Nyiragongo and its ultra alkaline magma – Part II

Nyiragongo history of activity and nature of its eruptive activity

(See here for Part I)

Photo by Lukas Spieker: Nyiragongo is easily one of the world’s most beautiful and stereotypical volcanoes, with its steep slopes, fluid lava, lava lake and simple cone, Nyiragongo looks just like every video game volcano, or every child’s drawing of a volcano. But it is also a threatening volcano. Here is a link to photo: http://www.lukasspieker.com/nyiragongo/

Nyiragongo’s beautiful steep cone, encased in its unsettling night glow, towers over the densely populated Kivu region that is home to millions of people. The volcanic edifice itself measures around 13 kilometers wide and rises to 3470 meters above lake Kivu, and sometimes is dusted in snow. The volcano has a rift system and flank eruptive deposits that span the entire Goma area and extends under lake Kivu. It is also owner of a lot of flank cinder cones, they are Nyiragongo’s smaller monogenetic children. To the west is the towering Nyiramuragira and to the east are the snow-covered Karisimbi, Visoke and Muhavura. Nyiragongo has around two million persons around it and most of its lower flanks have been turned into agricultural lands. Despite the dense levels of human activity on the slopes and the presence of a large human population, not a lot is known about Nyiragongo’s eruptive history before the 1880’s, other than that its a steep ultrabasic tephra cone that has dangerous lava lake drain-outs.

It is in one of the oldest populated places on the planet, and modern human beings been present there long before Nyiragongo was born. We are as a species way older than both Nyiragongo and Nyiramuragira. That says how young these volcanoes are. Goma became a major city center only quite recently, so the area is still quite unexplored, and the violent human history of the region has prevented research of the area. Still Nyiragongo has quickly made its way into geological research and volcano recordings, thanks in part to the volcanologists Tazieff, and the Kraffts videos and their photography. The modern information era has made Nyiragongo monitoring a much easier job. A description of the geological exploration and the eruptive history follows.

Nyiragongo has no doubt been climbed by the locals many times before recorded history, but the first European who recorded a visit was Gustav Adolf von Götzen (1866 – 1910 ) in the year 1894 when he explored what was 31 years later to become the beautiful Virunga National Park. He was one of the last people of the classical age of exploration in the European imperial age. In 1894 he became the first European to observe the lava lake and confirm its existence. The climb up must have been difficult without a well trekked trail.

A volcanologist who really brought Nyiragongo to the western worlds public eyes was the French Haroun Tazieff, he was born in 1914 and died in 1998 when I was only 3. Tazieff began to explore Nyiragongo in the late 1940’s and published video and still photos from the lava lake that existed from the 1890’s to 1977. The first Tazieff expedition to this volcano occured in 1948. These where major undertakings, taking weeks. The expedition teams lowered themselves hundreds of meters down to the lava lake, getting close enough to touch the lava lake. Over the decades Tazieff undertook numerous expeditions to Nyiragongo for photography, filmmaking and science as well, including the first color films of its activity in the 1960’s showing his geology students the activity. Tazieff became very familiar with Nyiragongo and he wrote his memories in the book “Nyiragongo The Forbidden volcano” that was published in 1979. Tazieff was the first to bring back color films and photography from Nyiragongo. He was also perhaps the first the bring volcanology into the public mind in Europe, perhaps pioneering that even before the famous Maurice and Katia Krafft that Tazieff was friends with. The Kraftts visited Nyiragongo in 1973, 1977 and in the 1980s. Tazieff was the person who made Nyiragongo famous through public media. The Kraffts discovered Nyiragongo through Tazieff’s old films.

During the modern era Nyiragongo has become an unusual tourist attraction. It has been visited by quite a lot of tourists, as a major attraction of the spectacular Virunga National Park. Tourism to Nyiragongo began rather early and possibly because of Haroun Tazieff who had made Nyiragongo famous in the western world with his popular science videos and books. The experience involves hiking to the summit lava lake and spending a night at the cabin huts on the crater rim. A visit to Nyiragongo can look like the following video, a good explanation of exactly what happens if you try to visit Nyiragongo.

Historical activity from Nyiragongo has been dominated by an open conduit situation with the circulating magma columns visible as Nyiragongo’s famous lava lakes with their cycles of draining and refilling. The 1977 and 2021 flank eruptions are examples of lava lake destruction when the magma column gets too tall and bursts the sides of the volcano. Nyiragongo belongs to the group of constantly active volcanoes, but in historical times it has not been very productive. It has just been open and constantly active with circulating lava lakes.

Most of the activity that you see on Nyiragongo involves Hawaiian style activity in the summit crater in the form of lava lakes or temporary fountain cones. Both styles of activity generally fills the inner summit caldera with vent lava flows or in form of lava lake overflows. Eruptive activity can last decades or even centuries with such open vent conditions, but in general not a lot of material is produced. Nyiragongo’s open vent is sourced from a deep and large storage region, with gas-rich magma rising quickly from source. Nyiragongo is significantly less productive than her larger and less alkaline basanitic sister volcano Nyiramuragira, but both are more or less constantly active. Nyiramuragira erupts as much lava as all other African volcanoes combined, while Nyiragongo acts more like an open lava gas vent.

As I mentioned there are different types of Nyiragongo activity while being the same lava.

Open lava lakes are the most famous type of activity from this volcano. There been two open conduited lava lake cycles in historical times up to this writing, one from the 1890’s to 1977 and one from 2003 to 2021, each one ending in catastrophic drainage through a flank rift. Like all lava lakes, Nyiragongo’s lake is basically a magma chamber pillar visible in the throat of the volcano. The rise of the lava in the crater fills the crater with thin sheets of lava overflows. Each stack builds a platform around the lava lake that keeps rising higher. The taller the magma column gets the more chance there is for it to catastrophically burst out through the volcanos flank. The rise of lava lake magma columns can take decades. It took nearly 20 years for the 2003 – 2021 lake to get to bursting point. Lava lakes are long lived and can last decades, or even longer than our lifetime.

Nyiragongo vents large amounts of gases during a lava lake phase. A huge steam plume often hovers over the volcano bringing acid rain. The birth of the 2003 – 2021 lava lake had a sulfur output of 50 000 tons a day! This lasted for quite a long time. After a few years the sulfur output dropped and became steady at 6000 to 8000 tons a day.

Source: www.virungaparkcongo.com The Eruption of Mount Nyiragongo

During this type of activity magma circulates constantly between the surface and the deep magma system, as hot fresh incoming magma rises and cooler degassed magma sinks back into the conduit. A lava lake may act very much like a lava lamp with its convective currents. A massive heat influx and constant supply is needed to keep the whole thing running and to keep it from solidifying. This explains why lava lakes are so rare on Earth. Nyiragongo together with Kilauea’s summit contain the worlds largest circulating lava lakes, with the 2003 – 2021 summit lake reached 260 m wide before it was destroyed in Nyiragongo’s 2021 eruption.

Another type of Nyiragongo activity is temporary caldera fillings. This occurs when the magma supply is lower, and is not enough to maintain a circulating magma column. Such type of activity forms lava fountains, spatter cones and rootless lava ponds. It is common after a major lava lake drain-out if the lava lake column fails to reform. The 1980’s and 1994 up to 1996 and the post 2021 caldera eruption are good examples of such kind of activity. This type of activity fills up the caldera as well. Lava is delivered to the crater surface but it is not circulating during this type of activity. Such activity can also happen together with open lava lakes as co- vents in the caldera floor. This kind of activity at Nyiragongo is very similar to Vesuvius early 1900’s effusive activity that filled its cone with pahoehoe lava, and such activity can last for years at a slow pace.

As placid as everyday typical summit Nyiragongo activity may be, it remains a very dangerous volcano, close to a large human population. A flank eruption and even a cinder cone could pop up right in the streets of Goma or even on the Kivu lake bottom. That would be the worst scenario, potentially setting off a catastrophic limmic eruption. Luckily for the people of Goma, flank eruptions are a relatively infrequent phenomena of Nyiragongo with only two examples in historical times, but it will only get worse the larger Goma grows and as the city is expanding towards the volcano itself. This brings us to the most dangerous and feared type of activity at Nyiragongo, flank eruptions.

Flank eruptions are caused either by a lava lake (magma column) that gets too tall and heavy and which bursts the side, or it can be caused by tectonic rifting that ruptures the edifice. The flank eruptions of Nyiragongo are superfast because of the pressure from the magma column and only last an hour or two. They are generally quite small in volume, but their speed and eruption rate are one of the fastest for any historical effusive eruption. The 1997, 2002 and 2021 rift eruptions all had fatalities, despite the small volume in these eruptions. In 2002 one vent just beside Goma airport allowed lava to to flow right through the city. Flank eruptions often exploits crustal weaknesses in Nyiragongo’s rift, and significant amounts magma that are involved in a flank eruption may be intruded in the rift and never erupt during a drain of the magma column inside. Not all flank eruptions been a fast affair. On Nyiragongo’s right side a large sparsely vegetated tube feed pahoehoe flow can be seen. Such long lived slow eruptions have covered the Goma area before a few 100 years ago. It would be a disaster in slow motion if it happens again. Formation of flank cones as mentioned are just as worrisome as the flank rift eruptions that involve the central magma storage, because a cone can pop up anywhere in Goma.

