The Great Alaska earthquake of 2021

Alaska can be a shaky place. Earlier this week, at 10:15pm local time on Wednesday, there was an M8.2 earthquake in the region. It was the largest earthquake on Earth since the M8.3 in Chile in 2015. Let’s award the US the gold olympic medal for earthquaking (after all, the Chilean winner was from the previous olympic cycle). (There have been two other M8.2 shakes since 2015, one in 2017 in Mexico and one in 2018 in Fiji, so the gold should be shared between three nations.) The massive earthquake did little damage. But was this an exceptional event? Or a sign of things to come, so soon after the Anchorage earthquake?

The Alaska earthquake and the Iceland volcano. This is the faf low-frequency seismograph plot, which should be showing the eruption but instead shows the Alaskan waves passing. The irregular part at the start (red) is the P-wave. The nice looking one is the S wave, arriving 10 minutes later but remaining visible for several hours.

Earthquake zones

Earthquakes this size occur somewhere on Earth on average once every one or two years. Since 2000, there have been 15 earthquakes of M8.2 or larger on Earth. They are plotted above. 10 of these were along the Pacific, and the remainder cluster along Indonesia in the Indian ocean. They include the Great Tohoku earthquake and the 2004 Sumatra earthquake. The Sumatra quake is particularly interesting since there are 5 M8+ events close together on the map: the M9.1, an M8.6 aftershock very close to it which happened a year later, a double M8.2/M8.6 8 years later, which were on the oceanic side of the subduction fault and presumably due to faults there which were stressed by the 2004 event, and finally an M8.7 much further along Sumatra in 2007 which may be due to stress transfer at the edge of the rupture zone of 2004. Seeing that kind of activity, people may almost be happy to live in Alaska instead. In contrast, the Great Tohoku earthquake had no aftershock above M7.

All but one of the 15 M8+ earthquakes since 2000 are on the edges of oceanic plates, and are located in subduction zones. Earthquakes of this size outside of subduction zone are very rare. The outlier was in Peru in 2019, an M8.0 120 km below the Andes. This is still in a subduction zone, but is much further downstream and is far underneath the continent.

Going back further in time, we do find some earthquakes this size which are not related to subduction. The largest ones are all caused by India’s collision with Asia, source of the Himalayas. Three earthquakes of M8.0 or larger occurred in the interior of China and Mongolia, in 1905, 1920 and 1957. Others were in Myanmar in 1946 and in Nepal in 1934. The worst by some margin was the Tibet earthquake of 1950. This event reached M8.6 and was so strong that it caused waves (‘seiches’) on lakes in Norway and England. That was 70 years ago. There were six such great earthquakes in the region between 1900 and 1957. But no comparable continental earthquake has happened here since 1957. It seems eerily quiet. If anything similar were to happen now in China or in the Himalayan nations, it would be an earth-shaking disaster. Subduction zone earthquakes tend to happen out at sea, or at great depth below the continent under which they subduct. This limits the damage they do (leaving tsunamis aside). Intracontinental earthquakes directly attack our cities.

Going back to 1900, it is possible to see which regions are most susceptible to earthquakes of this size. Almost all are along the Pacific ring. The coast from Canada to the Kamchatka has about one every 15 years. The Kuril islands just north of Japan have about the same frequency, but focussed in a much smaller area. North Japan, roughly from Sendai to Hokkaido, has one every 20 years, again in small area of no more than 500 km length. The region from southern Hokkaido to the Kurils has not had such an event since 1900. Tokyo had one in 1923, and the Pacific coast of Osaka had two in 1944 and 1946. Southern Japan has been quiet since. From here to the Philippines tends not have M8 earthquakes, until you get to the southern end of the Philippines where Davao has had three. The entire area of Indonesia is at risk, with about one M8 earthquake per decade. The same island of New Ireland has had three. The Tonga trench is a serial offender with seven. New Zealand is a notable gap: it did have an M8+ in 1855 but nothing since.

