Cumbre Vieja and the San Juan eruption of 1949

/ 18/09/2021

The volcano Cumbre Vieja in the island of La Palma has been showing signs of unrest. The question on everyone’s mind is, will there be an eruption? Maybe, or maybe not. This is always hard to know.

The Spanish National Geographic Institute reports inflation, a total of 10 cm of deformation. As such it is evident that there is magma on the move under Cumbre Vieja, it has intruded underneath the volcano.

https://www.ign.es/web/ign/portal/noticias

There have been multiple swarms of earthquakes since 2017 in Cumbre Vieja, a total of nine. Previous swarms were probably magma intrusions too, but which did not reach the surface. The recent swarm however is more shallow and more intense than its predecessors which raises the possibility that the outcome may be different.

The current swarm started on September 12. A total of 4530 earthquakes have been detected at depths of mainly around 10 km, although there are a few which have been very shallow. The swarm commenced under the summit of Cumbre Vieja, where a magma conduit probably exists which is supplying the intrusion. Earthquakes have propagated to the northwest. This probably represents the propagation of magma filled fractures, possibly sills, radially from the centre of Cumbre Vieja. However the earthquakes only show a but a blur of what is going on down there. The exact shape and pathways used by the intrusions cannot really be known with much precision. It is somewhat similar to the prelude to the eruption of El Hierro in 2011 which also seems to have commenced with a sill that later propagated a crack towards the seafloor.

Image from the NASA.

The location of the earthquakes suggest a possible eruption in the NW sector of Cumbre Vieja. However there is a factor of unpredictability. The exact path that the intrusion takes may or may not connect with the surface, such being difficult to know if there will or will not be an eruption . The precise location where the intrusion will breach the surface is also difficult to know. The fissure could open in the middle of a town, in a forest, or it could open underwater, which are wildly different situations with wildly different consequences.

We can know however the style that the next eruption of Cumbre Vieja will take, whenever and wherever it happens. To do this we must look at the past history of this volcano.

 

La Palma

La Palma is one of the Canary Islands. It was formed due to volcanic activity. The oldest rocks of the island are 3-4 million years old and belong to a submarine volcano. These submarine lavas are now found at heights of up to 1500 meters above sea level in the Barranco de las Angustias, in the old northern part of the island, which shows the enormous uplift that the island has undergone. Probably numerous sill intrusions have pushed the volcano upwards.

La Palma. From the NASA.

La Palma is shaped like an arrowhead. The northern part is formed by the old Taburiente volcano. Deep gullies dissect the ancient lava flows exposing the overlapping layers of volcanic extrusions and the frozen dykes and sills which cut through them. The volcanic edifice was destroyed by a series of giant landslides, the last of which took place around  560,000 years ago. Activity continued inside the landslide scarp until 530,000 years ago. Afterwards activity died out in the northern half of the island.

Large scarp formed due to erosion of Taburiente volcano. Some sills and dykes are visible on the left. From Wikimedia, by Zyance.

Volcanic activity in the southern half of the island has been ongoing for at least 125,000 years and has constructed another volcano known as Cumbre Vieja, or also simply as Dorsal Sur, “Southern Ridge”. It is a shaped like a ridge in a N-S direction. Despite being different edifices it seems that Cumbre Vieja is part of Taburiente’s structure. Taburiente had 5 subtle radial rifts. This is much better appreciated in submarine shield volcanoes which are often shaped like ridges or like three to six-pointed stars. Knowing well the shape of submarine volcanoes I can see that Taburiente displays the same five-pointed star structure, although being subaerial it is not so easily visible. The longest, dominant rift goes southward, known as Cumbre Nueva. It can be seen that Cumbre Vieja is the southern continuation of Cumbre Nueva.

Topography of La Palma. Note the northern volcano Taburiente which is cut by deep gullies and a central erosional crater, and the southern volcano Cumbre Vieja which is dotted by young volcanic cones. There is a bow-shaped ridge connecting both volcanoes, this is Cumbre Nueva, the ancient rift zone of Taburiente, partly destroyed by a landslide. From maps-for-free.com.

 

The main magma erupted in La Palma, as well as in the Canary Islands, is basanite, which is relatively fluid, but not as much as say Hawaii. The fluidity is comparable to the more frequently active Mount Etna in Sicily. The magma is not so fluid that all of it would flow away upon landing on the surface, but it is not so viscous that it is entirely blasted into light pumice and ash carried away by the wind. The eruption style is known as “violent strombolian” or “violent hawaiian” depending on whether it produces explosions or sustained fountains. It is the middle ground between the blazing rivers of lava and the billowing columns of ash. This style is ideal for producing pyroclastic material that rains around the fountain, rapidly constructing a mountain around the vent, known as a scoria cone. These conical mounds of ejecta are everywhere over Cumbre Vieja. Because the volcano doesn’t have any central vent that erupts repeatedly, then it makes a new fissure each time it erupts. The pyroclastic material rapidly oxidices. This gives the terrain various hues ranging from black to red, which together with the abundant canarian pine trees gives the characteristic landscape of Cumbre Vieja.

Desertic volcanic landscape near the southern point of the island. San Antonio volcano visible in the centre formed in the 1677 eruption, The brighter cone to the left of San Antonio is Teneguia, which formed in 1971. From Wikimedia by Tony Hisgett.

Other magma types present in Cumbre Vieja are the tephrite and phonolite groups which are more silicic and viscous. They are  present in trace amounts making small lava domes. A small volume of phonolite was emitted in 1585 producing tiny cryptodomes and domes, although the eruption was mainly basanitic.

Types of volcanic rocks depending on silica and alkali content. From Wikimedia by Woudloper.