Not so long ago (a few 100 years perhaps) Nyiragongo’s summit caved in and the current summit caldera formed. This was because of collapse of a shallow magma body, either through a Plinian paroxysmal eruption, or more likely effusive drainage into the rift. It must have been an impressive terrible event if anyone was there to see it, releasing a few cubic kilometers of magma from the edifice storage system, dwarfing historical rift eruptions in scale. The true nature of the formation of the summit caldera have not been researched much, but the volcano was much taller before, with recent summit lava flows cut off by the caved-in summit. Nyiragongo today displays effusive Hawaiian activity, and has moved away from gas rich pyroclastic violent eruptions.

Very little is known about Nyiragongo’s deep interior, but according to geological investigations it probably has at least two magma chambers connected by an open pipe-like pathway. Geological investigations have found signs of a shallow and deep storage at Nyiragongo. One shallow chamber is just under the edifice and a much larger deeper one is at around 20 km depth. The magma chamber storage explains the slightly evolved nature of Nyiragongo’s ultrabasic nephelinite magma compared to monogenetic nephelinites. The summit caldera of Nyiragongo must have formed by the drainage of a previous large shallow chamber and that happened very recently, knowing how young looking the caldera is. The magma conduit pipe in Nyiragongo is deep and is probably going down 100 km or more where it connects to the deep partial melting region. The magma supply is constant but perhaps not extremely large, and if it is large a lot is probably going into rift storage deep down rather than coming up. A surprisingly large amount of magma is likely resting below Nyiragongo and Nyiramuragira, a bit like Iceland’s deep rifts storage, with Nyiragongo having the deepest magma source among all of Virunga’s central volcanoes.

Photo by Maurice Krafft: the remains of a car in the lava flood from the 1977 eruption. The eruption lasted only an hour, Maurice and Katia arrived just two days after. Today this lava flow is overgrown by vegetation. The photo can be found here https://volcano.si.edu/gallery/ShowImage.cfm?photo=GVP-00252

One of very few volcanoes where lava is an instant threat

This is one of very few places where lava poses an instant threat. Almost no volcanoes have killer lava flows, even if many people think that the lava is the biggest hazard. Nyiragongo’s main hazards are its steep slopes and associated lava lake column ruptures as will later be described for the 1977 event. Nyiragongo and Hualalai are perhaps the world’s two most hazardous effusive mafic volcanoes. Their steep slopes and fast eruption rates as well as very low viscosity pose a great threat. Close to the vents the lava is estimated to move at perhaps 100 km an hour. As it flows down to communities it goes from running to fast walking speed. Nyiragongo is the only volcano so far where lava flows have directly killed 100s of persons and indirectly caused many more deaths during the last 100 years. The precise numbers of persons killed by Nyiragongo will never be known. No where else in the world does a steep sided stratovolcano host such a large lake and magma of such fluid low silicate magma composition and pose such a hazard to such a large population. Close to flank vents during a lava lake drainage you could never escape the lava. You would have to run from them lower down and the lava may move at walking speed over flat ground. The behaviour of this lava will be described in detail in the later parts of this series.

The 2002 eruption that had fissures erupting within the city has the most recorded fatalities: over 200 died and thousands of structures where destroyed. That is likely the most of any of Nyiragongo’s lava flows drain-outs.

Nyiragongo is problematic and dangerous volcano that is in great need of better monitoring. The region is dangerous too and suffers from many issues. Goma is growing fast and buildings are constructed on the volcano’s fissure fracture systems. That is a very problematic development that was discussed in Albert’s article on this volcano.

Source: Fodor’s travel. https://www.fodors.com/news/photos/know-before-you-go-how-to-hike-mount-nyiragongo-an-active-volcano

Steep slopes despite very fluid lavas. How Nyiragongo got it shape

Nyiragongo’s steep slopes and fluid lava confuse many people, and they wonder how that is even possible. But it is not as strange as it seems. Here we will have a look at a very simple solution for that mystery.

Despite having extremely silica-poor and fluid lavas Nyiragongo is steep. Nyiragongo’s steep slopes together with fast eruption rates are the reasons why the lava flows so quickly downhill. The steepness has to do with earlier eruptive behaviour. The whole Nyiragongo complex is ultrabasic, so something else rather than an earlier composition change is responsible for the steep shape.

Nyiragongo’s steep shape was most likely formed by violent lava fountains and their pyroclastic tephra fall. High fountains earlier in Nyiragongo build a huge pyroclastic mound… think something like Puu’Oo during 1983-1986 or the major Etna fountaining paroxysms of 2015. Short-lived overflows from a high-standing lava lake may also been responsible for forming a steep pile. Nyiragongo’s magmas are very gas rich, so this could perhaps have happened at earlier times with a less open pathway, or a quick rise of gas rich magma through a narrow conduit. Many other steep mafic stratovolcanoes may also have mostly formed form high fountains caused by gas-rich magma.

Volcanoes that produce fluid lavas can get very steep if the main vents produce mostly tall fountains and therefore a lot of tephra materials. There are many tall steep mafic volcanoes like Shishaldin, Pavlof, Villaricca, Stromboli, Etna, Pacaya and a few others that have been formed by paroxysmal fountain tephras and short basaltic flows. In fact it seems that the most perfect steep volcanic cones are paradoxically formed by mafic fountains from open vent cones like the examples above here. High silica lava flows forms lumpy dome volcanoes instead.

Nyiragongo is a very young volcanic cone with most of the upper steep parts only a few thousand years old. The change to mostly effusive lava lakes may have to do with changes of how the magma system degasses and how magmatic volatiles are allowed to accumulate. Lava channels are common on the upper slopes, suggesting past high lava lake stands. Before Nyiragongo got its caldera it was probably a steep tephra cone like Shishaldin, Villaricca and Pavlof, formed by high lava fountains. Nyiragongo’s lava are very gas rich, and ideal to build a large lava fountain cone like that, as mentioned above. Nyiragongo is now too open to produce tall fountains, as gases are allowed to escape. This idea on the formation of the cone is the most likely since the whole cone is indeed ultrabasic, and other nephelinitic polygenetic volcanoes are steep fountain cones.

The painting description is from Myself. The photo taken by Dr Richard Roscoe http://www.photovolcanica.com/PhotovolcanicaFullIndex.html

Not long ago the volcano’s upper cone collapsed (because of collapse of a large shallow chamber ), forming the current caldera that fills and drains in lava lake cycles. The caldera allows us to read the eruptive history in its walls. Most of the cone’s interior is composed of tephra pyroclasts. Nyiragongo’s caldera walls are mostly made of brown oxidised tephra and ash. Its only the very upper parts of the cone deposits that have lava lake overflow deposits, thin stacks of lava overflows from high-standing lava lakes that drape the steep tephra cone. The lava drapery likely protected Nyiragongo’s perfect pyroclastic cone from the tropical rain erosion. The change in Nyiragongo’s eruption behaviour must have happened very recently, perhaps only a thousand or even only a few 100 years ago.

In short, Nyiragongo is an ultrabasic fountain tephra cone, whose summit has caved in, and that now displays effusive lava lake behaviour and dangerous drain-outs.

Having had a look how Nyiragongo behaves, and why it looks as it does, we can now have a look at its magma composition and the behaviour of its lava, which I will look at at the next part of this series…

Jesper Sandberg July 2022

163 thoughts on “Nyiragongo and its ultra alkaline magma – Part II

  1. My next part is up 🙂 and the exciting last parts will be posted later ( me and Albert will edit them )

    Enjoy part 2

    • Fantastic work Jesper, what a great series thus far.

      Had no idea this volcano suffered such a stark change in character. It’s fascinating that the event forcing this change may have only happened quite recently.

      Also that was an extremely informative description of how a lava lake drainout occurs here. I learned quite a bit from this piece Jesper, thank you.

    • Thank you : ) and more stuff soon about Nyiragongo ( in the next part we will have a look at its magma in detail )

      Yes its one of the most unusual volcanoes on this planet and there is a lack of a good description of Nyiragongo on the internet and lack of a good source describing its magma and its behaviour

      Thats why Im writing this seriers for Volcanocafe.. its needed

    • Nyiragongo have always been ultrabasic.. Nephelinites / Melitlites .. its just changed eruption behaviour
      It haves cut off lava channels at the crater rim so the caldera collapse so Nyiragongo was effusive before that collapse happened as well.

      The change from fountain , subplinian paroxymals To effusive lakes probaly occured a few 1000 years ago …

      I also wonder If the parasite volcanoes Baruta and Shaheru are still active

      • I think that the other cones represent older stratovolcanoes, Nyiragongo is maybe not so young overall but the cone that is erupting today probably is. The present cone could be only a thousand years old for all we know, it might have formed at the same time as some of the large cones to its south, in a large rifting event, like happened at Pu’u O’o, and it stayed open. Given the rate of growth seen at Etna summit cones, the summit of Nyiragongo could have formed very fast, even more so if it is only a relatively small volume compared to the whole mountain.

      • Probaly looked like Shishaldin or like a massivly overgrown SEC before its summit caved in

        • There is a break in slope around half way down the mountain, which I think might reflect broadly the shape of the ground that was there before the modern cone formed. It is about the same height as the saddles it forms with Baruta and Shaheru too. This would give a cone that is about 1 km tall today and maybe at its peak was as much as twice that, although it was probably somewhere inbetween. A cone that is 2 km tall and 5 km wide (break in slope is at this point) has a volume of about 13 km3. Mafic tephra is about 1/3 – 1/4 the density of solid basalt, so maybe 3-5 km3 of magma to make the cone, and about half of that was removed to make the caldera. This is a minimum because there are also extensive lava flows beyond the dimensions given above, and the coen may welll have formed in a much deeper saddle, but the maps dont really give good indication of what lava actually comes from the modern cone or just the whole volcano in general, unless sufficiently young to be visible. Still, probably to make Nyiragongo as it is today, would have taken maybe 10 km3 of magma.

