 1984, 0.1 km3 is probably a sensible guess. So probably will not be more than 20 years to the next eruption…
The eruption will probably end in a few days, but we might get quite a show from this fountain before then 🙂
HTHH’e SO2 flux appears to have been underestimated. They seem to peg it as high as about half of El Chichon, but the interesting nugget is them touching on the difficulty in measuring it accurately due to the dynamics of the extremely rapid, explosive, water rich plume. Lots of interesting info in here.
I guess many of you have noticed the AI chatbot ChatGPT from OpenAI. I asked it some volcano related questions and got some nice answers. Then I asked it for something with the intention to post it here:
Me: “Write a poem about Mauna Loa”
“Mauna Loa, oh mighty one
Rising high above the earth
With lava flowing from your core
A sight of great worth
Your fiery eruptions
Are a reminder of your power
A force to be reckoned with
In every hour
As the lava flows
Destroying everything in its path
You bring new life and growth
A reminder of the earth’s aftermath
Oh, Mauna Loa
We stand in awe of your might
A reminder of the earth’s fury
In every fiery sight.”
Nice try but can do better..
I commented twice on a sheep jumping. However, neither one ended up at the right place. Can a Admin please just remove one, and put the other one immediately underneath the sheep?
We prefer not, because deleting comments can mess up the comment streams, at least it has done so in the past.
Pahoehoe on Etna. Not quite as shiny or liquid as Hawaii but it does exist 🙂
Thank you 🙂 its crystal rich tracybasalt, similar to the viscosus La Palma lava of first weeks, althrough little less alkaline than the 2021 Canary tephrite. But viscosity seems to be the same. Etna have over 1110 C in many cases, 1140 C for 1969
and its relativly low Sio2 47 % should make it fluid. I think its because Etnean lavas are very crystal rich, they dont form smooth surfaces at all. The main magmatic liquid of Etna is often refferd as quite fluid in many papers 1971 and 1983. Its perhaps like concrete with lots of sand in it in the fluid. But yes alot less smooth than Hawaii and Fagradalshraun that much less crystal rich. Etna can produce more hawaiian like pahoehoe as well like the Bronte.. But even They have a rather crystal rich nature and are known as Pea Lavas
As it becomes Aa you Maybe able to runn as well over the stiff But moving crust.
The base magma in Etna deep down is mildly alkaline basalt I guess
I have seen that video of the guy running up the lava but I think if yiu tried that with the lava in the new video your foot would go straight through. I guess if Etna does form a shallow chamber then it could become a lot more liquid, all that needs to happen is the crystals settle out. Without those the lava should be a very low viscosity, probably no different to Hawaii given the composition. The 1669 flows to begin with were supposed to have been very liquid but as things went on the standard stuff appeared. That eruption was both a lateral drainout and an eccentric eruption, I guess Etna can do rare rifting events.
Also the early La Palma lava was still very fluid. What you are probably thinking of is a spatter flow. That is where the cone becomes too heavy to support itself so begins to flow away. It is basically a blocky lava flow but it isnt made of lava directly erupted from the vent but rather the semisolid interior of the cone flowing, the lava flowing directly from the vent is very fluid and fast flowing.
A bit after half way it zooms in, you can see the channel.
Wow the lava have a competely diffrent luster and apparence than more normal thoelitic basaltic Aa flows. The Aa from fagradalshraun did not look like that, the texturers of these Etna flows reminds me of Erebusian Phonolite, just that this is somewhat more fluid. The orange color is rough indicator.. as more basaltic Aa appears white yellow hot inside when flow core is exposed. The crust also have a luster and texture that you dont find in Hawaiian and Icelandic Thoelitic surfaces. Its not super potassic, but its alkaline enough to have an effect on the mineralogy and the apparence of the surface.
USGS Mauna Loa livestream has been intermittent lately, but I did manage to see the two geologists working and then catching a ride home.
Looking at Mauna loas M5 cam (the side view), it looks like the fissure is no longer fountaining from the middle, but has shifted to the distal end. The fountains jumped in height along with this shift. Presumably the opening is narrower?