Cumbre Vieja last erupted in 1971, 1949, 1712, 1677, 1646, and 1585. It is the most active volcano in the Canary Islands. Eruptions have taken place at intervals of 20-60 years. The exception being the remarkable 237 years long dormancy between 1712 and 1949. Why did this happen? It is possible that the volcano follows cycles of more frequent eruptions separated by long dormancies. Another possibility is that the enormous 6-year long eruption of nearby Lanzarote Island, occurring in 1730, induced a long dormancy in Cumbre Vieja.

It would not be unexpected that now, 50 years after the last eruption, there was a new one.

The eruption of 1949

The eruption that took place in 1949 is an interesting example of a typical Cumbre Vieja eruption.

Swarms of earthquakes had been frequent since 1936 and leading until the eruption. The morning of June 24 some fumes were noticed, and soon afterwards a towering black column of ash was rising hundreds of meters, if not more, into the sky. A new volcano had formed along the crest of Cumbre Vieja. The fissure had opened a small distance north of the highest point of the ridge. The vent is known as Duraznero.

During the following days Duraznero continued to erupt, belching out ash and rocks. Earthquakes frequently rocked the nearby communities and steaming fractures opened in the  ground around Duraznero. Magma must have been making its way into growing fractures. Over the days the erupting fissure progressively grew to a length of 500 meters and developed 5 main vents, of which Duraznero 2, at the southern end, was the most active, creating a 170 meter-wide crater. The activity was entirely explosive but of a low intensity that must have been little more than a slight annoyance to the local population. The erupted lava was tephrite. Earthquakes were more impactful, they damaged houses, cracked roads, and occasioned rockfalls. On July 6 the ash was carried downwind over the island of Tenerife where it wrapped around the summit of El Teide in a menacing black cloud.

Fissures of Duraznero. Image by KrisNM.

On July 8 a stream of lava came out from a new location known as Llano del Banco, 3 kilometres north of Duraznero, and from the other end of a system of cracks that had opened up. It did so quietly with no explosive activity whatsoever. The lava must have been degassed by Duraznero, gone into cracks, and found an outlet at a lower elevation from Llano del Banco. The lava erupted was tephrite, same as that of the earlier phase of the eruption. The initial fissure died out at about the time the new vent opened.

It is common for eruptions of Cumbre Vieja to have some vents which are dominantly explosive while others are effusive. In the eruptions of 1646, 1677 and 1712 it also happened that the vents which opened at the highest elevations had explosive activity and built large cones of scoria, while other fissures opened at lower elevations, sometimes offrift, and even at sea level, producing solely lava flows. The eruption of 1949 shows how the process works. A vent that is high up degasses the magma and then it is carried laterally through fractures towards openings downslope from which it emerges effusively.

Lava descended in fiery tongues from Llano del Banco down the flanks of the mountain. People were being evacuated as the flow headed for populated areas. It took 10 hours for the lava to reach the main road of the south of La Palma. Later that day the flow had destroyed 20 structures, including houses, cellars, and barns.

On July 10 lava cascaded over a cliff into the ocean. From this day on the entry of lava into the sea became continuous, and a lava delta was gradually constructed. Cloud of steams rising over the waters were illuminated by the convoluted streams of incandescent rock.

A new change in the eruption took place on July 12. The composition of lava erupted from Llano del Banco changed from tephrite to basanite. It became less silicic. At a similar time a new vent opened 400 meters north of the initial vent of Duraznero in the location known as Hoyo Negro. Black cauliflowers of ash pierced with flashes of lightning rose rhythmically from the Hoyo Negro vent. It erupted various magma types including basanites, tephri-phonolites and phono-tephrites. Once again the vent uprift was explosive while the vent downrift was effusive. The basanitic magmas must have released their gas into the explosions of Hoyo Negro and then come out laterally through the opening in Llano del Banco.

Hoyo Negro projected bombs to a distance of 1 kilometre from the vent snapping the trees and setting portions of the pine forest on fire. Clouds of ash frequently dusted the western part of the island. The explosions excavated a 400-meter wide crater on sloping ground. This created a spectacular 200-metre cliff against the higher side of the slope, which exposed the many layers of ejecta painted in a variety of colours.

Hoyo Negro. Image by Rafael Medina.

A raging stream of lava continued to issue from Llano del Banco and cascade towards the coast. Despite erupting continuously for 18 days the vent produced no distinguishable ejecta, and shows how the gas had been entirely removed from the melt before erupting. The ground above the fissure collapsed among loud noises, the rocks fell into the stream and were carried away, a length of 150 meters of rock above the conduit was eroded away and disappeared leaving behind a deep chasm in the forest.

On July 22 the activity of Hoyo Negro was down to a solfatara. Llano del Banco was also dying down. By July 26 the eruption had fully stopped.

Early on the morning of July 30 the eruption suddenly resumed. Duraznero and Hoyo Negro exploded simultaneously. An hour later fluid basanite lavas emerged from the location of Duraznero 1 and poured into an old crater where it formed a lava lake which then overflowed and formed a narrow stream of lava that rapidly sped down the steep slopes of Cumbre Vieja, cutting the road of Santa Cruz de la Palma, and nearly reaching the sea after 11 hours of advance, when the eruption came to a stop. This was the last episode of the 1949 eruption.

The flow of July 30, although of rapid advance, it was fed at a rate of only 10 m3/s, which is very low. It was also similar to the mean eruption rate of Llano del Banco, which was approximately 14 m3/s. The explosive activity was of little volume so it probably does not change the overall numbers too much. As such the eruption of 1949 was of very low intensity, in both its effusive and explosive counterparts. Slow eruptions are typical of the Canary Islands. Such low intensity eruptions do not pose much of a hazard to the people, in fact no one died in the 1949 eruption, despite 120 houses or so being destroyed, and people having approached the eruption in order to view it. This doesn’t mean that the hazard is inexistent.