          Current supply rate seems to be low but the heat flux is very high, maybe the actual magma flow is not so low but pressure is being relieved at Nyamuragira (not directly, just through being close to each other and pushing on one another) which is generally at a lot lower elevation than the lava lake at Nyiragongo. 2002 collapse was a volume of 160 million m3, and took 18 years to fill, an average of about 8-10 million m3 a year. At that rate, it would take about 1100 years to make what we see today.

          Maybe this is too much assumption, but it shows that the volcano is probably very young, something that is supported by morphological evidence too. Would also explain why there are no eruptions like the recent historical ones in the older record, maybe 1977 was the first time the lake actually got high enough to do that since the caldera formed, the fact there have been two very similar eruptions since might not be a good sign. If Pu’u O’o is anything to compare, it sort of fell apart after its high fountaining stage, Nyiragongo might too and maybe more catastrophically…
          Is there any data at all for how deep the lake was in 1888? The caldera may have formed in the 19th century.

          • There is a clue in Lake Tanganyika. It has a peculiar chemistry because of the run-off from Virunga. That chemistry is only around 4000 years old. Before 10,000 years ago, the water in the rift valley ran the other way, northwards. This was blocked by Virunga which became the watershed. The Virunga bulge within the rift valley is therefore only about 10 kyr. The early eruptions were massive. We now live in more sedate times in which volcanoes grow rather than explode. So yes, the individual volcanoes are very young and still evolving as we speak. It is possible that the volcanism here will die down again as the magma supply is petering out. As Jesper points out, it is already not particularly productive.

          • Not sure where Jesper said the area isnt productive, I think I actually said that and it was in reference to Nyiragongo not erupting much lava given its enormous heat flux and gas output.
            Nyamuragira is one of the most powerful volcanoes on the planet today, it is actually the only volcano to get the distinction of having a higher annual heat output than Kilauea in a year that they were both erupting, more than once. For comparison even Bardarbunga failed to do that in 2014… Dying is about the last word I would use to describe Nyamuragira.

      • Yes the volcano looks very Young .. I guess its only a few 100 s years old the upper parts

    • Well its Haroun Tazieff for name correction .. I always writes his name wrong ..

      Wants his name correct in this article
      Up to the VC dragons

    • Yes coud have changed behaviour very recently .. since Only the outer parts of Nyiragongos cone is capped by lava lake overflows .. the rest of the interior is pyroclastic tephra .. I guess perhaps 1000 years ago the change to lava lakes happened ..

  2. The lava lake in 1959 showing vigorous degassing … it was to rise many many 100 s of meters before it was drained in 1977

  3. Some intresting photos from the 2002 eruption
    Showing the highly fluid nature of Nyiragongos lavas, but similar fluid glass features have been seen in Kilaūea ( Mauna Ulu , Halema’uma’u) and the lava drapery of the lava floods coating Fagradalshrauns upper cone

    But some of these photos ( twigs boulders coated in lava glass may suggest lower viscosity than thoelitic melts, but the high Eruption rates are mostly the cause why it looks like that. Lava is strange stuff and its hard to judge the viscosity of gas rich lava spatter in still photo. Its only when the lava toutch an object like here, where you may truely see How viscous it is, the 1977 s lavas where also degassed and one reason it looks so thin and glassy. Nyiragongo Maybe about as fluid as Halema’uma’u but at sligthly lower temperatures as well .. as Nyiragongos much lower Sio2 allows it to be less polymerized at any given temperatures ( had Nyiragongo been as hot as Fagradalshraun it woud be much more fluid than Hawaii and Fagradals)

    While the viscosity of Nyiragongos own Nephelinites ( Maybe not alot lower ) than Iceland and Hawaii ( it is still very fluid ) and it does remains less polymerised at any given temperatures compared to a normal basalt because of its low Sio2 content. Nyiragongo is like Halema’uma’u crystal poor as well and another why it flows easly

    A really primitive Nephelinite/ Melinilite lava Directly from mantle is probaly much more fluid than a basalt .. like those at Vogelsberg in Germany

    I Remeber I seen some old Krafft videos from 1977 s flows as They arrived a few days after the eruption of what looks like lava covered persons and cattle, dogs .. defentivly surreal horror, near the vents you cannot outrunn this lava.

    Im dicussing Nyiragongos composition and viscosity in the next part of this article seriers

    • The uppermost photo here ( enlarge it) and look at the twigs and boulders .. covered in thin glass .. that suggest very low viscosity .. perhaps lower than a hot basalt

    • In short How viscous Nyiragongo is depends on its temperatures.. it does seem to be about as fluid as Halema’uma’u.. so its probaly a bit cooler than Hawaii ( Had it been same temperatures.. then it woud have been more fluid than Hawaii )
      And most Nephelinites are a bit cooler than hot basalts

      But a truley deep and fresh monogentic mantle Nephelinite Maybe erupting hotter than typical shallow stoorage basalts and be more fluid than oceanic basalt thoelite .. As seen as Vogelsberg

      But the deep stoorage hot plume basalts are the hottest .. But souch pretty much never erupts fresh at the surface ( I gues Kilaūeas 1600 C very deep stoorage is about as fluid as Lengai and white hot )

      • If you could get an eruption directly from the plum head in Hawaii it would look like liquid metal, there would be no polymerization at all. Some basalts from Mauna Loa, and also Puhahonu volcano, were erupted at the temperature of the mantle, not in huge amounts but it did happen. I expect Kilauea may do the same at its peak stage.

        The hottest Hawaiian lavas are also the hottest lavas known in the Cenozoic by a wide margin and hotter than the highest temperatures calculated for the most recent traps eruptions, whatever is under Hawaii is really something a bit extreme even as far as mantle plumes go. It is really not beyond the realm of possibility that Hawaii could erupt komatiite, although if that happens it will probably still be below sea level. Lava temperature is calculated from the percentage of Magnesium vs Iron in olivine, or Forsterite count. A higher Mg value means higher temperature of the melt that the crystal formed in. Some olivines in 2018 formed at over 1300 C even though the lava was about 1140 C. The hottest Mauna Loa lavas were formed at 1650 C about 150,000 years ago. It seems that at the peak of activity of a Hawaiian shield the full plume heat basically reaches all the way to the surface levels or very close to it.

        The outer submarine flanks of the older islands also erupt nephelinite flood lavas, probably the largest lava flows to currently erupt anywhere on Earth, some near 100 km3, North Arch volcanic field. The ‘rejuventation volcanics’ on Oahu and Kauai are part of this, eruptions being on the flexure arch created by the weight of Hawaii and Maui Nui. The eruptions are said to be caused by decompression, maybe that is unlikely as the deformation isnt that much and Oahu shoudl be compressed by this action, but the outer edges of the plume head probably melt at lower rate and maybe magma from this is encouraged to flow into the areas of uplift at the arch.

        • The North Arch Volcanic Field doesn’t have any nephelinites though. It is mainly alkali basalt and basanite. I expect the more voluminous eruptions are alkali basalt, if not tholeiite basalt. It is typical that large volcanic fields with voluminous eruptions produce compositions ranging from basanite to tholeiite basalt, like with Al Haruj, Harrat Ash Shaam, Lanzarote, or Savai’i.

          The only location in Hawaii known to have erupted nephelinite, although I think the term melilitite is more appropiate, is the Honolulu Volcanic Series of Oahu, although the larger eruptions were probably basanites. Which is a small volcanic field with tuff cones and maars more fitting of melilitites,

          TAS diagram of the North Arch Volcanic Field:

          • Interesting, last I read the submarine lavas were also nephelinites, although the other lavas make more sense with the scale of activity. Maybe Oahu being an island and thick crust limited melting to small amounts and ultrabasic compositions where elsewhere it was more voluminous.

    • Exactly the Deep Plume magma in Hawaii is probaly as fluid as water and looks like liquid sunlight

      But formed at 1650 C or 1710 C does not mean they erupted at that temperatures .. or Did They ? 🙂

      • I am highly sceptical of those temperature estimates. If the original magmas were really so hot then why are the magmas erupting from Mauna Loa and Kilauea so much colder even when having near-primitive compositions, and in some cases entirely primitive compositions like the eruptions in the Keanakako’i Crater area. The chemical composition of Kilauea and Mauna Loa falls in the band that extends from tholeiite basalt, through basanite, and then melilitite, that is universal and seems to correspond to primitive magmas. Mid-ocean ridges, small volcanic fields, and large basaltic volcanic fields with voluminous long-lived eruptions always tend to fall along this band. Or in other words the stuff erupting from Mauna Loa and Kilauea is almost near identical to the original magma, having underwent only minor times of storage in their relatively small shallow chambers. To me it seems hard to believe such primitive-like magmas would have lost 300 ºC on their way up. Data must always be interpreted with caution.

        • Maybe perhaps the reasoning is, I think, has to do with the thickness of the crust under Hawaii. I would think about that talk about Olympus Mons’ magma chamber. The chamber was deeper, but when it grew, the net buoyancy pressure area became shallower and so did the magma chamber, perhaps because Olympus Mons is adding more thickness to the crust.

          The same thing could be happening to Hawaii, where the magma chambers were deeper to begin with but small and more alkalitic due to less melting, but as they grew, they became shallower and, overall the crust becomes thicker as the volcanoes themselves, by technicality, are adding more crust.

