The collapse of Anak Krakatau

Anak Krakatau, in better days

The parent is famous. The shock waves of the eruption of Krakatoa in 1883 reverberated around the world – in the atmosphere, in the sea and in the news media. This was the first large eruption in the era of instant communication. The eruption itself was luckily on an island at some distance from human occupation which should have limited the damage. But the tsunami came swiftly and with little warning. It was devastating.

Volcanic tsunamis are not uncommon. Over the past 400 years, there have been some 130 documented tsunamis caused by volcanoes, most recently by Hunga Tonga in 2022. Around 80 volcanoes have caused tsunamis in that time, many of them more than once – including Krakatau.

The name of the parent, by the way, was a typo. The correct name was Krakatau (meaning crab). In Portuguese it is Krakatao. After the 1883 eruption, The Times newpaper misspelled this as Krakatoa and this name stuck. But the typographical naming error is used only for the parent volcano, which no longer exists, except as a deep hole in the sea floor. It is not used for the offspring.

44 years after the destructive explosion, the volcano re-emerged, at the location where Verbeek, the guru of Krakatau, said it would. This was the first child of Krakatau. It did not live long but quickly disappeared again. There were two more, before the current Anak Krakatau (‘child of Krakatau’) appeared in 1929, grew to 30 meters high, and remained above the waves. When it became famous, in 2018, it was 89 years old.

Anak Krakatau is a basaltic-andesitic volcano which, like any child, loves erupting. The surrounding region sits in a shallow sea between Java and Sumatra, on a plateau of continental crust. Below is the subducting oceanic crust from the Indian ocean, which is what drives the volcanic activity. But the activity is not solely due to that. Due to a bit of rotation between Sumatra and Java, the area of Krakatau has some extension and this allows for magma chambers to form. Anak Krakatau sits above multiple magma chambers, situated from the moho at 20 km to 4 km depth. The eruption rate indicates that the magma rises up easily, at least at the present time. The magma chambers are not all the same: the composition of the ejecta of Anak Krakatau can vary a bit, and have even included dacitic material.

The parent volcano was very different: it had not erupted for 200 years before the end: its magma did not rise up easily. The difference between parent and child suggests that whatever had been obstructing the conduit was removed in the explosion, and therefore the obstruction had been located in the upper kilometers of the crust.

Anak Krakatau used its rising magma well: after its emergence in 1929, it build up a 338-m tall cone in less than a century, growing at an average rate of 4 meters per year or 10 cm per week. The same rate must also have occurred between 1883 and 1929, to get from the sea floor depth of 250 meters to the surface in that time, but this of course had not been seen. There was a brief interruption of the growth around 1950 when the cone actually reduced in height. But in 1959, the cone was 150 meters tall and in 1981 it had grown to 200 meters. At this time there was a change, with eruptions moving a bit to the southwest and the lava temporarily becoming more evolved. In 2007, the volcano was measured at 305 meters high, and the eruptions were intensifying. By 2018 it was 338 meters.

That was to be the end.

Hidden danger

The danger of Anak Krakatau had been recognized. A paper by Giachette et al. in 2012 pointed out that Anak Krakatau had chosen the wrong place for its emergence. It is not our choice where we are born – we just have to try to make the best of it. Neither do we have responsibility for the faults of our parents, but we still may have to deal with the effects of those faults.

It was known already in 1929 that Anak Krakatau was growing on a slope, with the ocean being deeper towards the west. Under water, the cone slopes considerably steeper towards the west than to the east. By 1995 that had not changed: the volcano had grown but had not filled in the hole to the west.

Giachetti and collaborators saw this and were concerned. Their paper in 2012 calculated the consequences of a potential collapse of the mountain into the hole. The abstract gives all the essential information, in remarkable foresight:

Numerical modelling of a rapid, partial destabilization of Anak Krakatau Volcano (Indonesia) was performed in order to investigate the tsunami triggered by this event. Anak Krakatau, which is largely built on the steep NE wall of the 1883 Krakatau eruption caldera, is active on its SW side (towards the 1883 caldera), which makes the edifice quite unstable. A hypothetical 0.280 km3 flank collapse directed southwestwards would trigger an initial wave 43 m in height that would reach the islands of Sertung, Panjang and Rakata in less than 1 min, with amplitudes from 15 to 30 m. These waves would be potentially dangerous for the many small tourist boats circulating in, and around, the Krakatau Archipelago. The waves would then propagate in a radial manner from the impact region and across the Sunda Strait, at an average speed of 80– 110 km/h. The tsunami would reach the cities located on the western coast of Java (e.g. Merak, Anyer and Carita.) 35–45 min after the onset of collapse, with a maximum amplitude from 1.5 (Merak and Panimbang) to 3.4 m (Labuhan). As many industrial and tourist infrastructures are located close to the sea and at altitudes of less than 10 m, these waves present a non-negligible risk. Owing to numerous reflections inside the Krakatau Archipelago, the waves would even affect Bandar Lampung (Sumatra, c. 900 000 inhabitants) after more than 1 h, with a maximum amplitude of 0.3 m. The waves produced would be far smaller than those occurring during the 1883 Krakatau eruption (c. 15 m) and a rapid detection of the collapse by the volcano observatory, together with an efficient alert system on the coast, would possibly prevent this hypothetical event from being deadly.

The research was perceptive and timely, and it gave time to prepare. But inexplicably, it was published behind a paywall! Perhaps for that reason it did not attract the attention it deserved. Geology does not do open science as well as some other fields of research. It is build on commercial interests, as much of geology is connected to mining. The publishers used the paper for income, rather than helped to disseminate the research as widely as possible. And so the paper was less read than it could have been, and nothing was done. The people who needed to know perhaps never saw the paper. The prediction came true, but it was unexpected.

Volcano-induced tsunamis are extremely dangerous. There is often little or no warning. They can come from submarine eruptions (as in Hunga Tonga), caldera collapse, pyroclastic flows entering the water (which happened in the Tambora eruption) or flank collapses. Ritter Island, in 1888, generated 10 meter high waves hundreds of kilometers away. Hunga Tonga caused two fatalities on the far side of the Pacific ocean, in South America. Krakatau’s tsunamis in 1883 killed over 30,000 people. (Around 1000 died from pyroclastic flows reaching the coasts, and the 3000 people who died on Sebesi (whether there were no survivors) died of a combination of tsunami, pyroclastic flows and 1 meter of ashfall.) The collapse of Mount Unzen in 1792 killed 15,000 – and it was caused by an earthquake, not an eruption. Volcanoes don’t have to erupt to cause a tsunami: the instability of a growing cone can be sufficient in itself.

Anak Krakatau had already given a warning with a small tsunami in 1981. And there were stronger warnings. INSAR measurements showed that after the 2008 eruptions, the southwest slope of Anak Krakatau subsided by 18 cm. No, the 2012 paper should have been widely distributed. Hiding it behind a paywall was problematic.

Rhymes and reasons

How was it that Anak Krakata, growing up on the heart of old Krakatau island, found itself on a slope?

Let’s go aback to the parent. Krakatau is a cyclic volcano which starts basaltic (as did Anak Krakatau) but evolves to dacitic magma over a cycle. This change is unusual for an Indonesian volcano. The cycle is terminated with a large eruption, and the cycle restarts. Anak Krakatau is at an early phase in the cycle.

Before the 1883 eruption, there were four islands in the group. Sertung and Panjang were remnants of a much older phase, seemingly delineating an old crater wall. These islands still exist. There was another small island in between them, called Polish Hat. It was destroyed in 1883.

The main island of Krakatau was much larger, and carried the volcanic activity. It is indicated by solid line in the image. It contained a number of separate volcanos: Rakata, the largest and oldest, extinct at the time, Danang, a double peak, and Perbuatan. Perbuatan erupted in 1680 and again in 1883. Danang probably also erupted in 1883. There were a further series of active vents along the line between Danang and Perbuatan. Note that the west coast side of the island was not explored in 1883 as it was too dangerous, so it is not known whether there was activity there as well – nor do we know where exactly this coast was located at the time of the final eruption.

From Deplus et al. 1995

Anak Krakatau grew up on the line between old Danang and Perbuatan, where Verbeek had predicted Krakatau would re-appear. It appears to be using the same magma path as the parent.

The original Rakata volcano, Panjang and Sertung islands may trace the outline of an ancient caldera. The large eruption thought responsible for this has been dated to 60,000 years ago based on drill data. However, the caldera may also have formed in a series of caldera-forming eruptions of which the one 60,000 years ago was the most recent one, in which cases the caldera may have build up over time.

Rakata already existed in the previous cycle, but it was largely destroyed 60,000 years ago. A new cone grew up on the remnant, reaching 800 meter high before activity moved to the new andesitic cones of Danang and Perbuatan. Half of Rataka survived the explosion in 1883 which removed almost all of the rest of the island. It seems to have collapsed along the old caldera fault, with the part situated outside of the fault remain standing. (The ‘B’ in the image shows the location of a rock pinnacle that survived in 1883, called Bootmans Rock. It seems to no longer exist.)

Source: Duplus et al. 1995

Bathymetry has revealed the shape and size of the caldera that formed in the 1883 euption. It lies between Rakata and Sertung . The hole covers much of the old island, but not all. The location of old Perbuatan and Danang is near the edge of the hole: the main caldera is centred a bit further west, out at sea. The cause of this offset is not clear. Were the Krakatau volcanoes actually located on an old caldera rim? It is not the same direction as the one determining Rakata’s collapse. Perhaps there was a complex structure with overlapping ancient calderas, each with their own ring fault. Once at fault, always at fault.

This meant that when Anak Krakatau started growing, it did so near the edge of the 1883 caldera, not at the centre. This is why it became build on a slope. This slope was the side of the caldera! It was not a safe place to grow up. This is why the 2012 paper warned -unheard- of the danger of collapse.

The year of living dangerously

The 2012 paper was based on a height of the volcano of 300 meters. By 2018 it was higher than that. There had been a series of intensifying eruptions which caused growth. The figure below shows the strong eruption sequence starting around 2008 and lasting until 2013. After 5 years of quiet time (a normal interruption for Anak Krakatau), July 2018 saw a new outbreak, now at higher intensity. The eruption peaked in September, reaching phases with time averaged eruption rates of 3 m3/s. It calmed down a bit after that, apart from a brief phase in mid November. The erupted volume from July to December was 0.025 km3. Much of this ended up on the southern slopes. The scene was now set for the events of 22 December.

Eruptions of Anak Krakatau. Source: Walter et al. 2019

In hindsight, there had been trouble brewing before these eruptions. From January 2018, the southwest and southern side had been moving 4 mm per month westward, while at the same time the slope was subsiding. This movement accelerated from July when the eruption restarted. But it was not noticed at the time.

On 22 Dec 2018, the eruption resumed, although the activity was relatively minor compared to the intense eruptions of September. Hot tephra was deposited on the slopes. The activity ended after about 6 hours. An hour later, there was an earthquake or explosion. Seismic signals indicate that the collapse started two minutes after this. And two minutes later, half the mountain had avalanched into the sea. Four minutes from the initial, small earthquake, Anak Krakatau was gone.

Was the collapse caused by the eruption or by the earthquake? The eruption had ended an hour earlier, so could not have directly cause the collapse. In fact, the ejecta from the collapse show that there was no hot magma involved. But perhaps it is a moot question. The eruptions of 2018 had left the mountain unstable, even if they had not provided the trigger. The cone had started sagging already a year before, and perhaps even as much as a decade. Every eruption contributed its bit. Was the final eruption on Dec 22, if a minor one, the proverbial drop which caused the bucket to overflow? Or was the collapse already set in stone? Had the fast growth in an unstable location made the outcome inevitable?

The collapse itself was not directly seen by anyone. It is however revealed by the seismic signals. These show that the initial earthquake or explosion was equivalent to an M2, so a small event. The signature was different from normal earthquakes, with a long-lasting high frequency component. After this initial event there were two minute of seismic silence, before the landslide started. The slide itself lasted 90 seconds, with a total energy equivalent to an M5.3 earthquake. It was also detected as an atmospheric infrasound wave, but this lasted a bit shorter, around 1 minute. This probably means that after 60 seconds the landslide entered the sea, and was no longer disturbing the atmosphere. The landslide was followed by a 5-minute phase of strong volcanic explosions, caused by the sudden removal of the weight of the cone. Over the following hours, volcanic tremors continued, but the seismic signature differed from those in eruptions before the collapse. They had the appearance of steam-driven explosions, caused by the magma in the conduit which was now at the surface. These explosions, including the 5 minute phase of intense explosions, also released a large sulfur cloud, something the eruption before the collapse had not done, and produced significant tephra that covered the remains of the volcano.

From Walter et al. 2019

The landslide had a ‘slide angle’ of 12 degrees, a bit less than the 18 degrees of the downslope in the sea. Clearly, there had been a plane of weakness within Anak Krakatau. This may have been caused by the southwest migration of the volcano 40 years before which meant it had started growing on the ejecta of the previous phase, rather than adding to the summit. Later we’ll see another past event that may be more likely as the cause of the fault. Even though the fault was buried, there was still a contact plane, not far above sea level. This may have been the ultimate weakness in Anak Krakatau: you can bury the past but it still affects you.

The physics of the event was not addressed in the paper by Walter et al. Imagine a rock sitting on a sloping surface. Gravity tries to pull it down the slope, with a force that depends on the weight of the rock and the angle of the slope. Friction keeps it in its place. Stationary friction, when objects are not moving, is quite high, so this is an effective way of keeping things in their place even on a slope. But the friction of a moving object is much lower. You will know this from experience: pulling something from a stationary position requires more force than what is needed to keep it moving afterwards. That means that once the rock begins to move under the force of gravity, it finds itself unable to stop. I have discussed this effect before, in the collapse of Kazbek.