If someone stands very close to the vents he/she could be asphyxiated by the noxious gasses or may be impacted by a lava bomb or by lightning. Rarely when lava flows reach steep slopes they collapse into blistering landslides resembling small-scale pyroclastic flows that could potentially kill someone. Conditions around volcanic eruptions can change suddenly in unpredictable ways and become hostile to humans. Safety is not guaranteed.

If Cumbre Vieja erupts in the future it will probably resemble the 1949 eruption in many ways: an earthquake prelude to the eruption that may deal damage to structures, unpredictable opening of fissures, some vents producing mainly explosive activity while others feeding mainly streams of lava that destroy human properties, and also the likely entry of lava into the sea.

Of course if the current earthquake swarm will culminate in an eruption or not cannot be known for sure. Swarms before the 1949 eruption occurred as early as 1936 and did not culminate in eruption until 13 years later.

 

San Martin volcano, formed in a 1646 eruption. Image by Rafael Medina.

 

Interesting links

Eruption of 1949 (in spanish).

IGN news (spanish).

GRAFCAN visor (includes geologic and topographic maps).

 

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1,260 thoughts on “Cumbre Vieja and the San Juan eruption of 1949”

    • And that quakes are the shallower ones… perhaps we could have an underwater eruption, like El Hierro.

      • What Sea depth is most of the seismic activity?

        It its below 100 meters we will only get some discolored seawater .. and submarine needs to be sent down to watch the live lava flows

        I hopes for an ephermal Island to form : ) eruption in shallower water

    • 7 quakes on last hour… one of them M2.9 at 34Km prof…

      • 12 quakes on last hour but the deep one i refered get revised to a shallow prof.

  3. https://www.google.se/maps/@28.601475,-17.8588494,17z/data=!3m1!1e3

    Looks like the 1949 Basanite was acually very very fluid for soure, flowed over the ground like glass flood near the vent.. and the lava channel is narrow and very smooth. 1949 must have been alot hotter than 1971 to explain close to vent viscosities diffrences. 1949 was very similar to Hualalai alkaline flows

    But its true that most of the Basanites from La Palma are relativly Viscous beacuse of low temperatures

    The next eruption maybe look similar to Heimeay in apparence Viscous and cool

    The steep Canary Island slopes will be problematic: the slopes are steep and it will flow quickly, and the hot Aa clinker will tumble down these steep slopes at terrible speeds.
    Not a tourist eruption If you are below the vents

  4. Thanks for the update! I’ll be watching with interest. Having been to Tenerife a couple of times, I’m fond of the islands.

  5. What i’m sometimes wondering, and maybe there’s no clear answer. When we’re talking about larger geological scales: is volcanic activity increasing or decreasing? I think over time as the Earth gets cooler, it might decrease (very) slowly. But at the same time I do think that on a human scale or civilization scale this effect is not clear, and even during the lifespan of complex life, it might be negligible. One could think whether hotspots are more frequent than they used to be? Probably not. Although we must know how hotspots form. Secondly we must also know whether fault lines are more common than they used to be? Was orogonation more common ever? And are the Himalaya’s the largest or highest mountain chain to ever form on the Earth. Difficult to answer probably.

    What I do think is that phases where one supercontinent dominate are different from phases where the continents are separate and those phases are likely more common than supercontinent phases, and better for the balance of volcanic eruptions.

    I sometimes hypothese that supercontinents are vastly different, and decrease volcanic activity, making regular volcanic eruptions less frequent, but as the heat needs to be balanced and flowing, that this decreased volcanic activity might exactly be the reason of the splitting of continents, the creation of new hotspots, fault lines and the build-up of large masses of volcanic materials, which might eventually lead to the LIP’s and trap eruptions.

    Thoughts?

    • Earth is indeed slowly cooling down.. and volcanic greenhouse emissions have lowered alot since Archean Era

      But the planet is quite large and still very hot inside, and will cool slower and slower over time as the litosphere thickens.

      Supercontinents indeed trap heat.. and causes the mantle to overheat and You gets Superplumes and flood basalting and breakup into New oceans. Supercontinent Breakups are acossiated with high volcanic CO2 levels and greenhouse eras like Meozoic

      Today We live in an geologicaly calm icehouse era. That We are warming ourselves with our burning of fossil fuels

      The dying sun will destroy the Earth before it cools down competely

      • What if… 😉
        Mankind would go 100% geothermal. Would that have an appreciable effect over a timescale of let’s say a couple of thousend years?

    • Earth will take 60 billion years I think to cool down to room body temperatures if it was left alone in space

      Jupiters Moon IO will be a volcanic hellscape forever since its constantly tidaly heated, even When all the stars are gone .. IO will keep glowing in the darkness

      • Io will not glow forever, its energy is from Jupiter, from its rotation. It will take a very long time but that is not finite. The ultimate volcanic world would be an Io that is powered by a supermassive black hole, thousands of planets form around SMBHs, and there is a general preference to more solid planets as the volatiles are driven off, so gigantic terrestrial planets and mega Neptunes instead of low density hydrogen dominant gas giants.

        SMBHs have the angular momentum of a small galaxy spinning at a significant fraction of the speed of light, like a flywheel the size of our entire solar system. Actually the biggest have event horizons you could fit our solar system inside 10x over, active accretion disks a lightyear across, heated to a billion K, no wonder you can see them across the entire universe, even the unaided eye sometimes. That is possibly what will happen to Sag A* in the future when the LMC collides with the Milky Way, Sag A* is very undersized for being inside a giant galaxy like our own, it has got some major catching up to do and that is exactly the event to do it. But that is a bit of a major tangent 🙂

    • Over another billion years or 2, sure, tectonics will slow down, far far away in the future we’ll become like Mars. I imagine this will mean geothermal piles from previous subduction being moved about less in the lower mantle, creating larger volcanoes and possibly more LIPs as there won’t be as much flow.
      But then you have the added curveballs such as impact events and the sun getting hotter and hotter through it’s life cycle.