          With thicker crust comes more heat loss, since they are not rapidly moving to the surface like we are seeing at Nyiragongo. They would travel and lose heat to the crust until they collect into the magma chamber where they are stored.

          For something hot like that to come the surface, either the magma has to travel fast from the source or the cust has to be thinner.

          • Unless there are open pipes of magma leading straight up into the 2 km deep magma chambers of Mauna Loa and Kilauea, which is more of what I have in mind. That way it wouldn’t need to get stuck anywhere and it would reach the chambers in its roughly original state.

            But I do understand what you say, and that it may seem reasonable to view it that way.

      • I go with Zach .. the thick litosphere and crust near Hawaii ..room for massive stoorage regions under Big Island .. and there is probaly a Big ”melt lens” under the litosphere in Hawaii where really superhot dense stuff sit. But Hawaii plume may have competely melted ( eroded ) the litosphere localy under the Big Island as well

        • Interesting, but even with parts of the lithosphere eroded, it would still have to go through the volcano itself and, since the magma is ascending at a steady pace, it would melt the surrounding rocks and add more to the magma (could be wrong).

          Another thing is the speed of the Pacific plate. Guaranteed, the plume has melted the lithosphere, but it won’t have enough time to completely erode and thin the lithosphere. If the plate was slower, hotter materials could rise.

          A major factor, however, is density. Perhaps, when the magma was rising or accumulating in a magma chamber, the denser minerals would accumulate, losing more dense minerals in the upper part as they sink. Perhaps there is a third way I forgot to know – the hotter something is, the less dense it is.

          I know this is nothing new, but the general rule for that is, we’ll, hotter rises and colder sinks. Ultrabasic magmas are mostly absent from that rule since they are alkalitic and less tholeiitic and also more gas than “normal” magma. For something hot, in this case, the plume would be hotter.

          • What exactly is the reason why ultrabasic magmas are so extremely gas rich? I believe it was Hector that posted the gas content comparisons of nephelinite / melinite vs basalt and intermediate magmas and it was sort of mind boggling.

            I’m sure the reason why was discussed in comments from one of the previous articles, but I think I think I need the explanation.


        • Right .. large stoorage areas in the volcanic edifices and the crust ( still Hawaiian lavas are one of the hottest and most fluid in the world in eruption temperatures with up to 1250 C to 1300 C for some summit lavas

      • The local litosphere is probaly competely gone under the Big Island ( or almost ) or its very much thermaly thinned as hot plumes does thermaly erode the litosphere from below

    • Virunga is not that hot .. below
      But coud Iceland be as hot as Hawaii is deep below ?

      • Iceland I am not sure, it is a lot bigger and the heat seems more spread out, but there is also a divergent boundary which should mean there is overall more heat flow. Iceland plume is not as deep as Hawaii though, which could be important.

      • If you look at mantle maps over Iceland it does extent into the outer core ( most of them do )

        Iceland is a core plume with very similar shallow chamber basalts as Hawaii

        • But the magma generation is different, Hawaii is basically all from the deep plume where Iceland is a lot more mixed, even Vatnajokull has a lot of MORB character. MORB and plume basalt are very similar so it is not a big difference, but maybe enough. If the Iceland plume was not on a ridge it would be much weaker than Hawaii.

          Hawaii really is very unusual, most plumes seem to die linearly after an outburst, yet Hawaii is seemingly cyclic and growing stronger, and potentially very old. The level of melting and temperature also stand out even going back far in the past against events of far greater magnitude, Hawaii is hotter than all of the LIP eruptions since at least the Jurassic. As said above the hottest Hawaiian lavas (and by extension the plume itself) are over 1700 C. Mauna Loa peaked at 1650 C, and only 100,000 years ago, Kilauea is currently over 1300 C despite having to share and being young, if it one day takes over completely it will probably get to the high 1600s too. There are many plumes and many other Pacific islands but none are this extreme.

          The calculated 1650 C rocks from Mauna Loa were shallow submarine dikes exposed on the Kahuku pali offshore of South Point. When active this area was probably land, so these superheated lavas were possibly able to erupt on land 🙂
          Most lavas would probably have been more normal though even back then.

      • Wow so it Did erupt at 1700 C at Hawaii? Then thats as hot as liquid titanium and probaly looks like that as well : D

        Rare cases where the deep magma reaches the surface

        Most of that is capped by cooler Thoelitic melt

        • Yes, the magma chambers allow the magma to cool. The magma system within the rift also is not as hot, 2018 lavas were ‘only’ 1140 C, compared with 1170 C for Pu’u O’o and over 1200 C for many summit eruptions. Not sure I actually buy that, the lava of 2018 was basically identical to the Pu’u O’o lava vidually and 1960 lava was over 1140 C despite greater distance and lower eruption rate. But in any case it shows the effect of magma cooling.

          One can wonder though, if an eccentric eruption did occur, like 1959 but with larger volume, it might erupt some really superheated stuff. The deep conduit at 10 km depth is supposed to go a bit southeast, so potentially a really deep divergence could erupt completely outside of the caldera. Eruptions like this happen rarely at other volcanoes, Kilauea summit is all under 500 years old, if a deep eruption happened
          near the summit 600 years ago we would never know.

        • Puu Oo was around 1150 C for most USGS figures Althrough thats from the pahoehoe peneration measurements

          Its possible that Puu Oo s main vent was hotter

          Hawaiian basalt displays remarkable smoothness and fludity even well below 1200 C

          Had Hawaii been under thinner litosphere I guess we woud see more of the superhot lava below

    • Yes the very deep plume magmas in Iceland and Hawaii are of course the hottest and the most fluid. They are so hot its very much like liquid sunlight for the eyes .. If you coud see it erupt

      ”Hot Basalt” I means the shallow hot fluid basalts in Fagradals and Halema’uma’u.. and comparing Nyiragongo To them

      Nyiragongos own deep magma is probably a ultrabasic Melilitite
      And Virunga is probaly too .. quite hot a 100 km down .. Althrough not as hot as Hawaii and Iceland

  4. Hi Albert .. well I dont think Virunga is dying at all .. ( as answer to your question above ) cannot find the reply bar there

    Virunga Volcanism is quite intense and became intense very recently and specialy at Nyiramuragira and both Nyiragongo and Nyiramuragira haves one of the very highest the highest heat production/ emission outside Hawaii as single volcanoes. Nyiramuragira vents alot more heat than Etna .. that already haves high heat loss .. and Nyiramuragira is probaly the worlds 3 th most productive volcano after Kilaūea and Mauna Loa

    • I expect the heat is just from magma that had collected before the crust cracked. It is stored heat

  5. Fantastic part 2, Jesper, and thank you. It’s amazing to think of this volcano as quite new, that people lived with it as it grew. I’m learning a lot from this series and I look forward to the next part!

  6. Thanks Jesper, great article. I remember reading from the 1894 expedition to Nyiragongo. The eruption style seemed similar to now. There were two small steaming pita with lava lakes inside them if I remember correctly. The crater floor was filled very high like before the 1977 eruption. It collapsed at least once in the early 20th century, although apparently the exact moment of the collapse is not recorded.

    • So fun .. you enjoyed it .. more stuff in part 3

      Im also looking for old films on Nyiragongo

  7. Watch it in Vimeo App
    Good HD video on Nyiragongos lava lake
    In most videos Nyiragongo does not look alot more fluid than Kilaūea or Fagradals .. but here in this one ..it does .. look more fluid than a normal oceanic basalt

    • Nice Thank you and in year 2021 Thats 45 years after the 2003 – 2021 lava lake was destroyed as well …

      Is a New open conduit lava lake comming back now ? Been intense thermal emission from satelites

  8. Sources To this Article series will be posted in this last part .. ( part 3 ) If anyone is curious

    • Hopefully this would help rank Nyiragongo based on it’s eruptions, present and past and the vulnerability of the area around it.

  9. I would suggest that the change in eruptive style occurred as a result of increasing magma production. Earlier, eruptions were separated enough in time for the conduit to cool and harden, becoming impermeable to gas. The next would then start with an explosive (or at least high-fountaining) throat-clearing phase. As the productivity went up the lulls became too short for the conduit to solidify and it has remained permeable to gas, so the magmas are able to degas gently and only effusive activity now occurs.

    This system is going to become a real monster once the main plume-head tholeiitic basalt begins to arrive, and when it does, Goma’s days are numbered. We’re witnessing the birth of a hotspot, with the plume only starting to deform the surface rocks 10Ka. It might be like being there for the birth of Hawaii, or Iceland …

    • Excellent observation and Idea .. yes the plumbing must have been more sealed before, Anyway yes I too think Virunga is the birth of a plume thats surfacing .. after all this is the only part of the Albertine Rift that is this active .. and intense activity started up very recently in latest Late Pleistocene

      Nyiramuragira Nyiragongos sister seems likley to become a very scary volcano in the future .. : O it Will probaly become like a large mix of Grimsvötn and Kilaūea thrown into one ( not as massive in edifice ) But capable of Laki sized events and shield building…. ( I wonder If Nyiramuragira was more alkaline when it was born )

      The real killer will be a possible future Holuhraun sized rift eruption under Lac Kivu … releasing many 100 s of km3 of stored cO2

      Better they move Goma towards Karisimbi.. but the whole arera Maybe turned into lava flows so Nowhere is safe

  10. Dont kniw about more sealed, just not as wide. Pu’u O’o started as a small open hole along a fissure, it stayed that way for 3 years more or less. During that time lava was usually visible although not erupting. When major flank vents opened up in 1986 and thereafter the conduit caved in and became wider, so pressure couldnt make lava fountains anymore. Long term effusion rate and gas emissions for the high fountain stage was not any different to later shield building though, just that it was continuous instead of erupting a month worth of lava in a day…

    I think Nyiragongo would be a lot like that, first making a tall cone but eventually the vent was not narrow enough to allow episodic fountaining. The high gas content probably meant that limit was a lot higher than for Pu’u O’o, but still a limit existed. The effusive stage probably began at this point, when fountains were not tall enough to land as tephra but rather as a liquid. Probably was not long after that the true lake formed and fountaining ceased almost entirely, and then the caldera probably relatively soon after that. I think the fact that lava lake breakouts only seem to have started in 1977 is important still, unless there actually are older breakouts I am not aware of.