The slow sliding of the slope of Anak Krakatau in the year(s) before the collapse was different. This was most likely deformation (shear) of the cone or of the region around the connecting layer. The static connection remained locked in place during this time. Earthquakes also act in this way. Imagine two tectonic plates moving past each other in a transform fault (the San Andreas come to mind.) The plates are moving past each other, smoothly and continuously. They have to: there is no way one fault can stop an entire plate! But while the plates move, the connecting plane is stuck. This makes the plate close to the fault line deform, in a shearing pattern. This deformation puts more stress on the fault plane, until it suddenly gives way, and the deformed zone can catch up with the rest of the plate.

Here is an example from Turkey, taken from the post on the North Anatolian Fault. The wall was built 70 years before the photo was taken. The fault, which is stuck, is just behind the man, at the location where the wall bends. You will understand that originally the wall was straight. The plate on which the photographer stands moves to the left at 1cm/yr, or 70 cm over the time the wall was built. At the bottom of the picture, the wall has moved by this much. The fault hasn’t moved at all. (One day, it will.) The region in between is where the shear deformation takes place. The angle of the wall shows this deformation in action. Once the fault gives way, this region will jump left to catch up with the moving plate: this is the earthquake. And now the wall will consists of two straight sections, offset by a meter or more, depending on when the earthquake happens. The property protected by the wall will now have a strange shape, but this is what happens when you build on a fault. In a thousand years time, the two parts of the property may have become unconnected. This has happened even to an entire volcano.

Underneath Anak Krakatau, out of sight, the same thing was happening. The connecting plane (the decollement) was stuck, but the mountain above was deforming down the slope. Until, on 22 December 2018, the mountain became unstuck. This was the earthquake which happened two minutes before the slide. In a normal earthquake, the rocks are stiff and initial movement after the failure of the fault is fast. The energy stored in the deformed rocks creates the force that causes the movement. As the rocks move, the deformation lessens and the force becomes smaller. Finally (within seconds) it is less than the friction force for moving objects. At this time movement stops. Now moving friction is replaced by the (higher) static friction, and the fault is locked in place. It will remain so until the next failure.

On a slope, it is different. The rocks in this particular case are much less strong. (Volcanoes may look impressive, but they are made of pretty weak stuff and are build on sand.) This made the initial movement much less forceful and smoother. The earthquake caused by the ‘unsticking’ was therefore a relatively small one, but longer lasting. But the cone above the now unstuck plane was still subject to the force of gravity, and moving friction was insufficient to keep it in place. The cone started to move, slowly at first. It started in one place, and the moving rock was being held in place (somewhat) by the mass ahead of it that hadn’t failed yet. This moved the excess weight to that part of the stuck plane, which was now also pushed over the edge and failed. Two minutes later, the entire slope was moving and gravity had free reign. In the end, gravity always wins. It just has to wait. And 90 seconds later, half the mountain was lying on the sea floor. This displaced a considerable amount of ocean water, and this displacement triggered the tsunami. The wave reached the shores of Java and Sumatra 45 minutes later, fully unexpected as no one was aware of or had seen what had just happened. It would be days before radar images would show a disbelieving audience that an entire volcano was gone. Again.

The slide produced large blocks, up to 80 meters tall, which now lie in the sea floor. They did not travel far: the debris is within 1.5 km of the shore.

Walter et al. estimate the volume of the collapse as 0.1 to 0.2 km3. Hunt et al, a year later, measured the sea floor debris and derived a volume of 0.175 km3. This is a little less than what was assumed in the Giachetti et al. warning paper from 2012 (0.25 km3, but it was not far off. The collapse event largely happened as had been predicted.

Past and future

It turns out, this was not the first collapse of Anak Krakatau. The mountain had also failed in June 1949. The photo below was taken in 1950, a year after this collapse. As in 2028, half the mountain had been lost. This had been a much smaller event as the mountain was a lot smaller at that time, and it had happened with little fanfare and without a recorded tsunami. It temporarily reduced the height of the mountain. The rebuilding entrained the plane of failure into the new cone: the cone of Anak Krakatau was build on this surface. This may well be the origin of the decollement which failed in 2018.

Source: Hunt et al. 2021

After the 1949 collapse the cone was replaced by a lake, having dropped to below sea level. It took a decade for the lake to be replaced by a cone.

Source: Zen, 1964

There may have been another event as well in the history of Anak Krakatau. There was a small tsunami observed at Rakata, with a height of 1-2 meters, on October 19-20, 1981. This may have to do with another landslide of Anak Krakatau, albeit small compared to 2018 and 1949. 1981 was the year when Anak Krakatau briefly erupted dacite, and when the eruption site moved a bit to the southwest. Wast this related to a small collapse? (The recent surveys of the caldera floor showed blocks that had not come from Anak Krakatau, and probably came from a collapse of the side of Rataka, sometime after 1883. So it is possible this Rakata tsunami was self-induced. But the fact it happened while Anak Krakatau was going through changes points the finger there.)

The collapse of 2018 took the mountain back to its height after the 1949 collapse. It was measured at 126 or 152 meters (both numbers appear in the literature). The crater is much lower, and as after 1949, initially was a lake. The lake did not last long. The cone rebuild itself remarkably quickly. Below is a youtube video from an eruption in July 2023, where the cone is nicely building up. On the most recent images, the cone is already close to the level of the old rim, although it has not yet filled in the entire hole. The eruptions are faster than before and the rebuilding is faster than it was after 1949.

But the seeds of future failure are still there. The collapse has not filled in the crater and the caldera edge remains as steep as it was before. It may take 100 collapses before this has changed and the caldera floor has been raised to safer height. So far there have been two collapses. And Anak Krakatau is rebuilding itself with vigour. The island is now larger than it was before 2018. The first collapse was 20 years after its emergence above sea, or 66 years after its onset on the seafloor. The second collapse was 70 years later. (We could call it the 70-year itch.) What happened twice (or perhaps thrice) will happen again. It is a matter of when, not if. And it may well be in this century.

As I write this, Ruang is having it second set of spasms. This too is a volcano with tsunamic history. In 1871, it caused the second largest known volcano-tsunami in Indonesia, with a run-up height of 25 meters. This is why people are worried about its eruption. Remember the 130 tsunamis from 80 volcanoes? Mathematics tells you that this makes volcanoes repeat-offenders. What it does once, it will do again. And unusually, in the case of Anak Krakatau we know we only have decades to prepare – not centuries.

And this is why scientific papers should never be published behind paywalls.

Albert, April 2024

More about Krakatau

If you would like to know more about Krakatau, there have been many posts here:

The rise and fall of Anak Krakatau

Prelude to Krakatau. I

Prelude to Krakatau. II

Prelude to Krakatau. III

Krakatoa: a blast from the past

Krakatoa skies: when the Sun turned blue


Walter, T.R., Haghshenas Haghighi, M., Schneider, F.M. et al.: Complex hazard cascade culminating in the Anak Krakatau sector collapse. Nat Commun 10, 4339 (2019).

Giachette, T.,Paris, R., Kelfoun K., Ontowirjo, B.: Tsunami hazard related to a flank collapse of Anak Krakatau Volcano, Sunda Strait, Indonesia. Published in Natural Hazards in the Asia–Pacific Region: Recent Advances and Emerging Concepts. Geological Society, London, Special Publications, 361, 79–90 (2012)

Christine Deplus, C., Bonvalot, S., Dahrin, D., et al..: Inner structure of the Krakatau volcanic complex (Indonesia) from gravity and bathymetry data, Journal of Volcanology and Geothermal Research, Volume 64, 1995, Pages 23-52,

Hunt, J.E., Tappin, D.R., Watt, S.F.L. et al. Submarine landslide megablocks show half of Anak Krakatau island failed on December 22nd, 2018. Nat Commun 12, 2827 (2021).

Kyra, S. Cutler, S. Watt, M., Amber L. et al. Downward-propagating eruption following vent unloading implies no direct magmatic trigger for the 2018 lateral collapse of Anak Krakatau,Earth and Planetary Science Letters, Volume 578, 2022, 117332,

Zen, M.T., Hadikusumo, D. Recent changes in the Anak-Krakatau volcano. Bull Volcanol 27, 259–268 (1964).

Mutaqin B., Lavigne F., Hadmoko D., Ngalawani M.,:  

Volcanic Eruption-Induced Tsunami in Indonesia: A Review 2019 IOP Conf. Ser.: Earth Environ. Sci. 256 012023 (2019).

275 thoughts on “The collapse of Anak Krakatau

  1. Thank you very much Albert, I appreciate your writing style and agree that sometimes paywalls can hide important information.

  2. And here is some footage of the Ruang eruption from the ISS.

  3. Thanks, Albert. Collapses are dangerous. It’s so difficult to predict when they will happen. They are probably the most underestimated volcanic hazard. Imagine a debris avalanche from a stratovolcano burying a whole city or a shield volcano collapsing into the sea and making a mega-tsunami.

    In other news, looks like the East Rift Zone of Kilauea is activating. After 3 days of 400 earthquakes a day, the East Rift Zone (connector) has become much more active than the Southwest Rift Zone. The earthquakes are also propagating and now happening around Hiiaka to the south, and around Puhimau to the north, areas that have not seen activity in 3 years. May be too early to tell, but the SWRZ episode may have ended with the February dike which didn’t erupt but did release the extension that had built up, now activity may be returning to the ERZ. Again, too early to tell, but things are clearly changing.

    • SDH is still tilting rapidly though too, maybe the rift is not quaking now as the tension is lower. Seems the rift is still involved, just not alone anymore.

      It also looks like the SDH data is indicating things are approaching a breaking point very rapidly, with 35 microradians in the past 3 days. The magma pulse that was so evident in the 10 km depth quakes seems to be making its presence known. 400 quakes daily might be the most I have ever seen on Kilauea without a dike growing, or of course in 2018. I remember saying that too in October last year when the SWRZ really took off, and again in January. But it seems Pele is always trying to outdo herself…

        • Sand Hill tiltmeter, near the start of the southwest rift zone.


          The blue line is measuring tilt coming from the direction of Halemaumau. The green line measures tilt from about the direction of the SWRZ connector, which is inflating.

      • The thing that is kind of weird though is that despite the number if quakes on the ERZ connector there is not as much uplift there, none of the tiltmeters east of the caldera are tilting anywhere near as much as SDH and UWEV isnt doing anything unusual at all, so Halemaumau seems not involved in this activity yet. I think the SWRZ might well still be where things break despite its silence, there hasnt been a case of two major intrusions there in a couple months before so the silence could well just be because of that.same as at Sundhnjukagigar you have a first noisy intrusion but more follow in the same place and are more quiet and faster.

    • Mega-tsunamis are luckily very rare. They may happen perhaps once every 100,000 years, while the run-of-the-mill volcano-tsunamis may happen once a decade and damaging ones once per century. Of course, the more build-up the coast line becomes the more often a run-of-the-mill one will become damaging!

      • Mega tsunamis arent that rare actually, just that they are usually generated in areas where the waves are local. Like in fjords or lakes, or where glaciers calve. The dont have the water volume to go far from their origin in the ocean.

        That is excepting for island collapses though, especially at close range as is the case in Hawaii if Mauna Loa collapses again. It also would probably be a massive problem if Etna collapsed the way it did to create the Valle del Bove, which it is thankfully not yet rebuilt to that point yet (which makes me think its current activity could well be extremely high compared to most of the Holocene).

        I will disagree on the underestimated risk though, if anything the risk is overestimated by most people it seems. When Kilauea erupted in 2018 most of the live chats were about the Hilina slump not the eruption itself, and obviously the same in 2021 at Cumbre Vieja, which has had notoriety in the same area decades ago.

      • I don’t know about that. The exact number of landslide events produced by shield volcanoes is often not well known. Many have polygenetic scars. Reunion is surrounded in every direction by landslide aprons so thick that they reach nearly to the surface of the ocean, if fact probably most of the edifice, unlike Hawaiian volcanoes, is a pile of landslides originating from the summit area, which is a few tens of thousands of cubic kilometers. I expect Piton can do a giant landslide every few thousand years. Although I doubt it would reach far away, but the tsunami would be enormous on the coasts of Reunion itself. The Canaries, Azores, Cape Verde, and Samoa, and lesser-known shields, also have some potential to generate them. Hawaii is actually really bad at making them because it already has other mechanisms that spread material outwards, the reverse faults under the volcanic pile, and the connectors to transport magma along the rifts. The west flank of Mauna Loa has seen repeated landslides, and may see another “soon”.

        But yes, it’s still something unlikely to happen during our lifetimes. Stratovolcanoes are far more dangerous and frequently collapse. There have been many historical catastrophes related to such flank collapses or their ensuing tsunamis, like Bandai, Unzen, Hokkaido-Komagatake, going from memory. A large debris avalanche can destroy tens of kilometers from the summit of a volcano, it can reach as far as an ignimbrite, if not more, as far as topography allows.

    • Is only the upper ERZ openening (Chain of Craters) or also the middle ERZ beginning with Mauna Ulu area?

      • The earthquakes are happening down to Pauahi Crater only.

  4. Thank-you for the interesting journey back to Krakatao/Krakatau, always exciting. The story of this volcano reminds a bit to the world of Jule Verne of the 19th century with adventurerers in the whole world and extraordinary places.