Beautiful image of Mauna Loa’s lava flow as seen in an infrared overlay over a natural-colour image, as published by NASA:
The full, short article can be found here:
Where is the papers on the 1600 C eruptions on the Mauna Loas South rift ? Woud be fun to read that
For weather watchers. https://www.bbc.co.uk/news/world-us-canada-63912257
Looks like the eruption will end soon, probably within the next day. There might be a few extra hours over the next week and restricted to the immediate area of the cone but unless the decline is due to a new intrusion the eruption is almost over.
On area alone, as well as duration, I wouldnt expect this to be all that big. 0.1 km3 is my guess. 1984 was twice this big. Given the lava flowed only a bit more than half as far and down a steeper slope this makes some sense. Still 0.1 km3 in 10 days would be a mid sized VEI 4 if it was explosive.
I wonder if this cone will get a name. Not many cones on Mauna Loa have real names, probably because the area probably has never been visited often on foot. But then this is the first to form in modern time, 1984 didnt really make so much of a cone, it was more effusive.
So far the summit is down by around 40cm. The decline is slowing but has not yet stopped. The tilt has reversed though, and I am wondering whether there is a change in the flow to the northwest rift. If the eruption stops now, there is a chance that after a while it will resume at a new fissure. But the bulk of the lava has now been erupted, I think, and the Saddle road should be safe.
As I recall, Saddle Road is a state highway, and you need a permit to block or restrict it, and those are time-consuming to get. So, regarding whether or not the lave flow will block the road, couldn’t we just find out if the necessary permits to do so have been obtained?
Or, are we assuming that Mauna Loa is the world’s largest criminal, along with being the world’s largest volcano?
It is worse than that. It is the only access to the Mauna Kea observatory. Blocking Saddle road would be a crime against the Universe. I can see this go to the supreme court of Andromeda
Camera lens must be wet. Abstract Art live stream currently. Lava Lamp-ish.
Not dead yet: its possible that eruption output coud match input turning it into a shield like vent, that happens to a few Mauna Loa eruptions and you gets a tubed pahoehoe like phase. But yes its slowing down
That only happens in times when it has high supply though, like in the 1850s, or in 1881. Outside of that all the eruptions are of similar style to this one although of a variable size. Mauna Loa at least for the past 500 years has been mostly a rifting fissure volcano that sends long dikes away from its summit down the rift zones like the Icelandic volcanoes do. Kilauea does this sometimes too but also has a big magma system within its rift zones, including whole satellite volcanoes and calderas, so lots of other places for eruptions to begin from before the summit gets involved. Shields are really only found within a couple km of a permanent magma body.
Mauna Loa does have some long lived eruptions on its flanks though, but not Pu’u O’o type, they are much higher effusion rate somewhere inbetween deep supply and the fissure eruptions, 10-90 m3/s. So you get massive lava tubes and flow fields of slabby pahoehoe and a’a, and probably up at the vent is a fountain not a lake, although the fountain would not have a visible flow outlet. Pu’u O’o type shields are only found up at the summit of Mauna Loa as far as I know, within the area of Mokuaweoweo. Hector probably has better data on this stuff.
Here is a more recent livestream, showing a slight increase in activity around 18:45 HST, Dec 9, just before the video becomes smeared (again).
Oops, here is the link: https://www.youtube.com/watch?v=hyrZskkw2iA.
Image removed for excessive size (10MB!). Thumbnail added at the bottom – admin
One of the tall fountains from the other day, up to 150 meters although this particular one is probably about 60-100 meters. You can also see the lava that flowed down the side as the fountains fell over the area.
The vent that was making this fountains is dead now though, the only active one right now is a glowing hole at the back of the cone that is spattering sometimes. Probably in the final day now.
It will be interesting to see what happens next. Mauna Loa will probably inflate quickly in a declining curve as it did after 1984. But Kilauea could be a bit unpredictable, it was steadily deflating from 1983 up to 2002 as Pu’u O’o was reaching equilibrium, and Pu’u O’o is on the ERZ which is its own structure so Mauna Loa didnt really have any affect. But now all the activity at Kilauea is in the summit which is on the side of Mauna Loa, so there could be something.
In any case, if Kilauea is inflating at a deep level then the low activity it shows now is not going to last, it barely made it the 3 months to a new eruption last year, and then flooded the crater all over again. If we end the year with no lava in Hawaii at least we can be assured of a show in 2023 🙂
Two of the video embeds in the article are now malfunctioning.