    • Collapse of the 2003 – 2021 lava lake
      Last year and It does look like that the shallow 2003-2021 pipe conduit really was ruined. But in 2003 the conduit quickly reformed after 2002 s drainout

      Look at that cone .. one of the most beautyful active volcanoes on the planet

  11. Talking about hot lava: Manchester had a minimum temperature last night of 26C. I am speechless (from the warmth..)

    • It is under 10C all day where I live, and down to freezing at sea level at least a few times… Tasmania is known for being cold by Australian standard but it is very rare for it to actually be freezing (and almost snowing) at sea level as it was yesterday…

      I dont want to jump to conclusions, but I wonder if Hunga Tonga is not unrelated to this. It was after all one of the biggest eruptions in the past few centuries and probably the one that has most effected the upper atmosphere since proper records began.

      • I won’t fully exclude this but it will be from disturbing the atmospheric circulation (water in the stratosphere) and not from sulphate cooling

        • That is more on the lines of what I was thinking. The SO2 emissions were not excessive but the sheer height of the plume and the volume of water it ejected, I expect that will at least do something. Eruptions of the magnitude we saw here are not a common occurence, maybe even the last was in 1883, even though larger volume eruptions have happened in the interval.

    • 49C in the garden yesterday afternoon here. Thermometer only goes up to 50C so probably best not to repeat this pm :;

        • Radiative temperature. The air temperature will have been more ‘moderate’. Here it is 36 at the moment. That is in shade, 1.5 meter high and in the open air

          • 40C just down the road …. and we are not going to be the hottest part of the UK

          • To be honest, temperatures like those are quite normal here in Saskatchewan, but it looks like temperatures like this have become more frequent, with it nearly being hotter last year. On that note, there also have been cold spells in the winter longer here, but that looks like it is now becoming shorter. The weather is getting wackier here.

    • Luckly you dont have Nyiragongo in your backyard Albert
      .. Althrough last evening I dreamt of Nyiragongo towering over London 🙂

      In part 3 I Will have a look at the magma itself and Will provide the sources

  12. If it’s any consolation to VC’s European brethren, here in northern California (not desert), our high today should be around 41C (105-106F). That’s only ~ 3-4F higher than “normal”…so pretty much business as usual.
    Mt. Shasta and Mt. Lassen are almost snow-free already with at least two months to go before the first light precip begins our rainy/snow season in late September/early October.
    I remember both mountains used to have a solid ice cover all-year round, but now, even the glaciers are gone come Summer.
    Oh well, glad I’m old enough to remember.
    However, other parts of the central U.S. are seeing temps near/over 110F…but with way more humidity than in NorCal…so conditions could definitely be worse in my neckadawoods. Thank goodness we’re not seeing a repeat of the mega-heat of June, 2021 when Lytton in British Columbia (north of 50N latitude) hit 122F, then burned to the ground a few days later when a train sparked off a wildffire just outside of town destroying 90% of the town and killing two people. Never before anywhere in the world has temperature hit 50C that far north.
    According to the math, temps that high would be physically impossible were it not for global warming.
    How sobering to know that 50C in the future will become more and more likely.

  13. Keep in mind that all of these high temperatures are occuring during a strengthening La Nina. It will be very interesting to see what temperatures we get when the next El Nino arrives. Here in the N American Pacific Northwest average temperatures are usually higher during El Nino periods.

  14. Enjoyed the article and enjoying the lively discussion that it has generated, including the weather reports from around the world. Nothing unusual, weather-wise, for the NY City metro area. Lovely summer so far.

    • I felt jealous – until I remembered what a normal New York summer was like

      • Laughing. I take your point, “lovely” is subjective, but compared to where I grew up, near the Mississippi in the southern Midwest, the weather here is mild. Your heatwave will pass soon. In the meantime, this link, if it works, may help you cope.

    • Leilani Estates is the same, was always between 19C and 24C no matter the weather. Might have been colder at night but not significantly so. The coldest place I went in Hawaii was the summit of Kilauea, which was probably about 10C, far from tropical but not too cold either. Apparently it has got to about 0C there before but rarely, in any case though climate up there is definitely more temperate, reminded me a lot of home.

      I was told that the middle of summer is significantly hotter than late April but most of the year is pretty mild. Hilo was not really hotter but a lot more humid, it didnt really ever rain properly just looked like it was going to all the time… 🙂
      I never went near Kona but it is probably a lot more temperature variable being more arid, the sun will probably feel more intense. 30C in the shade can be comfortable but out in the sun it is like standing next to a fire.

    • Kilaueas summit haves 3 climate zones, and the wet part is very much like New Zeelands temperate subtropical rainforests ( 12 climate zones on Big Island )

      Yes Kona is like an incenirator
      I been there many times .. Kailua Kona often push above 30 C in shadow and combine that with Hawaiis high humidity .. and its Impossible To be outside really
      Reason To go To the Kona Coast is To Enjoy their clear blue waters, Hawaii is the clearest waters in the world .. its isolated in the tropical pacific and haves zero nutrients, visibility of 70 m is possible in the water .. thats one reason to go to the hot Kona lowlands
      The dry side is very hot .. even in winter intense sun
      Im supprised

    • Hawaii in lowlands is quite hot all year around .. even in winter it can push above 30 C even at latitude 20

      It haves Equatorial Temperatures all year around in Kona .. 1600 Miles north above the Equator .. and in an oceanic area is as well.. and that suprised me the first time I was there

      Hawaii is in a High Pressure belt and that probaly explains the hot weather as the sinking air warms up .. causing a bit of like Sahara heating .. But over an ocean. The ocean is also quite warm in Hawaii ( 26 to 28 C ) depending on season .. and that too helps to warm things up I guess

    • I doubt Hawaii woud be any hotter If it was on the Equator

      But there woud be No dry side if it was on the Equator .. as there is No trade winds there

  15. Can regular VEI 6 or even VEI 7 eruptions gradually reverse the climate change by global cooling, or can we expect more disruptions of weather patterns by such volcanic eruptions?

    • It woud cool it If its extremely violent and sends the ash into upper stratosphere

      Multiple ones may form small nuclear winter

      But the global warming woud come back severely after a few decades of cool weather .. with more cO2 from human activities.. when the sun returns at full strenght

    • Instances of volcanic cooling are relatively short lived. Pinatubo’s VEI 6 cooled for 2-3 years. I’m unsure what the mechanism would be even for a much larger and more sulfur heavy eruption to last more than 5ish years; the sulfates work their way out of the stratosphere pretty quickly.

      I think some feel the LIA was caused by volcanic cooling, but I think it’s more of a combination of different forcings punctuated by some very large eruptions to force things even more downward for a while. Albert has published an article here about the LIA mentioning it may have been the beginning of the slide back into a stadial (glacial) period, as the Holocene has been quite protracted. Of course, our footprint has apparently terminated that slide as we start sliding upwards instead.

      Hypothetically if we could even somehow control VEI 6 eruptions and have them go off consecutively (and somehow safely for locals), I’m sure that could put a dent in the current +1C temperatures right now, but it’s hard to view that as anything more than a bandaid. So many variables at play, too.

    • Technically no eruption of a scale that is sensible on a planet like our own will be able to permanently effect the climate. We are in a glacial era now because Antarctica is an island at a pole, surrounded by deep ocean on all sides, anything will be temporary until a land bridge forms over the Drake Passage or the continent either moves away from the pole or breaks up. There might be other important factors too but volcanoes tend to be too short lived, even extreme events like major trap formations will be temporary excursions, as will our own effects. Probably anything a VEI 6 or lower will be maybe a year of actual effect, depending on variables.
      Actually this year is a good test, a major eruption in a place with abundant calderas at mid latitude, the caveat is most are shallow submarine. If Hunga Tonga has not had any affect on climate it might mean even very powerful submarine eruptions are not going to do much and that an eruption on dry land is a pre-requisite. That would leave only Indonesia and the northern part of South America as viable climate disruptors today. Everywhere else will be largely hemispheric unless you go all the way to VEI 8.

      If Virunga does actually evolve into a monster volcano or a traps formation, it is very much equatorial… Might actually be a big hit to the biosphere assuming it is still intact after we are done with it.

      • HTHH will be a weird case. Its 400,000 tons of sulfur release is something like 1/40th of Pinatubo’s depending on which measurement you take for that eruption.

        I know there are other volcanic particulates involved, but water vapor itself is a green house gas.

        In short, I have no idea what HTHH will ultimately be responsible for on a global scale this year, and I’ll leave that for people far smarter than I to ascertain. This one seems to be a confusing case, to say the least.