On the other side of the Pacific, Southern Mexico to Guatemala have had four, and there is a large concentration from Lima (Peru) to Chile (Santiago) which has one every 7 years. Other areas in the world have few, but not none. Pakistan had an M8.1 in 1945, and a few have occurred in the Atlantic ocean, one between the Azores and Portugal. But most non-Pacific-ring events are along the line from Myanmar to Mongolia.

Alaska in earthquakes

But let’s look at Alaska in more detail. After all, that is where this week’s winning event was. What can we say about the occurrence of large earthquakes in Alaska? Experience says that they are rare: this was the largest one in over 50 years. But it seems that they used to be less rare. Alaska has been rather calm since the major 1964 shock. Is it the calm before the storm?

The plot shows the local earthquakes of M8 or larger, since 1900. The 1964 Prince William Sound earthquake was by far the largest, at a staggering M9.2. There has been no earthquake of M8.0 or larger in Alaska since that time, and only one event (in 1986) along the Aleutian chain which reached M8. It shows how exceptional this week’s earthquake was.

Alaska is under attack by the Pacific ocean and its plate. This has always been true. In a way, Alaska’s entire existence is because of this battle. Te Pacific plate subducts along the Alaskan coast, forming a chain of islands and volcanoes in the process. As the plate sinks, it descends underneath Alaska. The red line shows the subduction fault.

The earthquakes are just on the other side of the trench, following the subducting plate. There is a tendency for the quakes here to be paired: three of the locations show two earthquakes in almost the same location, but far apart in time. Going through the events from left to right on the plot:

Rat Island. 1906: M8.3, 1965: M8.7. There have been two smaller ones recently, in 2003 (M7.8) and 2014 (M7.9)

Adak. 1957: M8.6, 1986: M8.0. There was an M7.9 in between Rat Island and the Adak quakes, in 1996. In some papers the 1957 earthquake is assigned a size of M9.1.

Unimak. 1946: M8.6 There is a large gap between Adak and Unimak

Perryville. 1938: M8.2, 2021 M8.2. There were an M7.8 in 2020 in the same region, which in hindsight was a foreshock. There was also an M7.6 in the same year, so make that foreshock a double. To the right, there was an M7.9 in 1900 on Kodiak Island.

Prince William Sound. 1964: M9.2. This was a bit further from the subduction fault but clearly part of the same sequence.

These pairings show a pattern. The largest earthquakes (M8+) are repeat offenders, with recurrence times between 30 and 80+ years. In the area of the current quake (Perryville is the nearest settlement) an identical earthquake happened in 1938. In fact, looking at the plot, until this week it was the oldest of the unpaired M8+ earthquakes along the subduction zone. This had been noticed in the past. Already in 1981 there was a paper stating that the repeat period in the area of the current quake was 50 to 90 years. This meant that a large earthquake was expected to happen before 2030. Such a prediction should be used with caution, as determining recurrence times on just two events is very uncertain, but events decided to conform to the expectation, and deliver the earthquake within the range of recurrence time


Earthquakes of size 8 or larger are called ‘Great’ while an M7 is called ‘Major’. But what does ‘M8’ actually mean, and what is the difference between an ‘M9’ and an ‘M9’?

The magnitude scale of earthquakes can hide how quickly they increase with number. The magnitude is related to the amount of energy that is released in seismic waves. Each 0.1 step in magnitude corresponds to about a 40% increase in energy. A full magnitude increase (from 8.0 to 9.0) is a factor of 30 in energy. That is why an M7.9 can be a foreshock to a M8.2, as it was in this particular case: it releases only 25% of the total energy of both events. The first event left most of the stress intact.

For an M8.2, the total energy in seismic waves is about 1017 J. The 1964 earthquake released 4 x 1018 J. That was a lot. In an average year, al earthquakes together release around 4 x 1017 J. Obviously this varies a lot from year to year: the 1964 event released 10 times that much in just one event. But taking this number, we can estimate that this week’s Alaskan event accounts for a quarter of the world’s total seismic energy of 2021. Not bad! Alaska certainly knows how to produce energy, not only the human economy but the ground underneath as well.