      I imagine our earth is becoming more and more cracked, think how many old old faults are still active, they’re all weak spots in plates. Even when cratons bond together there are still old weaknesses – they never conjoin fully. I believe at last count there was some 150 plates and microplates discovered on earth – this will increase and increase until we become one big eggshell in the medium geological term.

  6. Hector, thanks for very nice and informative post! I walked the Volcano trail on La Palma some years ago and that gave me a lot of questions! Now you gave me a lot of explanations!😊

    • Looks like a series of sills was emplaced togther with dykes going upwards

      • It looks like sills only because the depth data has been quantized to km resolution. I’d say this is a propagating dike. With a little luck it might extend out to sea before erupting. I say that because as much as I love seeing lava, I hate seing it destroy populated areas.

        • Would be a big first if it does that, I dont think there is any example of an eruption being entirely submarine from La Palma in the Holocene. There are some vents in 1646 eruption near sea level but the eruption began up on the ridge, seems the conduits go to the higher elevation and may or may not form flank vents lower down. Maybe notably the two eruptions down at the southern end of the island didnt form flank dikes, so it really could be entirely a feature of the upper levels of the volcano.

          Would seem unfortunately we are in for a slow but destructive eruption.

    • Chad.. Do you think this will erupt?
      Or will the Basanite / Nephelinite be stuck underground?

      I cannot see into the volcano and neither can you..

      I think this wont erupt .. But the swarms are getting shallow

      How is the swarm activity today?
      They say around 10 million cubic meters of magma have been intruded so a small event.

      If it erupts it may just be a lava flow a few 100 s of meters long and a small scoria hill. But I think its dying out ..

      • Given most eruptions result in deflation I dont think it is impossible for a bigger eruption to result from the current activity, there has been several years of intrusions, which are deep down so under pressure and will rise if a vent opens. I dont think we will see failed eruptions, that seems to be a construct we make up, when you look longer a failed dike is just a leading edge of something bigger, so an eruption in the near future is inevitable. Whether it is in the immediate future is different but within the 2020s very likely.

      • I should clarify a non-rinfting dike that doesnt reach the surfece probably hasnt got the volume to take away an eruption, just delay it a bit and possibly give an idea of the eventual location.
        The recent swarm at Kilauea was not a failed eruption, it did fail to erupt but has not completely removed the ability for another eruption to happen near term, in fact the volcano has already completely recovered, like it was just a bit of space filling.
        A true failed eruption might be the rifting of Thingvellir in the late 1780s, no lava but a rift means a dike could have intruded. Thing is Hengill probably only gets magma during an eruptive cycle at Reykjanes, that wasnt happening then, so if there was any magma it was probably not a lot and also more an accidental thing, with the rift being tectonic.

        Really my point is the only failed eruptions I can think of are small magma batches at big volcanoes, especially those which have rifts, then the small eruptions accumulate into infrequent bigger ones. Cumbre Vieja is not really a rifting volcano despite the shape so there is not really any big space to stor a lot of magma, which means it also probably doesnt take a lot of magma to cause an eruption.

  8. Thanks so much for this great overview. It seems this can be a very unpredictable volcano, and it’s unnerving to see the number of communities built around scoria cones… if it does erupt, hopefully there is enough time to evacuate.

  9. OT, but lava has crossed the berm protecting Trail A at Geldingadalir. Trail B is being closed now, too.

    • Where should that be? Nothing to see on the frames of the still cam.

    • Please provide a source link and/or image.
      I don’t see overflowing on the storhool stills cam image 15.50.

      • Sorry – that’s possibly bad info. I got a text from a geologist friend who now says she might be mistaken. :/

  10. There is going to be be a live meeting from the Cabildo de La Palma at 18:00 today on their Facebook Page or You Tube.

    Retransmitiremos en directo la reunión para informar sobre la alerta por riesgo volcánico a los vecinos y las vecinas de Las Manchas de Abajo, San Nicolás, Jedey, La Bombilla, El Remo y Puerto de Naos.
    🕧A las 18:00 horas
    📌En la cuenta de Facebook del ‘Cabildo de La Palma’ o por nuestro canal de Youtube ‘Cabildo de La Palma en directo’
    #CabildoDeLaPalma #VigilanciaLaPalma

  12. On the still cam Borgarfjall (above Nàtthagi) looking South East, left corner the first LAVA. She moves forward.

    • Aha, this is the dam further down, not the long one on top of the plateau.

      • That’s right, indeed, it’s the lower dam. Thanks also to Westfjordan.

    • Wow. When I thought that I was seeing the beginning of this yesterday on the Mila Reykjanes cam, and then looked at the 3D model from 9/9, I had trouble believing that the lava could have “climbed” high enough to breach the berm, but clearly it has.

      Fortunately, the lava is sufficiently viscous – it’s clearly lumpy A’a – that it’ll be a long time, if at all, before Svartsengi etc. are affected. That is, if things don’t change…

  15. (Fagradalsfjall:) No eruptive episode since an hour ago?

    • Almost 3h hours now. Another surprise, the volcano is sleeping again.

    • Great video. If people are confused about the location of the ‘lower berm’ mentioned above, this video shows it clearly.

    • This is a great drone video!

      Particularly at the very end of the video when the exit of the lava tube is seen in relationship to the crater. This shows how much the crater is already like proper shield and how high the crater sits over the surrounding areas.