        I will say, tracking Climate Re-Analyzer, the Antarctic has been showing negative temperature anomalies up to -5C on certain days, and consistently somewhere around -1C. Now we’re seeing continued volcanic sunsets in the Antarctic. Very interesting to say the least.

        But the NH remains pretty decently above normal, about + .06 C, and the SH has been vacillating between slightly below normal to flat.

        This is not data, just anecdotal observation. I’m very curious to see what is said and done after this year.

        And I’m even more curious for the next sulfur laden large eruption to track in the modern age. Perhaps somewhere near the Yucatan with all its anhydride (wasn’t this in part why El Chicón was so stinky?).

        That will be an interesting test case. Not of course for the locals near such an eruption, and as always with this sort of thing my guilt equals my curiosity.

        • Err, not really volcanic “sunsets” in the Antarctic, rather more like a continued volcanic twilight? Regardless, the recent images from there are JAW DROPPING.

        • Going to say while not extreme this year has been colder than I remember. As I type this it is 2C at 44 meters above sea level, last year I remember a few nights it was under 5C but this year is almost the norm… Two days ago it almost snowed at sea level.

          SO2 content of the magma is something interesting, I think a lot of it would have washed out but if Hunga Tonga Hunga Ha’apai is low then probably all of its neighbors are too.
          As for eruptions with very high SO2 emissions, we have had one, in Hawaii in 2018 🙂
          Kilauea SO2 emissions that year were comparable if not greater than from Pinatubo, though probably nothing significant of that became stratospheric. Holuhraun was also probably very similar. That is actually why I am surprised HTHH was such a low value as its magma was a mafic-intermediate closer to that in Hawaii ir Iceland than to a silicic magma like Pinatubo.

          • Yeah I thought as per Kilauea and Holuhraun, you really need that explosive component to get the SO2 into the stratospheric aerosol vale.

            Laki caused a profound decrease because it did have explosive components, and I’m sure the extreme heat generation created thermal updrafts lofting SO2 perhaps just high enough.

            Still wasn’t Laki 100Mt? If all of that hit the stratosphere, perhaps we’d be in the next snowball earth by now, lol (kidding).

            Seems like most of the gas from effusive events stays within the troposphere, hence most of Laki’s SO2 going on to regrettably choke people in Europe.

          • Given what we know about effusive volcanism I really doubt most of the SO2 from Laki would have done anything. It probably did make a massive vog cloud and a lot if problems in Europe but nothing stratospheric. I dont exactly know where Carl gets his data on the eruption from (also not saying he is wrong) but apart from the volume there is nothing inherently different between Laki and Holuhraun, the scale of features is similar. Laki was not a 25 km fissure all at once, it was originally 1-2 km long, like Holuhraun, the output was greater but the 6000 m3/s sustained rate is probably exaggerated as is the 1600 meter fountain height, I found fountains probably reached 400-600 meters, which lines up with other eruptions. Unlike Holuhraun more fissures kept opening without the original closing up, so the output probably did get 10x as high but it was also spread along 10x as much length, so activity at a single location generally speaking probably wasnt any different.
            Now, Kilauea was much more intense than Holuhraun in effusion rate. The numbers dont lie, the two eruptions were almost the same volume (1.5 vs 1.6 km3) but one lasted 3 months and the other 6. DRE effusion rate for Kilauea when it had settled at fissure 8 was around 500 m3/s, or between 1500 and 2000 m3/s bulk rate. Some surges might have doubled that, abd that is when we saw the raging lava rapids and the channel overflow all the way to the ocean as an incandescent surface.

            Explosive eruptions from Laki were probably eruptions under Vatnajokull, or maybe much more likely the reflection of the lava glow in steam or existing clouds. After seeing the way lava interacted with the lake at Kilauea in 2020, by doing absolutely nothing at all when we all thought it would explode, I have a hard time seeing the comparitively tiny amount of water present in the Laki area having any affect on the eruption at all. Holuhraun erupted through an alluvial plain too, with no fanfare.

          • There could have been an increase in albedo from the vog cloud itself, as a cause of cooling in 1783 too. There also was an eruption from Asama in Japan, a VEI 5 plinian eruption. On its own probably not enough but combined might be a different story, forming a high particulate layer to compound with the vog.

          • Chad you are far more technically informed than I am about these mechanics and processes, but from everything I’ve read here about Laki and elsewhere (a couple papers), I believe individual fissure swarms opened with an explosive phase.

            Laki is rated IIRC as a VEI4 on Smithsonian, and I’ve seen other sources cite it’s explosive component as a VEI 5. Obviously 15km^ 3 of total effusion, but still a decent “opening salvo” of explosive activity as the different fissures activated.

            My understanding is that Laki is a different case relative to Holuhraun or 2018 Kilauea.

          • I think it probably was a VEI 4-5 but I dont think most of that came from vent clearing of the Laki fissures, it probably came from subglacial fissures. There might have been vent clearing but if you spread out all of that along the whole line of fissures the volume coming from a single segment is not so big, it isnt like a 20 km line of plinian eruptions which is something I thought in the past. The same thing would apply to Veidivotn, it was a VEI 6 but nothing like a VEI 6 from a stratovolcano,more like a VEI 4 that lasts for a long time (most likely months).

            There is actually a tuff cone on the Laki fissures, maybe the first eruptiins did encounter groundwater, but the majority of the eruption outside the glacier seems to have been hawaiian-strombolian, lava fountain fallout can go along way especially for fountains in the 500 meter range like this so the isopatch doesnt necessarily need to be showing an explosive phase.

          • Eldgja probably was more exiting, however. Katla is an alkaline volcano, at least for Icelandic standards, and its magma seems to have an enormous CO2 concentration. Some sources say it is the source of 5% of all global volcanic CO2 emissions abd that is when it is dormant. For a volcano that erupts maybe 1 km3 of magma in a century or more, that is really quite an insane number.
            Eldgja probably was a very fluid magma, Katla basalt is typically under 50% SiO2 and the lava flowed 80 km to the ocean. But Eldgja was not a copy of Laki, it constructed a massive line of tephra cones and craters. Given what we know about these gas rich fluid magmas the fountains would have been intense, a lot of the things said to have happened during Laki probably actually did happen during Eldgja. The VEI 6 rating also seems a lot more solid than numbers for Laki too, there were major eruptions under Myrdalsjokull and possibly caldera formation. It was Katlas biggest Holocene eruption by a factor of 10. 🙂

          • Really interesting posts (as always Chad). I’m constantly re-ordering information in my mind about these events as I come to understand them better, and I appreciate your insights.

            Glad you touched on Veidivotn because that’s one event I couldn’t form a mental image of. Very interesting.

          • And yes, Eldgjá is one of the most fascinating events to me in existence.

            I can’t even imagine what it would be like to be a witness to Laki, let alone Eldgjà.

            There’s that one commonly referenced image of Eldgjà that looks like a large surface graben or channel. Was that entirely filled with a torrent of magma? I can link it if you’re unsure to which I’m referring.

            My wife and I are planning our fourth trip to Iceland this coming fall, and I’d really love to get to see some of these features in person. Some are more accessible than others and we’re relatively comfortable with hiking in remote areas, but the highland F roads are closed the time of year that we go.

            Always a decision between seeing these amazing volcanic features up close or seeing the Aurora borealis. It’s hard not to choose the latter…

            (Also, I’m weird and love the cold).

            I did stand on top of Langjökull though, which is pretty awesome.

          • Not sure you should take any of this as fact, it is just based on my own observation 🙂

            Veidivotn might have been a bit bigger than I said, the fissure like is 60 km long and most of it looks to be of rather normal scale volcanism, but two areas do have quite substantial craters and cones, those might have been sisable 5s in the proper sense. Might have looked like the massive surtseyan eruptions at Hunga Tonga the day before it blew up.
            Vatnaoldur, the previous Veidivotn eruption before 1477, mostly happened on a 10 km section of rift and made two massive tuff cones. The presence of the cones might mean most of the eruption was not plinian, so the wet ash could fall at the vent.

          • Very cool, those are fascinating events.

            It’s not so much that I take comments as facts as much as I absorb different tidbits of information and incorporate them into my flexible understanding of the event.

            Thanks man.

  16. Hmmmm this needs to be corrected in this part of the article Tazieffs Name
    Haroun Tazieff

    ”During the modern era Nyiragongo has become an unusual tourist attraction. It has been visited by quite a lot of tourists, as a major attraction of the spectacular Virunga National Park. Tourism to Nyiragongo began rather early and possibly because of ( here Haroon Tazieff )who had made Nyiragongo famous in the western world with his popular science videos and books. The experience involves hiking to the summit lava lake and spending a night at the cabin huts on the crater rim. A visit to Nyiragongo can look like the following video, a good explanation of exactly what happens if you try to visit Nyiragongo.”

  17. For the past couple of months, I have been checking the camera on top of Thorbjorn that continuously sweeps a 270° field of view from Grindavik to the Svartsengi area.

    Today I noticed that to the ESE of the Svartsengi Geothermal Plant, there are several white plumes, (steam/water vapour? possibly smoke?) emanating from the ground. I have not been aware of these plumes previously. I checked the Iceland News and nothing abnormal was being reported. To my totally untrained eyes, the earthquake and tremor plots didn’t seem to show much activity, though I could be totally mistaken.

    Obviously, this is a hot subterranean area, hence the geothermal plant. Is this type of sporadic venting activity normal? Indicative of anything?