    The 1883 eruption belongs to the type of the Minoan eruption. Both volcanoes have it in common to do repeatedly major explosive caldera collapses with great tsunamis and large destruction. They’ve left islands in the core behind. Anak Krakatau for Krakatau and Nea Kameni for Santorin. But Nea Kameni looks much more stable than Anak Krakatau. The last eruptions of Nea Kameni were lava eruptions, two phreatic and a dome eruption. The eruptions there were more gentle than Anak Krakatau, and the geological architecture of the island looks more solid.

    Looking at the physics of Tsunamis, the Krakatau tsunamis 1883 to 2018 all occured in shallow water. That’s different f.e. to the 2004 tsunami that was caused by a megathrust quake in the deep sea subduction zone graben. 2004 the energy of a whole moving plate on a long line caused the violent tsunami, while the Krakatau collapses happen at one point and in shallow (shelf sea?) water. A tsunami that is caused at deep sea, also moves at deep sea level through the whole ocean (until Africa), while a shallow tsunami probably doesn’t influence the deep ocean as much. But the deep sea energy of megathrust tsunamis rises to the surface when they approach the coast.
    Didn’t the 1883 tsunami migrate over the whole globe even until North Sea (with small waves)? Maybe this tsunami involved deep water more than the 2018 one.

    • 1883 tsunami outside of the volcano area was probably a meteotsunami caused by the pressure waves I think, not the wave from the eruption itself that did the big damage nearby. Same as for Hunga Tonga Hunga Ha’apai in both ways.

      I wonder if the magma composition affects stability of these islands too. Anak Krakatau is mafic-intermediate mostly, seems to be crystal rich magma that makes it relatively viscous but not explosively so. The strombolian eruptions make loose ashy gravel piles and erupt strongly which might be inherently unstable. Nea Kameni is dacitic and seems to be made of domes with some ashy cones. Lava domes seem to be able to erupt in water basically unaffected, even if the magma is not particularly viscous, it seems like water cant intrude into the lava at all if it erupts slowly so no significant explosive interaction occurs. The same thing happens when big a’a flow fronts and small pahoehoe toes enter the ocean too, so it might be just a density thing, littoral cones seem to generate where lava channels enter the ocean but not every example of a channel entry forms one either…

      I think though, the main bit is Nea Kameni is not built on sloped terrain, which means no inclination to slide to begin with.

      • I think though, the main bit is Nea Kameni is not built on sloped terrain, which means no inclination to slide to begin with.

        Pun intended? 🙂

  5. Hiding it behind a paywall was problematicnegligent homicide.


    • No, I would not call it that. It was not helpful, and will certainly have slowed down the dissemination, but ultimately the authorities are in charge, not the scientists. It is not easy to get funding for things like tsunami warning systems. You are competing with many other priorities, including health, education, etc. Scientists advise but do not decide. Of course, it is very tempting to de-prioritize things that ‘can be done later’. Politics is about the now and here, able to deal with crisis but far less able to deal with the future.

      There is a good chance of a crisis this year, and I wonder which politicians will step up to the challenge and which will deny reality. Climate-wise there could be a very bad hurricane season, and global heat has gone off the scale especially in the oceans. Bird flu has spread to cattle which is not a good omen (and to which the response has been by some to ‘just stop testing’..). And there are several wars that could easily spin out of control and spread. Volcanoes do not rank high in comparison. But that is not a topic for this blog.

      • Even if they knew the risk studied in the article, they wouldn’t have known when the dangerous event will happen. It is nearly impossible to protect coast settlements and towns against the threat by tsunamis.

        • It’s not hard to devise a warning system. Put sirens in the towns and a beacon gadget on the unstable slope that might collapse and cause a tsunami. That gadget would be designed to send a strong signal, maybe ELF, in the event it is suddenly immersed in salt water, similar to airplane black boxes, and to be likewise resistant to physical impact damage. It would need a battery with a short life time, kept topped up by solar until The Event(tm) and with enough capacity to power the warning signal for a while after it is submerged. The sirens in the towns on nearby vulnerable coasts would activate automatically upon detecting the warning signal, and the people would be informed to head to high ground immediately if the sirens ever went off.

          That could have logisitical issues if it’s a big city and not just a town though. The problem with big cities is it’s not really practical to evacuate them fast for any reason.

          An expensive solution would be to make “tsunami shelters” in vulnerable larger cities: underground spaces that could be made watertight and that had an indepentent air supply for a while, like fallout shelters. Unlike fallout shelters the oxygen, food, and water would likely only have to last a few hours.

        • It is hard to protect houses but easier to protect people. You need an early warning system, and that means buoys out at sea. For Anak Krakatau that would have given ~30 minutes of warning. Ask Mike Ross: he knows the details of such systems

    • I was already aware of this site. This was my source when I referred to changes in the volcano’s deformation.

    • And so does the WRM seismograph.

      So is the UWB seismograph.

        • And now they look like normal seismograms again. With tremor and a steady chatter of small quakes.

          Who is swapping images back and forth in VC threads and why?

          • They are direct links to the live updating images on HVO, the only way to have it not update is to save it as an image or a screenshot.

          • They are not images: they are links. For the seismographs, we recommend downloading the HVO image, storing it somewhere and linking to that. That makes it static.

          • Aaaand they’re blank again.

            What the <bleeep!> is going on??

  6. The Copernicus browser, using the satellites has an April 27th image of Ruang Volcano, but already most of the island is covered in ash, and this is before the latest eruption on April 30th.

    • I hope they do some bathymetric surveys once the current crisis is over, I’d be very interested to know if Ruang is indeed built on the ring fault of a large caldera. The eruption phase had appeared to be dying down but it looks like the andesitic dome blew up sometime around midnight (Soufriere St.Vincent-esque). Glad they seem to have managed it well and got everyone out of harm’s way.

      • I was myself wondering if Ruang has had a caldera cycle before. I don’t know much about this system, but looking over the activity on GVP it seems pretty unusual in its recent history to have had a VEI 4 20 years ago and then have two high level, collective VEI 5 events so quickly after (and so close together).

        Doesn’t that imply a healthy magma source? I understand these eruptions were lava dome destructions, but that’s a lot of material on the move here.

        Is Ruang at risk for anything else in this current eruptive cycle, or should the 0.94 cu km blast have been the main event a few days ago?

        • I think the throat of the volcano would have to become blocked with another sticky andesite dome before it behaves so explosively again. That has seemed to be the trigger each time for each of the larger eruptions. In between it has erupted mostly VEI1/VEI2 basalt & basalt/andesite vulcanian eruptions.

          The eruption out to sea intrigued me most as there is the basic outline of a volcanic structure there in what little can be seen of the bathymetry, but it appears to be separate to Ruang. Yet it’s also so close (as with Tagulandang Island) that the systems are almost certainly linked.

  7. Sundhnukur cone does small fountains occasionally, but predominantly looks like a Fumarole volcano that reminds to the view of Vulcano’s Fossa:

    • It’s really slowing down now. At the same time the inflation continues and the seismicity keeps increasing. Given the current inflation rate and seismicity levels, and comparing with previous episodes, I’d give it at least 5 days before something interesting happens. This is assuming that something gives at the same inflation and seismicity levels as before, an assumption that may or may not turn out to be true.

      • That’s consistent with your previous estimate of 7 – 10 days from 27/04/24?

      • Tomas, I keep watching the degassing going on to the north of the active cone which is right at the center of the fissure linement from this last eruption. I wonder if the new fissure flood will start from here again?

        • The degassing is probably more related to magma remaining in dykes that have already erupted, than it is a sign of upcoming eruptions. That said, I think new fissures are most probable to appear in the same area. The big question mark is what influence the still erupting vent will have on the course of events.

          • Normally an eruption should end before another one starts from the same source

          • True. What I really meant was “upcoming new fissures”. It would still count as the same eruption.

            Also, new fissures is just one possible scenario. Maybe the currently active cone will just suddenly go into hyperdrive. We’ll just have to wait and see. Whatever happens, I’m sure it will be interesting.

          • I think if it fully goes 100% then the fissure will have to open, the cone isnt big enough to erupt at 1000 m3/s without probably self destructing and becoming a glowing hole. But my guess is that unlike the last eruptions it will be centered at the cone and not further north where it started before, and the cone will be where the biggest fountains are.

            Probably Grindavik will really just need to get lucky, its a very real danger this time. And if even half of the lava goes south from the current cone we are looking at a major ocean entry. Its kind of ominous knowing this is a matter of days away at this point, if we reach the middle of May without it going then that is significant. If the cone stops erupting then the pressure will probably rise fast and push it over the edge.

          • Remember the rejuvenation of Kilauea’s Fissure 8? Went from dribbling the old rotten 1955 dregs, to nearly-pristine runny Puu O’o’ lava.

        • There is lava in and outside lava tubes/channels all around the cone. The effusive activity continues, but the lava fountains are less rigorous today. It looks like overwhelmingly degassed magma. It’s also possible that gas inside the magmatic plumbing system is migrating towards the next eruption and leaving the current one behind.
          The lava field with many spots and holes allow gas and steam to be released. This looks like “something new”, but it is still the ongoing low-scale eruption.

          • My best estimate is that it is not new, but I have seen cyclic reaction, in regard to microquake activity, but the large volume of degassing in the north area to me indicates some type of tie between it and the active cone.

        • Looks like it’s a leak in the side of the perched pond outside the crater. It’s in about the same place as people were walking on the lava last week.

          • It’s possible that lava tubes have taken a direction there and let the lava out somewhere to the NW of the cone. Sylingarfell video (inside the Mosaic livestream) shows that small lava channels are running on the lava field. It is difficult for us to estimate the lava tube activity. Does IMO or the university monitor this?

      • One more comment now that I took a look at the Sundhnukar 2 camera, the degassing has increased at the north area, looks like 4 fumeroles are now active.

  8. Fortunately for Europe Iceland doesn’t do Tsunamis or only very rarely. All Surtseyan eruptions both of Surtsey, Eldey and Grimsey happened without any Tsunami. Surtseyan eruptions and islands are likely too small to cause a tsunami. They can in most cases only produce ordinary volcanic waves that have the shape of meteorologically caused waves. Otherwise the low lying coasts would historically have seen a tsunami. The Soregga Slide was likely the largest Holocene European tsunami. Did Iceland cause any tsunami during Holocene?

    • Did Oraefajokull 1362 pyroclastic flows reach the sea?
      Snaefellsjokull seems capable of producing a localised tsunami.
      I’m not sure how else you’d get one other than a flank collapse somewhere like Eldfell.

      • It’s interesting that of the two large basaltic “medium igneous provinces” jutting up out of water, Hawaii has evidence of (very infrequent) large tsunamis from big flank collapses into the sea, but Iceland does not.

        Hawaii also has the higher relief, with mountains up to 4 km tall. Iceland does not seem to do that.

        The only major geological difference between them (they have similar magma supply rates and similar overall size and volume) would seem to be that the latter has a divergent plate boundary running through it, which the former lacks. So perhaps that prevents Iceland building up a lot of height, in favor of spreading out more. The plate motion is actually slower at Iceland, but the boundary at Iceland a) absorbs much of the magma supply into non-erupting sheeted dikes below-ground and b) furnishes a highway for magma to travel along, so you get a lot of little volcanoes rather than a few huge ones.

        There is one other thing, though: Iceland has spent a good chunk of the last two to three million years glaciated, which makes it hard for lava to travel far from the vents (and potentially build up a lot near the coastline). Of course ice would calve off, so Iceland must have dumped lots of bergs and hlaups into the North Atlantic during that time, but that doesn’t seem to kick up tsunamis much.

        But if it did, that mantle of ice might also prevent tsunami deposits being made on the island. Any that were made during glaciations would have been on top of the ice, and disappeared into the sea when the ice did. So there could have been some without much evidence being left.

        To determine whether Iceland really is much safer than Hawaii for tsunamis, I think it would be necessary to find evidence of pre-Pleistocene tsunamis originating there, or else fail to find such evidence after a concerted search. The question is what evidence of such would have survived after such a long interval, and wouldn’t have been destroyed by subsequent glaciations reaching the coasts of the North Atlantic?

        Are there any signs in the bathymetry of past large landslides off of Iceland, the way there are for Hawaii? A lack of such debris on the seafloor there would be good evidence that the big flank failures of Hawaii’s past indeed don’t occur at Iceland, because there’s no reason to expect poorer preservation of that sort of evidence at Iceland than at Hawaii, unlike deposits on low altitude land at a high latitude during an ice age where repeated scourings-to-bedrock have likely taken place.

        • Iceland’s volcano are less tall and are away from the sea – both help! I am not aware of large Icelandic tsunamis. In Hawai’i, the main risk is flank collapses into the sea, caused by the slope becoming very steep under water, especially to the south. There is a difference which you don’t mention: Hawai’i is sitting on a moving plate while Iceland is pretty stationary. So Iceland has build up a large plateau around its volcanic centres, while Hawai’i keeps growing new volcanoes from deep ocean floor.

        • I think it is more funxamental than tbat. Hawaii is made of gigantic shield volcanoes that build on existing sea floor covered in sediment which makes them inherently unstable. Iceland is mostly thick oceanic crust and the lava covering is relatively thin, the eruptions can be larger than those in Hawaii but the volcanoes are not even slightly comparable in long term output, you need to go into weird technicalities about their deep intrusive complexes to find something similar to Hawaii which, as you said, is rarely involved in actual eruptions in Iceland.

          So basically there is no weak substrate Iceland is built on, the volcanoes are entirely subaerial and relatively small above ground, where Hawaiian volcanoes all had to become giants to even reach sea level let alone grow so big past that. To be honest apart from at Reykjanes there are actually very few volcanoes in Iceland that can even reach the ocean with a lava flow let alone build an unstable shelf. The only eruptions from the big volcanoes that have a chance are the millennia apart massive lava floods like Eldgja and Thjorsahraun. Compared to Hawaii where basically every major eruption has dumped a huge volume into the ocean, so much so that several historical examples (1840, probably 1950, 1960, 2018) have had major revisions upwards on their volumes.