      It also shows that ‘theatre hill’ is only a few floods away from getting completely buried. It make take a while for the lava to flow in that direction again, but give it time and ‘theatre hill’ will join the fate of ‘telemetry hill’ which was swallowed during the floods that flowed into Meradalir.

      Looks like this long episode has come to an end and the volcano is take a rest again. Let’s see how long this rest will last. Maybe this would be a good cue for La Palma to start the action at Cumbre Vieja?

  17. On the latest Stoholl static cam picture, on the right of the picture, you can see the red of the Lava still creeping past the berm.

  18. 123 quakes in La Palma today and untill now… and they are rising in frequency on last hours…

    • Very good … goooooood…. goooood
      ( Palpatine Voice ) coughing and little laugther

    • Mwhehehe… hähähähhähä .. Hahaha
      Kmmm hufff kneww!!! .. ( slowly walking down to give vader orders )

      ( uses my force ligthing on La Palma )

  20. 2.6 mbLg

    N FUENCALIENTE DE LA PALMA.ILP
    2021/09/18 21:00:51
    1

    • es2021siyjx 18/09/2021 23:42:29 00:42:29 28.5741 -17.8664 2.7 mbLg N FUENCALIENTE DE LA PALMA.ILP

  22. I find the footage from the following video fascinating, from 10 minutes on it shows the progression of a gusher event.

    https://youtu.be/x4mNyVB8tTk

    I find it interesting that the gushers have changed in behavior again. Earlier in the eruption gushers caused the lava lake to rise and overflow and the lava to come out from the conduit. Now, when the gushing phase occurs, the lava lake level drops and the lava goes back into the conduit. It is quite unique this behavior. But then again gushers themselves are a very rare phenomenon which as far as I know is only reported in Surtsey and Fagradalsfjall eruptions, although there may be some cases that I’m not aware of.

    It can also be seen that magma upwells from multiple points on one side of the lake, I think this is sign that the conduit has widened substantially. Right now the conduit can move magma either up or down, normally conduits only move magma up except when an eruption ends. Fagradalsfjall can now perform both modes but only one at a time. It switches between both types of flow with the gusher cycles. A convecting lava lake would be able to perform both movements, up and down, continuously and simultaneously. I think that perhaps the new type of gusher event may be a step towards developing a more openly convecting lava lake. What is clear though is that Fagradalsfjall is evolving towards new modes of activity yet again.

    • At the moment the volcano is off already for the last 3.5h (-> highpass drumplot). There are many possibilities we can bet on: 1.Eruption ended today, 2. will wake up again with ~24h on/off phases, 3. wakes up with fast 10min cycles, 4. wakes up with fountains, 5. new vents come up, 6. will wake up and dances ‘put it on the Ritz’.

      • I think it will wait for possibility 6 a bit more but I wouldn’t be surprised if it does that as the last farewell tour encore, still plenty of ways to surprise us.. I was expecting it to turn off for a bit after 7-9 days looking at how it lately has been doing the approx half on half off split, so I thought as it was off for about 9days it had collected enough magma for around 9 days of eruption.. now the curious thing indeed is how is it “planning” to do the on/off now. one never knows 😀

    • What perplexed me is that (unless I missed it) that there was a lot of activity in the cone, but, no outflow visible. However, that lava-river-source was going strong. That lava river source is quite a ways from the cone.

      My wild guess; the cone is the site of most of the outgassing, but most of the lave goes elsewhere – such as under the lava field.

      As for the current cessation of activity, I’ll say what I did as the last hiatus began; the volcano will resume activity once a sufficient number of experts have declared the eruption over.

      • If you look carefully at the drone video posted above, into the active crater, gushing lava from 3 locations in the wall, you realize that all this lava is going somewhere. When the drone pans from a higher location and takes in more of the scenery, all of a sudden it hits you that all that lave is going to an underground pool on the southwest side, and finally pops up in the crescent shaped gusher feeding the very hot lava into the Natthagi flow..

        What is a question worth considering is if the volcano shuts off, that the underground connections will jell up and the volcano’s next eruption take a different exit.

    • What cessation? There’s still a robust lava flow going down into Nátthagi from somewhere. The tremor shows a level intermediate between the heavy eruptive episodes and the lulls from before. Perhaps this indicates slower, steady effusion, enabled by there being an underground exit the lava can take at a fairly low elevation?

      • The flow into Natthagi is coming from the lava lake. It will continue until the lava lake is lower than the outlet to Natthagi.

    • The different behaviour may be because the lava now has another exit below the surface of the lava lake, but the gas is expelled mainly through the lake

    • Excellent read Hector. Many thanks.

      RE:” the enormous 6-year long eruption of nearby Lanzarote Island, occurring in 1730, induced a long dormancy in Cumbre Vieja..” Extrapolating from the videos and other content since the beginning of this Icelandic event to the account of the Priest of Yaiza, Don Andres Lorenzo Curbelo regarding the 1730 event and my my visit to the national park at Lanzarote, it must have been an awesome happening to witness.

  23. The lava in Natthagi has been standing still for hours. Obviously there is a lack of supplies.

  24. Seems very likely this will end in an eruption, it is not certain but I think much more likely than not.

    There seems to be a general prevaling idea an intrusion has one chance to erupt or it fails, with a second one needing to do it all again. In practice that doesnt really seem to be the case, we know from Kilauea that it can hold magma in its rifts disconnected from the open cnduit for decades or much longer, but this still erupts as basalt when it can, taking perhaps centuries to evolve into anything else because of the great heat flux, fissure 17 was probably first emplaced back in the 1600s, but it coudl have even been centuries before, and despite being andesite it was superheated to over 1000 C so evidently even this far there is enormous heat flux.