  18. Not sure if it is a real signal but at Kilauea the last two DI events have really shown up on the GPS. Last week 3 of the plot points tracked way above the long term trend, then went back to normal, and now seems to be going up again. It is a bit less of a DI event and more an ID event, like the opposite.
    There might also be a rezponse at Pu’u O’o, the trend there is still down but not as much as before, and last week it even looks like it flatlined at the same time as the above mentioned excursion at the summit.

    The lava lake has been relatively boring too, even when tilt is high it is not nearly so active over the whole crater and the level has not risen much for a while now. Might be that the summit now has enough pressure to start sending magma to the rift zone again and has resumed doing so since the start of the month. ID events (or reverse DI events if you like) might be brief interuptions where the summit can pressurize a bit before resuming.

    If this is correct then ERZ activity could begin quite soon, in the next year or so, will be interesting to see how far east the magma can flow after 2018.

    • https://www.usgs.gov/media/images/global-positioning-system-k-lauea-summit-past-year

      Actually just updated and shows what I mean nicely. There is no sudden inflation spike anywhere but the cross-caldera measurement has jumped up, twice now. Very fast too only a few days either direction. Signals on this plot are verified and real, so something weird is going on. CRIM seems to be accelerating east, but not south, not sure what could cause this, because nothing has changed further east yet…

  19. Jesper, I liked your last post, but I LOVE this one! I am glad for you that you discovered your passion for volcanoes early in life. (When you were turning three, I was turning 39!). And, I am very glad to see that you invoked the name of the great Haroun Tazieff. During my late childhood & my teen years, Haroun Tazieff was the go-to guy for articles, pics & films about volcanoes. There were others. Maurice & Katia Krafft were starting to make a name for themselves then. And, there was the writings of the great Australian volcanologist, Tony Taylor, specifically about the 1951 eruption of Mount Lamington.

    Jesper, keep up your good work and you, too, will be a go-to guy when it comes to your writings about volcanoes, especially Nyiragongo.

    • Thank you Will be more Nyiragongo stuff soon ( pt 3 )

      Well of course indeed Maurice and Katia Krafft took volcanology To the worlds media scenery with their infamous films .. and I grew up with that ( I was born in 1995 and then it was Only the kraftt films that was the only good volcano recordings existed until 2000 s ) the Kraffts spectacular videos is what made me into a volcano addict. In 1970 s 1980 s and Early 1990 s Maurice and Katia Krafft was the best volcano recordings there is .. ( and their recordings are still the most spectacular that have ever been made of volcanoes .. with themselves going very close to eruptions )

      But Hauron Tazieff also tryed earlier with pinoneering volcanology for Public .. Althrough many of his films are a bit older and less quality .. his book Nyiragongo the Forbidden volcano is a book that I haves to buy 🙂 Tazieff was a close friend with Maurice and Katia Krafft and Jacques Durieux .. all have visited Nyiragongo as well … Tazieff have taken most of the pre 1970 s footage of Nyiragongo

  20. Part 3 and 4 is upcomming : )

    But I haves to edit them .. and improve them and adapt them as single parts. Im on vacation now and I dont have acess to a computer, so cannot edit them effectivly now

    I will send texts to Albert that be can stuff in Part 3 .. to improve it

    • Can’t wait! Really excellent stuff so far Jesper.

      I’ve learned a lot in the past couple years but one thing that really eluded
      me was a better grasp on magma chemistry. I have to say you’ve been a constant source of wonderful little nuggets of info across all these different articles that have helped me form a better picture.

      And then this article series of yours, your first published pieces here, have been absolutely outstanding! Keep it up man!

    • Very good .. and now I Will start editing Part 3 will send you the Introduction tomorrow.. yes part 3 needs To be worked on and Refined ( will be much faster When I gets back to the computer later )

    • Very good But please add the photo credit and source as small text below it 🙂

      • The photo credit I sourced in mail .. so please add them under the photo that you added in 🙂 its a must

  21. Nyiragongo is a far more capable and productive than a first tought, in 2016 – 2021 it had almost kind of like a ”shield building in the caldera” with that spatter cone effusing lava at rates of 1 to 4 cubic meters a second for years and that is pretty Impressive. At current violent spatter cone activity seems to be occuring in the caldera as well 2022, coud Nyiragongo too grow into a rouge volcano with ” devilishly scary capabilities”? Nyiragongo seems to like small infant seed of something much larger
    Perhaps Nyiramuragira looked the same a few 1000 years ago



    • Spatter cone was flowing back into the lava lake though, a lot like at Kilauea late last year the vent output was a lot higher than the actual magma flow because it was a circulating system. It is possible though that fillign rates that hig hdid happen in 2020 and 2021 though, it filled up that crater pretty fast that year compared to before.

      It looks like the lava lake has reopened, part of the cycle. Probably will drain out again in 2048.

  22. Chiles-Cerro Negro is chugging out 2000 quakes a day now with a significant increase in LP quakes, Hydrothermals are getting hotter, and deformation is on the rise. This would be the third major swarm but we still have no explanation on what’s the cause. I’m going to write an article after I get some some more information.

    • Will be fun: for now me and Albert are working on Part 3.. Making it more readable and Improving it

      I dont have acess to computer at moment but will have in a few days

    • Is there a website or link that shows you daily earthquakes at that volcano? I couldn’t find anything but maybe that’s to do with the fact I searched in English rather than Spanish.

    • If it does erupt I think it will initially be effusive, and then explosive at the end of potentially rather massive scale (you get your VEI 6 🙂 )
      Basically a whole new mountain to form over the bext years or so. Could well be a lot like Quizapu in Chile, effusive first stage that lasted for decades and erupted basically the entire magma spectrum sequentially starting with rhyolite, then another silicic pocket was breached in 1932 and the whole thing ended off with a plinian stage that was a VEI 6 by some estimates.

      Will be quite exiting to see such a long dormant volcano erupt, usually such events are of large scale regardless of eruption type 🙂

    • Please do, I’ve been following it as closely as I can and as far as I can tell, things have been looking rather spicy.

      I do hope, if warranted, they’re able to evacuate all of those that would need to. I think part of the concern would have to be not having much of a handle on its eruptive characteristics given the extremely long dormancy. I’m sure the local agencies know much more about the mountain though.

    • I read a report that lava from that eruption flowed through the jungle at 10 km/h, carrying trees to the ocean. There hasnt been an eruption like this after WW2, but Ambrym can do some big eruptions. It is hard to see though because the climate is tropical to the extreme and there is a lot of ash.
      What I can read though is the 1913-1914 eruption was a major rifting event probably of similar scale to Holuhraun or Leilani, and bigger than what happened there in 2018. Ambrym might do cycles of high activity, abd most of the past 50 years was low, so only lava in the lava lakes and not erupting. That might change soon.

    • I Wonder How fluid Ambrym really is
      Its probaly almost as fluid as Hawaii the reason Ambrym looks clumpy and frothy in its spatter is mostly because its so very gas rich .. its also quite bright so high in temperatures, coud be a bit more crystal rich than say thoelites

      But Ambrym is really really really fluid as fluid as many Icelandic magmas althrough the gas compositon is more cO2 rich than Hawaii and Iceland.. defentivly lower viscosity than most other subduction zone volcanoes, its rising quickly from source


      • The lava lakes and most summit eruptions are a bit more evolved, even up to andesite in 1986, the high temperature covers this but the lava is a bit more strombolian.
        The flank eruptions like 1913 though are fed by the larger magma system below, and those erupt lava that is very similar to that in Hawaii. 1913 was described as a fissure eruption with very fast lava rivers and pahoehoe, so it is likely the lava is at least the same temperature range as Hawaii or Iceland. The 2018 intrusion was part of this category, although it didnt erupt on land but offshore (probably quite deep)

      • Yes it looks more clumpy and less fluid than Hawaii and Nyiragongo

        But in some videos it looks almost as fluid as the latter



        Ambrym is a very fluid lava and If the lakes overflowed you wood almost certainly get sheet pahoehoe that spilled out… the high temperatures 1160 C is probaly the cause of that

        Masaya is the same

        • Nearby Aoba is quite interesting, too. The volcano is very much more dominated by basalts, more so than Ambrym, but it can’t really form the unique lava lakes of Ambrym due to a lake of water at the summit that keeps it explosive.

          • Both of them are basaltic, Ambrym has a tiny portion of silicic rocks but these constitute only about enough dacite to do a VEI 4, it probably erupted from a caldera fault as it collapsed but was neither the cause of the collapse or what set it off. Ambrym is basically if you put Grimsvotn on an island.

            Ambae/Aoba did have an effusive phase in 2018, where the lake was temporarily excluded, its lavas seem to be a bit less fluid actually, more like the stuff that Etna erupts. That might have been from older magma that had cooled though, but Ambrym is definitely the hotter of the two.

          • On that note, Ambrym is quite different from Ambea in that there were older structures that go in a N-S direction, in which they look to be like stratovolcanoes.


            Looks like, hypothetically, Ambrym was a collection of N-S stratovolcanoes before something happened where it changed to a singular location and activity became more E-W… maybe even the caldera formation might be some sort of transition era from the typical stratovolcanism to this now. Again, this is a little speculative.

            link replaced with smaller image which should actually load – admin

          • oookaaaay… looks like the picture is somewhat visible on the comments, but still need to look a bit closer as the text is small.

          • Besides the point, Ambrym is less of a shield volcano compared to Aoba, but since Aoba is less studied than Ambrym, I can’t really know for certain if Aoba had older structures, which is less likely, or if it had been in a shield-volcano building mode like since it first popped from the ocean surface. At least, based on the map, Ambrym’s history is at least clear, but, unless otherwise, the exact geological history of Aoba can’t really be certain.