To give some indication how much energy this is: the Alaskan quake released about the same as the 1980 Mount St Helens eruption. It was also almost the same energy as the largest nuclear bomb every detonated, but let’s not mention that. Comparing to human activity: Alaska produces around 500,000 barrels of oil per day (declining, because the oil fields are now ‘mature’). Each barrel contains around 6 x 109 J of energy, so oil in Alaska accounts for about 1018 J per year. This week’s great earthquake produced about as much energy in seismic waves as Alaska produces in oil each month. The Earth of course produces a lot more energy itself, mainly from internal radioactivity. Less than 0.1% of the Earth’s energy is used to produce earthquakes. The remaining 99.9% produces geothermal heat, amongst others driving volcanoes. Looking at it in this way, earthquakes are not so bad.


Large earthquakes rupture a large length of fault. This length will now need time to rebuild the stress, for the next earthquake olympics. During the rebuilding, another segment along the fault may rupture. Turkey’s Anatolia fault is a case where the rupture sequence can be followed nicely, with adjacent segments failing one but one, in a sequence heading towards Istanbul. That is a transform fault where a rupture causes movement along the fault and adds significant stress to the next segment. In a subduction fault, the movement is perpendicular to the fault and therefore there is much less (or no) stress transfer to the next segment. Each segment ruptures in its own time, independent of what the neighbour does.

The rupture length depends on the size of the earthquakes. This is why repeating earthquakes may have similar size: they rupture the same length segments. On the other hand, a monster quake such as that of 1964 may rupture a series of segments in one go, thereby inhibiting the usual recurrence of earthquakes there. This regularly happens on the San AndreasVolcano at fault: Neenach and the art of moving mountains where the great earthquakes rupture great lengths of the fault, and do not confine themselves to their own segment. That makes it next to impossible to predict the size or location of the next one.

The plot above shows that the 1964 Prince William Sound event has silenced a large region of he subduction fault, all the way to the current event. Perhaps there was also a long silent period before 1964, which allowed the stress to build up to the level where this earthquake became possible.

How far did the 1964 M9.2 rupture the fault? It is thought to have extended to the western end of Kodiak Island. The length of the ruptured segment can normally be measured from the locations of aftershocks. A plot of the various segments is shown below, taken from Davis et al 1981, Journal of Geophysics Research, Vol 86. It shows the great length of the 1964 rupture, ending only at the segment that ruptured in 1938 and which had not yet build up enough stress to take part in the great quake. The 1938 segment acted as a roadblock and the 1964 rupturing ended there.

1964 is a long time ago. The stress along this section is slowly building up again. It won’t always be this quiet. But nothing like it is on the cards for now, and next time it may rupture in smaller sections, a a series of smaller events. Not small, but smaller.


The plot of the segments contains a few threateningly looking black regions called ‘GAP’. This is not the UK clothing store which did not survive the pandemic, but it indicates areas which have not ruptured for a worryingly time. The one with the big black arrow pointing at it (actually this arrow the plate movement direction) is called the Shumagin gap. To the left of it is a tentative gap, the Unalaska gap. Nowadays, the 1946 eruption is assigned M8.6: it may have ruptured a much larger area than shown in this plot. In fact, the two gaps seem to fit this earthquake rather nicely. The two gaps therefore present a region which last ruptured 75 years ago.

As an aside, the plot from the Davids et al paper assigns a much smaller magnitude of M7.4 to the 1946 earthquake. Their number represents the surface magnitude, and it was estimated from the short duration (20 seconds) and the small aftershock area. The value of M8.6 is the estimated moment magnitude of the earthquake. The large difference is a bit of a mystery. The event generated a large tsunami, which suggest the larger magnitude may be right. A more recent study (Lopez & Local 2006, suggests that the aftershocks had been misplaced in the original measurements, and that a much larger segment ruptured than was thought at the time.