      • I think the pyroclastics did not but the jokulhaups probably did.

  9. Hawaii update:
    “Over the past 5 days there have been over 1300 earthquakes beneath the upper East Rift Zone and approximately 225 earthquakes beneath the southern end of Kīlauea caldera.”
    Although the seismic activity centers on upper ERZ, “Ground deformation continues with ongoing uplift at the summit and south of the caldera into the Southwest Rift Zone.” The SWRZ is not out yet. Do we get a period with both rift systems active at the same time?

  10. Something has been nibbling on the rim of the cone overnight, and there is active lava northeast of it. The pond south of the cone drained and the undermined crust has caved in in places leaving gaping holes. There is active degassing from those holes so there must still be lava moving through there. A path developing for it to quickly drain around the cone and to the north could explain most of this, but not the alterations to the top of the cone itself …

    • The lava from the breakout to the west is now slowly trying to form a channel back to ward the south, close to the cone. I think the top or the cone eroding away is likely to be just the wind and rain of the past couple of days, slowly eroding the top that is no longer being rebuilt due to the weaker lava spurts inside the cone. Just my thoughts anyway.

  11. Kilauea is now seriously swarming in it’s Upper East Rift Zone.

    • Still not in an E/W direction so its not a dike forming, just the connector pressurizing. But realistically the connector isnt that voluminous by itself so somethings going to give eventually and by the size of some of the quakes now it will probably be sooner than later. But just like in February once it goes it will be really obvious, probably double the current quake count or more and a long line of them forming within a few hours. An eruption will probably begin within that first rapid growth stage otherwise it will just stay an intrusion. Most likely the latter with the caldera floor still being around 150 meters lower than the quaking area but if it is a gas rich magma it could erupt. Small in volume but probably big fountains and high intensity if it does go.

      • “the connector isn’t that voluminous by itself”

        Unless it’s the seismic expression of the deep rift.

        • Yes thats true, although I dont know if that necessarily changes the outcome as the pressure isnt yet high enough to form a dike just yet. But probably getting very close now, even if the surge stops the next one will probably immediately break out, which is probably what happened in January, that was a quiet month that got a day of quakes before the dike started.

          The thing that will be interesting to watch is how the rest of the ERZ responds later. So far there is no magma feed to the actual ERZ proper and there hasnt been for a few years now but all that time there has been south flank sliding. It is very similar to following 1975, only that now Pu’u O’o is already there so the middle ERZ is no longer a convenient exit. The south flank has been moving continuously all the way down to near the highway, where the 2018 dike started, so if the ERZ does capture the full flow the same as it did in 1983 then there will probably be a lot of activity east of Pu’u O’o. So Kalapana and Kaimu might well be in trouble again, but potentially so is Pahoa, if it can be directed that way.

          Its still far from certain, Halemaumau might become connected again and suddenly erupt tomorrow, and there might also be another dike down the same rift as in January. But given how fast this has all changed it is very unpredictable, only a couple weeks ago I was talking about another Mauna Ulu/1961-1974 type rifting and lava shield sequence on the SWRZ and now it goes back the other way…

          • After a calm period 1952-1955 Kilauea moved quickly from summit to lower ERZ eruptions. Maybe we get a period with summit eruptions and ERZ intrusions before some years afterwards ERZ does the major eruption. During the 1950s Kilauea was all in all less active than around 1970. So partially comparable to today’s state of Kilauea.

          • “Calm period” applied to the period between 1924 and 1950 when Kilauea did few eruptions while Mauna Loa was strongly active.

          • Kilauea now is more comparable to after 1975 than anything before 1950, the supply rate now is much higher.

    • HVO update for today included this bit of information:

      “Deformation levels indicate that the south caldera reservoir has regained the magma that it lost during the intrusion. Current pressurization levels are now even with pre-intrusion levels after 2 months of magmatic recharge.”

      So basically Kilauea has a supply rate of 30 million m3 in 90 days more or less, not counting the surge last week. Its very similar to the sill under Svartsengi actually. I dont think we will get a big volume eruption but a very intense and visually impressive one is a distinct possibility. If a dike intersects one of the pit craters though then it could get interesting, filling it with lava and maybe starting with huge fountains.

    • Should we expect stronger earthquakes to occur before something significant happens again? I’m just reading the chronology 1954 when on March 30 two months before the eruption a Magnitude 6.5 strong, scary earthquake happened. The eruption 1954 was nearly the same location as September 2023, but lasted only three days.

      • Maybe, but that was probably also because the ERZ had been stuck for a long time in 1954, maybe over 20 years. There wasnt a quake in 1960 which was a much bigger and more intense eruption.

        • How much tectonic tension is now in Kilauea’s systems? Can we estimate it or would earthquakes from human perspective happen randomly?


    Nice documentary of the 1964 surtsey activity, Surtsey is a good example of the life of a small lava shield infact two shields where built.. Surtur 1 and 2 and Surtsey still remains of the very largest icelandic eruptions in modern recent historical times ( 1,2 km3 ) It was a pretty good tourist eruption when it entered its tube feed pahoehoe phase where one coud on fair calm days visit by boat and then hike all way up to Surtur craters and watch the boiling lava lakes and watch lava tubes and poke pahoehoe and seeing the lava flow into the ocean. But during the early effusive phase you woud not want to board the Island with giant sheet Aa lava flows moving at near running speeds from Surtur 1 s lava pond

  13. Apparently some scientists are interested in what is happening with the active cone tonight, Friday-Sat May3rd/4th as two very slow moving objects in the air were visible in the Langihryggur camera around 2:15 am, hovering and moving very slowly, almost like weather balloons. See . The active cone seems to be leaking on the west side.

    • 3 am and spatter cone has definitely picked up activity and is spraying lava high into the air above the highest part of the cone.

  14. Any thoughts on prospects for the next pandemic? Current developments with avian influenza or more specifically H5N1 have caught my eye. Since 2020, there have been constant outbreaks of the disease that never seem to completely stop and increased spread to other mammals. As long as these outbreaks continue, the greater the chance of new strain developing capable of human-human transmission. It is currently so hard for humans to get it that it’s hard for me to imagine it producing a global pandemic over the next few years but I do believe it has that potential over the next couple of decades. An avian influenza pandemic has scary potential as studies have shown that this virus is capable of producing mutations more deadly than the Spanish flu. Concurrent with the global pandemic, massive losses in the poultry sector would threaten the agricultural sector directly. An Avian influenza pandemic would be infinitely harder for the world to deal with than COVID-19 and I would have no faith for an intelligent response for such an event.

    Another virus that I think could have pandemic potential in the immediate future is MERS. Covid-19 was SARS.COV2 what if MERS-COV2 develops? The MERS outbreak was more persistent and deadlier than the SARS outbreak so a similar comparison could happen with a hypothetical MERS pandemic. On the positive end, naturally gained antibodies and the vaccine obtained from Covid-19 pandemic could possibly limit the mortality rate of a MERS pandemic. It also might not. Interesting possibilities all around.

    Current political drama and cultural trends concerning another pandemic would likely see a more stifled government response and public backlash against pandemic mediation efforts. A lot of people see the Covid-19 pandemic as an overblown or just a flat-out hoax and this would definitely hamper responses in critical moments of the next pandemic. No new policies or laws have been made to rectify the mistakes that were made during Covid-19. Unless divine intervention takes place, an avian influenza pandemic would be FAR deadlier than covid-19 while the jury is still out on a MER pandemic. No lesson learned and still threats abound

    • I think the chance of H5N1 evolving to infect people has increased a lot now that it has established itself in cattle. That is in fact the same route that the spanish flu took: it jumped to humans on Kansas farms and was exported to Europe by the movement of soldiers. (It had nothing to do with Spain..) Two mutations are needed, one to infect people and another one to spread from humans to humans. But we know how to make flu vaccines. Because flu is so infectious, lock-downs are not as effective, so we will depend on vaccinations. It also affects people of all ages more equally: that makes it less likely that you get the kind of objections that you got against covid vaccines. People tend to become more reasonable when their own lives rather than those of their elderly neighbours are at stake.

      Sars, Mers and Covid are all from the same family of virusses. The family has gained the ability to jump to people sometime during the 20th century. Covid had a lower fatality rate than the other two but (partly because of that) spread much more easily. There will a 4th version at some time, possibly quite soon, but we now know how to make vaccines. I think the biggest risk is actually when it evolves to spread through cats and dogs. Covid could infect those but did not spread between them. Once that changes, it may spread faster because we have much closer contact with our pets than we do with farmed animals.

      Covid itself is also likely to stay around for decades: new outbreaks could be a problem especially for older people but the vaccines have helped a lot.

      • Not sure that’s entirely likely to be completely correct. The covid is an ACE-2 binding virus and these are hugely common and mutate rather freely. Before covid about 3% of common colds were ACE-2 (covid) viruses. However because as a group they are somewhat similar there is x-resistance to them more-or-less as a group. Those old covid cold viruses did all of us a good turn by providing partial immunity to the group as they circulated. Mers was sufficiently different to cause high mortality (it seems) although personally I’m not sure if all the non-symptomatic people were counted. Its why in actual fact the mortality and morbidity of C19 was actually rather limited. Basically two groups, those with impared immunity/poor lung function and groups that were exposed to very high doses of virus from the off (bus drivers/some hospital staff). C19 is now endemic and giving us protection.
        Flu is another matter. Birds are prone to flu (no idea why) and the depredations in wildlife have been extreme. A year or so ago it was common to find pigeons on the ground dying and gasping for breath. Even today bird numbers are drastically reduced from a few years ago. I cannot remember if there is a vaccine for this strain of bird flue, but I hope so we may need it soon.
        Or never, who knows.

        • Different virusses can use the same route into people, in this case the Ace-2 receptor (if that is the right word). It does not mean that the virusses are related. The corona virusses that cause the human common cold are recent. They started infecting people on the 20th century, and most common cols come from other, older virusses. It does mean that some corona virusses cause rather mild disease. The Sars family is much more serious. You are correct that the fatality rate for sars may be lower than measured if mild infections were missed. But with three family members jumping to us in the last 20 years, and many others may be waiting in the wings, it is a family to monitor very closely.

      • H5N1 is still not on that level just yet but the current concern is that dairy and cattle farmers do not have experience with the disease and are in some cases, not allowing scientists to get data in some areas. In a lot of states, the CDC only has a limited scope of the current outbreak. This a terrible position to monitor the virus for future mutations. It’s so ridiculous when you consider the potential of a pandemic over the next decade. There are vaccines but who knows how effective it would be for future mutations.

        • There are reports of farmers refusing permission to test for the virus. But they can also test waste water (just as they did for covid) and this suggests it is spreading at least among dairy cattle.

      • “The family has gained the ability to jump to people sometime during the 20th century.”

        I suggest you look at HC43, which it appears might have been the last coronavirus to jump to humans. The so-called ‘Russian flu’ pandemic of 1889, with the experience of covid and the benefit of hindsight, looks a HECK of a lot like a covid-type illness, and not very much like flu at all.

        In particular, the morality curve for influenza is typically a ‘U-type’ – it has the worst effects on the very young and very old. Covid is a ‘J-type’ – in most cases, it scarcely affects the very young, but affects the very old severely. The ‘Russian flu’ was J-type – and it corresponds very closely with the time when it appears HC43 coronavirus entered the human population, based on mutation rates.

        • I saw the claims that it was a coronavirus. The jury seems out on this. We know from immune data that there was a flu epidemic around this time, because people born before 1890 were immune to a flu virus while people born after 1899 were not. This is the same way it was shown that the 1918 epidemic was a flu. But it is not full evidence. Many symptoms agree with covid, such as loss of smell, but not all symptoms do, and of course covid has shown a large variety and changes of symptoms. That is not full evidence either. I am keeping an open mind on this!

          • Worth pointing out that HC43 has also been dated to around 1899, a decade too late for the russian flu, but coincident with another significant epidemic

          • Also there are a couple coronavirus common cold types that are probably also relatively young, but not 1900s or even 1800s young. Not entirely clear why, but some change has made it easier for coronaviruses to jump to humans in recent centuries.

          • Population growth and global empires…? Especially Europeans are present on every continent now and in the modern day everyone from everywhere can basically go anywhere so regional diseases and regional resistances become global.

      • I would need to.look back through information I acquired a few years ago and read/type properly from a PC instead of my phone. However, a couple of quick things. The SARS and MERS coronaviruses are from different groups, with different targets for binding. SARS-CoV was also more virulent than SARS-2-CoV.
        In terms of influenza, there is a paper suggesting that most circulating strains contain remnants of Spanish flu, so there is some cross-imnunity. There are a lot of u known though and the same paper links to an 1890 outbreak that has also been suggested by others to have been a coronavirus now in general circulation.

        • The evidence for the 1890 epidemic as a coronavirus is not particularly convincing, in my opinion. It also contradicts the timing for the evolution of that virus, which fits the 1899-1902 epidemic much better. Spanish flu remained in circulation until the 1960’s or so.