    La Palma is not nearly so active, but it is a substantial volcano, as are all oceanic islands, the supply to these is probably on a general average higher than a land volcano, and the heat flux is likely to be substantial as well as highly insulated, there is goign to be a lot of stored magma and free space to move without resistance. To me the swarms of recent years are not individual intrusions but the same one steadily breaking upwards with pulses of magma, it will eventually break upwards, and it may well do that right now.

    Just based on the surface too, it looks like Cumbre Vieja is a lot more active than the common maps show. Most show that a lot of its surface is pleistocene age even today, unless cones are frequently reoccupied this seems very unlikely. Most flows preserve the same surface texture as recent flows just a bit more weathered.

  25. https://www.youtube.com/watch?v=7Smle75XsNI

    Documentary on the most recent eruption on La Palma. Looks like the general sequence of eruptions here is that the first eruptions are more violent, tall fountains and more viscous flows. But later on flank vents open and lava becomes more fluid, fast flowing. The flank vents might even be a direct consequence of this, the fluid lava cant hold insode the cone so breaks out, and is also encouraged to break out down low on the island as a whole so will try to do so if possible. The Llano del blanco vents do look to have been very fluid, the early stage might have been a’a but most of the lava was pahoehoe and flowed quickly, it is lucky that lava wasnt the stuff that erupted first or there could have been casualties.

    It would also seem the lava must be hot, if it is erupting as an intermediate tephrite or silicic phonolite that is still flowing as a mobile liquid. It is the same as at Erebus, also a phonolite volcano, the eruptions there are very passive but there is obviously more to it. Silicic rocks take an enormous heat flux to heat to 1000+ C, so under these sleepy looking volcanoes must be a real powerhouse.

  26. Chad muchisimas gracias for the ‘movie’ ,enjoyed the menacing music-typical of those times! Now it just wait and see.

      • Emperor Palpatine laugther…..

        Then it means that the magma is close to the surface

          • They have changed the M3,3 to a M3.2 and now with a zero depth.

          • The 3.3 was a 111 1V intensity and felt over most of the island.

            EVENTO: es2021sjltt 2021/09/19 06:28:35 28.6195 -17.8753 0 3.3 S EL PASO.ILP
            Actualizado 2021-09-19 06:46 UTC
            RELACIÓN DE INTENSIDADES (EMS) Y POBLACIONES
            EN LAS QUE SE HA SENTIDO ESTE TERREMOTO:

            III-IV EL BARRIAL,EL PASO.TF
            III BARRIAL DE ARRIBA,EL PASO.TF
            III CUATRO CAMINOS,LOS LLANOS DE ARIDANE.TF
            III EL PILAR,EL PASO.TF
            III HERMOSILLA,LOS LLANOS DE ARIDANE.TF
            III LA CONDESA,LOS LLANOS DE ARIDANE.TF
            III LAS MANCHAS,LOS LLANOS DE ARIDANE.TF
            III LOS PALOMARES,LOS LLANOS DE ARIDANE.TF
            III LOS PEDREGALES,EL PASO.TF
            III MONTAÑA TENISCA,LOS LLANOS DE ARIDANE.TF
            III SAN NICOLÁS,EL PASO.TF
            III TACANDE,EL PASO.TF
            III TAJUYA,EL PASO.TF
            III TENDIÑA,LOS LLANOS DE ARIDANE.TF
            II-III BUNGALOWS DE TAJUYA,LOS LLANOS DE ARIDANE.TF
            II-III CARDÓN,TAZACORTE.TF
            II-III EL LLANITO,BREÑA ALTA.TF
            II-III EL PARAÍSO,EL PASO.TF
            II-III EL PASO.TF
            II-III EL PEDREGAL,LOS LLANOS DE ARIDANE.TF
            II-III LAS MARTELAS,LOS LLANOS DE ARIDANE.TF
            II-III LOS LLANOS DE ARIDANE.TF
            II-III LOS PEDREGALES,LOS LLANOS DE ARIDANE.TF
            II-III MIRANDA,BREÑA ALTA.TF
            II-III RETAMAR,LOS LLANOS DE ARIDANE.TF
            II-III TACANDE DE ABAJO,EL PASO.TF
            II-III TAZACORTE.TF
            II-III TODOQUE,LOS LLANOS DE ARIDANE.TF
            II DOS PINOS,EL PASO.TF
            II FÁTIMA,EL PASO.TF
            II LA LAGUNA,LOS LLANOS DE ARIDANE.TF
            II LOS BARROS,LOS LLANOS DE ARIDANE.TF
            II PASO DE ABAJO,EL PASO.TF

        • Bwahahahahähäh
          ( uses force ligthing to awake the volcano )

          Does it mean that magma is moving up to the surface?

  27. Thanks Hector! Very Nice! i learned a lot and i hope the next eruption will not impact the population.

    • And another 3.2 at no depth.

      es2021sjnfy 19/09/2021 07:12:27 08:12:27 28.6152 -17.8694 3.2 mbLg S EL PASO.ILP

        • Yes, 92 quakes untill now just today and much more biger than M2

          • Number of earthquakes (different magnitudes) according to IGN:

          • I was comparing with last two days, not with the begining of event, and they are more shallow too. That’s what i’m seeing on last days.

  28. Fagradalsfjall is going back to sleep mode. We have had 7 days of hyperactivity after 7 days of dormancy. How long will this sleep last?