True. I have removed them. The webcams and youtube channels can be changeable and temporary
Lascar volcano had an eruption. Not big, but Chile is always notable
Is this likely a ‘one and done,’ or is there a chance for continued eruptions? I see Lascar has some interesting history and I enjoyed learning it about it just now. Not a volcano I was familiar with.
It had a nit small eruption in 1993, a VEI 4. But mostly seems to be the same as it is now, effusive lava domes with some vulcanian eruptions. That is like nearly all of thecAndes volcanoes though, effusive.
Although these effusive volcano clusters are probably what turns into VEI 7-8 calderas once every now and then, and there are some number of those of varying age in the mountains up there 🙂
The eruption in 1993 was a very pretty one. I found a pdf full of phots from it. Here’s the link: https://planet-terre.ens-lyon.fr/pdf/eruption-Lascar-1993.pdf
Incredible images. I love how well recorded the 13:15 explosion is, with 13 different images. Pretty indeed:
Have you seen the YouTube videos by the guides who are down the slope of this event as it happened? Reminiscent of Galeras. Had it been a true pyroclastic flow there would be no videos
Yes, I saw those videos, it could have been bad. You can never trust stratovolcanoes, they suddenly throw a gas-driven explosion in your face.
Something for Albert: InSight seismic data have now revealed an active mantle plume below Athabasca on Mars. The Young Mars flows there makes sense.
Mars is between the Earth and the Moon in size and cooling rate should be too, makes sense that Mars is not stone dead yet.
Looks like Mauna Loa and Kilauea have both stopped. Kilauea is only a matter of time, it is inflating everywhere, even down at Pu’u O’o a signal is showing up now. But Mauna Loa is also now reinflating both at its summit and in the dike up to the vent. The eruption wont become intense again if it resumes unless this really breaks the historical trend (although this already did happen in one aspect, so who knows) but the eruption could resume still, as an effusive vent at a lower elevation possibly, or in a few years as a separate eruption potentially on the SWRZ. In any case it seems likely the next eruption is not going to be 40 years away, 1984 was at a very low elevation for a NERZ eruption and fissure 3 is much higher up, probably not more than half of the magma was drained compared to 1984. But
Noticed that in the latest update. They also said that the tremor has pretty much stopped as well, so the continuing inflation is interesting.
It did happen in 1984 too, so not necessarily a sign of anither eruption soon. In the 10 years after 1984 it inflated the same amount as between 1975 and 1984, but didnt give any sign of erupting at all. So this might just be the result of low pressure in the summit allowing deeper magma to move up rather than an actual increase in the supply. This also happened at Kilauea after 2018 but because the magma supply is directed there the low pressure was filled in very fast.
This interpretation could also be wrong and another eruption from Mauna Loa could be in the works. If things recover quickly that is a telltale sign. But the lack of earthquakes at all would lead me to think this is over. Kilauea is where we should look for the New Years fireworks, it has been basically asleep for the past few months and actually did stop erupting yesterday, which means increased pressure so things might get lively when the shallow connection is restored.
This is from the Fuego live cam. Usually there seems to be a small spattering vent or maybe a lava pond in the crater, and lava fountains when it does erupt. But this was a full self destruction of whatever was in the crater…
Fuego goes to show well how magma type doesnt really always reliably indicate the eruption style. Most of its eruptions are hawaiian-strombolian but it is so extremely steep that even these basalt flows collapse and slide down the flanks to turn into a pyroclastic flow.
And with water contents of the magma going as high as 6% by weight in some eruptions when a serious lava fountain does happen it tends to backfire into the conduit and become plinian. Pacaya and Fuego are basically very logn lived scoria cones if you think about it.
Stratovolcano volcanism is typical of water-rich magmas. It mainly occurs in subduction zones. It happens only sparingly in areas of ultrapotassic volcanism (usually phonolites and nephelinites), like Virunga and Tanzania, where water is also high in the magma. The Cascades are also an interesting example, there is active subduction under the northern part centred under Rainier, where it fuels more typical stratovolcanoes, like Saint Helens, Rainier, or Glacier Peak. To the south there is no seismically active Benioff Zone, you get drier volcanoes that are more effusive, with many monogenetic and polygenetic shield volcanoes, and the stratovolcano edifices are rarely active. Seem that a high water content in the magma changes the conduit dynamics a lot, what would be monogenetic vents elsewhere turn into long lived polygenetic vents.