      • Yup. From memory I think its more that people have looked for prionic diseases since BSE and found them, although CWD was first identified in farmed deer, it really wouldn’t be surprising to find its the deer equivalent to scrapie.
        I know more that I would like to about this bunch of diseases which are filled with erroneous information, sometimes from sources who (if they were not chasing grant money) should (and do) know better.
        Personally, I think its is one of those diseases that is really a symbiotic one. Consider this:
        Deer are fast and hard to catch.
        They live in huge herds.
        They have a mortality of 50% per annum (approx).
        They need time left in peace to graze and ruminate.
        They are hunted by a number of predators, typically as they pass across predator ranges.
        Being hunted means running about during the hunt evading predators, this is bad, you cand’t eat or ruminate. The whole herd suffers.
        In any case eventually the required number of animals is killed each day anyway.
        So how about you arrange for one of your number to quickly get killed, leaving everyone else in peace to get on with spending all day making more deer?
        Get a small number to behave oddly, easily spotted and caught by predators who are done for the day.
        Have a prionic disease at low level in your population and problem solved.
        humans, dogs and pigs seem to be VERY hard to infect with ruminant prionic disease. These are consummate scavengers. Cats, though, very susceptible.

        • This type of disease was likely an inspiration for zombie movies. Brain diseases like CWD and CJD change the behaviour of an animal and human. It can make them stoic or aggressive, but usually they can’t act much because the neurological disease also blocks intentional movements.

    • sorry, all I needed to check the dates… (red faced) … trying to check the upward motion on all the stations, the reading was valid but the graphic is for March, not May

  15. Looks like a deep M7.5 occured in the mid Atlantic Ocean ridge between Liberia and Brazil today. Not sure if the depth is just a rounded number or not but it looks as though it was around 750KM deep.

    • This might be a measuring glitch. The event is now listed as a M5.8 which makes more sense. 750 km depth is very deep. Some subduction earthquakes can approach this depth, but mid-ocean rifts only have shallow events, so I expect that the depth will end up being no more than 20 km.

      • Was changed to 10km depth and M5.8.
        The Romanche Fracture Zone has had 43 earthquakes M5.8 & above, with three M6.9.

        • I seem to recall someone saying that 10km is the default reported depth, for when they do not have an accurate depth measurment.

          This is why so many quakes are 10km deep. Unfortunately I cannot remember where I heard this.

      • It is, it’s a ‘magic number’. 750km is the ‘bottom of the system’ in SeisComP, which is a commonly used earthquake locating package… it’s the deepest SeisComP can place an earthquake, and if it is the lowest ;residual, it’s the depth that can be offered in an initial automatic solution, based only on P-picks.

  16. Sundhnúksgígaröð is building a cone-within-a-cone now. It’s almost exactly copying the Litli Hrútur eruption’s behavior with a slightly stretched time-scale; if so it is likely doomed within another day or two … except that the sill is just about at the breaking point again and will either inject a load of hot fresh gassy magma into the dike that’s feeding it or else create a new intrusion nearby, also likely within another day or two. Either way the existing eruption is likely to be affected.

    • I hope it erupts elsewhere, just for variety’s sake. Maybe it unzips that portion of the dike inbetween January and February eruptions.

    • This may indicate that the eruption weakens and the magma conduit becomes narrow.

      • It seems likely. The sequence of events is basically the same as at Litli Hrútur: fissure -> focuses down to one vent -> builds a cone with a channel coming out -> channel roofs over close to the cone -> episodes of overflowing and a sector failure or two -> this stops and lava ponds close to the cone without a robust river flowing away anymore -> eruption vigor begins to fluctuate, with periods of significantly reduced intensity -> ponds crust over and become less active -> cone starts building smaller nested cone -> eruption dies.

        • This reminds to the reduction of Mauna Loa’s active lava flows 2022. As long as the magma/lava rate was high, the lava tongue continued to expand in length. When the flow reduced, lava escaped from the tubes/channels at shorter distances from the source, because it couldn’t keep the whole long path of lava flow anymore.

  17. Noticed several deep quakes (16-18km depth) coming from deep feeder Greip today.

  18. A matryoshka crater. Seems that there is a small crater inside the crater and I bet there is another one inside the one inside. Perhaps a metaphor for live? Maybe not.

    • Its “life” not “live”. On the other hand, it is also a metaphor live (on live stream). But I meant the life stream, the stream of life, obviously.

    • The cone next to Litli-Hrútur did the same thing before it shut down. It’s strange how it feels like ages ago, when in reality less than a year has passed.

    • Big cones have little cones,
      look down their throats to sight ’em.
      And little cones have littler cones,
      And so ad infinitum.

  19. The Caldera of Krakatau belongs to the type of “Caldera with a volcanic cone inside”. There are calderas with no volcanic cone (f.e. Askja, Kilauea). There are Somma volcanoes with in fact a big crater with a smaller volcanic cone (Vesuvius). Calderas which host a volcanic cone inside, are f.e. Santorin (as mentioned above), Taal, Crater Lake and Toba (at least four stratovolcanoes). Mauna Loa’s Caldera occasionally also builds cinder cones, f.e. the one of the 1940 eruption.

    • I think Okmok Caldera in Alaska is starting to push things as far as calderas inside calderas, not to mention a Tulik volcano in the SSE quadrant which probably is an outlier to the main magma feed.

    • Depends on what point you’re considering whether Kilauea had a cone inside a caldera. Halemaumau was in fact the summit crater of a large shield within Kilauea Crater, sometimes manifesting as a spatter cone that roses above the high point of the caldera. (Going further, there have been cones built on the floor of Halamaumau!)

      • Halemaumau wasnt a fire fountain cone though, except for maybe very early in its existence back in the pre-1823 time. And I think the lava shield was only really a thing going into the 1870s up to 1890s, and again in the decade before 1924. Pu’u Puai is a fountain cone within the caldera though just not a polygenetic one 🙂

        For a while I thought the June or September eruptions last year might vecome a fountain cone, but they didnt, despite both erupting mostly outside of the lava lake and not having the problem of drowning like earlier eruptions. In hindsight that really should have been the big clue the rifts were waking up, the September eruption actually had a SWRZ connector flare up before it and then switched, and it took only a month for said rift to act up again. And now we have the ERZ going too…
        I dont think we will see any long eruptions for a while now that magma can easily escape the summit, we will see many intrusions and tiny eruptions that get bigger maybe on both rift zones now, and in a few years to a decade another persistent paroxysmal eruption like Mauna Ulu or Pu’u O’o. I am putting a bet on that opening up near the 1977 eruption fissures, between Kupaianaha/2007 vent area and Heiheiahulu. And to be fully honest, another 2018 type eruption after that. And only when that distal eruption can erupt offshore and induce a total collapse of the deeper chamber to cut off the rift zones will things truely reset back to filling the summit. That might well take decades longer, with the interval between nkw and then being successive massjve shields and flood lavas, maybe not as big as Pu’u O’o but still very large.

        I remember a while back Hector talking about how Mauna Lia and Kilauea a couple thousand years ago both had massive resyrfacing events and that even dominant periods at both since then were not as impressive. That was up to 1840 when Mauna La had 30+ massive fissure eruptions in a century each an equivalent volume of a VEI 4 maybe even a 5… Then Kilauea has its biggest ERZ eruption in the last few millennia. Seems like we could be in for a wild century…

        • “I remember a while back Hector talking about how Mauna Lia and Kilauea a couple thousand years ago”

          About 2000 years ago. Most of Kilauea’s ERZ that wasn’t covered by Kane Nui o Hamo or later LERZ eruptions dates back to around the same time to an episode that resurfaced much of Mauna Loa’s SWRZ (they have the same paleomagnetism although only the Mauna Loa eruptions are radiocarbon dated). Pu’u’oke’oke’o is one of such eruptions, but there are huge long lived cone complexes, many of them with multiple fissure eruptions that date to around this time, all along the SWRZ of Mauna Loa. Better research would be interesting, but scientists are not looking carefully into old Hawaiian flows and tend to assume activity has always been the same, which has not.

          • Yes I have the same confusion why HVO doesnt talk about prehistoric ERZ activity at all, it could be partly because it is buried now but most of it wasnt as recently as 40 years ago…

            The way Kilauea is behaving now isnt really anything like the rest of the historical period. Post 1790 there was probably as much as 10 years before eruptions resumed, and when they did the eruptions were entirely in the caldera for another 10 years in all probability. All of tge SWRZ post-1790 flows probably erupted after 1815 and maybe even all after 1820, clustered into a couple years of strong activity that ultimately saw the south flank shoved out of the way in 1823, alongside letting the caldera lake drain. That us my hypothesis anyway.
            By contrast after 2018 the ERZ never stopped moving and magma even kept going there in preference until it broke out in Halemaumau ending 2020. If Halemaumau was not formerly a 600 meter deep hole and all sat at the downdropped block elevation I think the ERZ would have erupted again before anything else.

            The fact that all of the lava after 2011 has been basically identical composition as melt, crystal free at 6.8% MgO, is particularly interesting, at every other volcano this homogeneous magma is considered a primary indicator of a huge magma chamber that will probably do a total caldera collapse. A 5×5 by 6 km deep area contains 150 km3… tge potential is there.

          • Mauna Loa’s history could be studied MUCH better if paleomagnetism and geochemistry were thrown into the mix of its already extensive radiocarbon data.

            Though the only way to gain full understanding of Hawaiian volcanism would be drill-cores: combining stratigraphy, chemistry, and paleomagnetism in cores obtained from drilling.

          • Apparently HVO scientists don’t see the need for deep digging into distant past. Maybe they view their first task to advice the Emergency Administrations on what to do next. They likely have a more “Now Cast” oriented scientific interest with modern tools & toys than for historical questions.

          • They do dig deep into the past but not for the entire volcano. The records HVO have for the explosive eruptions at Kilauea is fascinating but they leave out both rift zones which is aproblem that I dobt understand. If I can think of it as a random guy with an interest then surely they must be aware of it too…

            As an exame, Kilauea supposedly is in an effusive state now and was explosive from 1500 to 1800. Except, there was a massive resurfacing of most of the ERZ in the 18th century including at least one long lived vent, the supply was high just not going up. And geologically speaking too the Keanakako’i tephra is still the surface layer of 99% of Kilaueas summit outside the caldera… and the amount of lava erupted at the summit in the past century is only about 8% of the total lava erupted in said time.

            At the very least after 2018 I am surprised there hasnt veen intense interest in trying to find out if more eruptions of similar scale have occurred before. 1960 was a similar intensity just shorter. Ahu’aila’au is not particularly impressive as a vent structure compared to its neighbors. There arent any other lava channels like the one in 2018 true but that flow also took a very long path to the ocean over 13 km, and on flat ground not just going right down the south flank.

      • I should have additionally distinguished between calderas inside of shield volcanoes and classical calderas. Classical calderas can produce minor cones inside the caldera because they do f.e. strombolian or dome eruptions. Calderas of shield volcanoes usually do liquid hawaiian eruptions that prohibit the formation of a significant volcanic cone.

    • In volcanic arcs, polygenetic cones are the norm, so it’s usual for calderas to develop cones inside.

      • They also have the advantage to make cones by lava domes, that are unkown to basaltic calderas. Viscous domes sometimes rise hot but nearly solid like a mushroom from depth without any ability to flow anywhere.

        • Many fluid basaltic cones do exist in arc settings though, and Hawaii does have the ability to form such cones too like at Pu’u O’o, only they often only erupt that way for a short time before self destructing from erosion by the lava. Pu’u O’o from 1983-1986 was basically a small stratovolcano.
          I think such structures dont form within Kilaueas caldera because the pressure to do repeated paroxysmal fountains would be too high and a rift intrusion would occur, two of last years eruptions were perfectly located to start erupting this way and yet didnt. Even way back in 1959 this nearly happened but was terminated by magma going into the ERZ, and this was when Kilauea had an immature magma system that let the ultramagnesian deep magma erupt directly which is likely impossible today.
          I do wonder, Kilauea Iki was able to do lava geysering for only a month, Mauna Ulu did it less often but lasted a year before the conduit failed. Pu’u O’o lasted 3 years. A similar eruption east of Pu’u O’o might well last even longer, Heiheiahulu did become a pahoehoe shield eventually but its a’a flow field is larger and seems to have been the majority of the total.
          Kilauea Iki 1959 vent is at 1040 meters elevation, Mauna Ulu started at 920 meters, Pu’u O’o at 730 meters, while the land between Pu’u O’o abd Heiheiahulu is only 500 meters. The floor of Halemaumau is lower now too but still 900 meters elevation now, so it is at least as high above the area east of Pu’u O’o as 1983 Halemaumau was above where Pu’u O’o itself formed.

  20. Cone drones now at 22:42:09 – two drones swooped in taking pictures.. hope they appear on YouTube soon. . I guess the cone inside the cone building process is intriguing.

  21. The obvious analogy to the Anak Krakatau land slip is the famous Mt St Helens eruption, where we have live footage. If Mt St Helens had been an island stratovolcano the tsunami would’ve been very similar. (The YT is geoblocked but available if you access via a US server.)

    • St. Helens 1980 was a dry Pelean-Plinian eruption. There was an Andesite “cork” from an earlier historical eruption that prohibited a vertical ordinary Plinian eruption. St. Helens switches its magma type all the way from Dacite to Basalt occasionally.

      It is difficult to compare this with a Phreatomagmatic collapse eruption. The movements caused by steam explosions are different to the movement of a landslide. I’d assume that the St. Helens landslide into the ocean would have caused a smaller tsunami than Anak Krakatau 2018. But if a phreatomagmatic component was added, it would be much different.
      2002 Stromboli did an example for a volcanic landslide that caused a tsunami without a Phreatomagmatic element. It was a high-end Strombolian eruption, much smaller (VEI3?) than St. Helens Plinian eruption. But it shows a difference to phreatic/phreatomagmatic tsunamis.

      • St Helens in 1980 basically evacuated the entire volume of Spirit Lake from its lakebed and washed it up the hills, if it was near the ocean and blasted into it the wave would have been enormous. For being ‘only’ a VEI 5 the eruption was extremely powerful, it is kind of silly to compare massive calderas to their proportional size compared to this eruption. Ruang just did an eruption that was technically bigger but relatively only an inconvenience outside the immediate area, if it blew half its volume into the ocean at mach 0.5 the whole Pacific would be on alert.