There is also a dark gap on the far left which has not yet been filled in. A fourth gap on the far right along the Canadian coast has been filled since, with a M7.8 in 2012 and a M7.5 in 2013.

Which area ruptured this week? It is clearly seen in the USGS earthquake plot, shown below, which contains the earthquakes following the main shock. The main one is indicated by the large blue star. The aftershocks follow a 150 km section, mainly east of the main event. The area closely agrees with the rupture of the 1938 event. Not only were they the same magnitude, they were also the same size and covered the area. This was a copycat event. I confidently predict that a very similar earthquake will happen in 2104. You read it here first. (It is pretty safe to predict this. No one will remember unless it happens to be correct.)

What about the foreshocks? It turns out, they were just at the western end of the current series of aftershocks. They are the two smaller dark blue stars, with on the right the M7.8 of July 22, 2020, and on the left the M7.6 of Oct 19, 2020. Being smaller, they will have ruptured a smaller section. They went off around the eastern border of the Shumagin gap, or in other words at the edge between the 1938 and presumed 1946 ruptures.

After the July 2020 earthquake, an update to this plot was published (Liu et al. 2020, Geophysical Research Letters, sorry but access is blocked to the public) (I am not sure why scientists publish work where it can’t be read). It is in much prettier colours but with the same dark message that the area of the 1946 earthquake (for which they assume the low magnitude) may be next in line.

We know rather little of earthquakes before 1900. However in the region of this week’s event we know of two major earlier events, accompanied by tsunamis: one in 1847 or 1848, and a double event on July 22, 1788 – the same day as the 2020 event – and Aug 7, 1788. If those are the previous ruptures, it indicates a recurrence time of around 80 years. This would predict that the next event will be around 2018. 2021 is indeed not far off – I wish I had predicted this last week. The 1788 and 1847 event may have ruptured the Shumagin gap as well, in which case it will have a similar recurrence time. The 1946 event would have been 20 years ‘late’. It seems plausible the Shumagin gap will rupture within the next 25 years. The main uncertainty in this is that we do not understand the 1946 earthquake well enough.


What causes these subduction earthquakes? The cause is the Pacific Plate, but the earthquake itself is in the continental plate. The plot below shows the Pacific plate moving from right to left while descending into the deep. The continental plate gets stuck to it by friction, and it is forced to also move to the left. This causes it to buckle, and to be pushed up. At some point the stress gets too much, the friction fails and the lock gives way: the continental plate whips back in place. The movement can be 5-10 meters for large earthquakes.

The Perryville quakes all have a depth around 30 km and occur some 100 km from the trench. As the oceanic place goes deeper, the continental plate gets hotter and more ductile, and is finally replaced by the mantle. Here the friction is much less and so the two don’t get stuck as badly. The earthquakes here are frequent but are very much smaller. The green dots show low frequency earthquakes which are slow-slip events: they occur in this region

A bit deeper the descending rock begins to melt, and the melt starts to percolate up through the continental crust. On the surface a volcano forms. In the case of Perryville, that volcano is Mount Veniaminof, site of a VEI 6 eruption around 1750 BC. Alaska does geology rather well.


This week’s event generated a tsunami warning. Tsunamis can be caused by large subduction earthquakes and this event was large enough to raise the alarm. However, nothing appeared: the tsunami did not come. Twenty years ago we had become quite complacent about tsunamis. Now, after two disasters with 300,000 dead, we know better and we take warnings seriously. Even science deniers do not deny tsunamis. Large tsunami are often associated with the largest earthquakes (M9) but smaller ones can also cause them. The 1946 tsunami is an example, as the earthquake itself appeared to be relatively small – but the wave wasn’t.

A tsunami is a tidal water wave. The origin is simple: a large displacement of rock or sediment under water displaces the same amount of water, and sets the wave going. The displacement can be caused directly by the earthquake. As mentioned above, the buckling, locked plate gives way and unbuckles itself. If the buckle extends to the surface, then the surface will suddenly drop. Water rushes in to fill the void. Further upstream the plate moves forward, and this pushes the water out of the way. And this happens over the entire length of the rupture.