  29. The Cabildo of La Palma have closed some trails and hunting areas.

    The network of La Palma Trails and forest tracks that run through the municipalities of Fuencaliente, El Paso, Los Llanos de Aridane and Villa de Mazo is closed.
    ❌ The minor game day is suspended in these same municipalities.
    🇬🇧 The trail and forest tracks in Fuencaliente, El Paso, Los Llanos de Aridane and Villa de Mazo are closed.
    ❌ The small game hunting day in these municipalities is suspended.
    #VigilanciaLaPalma #CabildoDeLaPalma

    ?_nc_cat=110&ccb=1-5&_nc_sid=730e14&_nc_ohc=Ob_TJrI0dKAAX8DOtrS&_nc_ht=scontent-lcy1-1.xx&oh=99f1b20a8c0837f735a068076c1d7003&oe=616D2406

    • I did not write the link bit I just tried to post the link from the Cabildo face book page and it came out like this.

    • Thank’s! This shows the situation is worsening… and quakes don’t stop. Now there are some deeper quakes too…

      • More closures from the Cabildo de La Palma.

        Some precautionary measures
        ❌ Closure of the Pilar Shelter Recreation Area
        ❌ Close of the Center for Fire Pipes and access to the Cave of the Palomas
        ❌ Access to other localized cavities in the area is prohibited
        🇬🇧Some precautionary measures
        ❌Closing of the Refugio del Pilar Recreational Area.
        ❌ Closing of the Canos de Fuego Center and access to the Cueva de las Palomas.
        ❌Access to the rest of the caves located in the area is prohibited.
        #CabildoDeLaPalma #VigilanciaLaPalma

  30. A lot shallower earthquakes tonight between 0 and 4 km depth, stress relesae due to the inflation and intrusion?
    I do not think that magma is that close to the surface yet,.

    • Well vulcanologists there say that magma is mooving and close surface, but it seems there are not a big principal conduit but several dykes where magma is migrating… at least it was what i understand.

      • I think we also have to consider, and I might be completely wrong on this one, that each new volcano in la palma is piled on top of the collapsed flank of an older one (cumbre nueva on taburiente and cumbre vieja on cumbre nueva) could this cause an area more prone to “movements” where those shallower quakes are ocurring now?

        • Probably is that too but most realistic and likely option is it is magma right now. It is not really likely such a fault zone would move without magma getting into it anyway, so still requires magma to be in that depth range.

          • I read that the 1971 eruption of Teneguia that this was a cinder cone. If its Cumbre Viaje that erupts this time does that mean the eruption will be completely different to the one in 1971.

          • Cumbre Bieja is the volcano, Teneguia is just a cinder cone that formed around a vent on Cumbre Vieja, it is the same as Pu’u O’o being a vent on Kilauea, if you want a more familiar example.
            1949 eruption as it says here formed Duraznero and Hoyo Negro volcanoes which are near the summit of the mountain, the eruption of 1712 created El Charco, at least that is what GVP calls it, that is a bit further south from Duraznero.

            The earthquake activity today seems to be a bit to the north of El Charco, and a bit on the west side of the rift, it isnt going to be at the southern end of the island which is where Teneguia is.

            I dont think there is any relationship of the 1949 vents being near the summit and 1971 eruption near sea level either, it isnt a Kilauea Iki – Kapoho situation, more a coincidence I think.

          • The shallow activity continues with another 3+ at 1km, they seem to be too concentrated and energetic to be only stress release, inflation is now around 15cm. I guess magma is really close to the surface,sadly that area is a relatively densely populated one so even a small eruption could cause some material damage.

          • Yes, will be very destructive if it erupts where it is centered now. At least the first lava will probably not flow fast and the locals are obviously aware of it by now so should be relatively safe. Should get some good videos of it, I expect there will be a crowd at the nearest safe view waiting to see it, for better or for worse. I do hope they are more expecting of this than those in Hawaii in 2018, the risk is about equivalent in both areas, about once or twice in a century, so not that low really.

            The real danger might be in the reputation this volcano has, the mass fearing of a non existant risk to have the volcano collapse. But most people will never think about this, just read the 20 year old theories, even though those also negate that La Palma has actually already erupted since 1949 anyway…

      • 1949 was very runny too .. as I shown in links far above.
        Will be bad on the steep slopes.. the fluid Aa will race downhill .. the the vents you can even get ”flood pahoehoe”

        This is Basanite lava and it haves a very low sillica content as low as 40%

        But most Basanites emerge cold and Viscous ..

      • Another closure by the Cabildo de La Palma

        As a precautionary measure
        We closed the road of Los Brecitos LP-214
        As a precautionary measure
        We closed the Los Brecitos LP- 214 road.
        #CabildoDeLaPalma #VigilanciaLaPalma

  31. Excellent article Hector, thank you.
    Watching with interest.
    And also watching those Icelandic volcanoes , so many of which seem to be in a state of readiness.

  33. IIRC, the risk of Cumbre flank mega-slumping due phreato-magmatic ‘kicking’ *may* be less than feared due to the ‘adit’ water mines / aqueducts now dug deep into those flanks. As result, water table is much lower than ‘natural’, and the adits may provide relief channels for steam & gas. Also, some warning if intrusions reach those zones….

    Tangential: Why are the Canary islands even there ? Why volcanism, not a chunk of stray ‘continental’ ?? There’s no ‘junction’ like the Azores, no ‘hotspot’ like the Tibesti Massif. Um, could latter be evidence of a subducted mini-plate as Africa closed Tethys ?? Per Farallon under US ??

    I’ve read Canaries are due to changing ‘stress fields’ across North Africa ‘semi-plate’ as it variously shunts Iberia as Africa heads North-ish. The ‘stress relief’ phases providing melt. Perhaps…

    If Eastern Atlantic margin really, really is developing a subduction zone near Gibraltar, I’d expect a nascent arc to recruit these islands…

    • Its a weak hotspot over a very slow moving old seafloor

    • Nik, I took a tour of one of those water tunnels, and unless things have changed, they are in only the northern part of the island, not Cumbre Vieja.