The speed of inflation at Mauna Loa right now is spectacular. The tiltmeter MOK in the caldera rim has recorded 8 microradians of inflationary tilt in ~4 days. Kilauea would take an entire month to inflate that much. Assuming Kilauea’s magma supply is about 3-4 m3/s, then we could be looking at a rapid influx of 22-30 m3/s. Of course this is very very rough approximation, given that the storage of Kilauea and Mauna Loa might are differently shaped and produce tilting in contrasting manners. The location of MOK and UWE (Kilauea summit) tiltmeters is very similar to their respective volcanoes, but not fully identical.
The dike intrusion seems to be long over, so I don’t think it’s that. Kilauea has never done something like this, nor any other volcano I know for that matter. I’m not sure what’s going on, but maybe a deep magma storage is rapidly recharging the shallow magma storage. This would be an interesting possibility given what I have discussed in the past with Chad, that Mauna Loa sometimes produces eruptions that keep high eruption rates for unusually long periods of time, like the Kipahoehoe eruption in ~1550. I don’t think eruption will resume though, and the rapid inflation is slowing down, so will probably drop to more normal levels soon. But nonetheless is an interesting insight into Mauna Loa’s system.
It is an ultrafast recovery. The tilt is approaching the pre-eruption levels and the trend is looking like it may stop there (always dangerous, those predictions). Earthquakes have ceased almost entirely since 2 or 3 days. The eruption is over. The change in tilt was a surface response to the stress in the rift zone. When the dike formed, the stress moved downstream and the summit tilt responded. Now that the dike has closed, the pressure is back to where it was. The tilt change is a relaxation: it is the response to a return to the pre-eruption condition.
Note though, that there is a 50 microradian inflationary change, from the dike intrusion (this change will be slowly undone by slow spreading of the summit), it is also visible as a >35 cm extension of the caldera (which is probably permanent, rifts spread after all). A dike is like an earthquake in some ways, it releases tension, it is an elastic rebound, the strain will build back from the continuous slow spreading of the summit, but the opening stays. After this dike change there was an almost 60 microradians deflation from the magma chamber draining, that adds to the dike signal. It must recover those 60 microradians to really return to a pre-eruption inflated magma chamber.
All of this is when looking at the 328 degrees component of the MOK tilt, which is the radial component to the magma chamber. Shown as a blue line:
There was this sort of rapid inflation after 1984, maybe not this high but way higher than the base supply rate ever is. Like you say I think it is magma from the deeper system moving up but not all the way from the mantle.
I did notice one thing. While there are a lot of examples, including historic examples, of long lived eruptions from Mauna Loa, all of the Kipahoehoe type a’a shield eruptions are on the SWRZ, and at least 1 km below the summit getting bigger further down. There are none on the NERZ that I would count as this type. I also think possibly these eruptions could originate deeper than the summit chamber entirely, as they are not associated with calderas. Pu’u Ohohia is a pair if cones on the west slope downhill of Pu’u O Keokeo. The latter we discussed, seems to be the biggest a’a shield. It doesnt hace the halmarks of a caldera though, no picritic magma, no deep open channel, and there is no fissure instead it looks like many vents opened in the general area over time. My interpretation is this came from a deeper intrusion that started from whatever source is below the summit chamber. The mechanism may be very similar to the intrusions to feed the eruption on La Palma a year ago, which was also a high effusion rate and relatively very long eruption for that sort of activity. Pu’u Ohohia did erupt a massive picritic a’a flow, and overlies the Keokeo flows. While nit possible to knkw the huge size if the flow (as big as Hapaimanu) and compositikn indicate a caldera formed. Presumably the shallow chamber connected and this let gravity do its thing.
There are only really a few of these a’a shields in general really, they seem to be pretty rare. Also,possibly entirely a coincidence or maybe not, they have been entirely absent in the past 500 years. Kilauea was a shield before 500 years ago, but not after. Maybe if Kilauea has a caldera it lers Mauna Load BERZ have a bit hmm
New post is up! Is this the only volcano named after a criminal? Welcome to the Wild West
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