The wave of water ripples out, at speeds approaching that of an airplane. In the open ocean the wave may only be centimeters high, but 100 kilometers wide, with a length initially equal to that of the ruptured segment, slowly expanding as it moves out into the ocean. A wave that size is invisible, but contains a lot of water. When approaching the coast, the wave slows down. This makes the wave less wide but it still contains the same amount of water. The wave rises up to compensate. In extreme cases it can reach 10 meters or more. At that point, Lurking’s maxim ‘don’t be there’ applies. And this is what the tsunami warnings attempt to achieve. It gives people a chance.

This particular earthquake apparently did not have much effect: there was no significant tsunami. But this is not known until the wave fails to arrive. This can be annoying, but far worse would be if no warning was given and the tsunami did come.

Many of the great Alaskan earthquakes have caused tsunamis. The 1946, 1957 and 1964 all did, impacting not only Alaska but locations around the Pacific. It seems common. In 1788, a 30 meter high wave was reported (this should be taken with some caution). There has been no significant tsunami in Alaska since 1964. But there had also been no great earthquake since that time. Nothing happened this time – but the next great earthquake remains a tsunami risk.

Final words
There are no final words on earthquakes. They have happened before and will happen again. Some areas of the world have been hit hard: Indonesia and Japan come to mind. Others have had time off. But in a way, that can be more dangerous. They will come again, and people may no longer be sufficiently prepared. This event, large but without damage, was a useful warning sign. The years of quiet may be coming to an end. Other places are more at risk, especially places such as China and Pakistan which similarly have not seen anything on this scale for 50 years or more, but have had them before. After the tsunami warning has passed, the earthquake warning should remain.

Albert, July 2021

253 thoughts on “The Great Alaska earthquake of 2021

  1. We are interrupting the ice core doublet for this special news bulletin

    • Great post, and alerted me to checking the seismometer which we build with kids a few years ago. It has the event!

      But…isn’t there something strange with the energy equivalent plot? For M8.2 I get about 125 PJ, which is 30MT TNT equiv., and so checks out with the thermal energy of the Mt. St. Helens eruption 1980. In the graph however Mt. St. Helens seems to sit well below M8.0. And also, what is the event marked in green? Something seems odd with the graph…

      But great post overall!

      • Yes, I had noticed it didn’t look quite right but it had the comparison in a nicely visual form. The left axis has no tick marks, so we can’t see where ‘8’ begins. I think 8.0 corresponds to the bottom of the ‘8’ and they have assigned this to the nuclear bomb and St Helens a bit below it.

  2. Everyone i talked to who felt it said it was like being at sea. a very different earthquake for here…. but at least it wasn’t the jerky kind that wrecks my back; more like a gentle roller. (from the Kenai area anyway)

    • Another great article and You make things so ‘seeable’…… Thanks, Albert. Friend called me from Seward and asked for info on quake. The tsunami sirens were going off and he wondered what was up and knowing i’m always on the internet, he figured i’d have info. He has many dogs and livestock and doesn’t like going up the hill unless necessary. i told him my best guess was to stay put as i thought it too deep to form a tsunami. BUT to follow Noaa tsunami. He is elderly but would take offense at the term. Glad it worked out for him. We have loud audio warnings that come in on every phone in the house wether it’s turned on or off. Handy. Well Looking Forward to the next Alaskan Earthquake covered by Albert! also the part two of the vol. on ice. Gold Star, Albert… You were fast on the draw.

      • Yes I think Albert is ingenious with the Pacific Ocean. He has a feeling for it and works things out very logically.
        He made me love it with Hawaii and Wrangellia.
        He just hasn’t found out why the Emperor chain suddenly takes a kick to the north.

        And Carl but also Albert (The mountains of the Moon) made me take a profound interest in the African Rift, also its people.