        • If a St. Helens eruption had happened in/close to sea shore, the phreatomagmatic component would have increased the VEI to VEI6 or VEI7. The major explosions both of Adult Krakatu 1883 and Anak Krakatau 2018 were caused by water that seeped with big volume into the magmatic system. If something like this would have been added to St. Helens 1980, the whole volcano would have blown up. Then we would have a St. Helens caldera instead of the horseshoe shaped Somma crater.

      • Pretty much agree with that. On the other hand the Mt St Helens event was a landslip which basically pulled the top off the volcano, including the lava dome plugging the conduit. You can see from the video that once the whole mass of rock slid northwards that the conduit was exposed and erupted in Plinian fashion – but only after the landslide had occurred.

        At sea level that would’ve then let seawater into the vent, and that’d be a big phreatomagmatic kaboom. But just a landslip of the size of the Mt St Helens’ one itself would be enough to cause a large tsunami.

        On Krakatau the Royal Society report is available online, and makes for fascinating reading.

        The eruption of Krakatoa, and subsequent phenomena (1888)

        • The tsunami of Ruang 1871 was likely caused by a collapse event. I don’t know if there was a Pelean element in the disaster. A Pelean eruption means that the Plinian force goes horizontally instead of up. St. Helens 1980 started as a Pelean eruption. This killed David Johnston 9km away from the volcano. If the eruption would have started Plinian (vertical), it would have killed fewer humans.

  22. HVO put out an article about the 2018 collapse and 6 years since and the developments. This part really caught my attention.

    “The volume of summit collapse was approximately half the volume of lava erupted in the lower East Rift Zone—approximately 0.8 cubic kilometers (0.2 cubic miles) of summit collapse compared to 1.5 cubic kilometer (0.4 cubic miles) of lava erupted.”

    Might be the only example of an eruption being bigger than the caldera it created I can think of…
    Also erupting 1.5 km3 of lava in 78 days, the average is almost 20 million m3 a day. Holuhraun took 2x as long to erupt only slightly more. T

    Also the fact people lived within 1 km of the vent the whole time is crazy, where Holuhraun was causing health problems in Reykjavik with lower SO2 output… 200,000 tons of SO2 a day for 2 months.

    • Also about the Kīlauea volcano, never seen these before on the KKO seismograph (although it may be from nearby earthquakes), but it is typically much more silent and consistent… (this is within 48 hours)

      • And here is what HVO said today:

        “Activity has slowed significantly in the past 24 hours. Earthquake counts have decreased significantly with approximately 75 earthquakes in this area in the past 24 hours and 7 in the past 8 hrs. Earthquake locations remain focused primarily from the southeast side of Kaluapele (Kīlauea caldera) beneath Keanakākoʻi crater extending to the intersection with Hilina Pali Road. Earthquake depths remain unchanged, averaging 2-3 km (1.2-1.9 miles) beneath the surface, and magnitudes have not exceeded M2.0 in the past 24 hours. There have been no earthquakes in the caldera south of Halemaʻumaʻu over this same period.”

  23. How long did the high rate phase of the current episode of Sundhnukur last? When was the end of the high rate phase?

    We should view the low rate phase as a partial continuation of the dormant phases from December to March. Then the eruptions lasted a few days and switched off completely soon. After 16th March the eruption didn’t switch off completely but continued on a low level until totday.
    Already at noon on 17th March IMO wrote “The volcanic eruption that began at 20:23 last night continues, but during the night the intensity of the eruption decreased”.
    21st March IMO wrote about that the “Average discharge rate for 17 – 20 March is 14.5 m3/s”
    Did the eruption already decrease to low level on 17th March? If so, this would be comparable to the February eruption that died on its second day. All in All the eruptions/episodes of Sundhnukur continue to do short high level spectacular eruptions. After 1st day, the main episodes are quickly over, and a dormant period or low level rate activity take over. If an eruption doesn’t die completely (as on 17th March), it continues on low level and delays the next episode.

    • I think the curtain of fire stage was pretty standard, maybe a bit bigger than earlier fissures but that isnt unexpected. The eruption didnt immedistely slow to present level it took a while but by the time it was stuck at just the south end the eruption rate was around 15 m3/s. Which is a lot more than 3 m3/s but both are tiny compared to the nearly 1000 m3/s of the fissure stage so are basically the same. I think you are right to compare this long eruption to the quiet intervals between the others. It will be interesting to see if low level activity continues after the next fissure/surge or if this was kind of a random one off.

  24. Anyone have thoughts about what’s happening on Reykjanes Ridge tonight?

    • Business as usual.

      If you look at Reykjanes Ridge activity the last few years, the activity has been high with many swarms like this. Some swarms happen close in time to eruptions or dyke intrusions, so they may seem correlated, but then there are Reykjanes eruptions with no simultaneous swarms at Reykjanes Ridge, and vice versa, swarms with no corresponding eruptions. I think it’s just a generally very seismically active area and it’s not a good indicator for what is happening on the peninsula.

      Eventually, there will be eruptions out at Reykjanes Ridge, but for the moment, the most interesting action happens on land.

      • It matches with Eldey volcano though, which already saw an intrusion-like swarm in 2023, it might be worth keeping an eye on.

        • Reykjanes Ridge and Eldey probably never had a real break that the Reykjanes Peninsula had. Around 1990 there was a deep submarine eruption on the distant Reykjanes Ridge. They could measure it by volcanic tremor. If we think about historical times without instruments to observe tremor, there were probably many submarine eruptions without any notice by humans.

          The last small Surtseyan eruption of Eldey was 1926. Often eruptions there are too weak to build islands. They can still disrupt the airport of Keflavik. The eruption 1926 was even too weak to cause tephra fall.

      • The Reykjanes Peninsula did earthquake swarms like this frequently long time before the recent general unrest of the new “Reykjanes Fires Age” began. Earthquake swarms are likely the normal natural behaviour of both Reykjanes Ridge and Peninsula both inside and outside of eruption periods.

        It is challenging to distinguish between “normal” earthquake swarms and “alerting” earthquake swarms that lead to eruptions. If we look at the first significant intrusion of Thorbjörn/Svartsengi 2020, there was a much different magnitude of an earthquake swarm than the ordinary swarms.

  25. t0 minutes past midnight on May 6th. Someone in a vehicle exploring around on the far left hand side. Two steam fumeroles near the center of the latest fissure lineament still steaming. A new breakout north of the cone. And the active cone itself.

      • No one has mentioned the tremor graphs recently, but to me they have been correlating quite nicely with the cone activity. A steady 4000 blue on the GRV graph over the whole eruption until this week when it started to reduced and vary. Then yesterday it started to drop as people mentioned the cone quietening.

        Then this evening it jumped quite a lot. I was expecting to see a strong increase in the cone, but maybe it’s not fountaining out of the cone but running through the tubes. Either way the tremor looks like more magma is on the move again.

        • For some reason, when I went onto the link, the graphs seem blank. Maybe it has to do with user location or something?

          • Your browser is blocking the images since they are http and the main page is https. Try dropping the s from the main page URL.

            The jump last evening was caused by a quake swarm off the coast at Eldey.

    • Nice. The location is not surprising. The Keanakakoi area I already suspected is the one that inflates during the UERZ seismic crises. It’s a long-term inflation focus, but it’s the first time I see it developing live. The inflation rate is impressive. There’s 10 cm of uplift in about 5 days that the swarm has lasted. 2 cm/day is even more than during the SWRZ swarms of previous months, but the inflation area was somewhat larger back then. PUHR GPS, which is closest to the center, has skyrocketed.

      • Its more surprising that it just stopped and is possibly ramping up again. I expected it to start an intrusion but apparently not.

        • The ERZ connector has a very dense earthquake concentration over a longer distance than the SWRZ connector, so I think we may see more impressive rates now.

          • Is the Summit able to do a southern eruption outside the Kaluapele caldera close to Keanakāko‘i Crater? Or does it need more magmatic pressure to build up an eruption on the high altitudes?

            HVO says that the “South Caldera magma reservoir” has had more magma recharge than Halema’uma’u’. Does magma from this reservoir prefers to go towards the southern caldera area or towards the pit craters of upper ERZ?

          • An eruption outside the caldera seems unlikely to me unless there’s efficient rift transport and the eruption happens at altitudes much lower than the summit caldera floor.

          • Going by total elevation, the caldera floor is 900 meters elevation. The ERZ doesnt reach that elevation until Makaopuhi crater, so if gravity is the only factor then an eruption is only favored on the ERZ if the connector goes at least that far continuously. The SWRZ is steeper, 900 meters elevation is at Mauna Iki, and the February dike actually did intrude far enough that it went outside the 900 meter contour. But it still didnt erupt anyway…

            The floors of Pauahi and Hi’iaka craters are about 900 meters elevation, so a strong eruption in there actually is a possibility if a dike cuts across one of them. But I would doubt a dike that starts anywhere else on the ERZ connector would erupt, or at best it would be more of a glowing fissure that fountains but doesnt make a lava flow of any size like happened in 1968 at Hi’iaka crater.

            A circumferential dike could erupt in the south caldera area outside of the caldera pit but it actually isnt clear if Kilauea can do these. The eruptions within the caldera that arent inside Halemaumau follow the same orientation as rift zone eruptions, like the caldera itself is not an active volcanic structure but just another mobile fault block area superimposed on the overall south flank block. Mauna Loa is the same in a different way, it has a caldera as a topographical structure but all of its summit eruptions since the 19th century, except for 1942, happened from nearly exactly the same spot, a fissure through the center of Mokuaweoweo going beyond both ends, even decades apart the same structure is dominant, it is a gigantic fissure volcano.
            Basically the Hawaiian volcanoes are rift volcanoes that sometimes form calderas, and Galapagos and Iceland which are calderas that sometimes form rifts. Calderas there are permanent and fundamental, where Hawaii they are transient and nothing more than topography after formation. At least in the present day, the massive surge deposits surrounding Kilauea would suggest it had more mature caldera-focused volcanism at some points in the past.

          • This is all of the dikes (blue) that have happened at Kilauea between 1961 and 2018, not including the 2018 LERZ intrusion. The pink line is at 520 meters elevation, the same as the bottom of Halemaumau before it began filling in 2020. The orange circles are the conduits of the 2018 lava lake, Mauna Ulu and Pu’u O’o.


            As can be seen basically all of the intrusive activity in this timeframe stayed below ground that is higher than the 2018 caldera max depth. That is to say, it really should have been no surprise that eruptions have stayed in the caldera ever since. The dikes of 1961 and 1977 did partly go beyond the 520 contour but barely and both started well within it. 1961 started at Napau while 1977 might have been closer to a proper LERZ eruption but never erupted primitive basalt from the summit. Alternatively it might have erupted magma that was stirred up by the 1975 quake.

            To get a large ERZ eruption soon the connector will probably have to extend a lot further, maybe even past Pu’u O’o, which is not impossible and might well happen quickly with how the south flank has been moving, but there is no evidence of it doing this right now either. Pu’u O’o took 8 years to form after the 1975 quake, and that one was without the summit collapsing, so it makes sense this time will take a little longer.

      • It looks like the southern rim of the deep caldera has been quaking just now too following the pause in the quake swarm, right under the viewing area… Unlikely an eruption happens here right now at least not a big one, but this is where the 1971 and 1974 eruptions near Keanakako’i started from so magmatic activity should be considered. It could well be intruded in the near future.

    • Isn’t this part of the deep caldera? As far as I know, the conduits of the caldera pass through the base of Koa’e Fault and the whole southern region of Kilauea’s summit area.

      • The exact point that the Koae faults turn into the outer caldera ring fault is a bit unclear really, its more just that the fault lines go from linear to curved. But south caldera eruptions historically have had allignment with the Koae faults even within the caldera boundary.

        • HVO has recently written that “Patterns of ground motion and tilt show that the magma bodies below the southern end of Kaluapele (referred to as the south caldera reservoir) and below Halemaʻumaʻu are inflating. … Deformation levels indicate that the south caldera reservoir has regained the magma that it lost during the intrusion.”

          This sounds like there are two independent magma bodies: Those below Halema’uma’u and those below the southern end of Kaluapele. The southern magma chamber appears to be loaded and able to erupt or to do an intrusion.

          • South caldera area I think is the big magma chamver that feeds everything, theres nothing above it at that spot I guess. The magma flow is open up to it and only shows quakes when very high supply feeds it like I think happened the other week. It needs to make a connection to one of the shallow magma chambers to be likely to erupt but it seems all of those are at max pressure as standard so when that does happen things move very fast. Kilauea gives plenty of warning of potential to erupt but it makes Hekla look predictable when you want to be more specific than that 🙂 and as we have seen swarming like this doesnt mean anything by itself unless a dike is created, it can go crazy and just stop like that and restart again, its just pressure, like turning a hydraulic line on and off.

          • Was the south caldera area the source for eruptions close to Keanakāko‘i Crater? Can the magmatic systems there both feed summit and upper ERZ eruptions?

          • I would guess not, because the 1971/74 lava at Keanakako’i was more evolved than Halemaumau (relatively, still very hot and fluid) so probably came from a source outside the deep big magma reservoir. The very mafic lava erupted in 1959 is probably the deep south caldera chamber, 20% MgO and at a temperature of probably over 1300 C, it is borderline ultramafic and probably the hottest lava of any volcano today. But it probably only very rarely erupts directly without mixing with magma stored in the volcano. Halemaumau seems to be still primitive only having lower MgO from olivine settling out, but going down the rifts the magma evolves considerably.