      What Cumbre Vieja does, have, though is a road tunnel through it. (Northern flank, the LP-3 road.)

    • http://madeiraislands.net/geology/the-origin-of-madeira-island/

      I’m inclined to think that the sea floor here is fractured with propagating faults from the African/European collision or perhaps when Gondwana split, and added to the fray is the African LLSVP (large geothermal pile antipodal to the one in the Pacific) that creates a hotter nearby mantle and therefore hotspot offshoots. A combination of a weak spot and hotter than usual mantle.

  34. Been reading up, this swarm is looking very likely to end in eruption. There were 5 swarms last year, and already 3 others this year, all deeper, and now this one which seems to be getting very close to the surface. There was also a swarm each in 2017 and 2018.

    This is not a stand alone event, but rather the probable cumlination of several years of buildup already, with an obvious acceleration in the last 2 years. Based on the quakes now I doubt it will be more than a day, Teneguia was preceded by a few days of similar activity, maybe add a bit more time for the 1 km extra elevation above the swarm center.

  38. Do we think that Cumbre Vieja is it’s own edifice in the making or is still a rifting arm of the Taburiente caldera? I’ve seen it referred to both ways. Seems clear that the deep source is now below Cumbre Vieja though.

  39. Now, the million dollar question: live streaming webcams on La Palma?
    I’ve been looking about with no success so far.

  40. Looks like the magma is shallow now
    1 kilometers down it is right? Or is it deeper and pushing up?

  41. ?_nc_cat=109&_nc_rgb565=1&ccb=1-5&_nc_sid=dbeb18&_nc_ohc=E3RZzWgbLZYAX-c0LyY&_nc_ht=scontent-lcy1-1.xx&oh=f364f0ec4d9a5950e3023f1282509424&oe=616D9885

      • That is the tremor graph from IGN today someone managed to capture but IGN is down at the moment can I add it from my photos on my android phone on here? Or can I email it to someone on here to add?

    • Bwhahahahah hahahaha.. hähähähähäh hughhughhuhuhu!!! häää

      ( uses force ligthing on La Palma! )
      ⚡️ ⚡️⚡️⚡️⚡️⚡️

      • Ever thaught of buying a church organ? True villains play church organ while laughing…

        Meanwhile in Iceland: The good old romantic Rückenfigur doesn’t work anymore. Modern romantic images show men turned towards the artist, but refusing to take part in the event by shifting their attention to their second lifes on the web. Yes, we are on the webcam right now, hence we really exist.

        • It’s ridiculous. Nature’s force at work and what are these people doing? Staring at their mobile phones.
          What are they thinking? “Look at the volcano and lava! Oh, wait, I have a funny cat video from Lars…”
          I despair sometimes! 🙂

        • “Holy ‘Look Ma, top of the world!!”, Batman!

          They log into the website and look at themselves looking at themselves on the screen, and/or call into friends and invite them to do the same.

          It’s when you need to get a life.

  44. The evacuations have started La Palma.

    The evacuation of people and livestock begins as a precaution against the risk of eruption
    As a priority, it begins with people with reduced mobility in the population centers of Las Manchas (Las Manchas de Abajo, Jedey, San Nicolás and El Paraíso), which includes the municipalities of El Paso and Los llanos de Aridane; El Charco (Fuencaliente), La Bombilla (Los Llanos de Aridane and Tazacorte) and El Remo and Puerto Naos (Los Llanos de Aridane)
    The Scientific Committee of the Special Plan for Civil Protection and Attention to Emergencies due to Volcanic Risk (PEVOLCA), meeting today Sunday, has recommended to the Plan’s Steering Committee the preventive evacuation of the population at risk , after verifying that seismic activity has reached the maximum since start of the swarm on La Palma. Based on this information, the Steering Committee has decided to begin evacuating, as a priority, people with reduced mobility in the population centers of Las Manchas (Las Manchas de Abajo, Jedey, San Nicolás and El Paraíso), which includes the municipalities of El Paso and Los llanos de Aridane; El Charco (Fuencaliente), La Bombilla (Los Llanos de Aridane and Tazacorte) and El Remo and Puerto Naos (Los Llanos de Aridane).

    The volcanic traffic light remains yellow, although civil protection actions are intensified and the Technical Directorate is empowered to program the selective evacuation of other areas of the Cumbre Vieja, if necessary, under the coordination of the Cabildo and city councils. The estimated population is one thousand people.

    The different administrations have also taken measures to control roads, with access cuts and suspension of activities.

    This afternoon the Scientific Committee and the PEVOLCA Steering Committee meet again.

    https://www.canarias7.es/canarias/la-palma/comienzan-evacuaciones-palma-20210919131330-nt.html?ref=https%3A%2F%2Fwww.canarias7.es%2Fcanarias%2Fla-palma%2Fcomienzan-evacuaciones-palma-20210919131330-nt.html

    • Yellow? The ashy throat-clearing phase could start with literally only minutes’ notice now, if that. Shouldn’t they raise it to orange?

      Also, I thought El Paso was in Texas?

  45. It’s reassuring the authorities in La Palma are evacuating the less mobile residents from certain areas. They’re taking this seriously and I hope this pays off. Even if it is a failed eruption (which I now doubt) it’s a good exercise.
    Good luck to the residents. Hope nothing gets too bashed by any eruption.

  48. Bwhahahahah hahahaha.. hähähähähäh hughhughhuhuhu!!! häää

    ( uses Palpatines force ligthing on La Palma! )
    ⚡️ ⚡️⚡️⚡️⚡️⚡️

    Uuuuuuunliiiimited vooolcaaaanic power!!!!
    Aaaaaarrrgh!

    Hopes we gets an eruption soon! : )

    • It seems that an eruption is starting


      ?d=1632061771121

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