          • Ambrym is a pyroclastic shield, which is basically a stratovolcano that has the shape of a shield volcano. It is though relatively rare in that it is basaltic and actually does have liquid lava, most pyroclastic shields are more silicic.

            Stratovolcanoes and shield volcanoes are basically the same thing where one is able to get further away from the vent than the other on average, is how I think of it. A cinder cone is just an earlier stage of either of the others, as we have seen such cones evolve both into shields (Pu’u O’o) and into stratovolcanoes (Etna South East Crater, Izalco, Cerro Negro), and lava composition seems not so important as all of those examples are basaltic or close to).
            There are also cases of shields that turned into stratovolcanoes, and Etna has even partly turned back to a shield again. Shields of any sort might be a good indicator of high magma supply to an area regardless of how active the area actually is by eruption rate.

          • I know that Ambrym is a pyroclastic shield and that shields can change into stratovolcanoes and back to shield. What I am thinking is that there was a chain of stratovolcanoes that go in a N-S direction to form an island. Something happened, probably because of the formation of the caldera about 1900 years ago, that made the stratovolcano phase, which was both ankaramite and basalt then just basalt towards the ends top, stop. Then, the modern Ambrym began to form along a sort of fracture zone, where basalts filled the caldera and eventually forming rift zones along that fracture zone. Like, there is not really a transition between the stratovolcano phase and the shield other than that big eruption. It looks, in a sense, not your traditional stratovolcano-shield like Etna.

          • Remember about that thought that rifting are sometimes associated with supervolcanic activity (I.e. Taupo)? Maybe, and hear me out, but the rifting probably came before the caldera formation, acting as a sort of room-maker for a large magma chamber, maybe kinda similar to Yellowstone but on a smaller scale. The caldera forms and the magma input rates increase to the point basalt became the dominant material erupted again.

    • I feel like the next Katla eruption will be an absolutely major problem for the modern state of Iceland, with respect to the incredible number of tourists present nowadays. With the south and Vik being one of the first sections of the country most tourists visit, an eruption from a large volcano just about the southern part of the Ring Road would be exceptionally disruptive. To say nothing of the jökulhlaup.

      Would have to hope for ample advanced warning.

      • Katla rests just above* the southern segment of the Ring Road, not about.

        iPhone autocorrect is both a marvel and a scourge.

    • Katla is usually a bit twitchy in the summertime due to the melting glacier. Shallow quakes during summer are nothing out of the ordinary – Katla does them regularly. Most are small, but anything up to M4 is not unusual. If you start seeing deeper quakes, then it’s time to pay attention.

      Having said that, all of south Iceland looks a bit twitchy today. From Mýrdalsjökull through the SISZ up to Langjökull and then the entire Reykjanes peninsula. There’s even some activity out in the dead zone between Mýrdalsjökull and Vatnajökull.

      • Yup, definitely. Just started thinking about how even as recent as 2010’s Ellafjallajökull eruption took place with a much lower tourist load than the island carries today, mostly year round but of course with the most activity in the summer months.

        Still, we’ve been there three times between 2017-2019 in the late fall and the amount of tourists was absolutely massive.

        Icelanders know what they’re doing and they no doubt have their contingencies mapped out for an eruption from any of the usual suspects, but I’ve been wondering lately just how they’ll manage a disruptive event from say Katla, especially if it occurs on relatively short notice.

        Even just the routine storm / wind warnings go ignored by overzealous tourists overestimating their ability to handle the often rough weather conditions (often making Icelandic SAR come and save them, at their own peril of course). Add a large eruption to the mix and I can see a lot of potential issue.

        Such an amazing country for so many reasons. The rest of the world has started to catch in and flock there. Volcanoes and hapless tourists don’t mix.

        • I dont think Katla is their worst case not even close, it is capable of some big eruptions but not huge eruptions, VEI 5 or so, which is not big enough to directly be dangerous to the road or to Vik. Katla VEI 5s are not ignimbrite eruptions either, they are episodic plinian eruptions, usually lasting many days or weeks, if the ice was gone they might be sequences of violent high lava fountaining instead. Floods are a problem but also not one that is unknown, actually there is a flood warning just about any time Katla does anything at all, so chances are the eruption will be more surprising than a flood even if it is a once in a millennium jokullhlaup. I think that Katla really is exaggerated in its danger following what happened in 2010, I actually think it is one of the few places that could have a full scale VEI 5 and be safe to view relatively up close.

          I think being realistic as a point of view of largest cost, the worst case is an eruption at Hengill or Svartsengi. Both of these are directly related to electricity generation for Reykajvik, which is a problem considering Svartsengi is waking up and -very- likely to erupt this decade or even this year if things keep going… An eruption at Veidivotn could also be a big problem, given its proximity to the Búðarháls power station and dams along the Thjorsa and Tungnaa rivers.
          There is also the case of the next Laki, but I dont think anywhere in Iceland at present has got enough magma in the right place to do that. The aforementioned eruption from Veidivotn is probably an upper limit on size today, the area is due to rift this century but Holuhraun has already taken off a lot of pressure.

          • The worst case would be an unexpected eruption in a town. Think Eldfell. If this had erupted just a kilometer west, the town would have been overrun by lava in the middle of the night and there would have been significant casualties. It was a close thing, even with the well organized rapid evacuation- helped by the fact that much of the fleet happened to be in harbour because of the weather. But that would not have helped if the eruption has been in the town. Remember Kapoho – the evacuation route could easily have been cut much quicker, leaving the residents trapped. We remember the successful evacuation but easily forget how much worse it could have been.

          • I was definitely thinking along the lines of a sudden explosive event as they really haven’t had one in the peak of their tourist era that began in the mid 2010’s.

            But I absolutely see how a poorly placed, large effusive event could be the most damaging and hazardous.

            Thank you as always for the information you choose to share, Chad. I’m always learning something.

          • That would still be Svartsengi as a worst case, under Grindavik. That eruption could still end up being harmless and more likely than not it will, but it is not a low chance of a disaster.

          • It’s very unlikely that a sudden explosive event from Katla would happen without precursor activity. Most likely, there would be an intense earthquake swarm with thousands of earthquakes and plenty of time to evacuate.

  23. Hi Albert I sent More information to add on
    part 3 .. of my seriers.. I dont have acess to computer at moment so thats why I asks you to edit it … you can also send it over to me later so I can edit.

    Part 3 and 4 is upcomming : )

  24. I’m thinking about going somewhere volcanic for my birthday next year, does anyone recommend anywhere that is a) fairly cheap b) safe – more in terms of crime etc. and c) interactive, somewhere with guided tours and museums etc. but also maybe with other nearby volcanic features that can be visited

    Iceland is the obvious one but i’d prefer somewhere warmer given the time of year.
    Italy also but heard bad things about Naples and Catania (could stay in Florence I suppose!)

    I have been saving up for somewhere a bit more exotic.

    • Firenze (Florence) is absolutely gorgeous; as is Vesuvius in person. In 2008 I spent four months in Firenze studying abroad, and it was one of the best experiences of my life. Rome and Naples aren’t the “safest” as is part of your criteria, but we walked all over Florence day and night, often quite inebriated (as twenty year olds abroad often are) and we never had anything approaching a problem. The local people were a delight.

      Sorrento is an option (though a bit further south) to use as a “base” to get you to Vesuvius, Campi Flegrei, Ischia, and then you’re right there by Capri (also wonderfully beautiful). Sorrento was lovely and felt safe. Do have some limoncello if you go there!

      Aside from Italy, the Cyclades off of Greece are one of the most beautiful places on earth. Seeing Santorini / Thira in person is one of my most incredible and vivid memories. I’m from the northeast US but dated the daughter of Greek and Italian immigrants when I was a bit younger, and spent a couple summers with them in Evvia at their family home. Greece is very special.

      Can’t go wrong with either IMO.

    • Hawaii. Big Island is very safe as long as you are not a tourist from America (even then it still is, just people wont like you). Pahoa greater area has a bad reputation but I never felt in danger even though I walked from Leilani Estates to Pahoa marketplace along the side of the highway.

      Especially now, Kilauea will be erupting non-stop for decades again and its summit is very accessible. The lava viewing also gets better every year as the lake rises, in a years time is should have flooded the downdropped block completely, and in a couple more it will overflow into the northern part of the caldera. After that it will go outside entirely, into the kau desert. It is relatively boring, but there is always going to be lava to see. And if the eruption pauses like it did last year, then it will return in spectacular fashion if are there at the lucky right time 🙂

      Accomodation also is surprisingly very cheap as long as you dont have too high standard. I was able to go for a week and probably only about $1200 AUD including accomodation. $3000-4000 AUD would get a couple a comfortable trip of a week.

      • Will be going to Hawaii for the first time sometime in April. Quite interesting to see what developments Kilauea will make during that time until I arrive there.

        • I went in April this year, so it will be a 1 year difference. The effusion rate has been very steady, and Pu’u O’o was able to stay this way for decades. Even at the low end of 2 m3/s, which is lower than the actual observed rate, the 2018 collapse will completely fill up to overflow in the early 2030s, in 10 years or so. At the observed rate it will overflow in 2027.

      • Yes Hawaii is astonishing and is one reason Kilaūea is my favorite volcano as well ..


      • It’s a good suggestion but it would cost me £1500+ in flights alone for a week.
        I usually spend £1200 max. on a holiday all in with travel money.

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