  26. There is NOT a pot of gold at the end of this rainbow as the helicopter circles overhead –

  27. I’m really wondering what happens next at Svartsengi. A specialist from IMO reported today that the volume in the sill (or shallow storage below Svartsengi) is roughly 13 mio m3. The current eruption rate is estimated to be 1 m3/sec or less.

    It is intriguing that the current eruption is slowly coming to a stop although magma keeps accumulating. This probably means that there is no direct connection between the sill and the current eruption site…. if there is, the eruption should go on, right?
    Is it possible that the increasing pressure from the sill compresses the dyke and is literally squeezing it out?

    I wonder what will happen next: reopening of the current eruption site with full force or a new dyke.
    Interesting volcano, at least from a scientific point of view.

    • Pressure is not the only variable for an eruption, you also have to think about conduits and strain. Although much more magma is flowing into the system than there is leaving it. That alone won’t sustain an eruption if the conduit isn’t good. The conduit is smaller with less liquid magma flowing through it since the eruption started so it’s not going to be able to pull as much magma. It looks like it will solidify if current trends continue. There also needs to be stress in specific areas of weakness to get an eruption.

    • The ongoing low level eruption has increased the time between the main lava flash flood episodes by a possible factor of 3. Before 16th March the dormant time was usually around 20 days, sometimes there was an intrusion instead of an eruption. If we assume 60 days (factor 3) until the next episode, the next eruption will be around 16th May.

      The real 4th episode lasted from 16th to 17th March. What we had after 17th March, was a higher general level of activity of Sundhnukur, but not the continuation of the episode. The volcano both does short episodes and a longterm curve of activity. When the general activity is high enough, it allows the volcano to erupt during the previously “dormant” phase.

    • No expert, but my view was that the magma accumulation under Svartsengi caused the crust to split at Sundhnúk. This may have allowed magma to rise directly under Sundhnúk (rather than take a detour from Svartsengi); i.e Sundhnúk has its own feed. I could be wrong.

  28. Read back through this report by HVO in 1950, if anyone wants an idea of how crazy fast dikes can open during big eruptions then this will get the point across. I have read this report many times and even said what I am going to say a few times but today was the first time I really did the numbers. Nothing we have seen at Svartsengi even comes close….

    “On the evening of June 1, 1950, Mauna Loa volcano erupted from vents along its southwest rift zone. Glow was first seen from the Volcano House at about 9:25 pm, but, as the seismograph registered harmonic tremor starting at 9:04 pm, it is probable that the eruption actually started then or very shortly afterward.
    The first outbreak was high on the rift. At first two narrow, illuminated columns of fume were visible, but these rapidly expanded down the mountain slope. A fissure 2.5 miles long opened from about 12,600 to 11,000 feet altitude, with its upper end close to the small pit crater Lua Hou”

    “At 10:15 p. in. on June 1 observers at the Volcano Observatory and along the highway between Kilauea caldera and Pahala noticed a small puff of fume rising from a point on the rift at about 8,250 feet altitude.”

    These two locations are 19 km apart and opened 50 minutes apart from each other. The dike intruded down the rift zone at an average speed of over 20 km/hr. Literally, it went downhill faster than you can run… The dike that fed this was probably 1-3 meters wide and around 3-4 km deep, maybe 3 on average. That is 0.1 km3 of magma, and there were at least two dikes in reality possibly even 3. So say 0.3 km3, in an hour, 85000 m3/s flow rate. Over 10x the flow rate of the November intrusion at Sundhnjukur.

    The other thing is that basically all of the lava erupted by the upper 10 km of the fissure system was erupted in about 2 hours as an overflight of the eruption 6 hours after its start found all of the vents above 10,000 feet dead and the glow was weak as early as midnight. That upper source lava covers over 70 km2 and if it is like the recent 2022 summit flows it is probably 1-2 meters thick maybe even as much as 5 at the distal ends, amounting to a volume of about 0.15 km3. By this time too the first ocean entry had happened and the other two flows that would later reach the ocean had started. All of this in 3 hours…

    First few hours of the eruption might have erupted 0.2 km3 of lava which is about 60% of the total eruption volume and by itself nearly as much as the entire volumes of the 1984 and 2022 eruptions. The eruption rate for that to occur is 18500 m3/s. The other way to look at it is that 0.2 km3 of lava is about the same as 0.6 km3 of tephra, the largest basaltic explosive eruption in the past few decades, Grimsvotn 2011, erupted 0.8 km3 of tephra but it took about a day to do that, so about 4-5x less intense…
    Also… Ruang just the other day erupted about 1 km3 of tephra in 3.5 hours, which is crazy, but the DRE is probably around 0.5 km3, which is only about 3x the amount erupted by Mauna Loa in the same interval in 1950. So Mauna Loa in 1950 was within a factor of 2-3 of the hellscape we got to see a week ago. An effusive eruption should NOT even be able to compare in intensity to a VEI 5 but here we are…

    Honestly, these numbers are borderline Ionian in scale and intensity, and the intrusion even if I overestimated everything by 50% is still 40,000 m3/s, which is almost like a dam bursting but lava… Laki was much closer in eruption rate to the current spattering near Grindavik than it was to this portal to hell that spawned on Mauna Loa.

    • The graph of volume far down the report gives an official volume of 0.15 km3 of lava for the flows erupted from vents that died in the first few hours… So over 13000 m3/s directly from the HVO report. Its less than my number above but no less absurd. It would take it only 40 minutes to erupt the same amount of lava as Svartsengi has in the past 2 months.

      The volume is also estimated at over 0.46 km3, 0.1 km3 of lava flowed into the ocean in a few days. With the uncertainties about the intrusion size I would not be too surprised if over 1 km3 of magma left the magma chamber that night.

      “Any error in thickness and volume is probably on the conservative side. The total area of the flows above sea level is 34.9 square miles, and the volume is about 500 million cubic yards. It is estimated that more than 100 million cubic yards of lava flowed out under the ocean and is now lost to view. The total volume of lava erupted, therefore, was very probably more than 600 million cubic yards.”
      “Approximate calculations indicate that between a third and a half of the total volume of
      lava was poured out during the first 36 hours of the 1950 eruption”

    • The 1950 eruption happened only one year after the long 1949 Summit eruption. During the active periods of Mauna Loa there often were twin eruptions like this: 1. a Summit eruption, 2. a rift zone eruption.
      Mauna Loa varies the location of the eruption each time. Is there a pattern? It looks like the different locations of Hekla’s lava flows. But once Mauna Loa tends to return to previous eruption locations. F.e. the repeated summit eruptions or the Mauna Kea Saddle oriented eruptions like 2022 and 1935-36.

      At present the GPS stations on Kilauea’s southern area are skyrocketing:


      PUHR station is close to the first upper ERZ pit crater Puhimau Crater.
      There are steam fumaroles that make plumes occasionally. Maybe this depression is deep enough for an eruption. The Pit Craters there were not caused by volcanic eruptions, but by tectonic cracks and collapse.

      • Actually, the youngest craters probably formed in 1790 during a magma draining. Since none of the main pit craters have grown at all since 1823 and the youngest craters cut 18th century dated lavas (Makaopuhi, North Pauahi, possibly Alae, possibly Hiiaka) they must have formed together with the major summit collapse of 1790. The idea of gradual collapse is based on Devils Throat, which is much smaller and probably a collapsed lava tube.

        • Would make sense that at least some of them are very young, considering two of them filled in completely in less than a decade of eruptions nearby and a 3rd filled in half way. If they were much older then only the largest ones might still exist and perhaps even then only as shallow depressions as Napau is presently.

          I wonder how old Kilauea Iki is then. The easternmost part is old, part of it is probably the original Aila’au shield crater even, but the larger east crater and the west part where Pu’u Puai is are probably younger, maybe also from 1790 with how the crater had a deep topography until 1959. The center of the main crater is also about where the caldera wall would have gone if the crater was absent too although that might not matter.

          • Yes, the youngest ones are post-18th century activity but pre-1823. Kilauea was well monitored after 1823 by missionaries that were always making observations, so a pit crater collapsing would have been noticed. In old satellite images of Kilauea, some craters do not have any lava inside, and as you well know, the 18th century saw many fissure eruptions across the East Rift Zone of Kilauea. The places fissures open first and foremost are the pit craters themselves. The 1960-1969 fissure eruptions in the ERZ flooded within a matter of years practically every pit crater in the ERZ, some multiple times. We also know one of the pit craters, Napau, turned into a huge lava lake somewhere around 1780 or so and broke out though a dike making the huge shallow crack system from Napau to the LERZ and the violent flood described by Ellis, the same must have happened to the other craters, they formed lava lakes that being. Makaopuhi itself is floored by lava that looks 18th century in age, and was considered that way by Holcomb, but the younger western pit cut those lavas. The western pit can hardly be any age other than 1790. A similar thing can be said for Pauahi, where the northern pit cuts 18th-century filling of the central pit. I think that Hiiaka was also lava-free in old satellite images, and Puhimau, so those two are probably 1790 in age too. The inner Alae crater had 1840 lava inside, so could also be 1790 in age. Aloi is older and had 18th century lava fill, I seem to remember. The big old craters, Napau and eastern Makaopuhi, and probably greater Alae, I suspect, are very old, from the era of Kane Nui o Hamo.

    • By the way. Since the UERZ episode ended a few days ago, the summit of Kilauea has been inflating really fast. Uwekahuna is going up at almost 2.5 microradians per day. I think it’s been a while since the last time it happened. Looking at captures I’ve saved of the graph, I don’t think Halema’uma’u has inflated so fast since January or November.

      • Now that I look at the maps, it looks like the UERZ is ramping up activity again. And the south caldera rim activity is weird.

        • 2024-05-07 19:26:03
          2024-05-07 19:25:37

    • The DI events stopped at Halemaumau, now it is just a constant 2 million m3/day supply of magma, around 5x the normal rate, or close to 1 km3/year if it lasted that long. Obviously it wont do that but if this doesnt stop soon then Pele will be paying a visit by the weekend.

      The September eruption was extremely gas rich, the videos I saw showed lava that looked almost like sea foam flowing from the vents. The magma chamber in 2018 was degassed by the 10 years of lava lake activity but it seems like all of that drained out and the stuff there now, while compositionally identical, is much more volatile.

      • SDH increases steeply together with OUTL’s GPS and an increasing earthquake activity around Keneakoki crater and lava flow:


        In July 1974 one eruption fissure was between Keneakoki Crater and Lua Manu Crater. It crosses the Chain of Craters Road. An eruption like this would be a threat for hikers there.

        • It may be worth noting that the lava lake has gone down over the past week by about 10 cm. That could be due to expansion of the crater or a change in the feed, such as less gas going into the lava lake

          • The tilts of both SDH and UWEV are expanding, so likely the whole caldera. The three days eruption of July 1974 had two parallel fissure eruptions: One in the Caldera (comparable location to September 2023) and one from Keneakoki to Lua Manu Caldera.
            “the July lavas actually exhibit a bimodal composition reflected in their vent locations (table 4). Lavas erupted from fissures south of Keanakako’i Crater (figs. 2, 3) (here after referred to as the “southern” fissures) are distinctly more silicic and less magnesian than lavas erupted from fissures north of Keanakako’i Crater (hereafter called the “northern” fissures)”
            It’s possible that an eruption does two seperated fissures with two seperated magma types/sources. Were there two parallel dikes in July 1974?

          • I actually didnt know the fissures that erupted in Keanakako’i and Lua Manu had different composition from those in the caldera, they were erupting simultaneously. The south caldera fissures might have erupted from the Halemaumau source then, at least the early stage of it, while the fissures in Keanakako’i erupted from a local magma source, probably what collapsed to make Keanakako’i itself at some point.

            The later Halemaumau eruption and especially end of year SWRZ eruption were very magnesian, 1974-5 might have been the last time the magma system of Kilauea was not completely homogeneous, more of a sill and dike complex of many compositions compared to now where it is probably an actual voluminous single chamber. I would guess the 1975 quake started that, opening the ERZ enough that the summit drained in and subsided, and probably for the next 40 years the summit was primarily just a flow through area, with exception to maybe 1982. The summit storage probably became homogeneous and a true magma chamber after 2010 and the lava lake started rising in the conduit and becoming permanent.

            I think the next eruption will be in the 2018 caldera but maybe along the south side. There is still a distinct possibility of another SWRZ dike though, I think maybe still more likely at this stage than a whole new one opening on the upper ERZ within a historically rarely active area. It could well be both, a south caldera fissure and something like in December 1974.

  29. The active cone is on its last breath. . I have noticed that the north steaming fumeroles activity seems to correspond with the activity of the active cone, suggesting to me that they are connected in some way. (my own opinion)

    • One way they are connected is through the weather, which has a large influence on the visual appearance of the steam.

    • IMO sees two realistic scenarios:

      1. New eruptive fissures could open in the area between Stóra-Skógafell and Hagafell, and/or the current eruption site could expand due to a sudden increase in lava flow, which may be comparable to the initial phases of the last volcanic eruption in the area. This could occur with very little to no warning.

      2. It is also possible that the flow of magma from the magma chamber beneath Svartsengi into the active vent at the Sundhnúkur crater row may increase steadily until there is equilibrium between the inflow of magma into the chamber and the outflow onto the surface.

      • It seems like the opposite of option 2 is happening, so option 1 is the most realistic scenario.

        The seismicity is still increasing. The day by day cumulative seismic moment in the dyke is increasing with an increasing rate in an almost perfectly convex curve. It’s a bit slower than I first anticipated – the initial estimate of 7-10 days passed yesterday. Both the slope of the curve and the absolute value are currently maybe 2-3 days away from the level where previous eruptions and the March intrusion started. The first scenario seems inevitable and it will happen any day now.

        • ‘any day’ is a bit vague as prediction.. But we will accept this. Bets are open!

          • It was intentionally vague, due to the inherent sketchiness of volcanic predictions, but let’s make it a bit more precise and say I think something will happen somewhere between now and May 11 (deadline at 23:59).

          • I vote for the 13th, building up a bit slower than last time, so think will overshoot timewise a bit…

          • I will guess May 8th or May 9th, but put me down for May 9th.

          • A hard do falsify prediction! Do good predictions contain theses that are difficult to falsify or theses that are loaded with rich information but are easily falsified?

          • A good prediction is one that is so far in the future that people will only remember it if you are right

          • A good prediction is one that is repeatable using the same method again in the future. It should add value to what is already known.

            So what do we know? Well, we know that there will most likely be renewed activity of some sort. New fissures, increased eruption rates of the already ongoing eruption, or just a new dyke intrusion that does not erupt. Something is bound to happen. We also know that the accumulated magma is at similar levels as when previous events happened and that seismicity is picking up in the area. Stating that something will happen any day was a good way by me to make sure that I’m right. It’s vague enough to cover all the most likely scenarios. Is it a good prediction? Did it add any value? Maybe not.

            Narrowing it down to a time interval, based on all available data could be a better prediction. Did I get it right? We’ll know soon enough. If so, can I use the same method again to get it right next time? Only time can tell. Did it add value? You tell me.

            If 100 VC readers come with one guess each and someone gets it correct down to the exact minute, is that a good prediction? I would say no. You win the bet, but unless it’s based on some observation that can be repeated and used to predict more future events, it’s just a lucky guess.

          • @Tomas: I totally agree about your statement regarding predictions. If somebody predicts a 6 in a dice and it actually comes up, it’s still a stupid prediction. Quality of predictions can be measured only in the average. There is a terrible misconception about this in the public…

        • Do earthquakes on the RVZ indicate an extension force of the sill/graben? Currently there are both earthquakes NW of the Sundhnukur lava field and E of the lava field (Fagradalsfjall). Between the zones of earthquakes is a “calm zone” without earthquakes. There is approximately the sill below. Are the earthquakes caused by magmatic pressure on the edges of the sill?

        • Possibly signs of tremor around 11 00 and 18.30 Icelanduc time too.
          The uplift at HS02 is around 70 cm above the height at the last eruption. I haven’t followed closely enough recently, but I think tha is very similar to the previous episodes. I would expect something vert soon, perhaps 1-2 days at most. Of course I’m now bound to be wrong 😜

          • 70mm, not 70 cm 😉 But yes, most of the uplifts are now above previous levels.

            There were a lot of quakes were in Krýsuvík and Brennisteinsfjöll which if my googling is correct is significantly to the East of the current eruption, in fact it’s east of Fagradalsfjall.

  30. Question
    Can anyone identify what this signal is below. This is from OLTD 5_8_24 and the signal time I am interested in the box is about 8:40 – 9:00am UTC. It also shows up on PUHI and NAHU. I thought it was a large quake at some distance from the big Island, but they would also usually show on DAND or TRAD.

    Instance I think it is associated with,
    2024-05-08 08:43:45


    • No idea. I would have assumed a distant earthquake, but not if it’s local.

    • Related to an earthquake. 6.1 at Vanuatu 2024-05-08 09:17:15 (UTC+01:00)

  31. SDH radial tilt to the south caldera area, at Kilauea, has risen 40 micro radians in 3 days. It’s the fastest thus far, even faster that in the first days of October when the ground rose at 1 cm per day in the SWRZ region right next to the tiltmeter. Inflation focus seems to still be in the south caldera area, but has moved a bit away from PUHR GPS and closer to OUTL GPS. Now both rift connectors are swarming instead of just the UERZ. PUHR seems to be going up at 2 cm/day in the last data point released, not sure if it’s live, sometimes they are lagged. With OUTL I can’t tell because of the scale, but could be even more.

    • GPS data is probably lagging two days behind if CALS is updating at the same time as the other stations. CALS (first time I see it with data) shows over 3.5 cm of uplift in 1 day! Not sure if this uplift is centered on Halema’uma’u, the South Caldera region, or both. Maybe it’s a mistake, but with how both the Uwekahuna and SDH tiltmeters are skyrocketing, I wouldn’t be surprised if this rate is accurate. Presumably, it has kept at this over the past two days too.

    • Looks like Kilauea haves a major supply sourge for soure, but its supply its always crazy compared to any other volcanic systems avarge, but this reminds me of the middle 2000 s era when supply was also incredibely high, USGS haves some estimates of up to an 0,4 km3 supply a year for a paticulary vigorous supply episode just before 2010 s that likley had something to do with formation of the overlook lava lake, setting up of the shallow system that collapsed in 2018, we have a a real monster volcano with a supply so fast it can form whole magma chamber complexes that have same size as many in lesser volcanoes but forming that in just a few years ( when other volcanoes requires 100 s ) which is one of the most crazy things with Kilauea anyway. I hopes for a caldera eruption and lava falls at the pit walls at 2018 s downdrop that cut 1974 flow

    • How much can the ring fault of the caldera be involved in the current and future development?

      • I don’t think the ring fault is too relevant.

    • Strictly speaking they should say that the current eruption has paused..

    • Yes, this should accelerate the path towards the next lava flash flood event. The erupting cone was a factor, because it reduced the increasing pressure in the system a bit and delayed the next event by this. Since 17th March we’ve had 53 days. The break of 20 days has been delayed by the erupting cone by a factor of nearly 3. So after 60 days the next event would happen on 17th May, if the cone still was active. Without the erupting cone, the path towards the next episode is probably back to the 20 days time frame.

      • The amount of magma in the reservoir is probably already over 12 million cubic metres, so I can’t see it lasting that long unless it has found more space.

        • With the vent now dead, and being realistic it was probably dead at least a few days ago, all of the magma is now filling the sill. At the 7 m3/s average to get 1 million m3 takes about 2 days so to go from 13 million m3 now it would be at 17 million by the 17th, which is a lot more than what other fissures opened at.

          So either the eruption resumes in the next couple days or it does pause for another week or two and the resulting eruption is much bigger. In both cases I expect the whole fissure to open but focus to the new cone, maybe even start there and with the strongest fountains. I am expecting an ocean entry next time.

          • Without the active cone it should go off next days very soon. Based on the location of most recent earthquakes, the area close to Stora Skogfell (Big Wood Mountain) looks like a possible location.

            As previously the first day is the most dangerous day. Most of the eruption happens on this day. The eruptions began with a huge lava fountain and fast lava flash flood, that ran as a burning lava lahar downhill. If we look on risks for human infrastructure, the Blue Lagoon likely bears the greatest risk to be buried by lava.

        • Where would you expect the place for the next lava spring?
          (Pre-)Historically most eruptions happened towards the NE from recent vent. Some eruptions happened towards the SW close to Grindavik. Based on this the probability for the migration of the Fires towards the NE is higher than a SW migration. Towards the NE there is big space until the fissures intersect with Fagradalsfjall’s lavafields.

          Just as I’ve mentioned Fagradalsfjall: June should be next eruption month, if it stays in the 11 months frame. It will be a “quasi-experiment” whether the onset of Grindavik’s Fires changes the pattern of Fagradalsfjall.

          • Volcanophil
            I would guess near Stora Skogfell too. I also noticed that as the cone died the fumeroles steaming to the north have died down too (as I suspected they would do).

          • There is another cluster NW of Grindavik too, so probably one of those areas is most likely, although there may he a smaller cluster close to Husafell.

    • The Husafell (house mountain) cam should supply good view for next eruption. It already/still shows steam plumes on the dormant cone.

  32. It has been u above at some point I think, the ‘on-off’ occurring the past week at Sund shows up in the graphs I guess. Like Fagradalsfjall did!

  33. there are 3 confirmed CMEs heading towards, one of which is a strong cannibal CME. Another X-flare is taking place at the moment I am writing this article with the potential to throw another CME. NOAA forecasts G4 and with another possible CME on it’s way could we see G5 storms?

    • Sunspot 3466 is now as large as the massive Carrington sunspot group of 1859, which when it erupted a series of CME’s set telegraph stations/line on fire due to the induced ground currents.
      A G4 storm (severe) is exceedingly rare, occurring perhaps only once or twice a century.
      As of 1900z on May 9, three different CME’s are expected to be entrained by the time the main shock hit’s Earth most likely sometime on the 11th (though it could hit sooner?). All told, there have been 9 major flares in the last ~36hrs, with 5 being X-class or stronger.
      IMHO, the NOAA G4 forecast/watch may be too conservative since it likely isn’t factoring in the latest X-1.2 flare/CME just a couple of hours ago. This could go sideways in a hurry if we indeed get a G4 storm as speculated…with extensive damage to satellites, power grids and global communications becoming likely.
      For more info and up-to the minute data, check out and the NOAA/SWPC website

      • Yeah I think G5 is a good bet. 3 of those CME are going to cannibalize into 1 big dense bastard with 2 more behind it. 3466 is still looking extremely complex so another X class flare likely.

        • At the end of the last cycle peak, there was speculation that this cycle would be weak, how wrong could they be. It’s the time of year where it is better to he further south, as it will probably be too light to see the Aurora, even as strong as it will probably be. It all depends on when the peak is though.
          Communications could be a major issue though, I think the last really strong flare occurred when we were less reliant on satellites.

      • Not ground current but currents directly induced into the wires. Satellites should be fairly well protected against flares. Electronics is radiation harded – hopefully. North-south wires are most susceptible: electricity lines in the northwest US, trains in the UK. But this classified as an X2 flare, I believe. In 2003 we had a flare that exceeded X20. We are not yet in Carrington categories.

        • The danger to satellites comes from the energy dumped into the ionosphere, which heats and expands and can drag low-orbiting satellites to their fiery doom.

          • That’s one danger fer sure. A similar event occurred a year or two ago when a sudden solar wind burst brought down a whole slew of newly deployed Starlink sats.
            Another danger is the solar wind (i.e. plasma) impacting satellites can charge it’s outer skin…sometimes catastrophically…a lesson well learned in 2003 after the “Halloween” solar storms knocked out many, many satellites (including LASCO which was a primary observing satellite at the time) as well as altering GPS readings, et al.

        • Granted the parent flare(s) are nowhere near as powerful as those in 2003 (peak estimated at X-45 since the sensors saturated at X-17), but due note that what’s setting this particular storm(s) apart is the flares are in better geo-effective position than in 2003, plus due to the rapid succession of flares, there are going to be multiple CME’s hitting at the same time…i.e. a Cannibal CME. According to the last report from NOAA, at “least” three CME’s will have combined by the time it reaches Earth sometime on the 11th…and that’s not including the X-2.2 and X-1.1 flares from earlier today. In all, there have now been 10 major flares in the last 48hrs…7 of them producing CME’s with at least a partial earth-directed component that could spark aurora on their own.
          But predicting solar storms is about as difficult as predicting volcanic eruptions.
          Cannibal CME’s are notorious for their chaotic magnetic unpredictabilities and have historically both produced storms much below or much above expectations…but as of this writing, there is no reason to think this upcoming event will come close to a Carrington level event (though the spot sizes are equivalent, 3644 is not storing the same amount of energy)…but still, a high-end G4 storm is capable of doing damage..albeit not catastrophic like a G5 could be.
          Plus, think of the great light show many of us may get? In my 72+yrs living in northern California, not surprisingly I’ve seen aurora only once (in 2003)…and that was just a faint red glow.

        • Thanks Albert for the heads up on ground currents…and I stand corrected.
          I did some further investigation and discovered some telegraph lines were still operational even after the batteries were disconnected. By 1859 I think US telegraph had already changed from two wire to one wire (grounded) telegraphy (but I’m not certain on the date)…which in turn led to the misnomer but still widely used term of “ground current” to explain the failures and arcing.
          Regardless, with the batteries disconnected, the power to run the telegraph had to be coming from a capacitively coupled current being generated in the wires themselves as you said.

          • Global warming, innit?
            Everything these days is global warming, its todays meme.
            As if it just happened in the last few years instead of being predicted as far back as the days of Thatcher.
            Nothing actually happened to stop it then, and not enough will happen to stop it now.
            Until mass migration/starvation/war etc takes us back to the middle ages which will definitely solve the problem.
            PS Thanks for the heads up Craig, this important development had completely passed me by. Not in science mags I read either.
            PPS This place is amazing, thanks to the dragons for its vitality.

  34. Landsat 9 OLI satellite took a picture of Ruang Volcano Indonesia on May 2nd. The volcano has dusted almost all the island with heavy ash.

  35. I am just looking in on the Sundhnúksgígaröð cone and after this morning’s lazy general smoking, it is now smoking quite vigorously from the left side as seen from the Hagafell camera. Some of the smoking seems to have some power under it, too.
    I’m wondering if magma is on the rise again under that cone.

  36. Just got wind of a new paper now under review that’s concluded Hunga Tonga’s eruption caused a net cooling despite most models suggesting a net warming should have happened due to WV’s greenhouse effect. My guess is HT released/created more SO2 aerosols into the Junge layer than previously thought? A second guess is the lighter WV, being propelled to near the mesosphere got spread out vertically throughout the stratosphere (i.e. dispersed) instead of being more concentrated within confined layers thus minimizing it’s GH effect?
    Also, it will be interesting to see how the authors (Andrew Dressler, et al) separate the global effects of the recent ENSO+/ El Nino which disgorged a huge amount of stored oceanic heat that led to Earth experiencing it’s hottest year on record.

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