  3. On a side note, I’ve noticed in trying to do past research that there is a distinct lack of historical records taken for prehistorical tsunamis and earthquakes. We have a lot of historical evidence for past volcanic eruptions, which makes sense because finding ash deposits and tuffs is likely easier and a lot more “visible”. But I can’t help but think from a mitigation and risk management perspective, it’s more important to understand historical patterns of tsunami and earthquakes.

    • I just read an article of yours from 2017, the frozen north. Geolurking points out that aquatic eruptions, or shallow caldera eruptions are less likely to show up in the ice core as some of the sulphates are dissolved in the water. There may well have been more of these large eruptions than we might expect that might not show up in the record but created some weather disturbances nonetheless.

  4. Spotted an undated fairly-sized caldera near this particular area – Yunaska.
    Not much info on it. And of course the Unalaska gap is above Okmok and Makushin.

  5. Very informative post on earthquakes this time – and such a short interval since the ice core education.
    Hope an 8.2+ doesn’t follow along as quickly/

  6. Notable on the map is that the US west coast is the longest stretch of the ring of fire to not have an M8+ since 1900. Wonder when the luck will turn, no really strong (>M7.5) earthquakes in United States outside of Alaska in over 100 years. The San Andreas has three sections that produce strong earthquakes and is capable of weak M8 earthquakes, but often falls just short, both the San Francisco (1906) and Fort Tejon (1857) earthquakes were M7.9. Would be great to have a Volcanocafe article on the Cascadia fault. The only serious contender for a M9+ in the lower 48 deserves some attention.

  7. On the previous topic of identifying mystery eruptions, I’d suggest taking lakebed sediment cores from lakes located downwind of known volcanic areas, worldwide. There should be tephra in these that would fingerprint the culprit volcano, as well as organic matter that can be carbon-dated. If the sediment has identifiable annual layers, so much the better. (This might happen, at the very least, if there’s a river feeding the lake that experiences regular annual floods. The annual flood will bring a surge of sediment that might have distinct characteristics, making the flood deposits identifiable annual bands in the cores.

    • Perhaps somewhere like Lake Baikal? It’s been pretty much undisturbed for 25 million years.

      • Lakes can be useful for ash but not for sulphate. They mainly see nearby volcanoes, of course, and especially so if they get run-off from a river from that volcano. Dating can be difficult, and you would normally assume a constant rate of sedimentation over time. Peat marshes are also used and they have the advantage of no run-off from rivers

  8. Cascadia the reason I left the Oregon coast for good.
    BTW has several videos (videos really ,) about PNW mega quakes.

  9. One other thing: I’m back finally got things sorted out.
    Computer, car wreck, wife’s
    Estate, and two months under a Doctor’s care.

    • So the French say “Courage” when going through these hard times…
      So: Courage. and Peace.
      Hugs, mots

      Glad to have You back.

  10. I have got a question, is there generally a correlation between the depth of a caldera and the altitude of a flank eruption creating it? Kilauea in 2018 sank by around 550 meters, so that the bottom of the caldera was a bit over 500 meters elevation. Ahu’aila’au is at an altitude of 230 (actually now 270) meters but the place where the dike originated under Heiheiahulu is in fact also about 550 meters elevation. I dont know though if these are all coincidences or if there is a greater meaning here. Would seem an eruption like in 1960 that first originates from the area near Leilani and PGV can result in a significantly bigger eruption than 2018, with a theoretical caldera collapse of around 900 meters, or to only 150-200 meters elevation.

    Reason I ask is that I think I have found the place where the eruptions creating the greater caldera of Kilauea happened, or if not that one of the other major collapses.

    • Not always. Clouding the issue further is the definition of a caldera. Kilauea 1960 erupted at approx. 10m ASL, but the collapse at the summit was nowhere near that deep–and no one considers the collapse at Halemaumau a caldera. 1955 was at approx 100m ASL and there was no collapse. 1971 was on the floor of the caldera–above Halemaumau–and the floor of Halemaumau dropped ~25m.

      Mauna Loa, OTOH has not produced a caldera since at least 1500 and probably not even then, but every eruption has been well below the floor of Mokuaweoweo, and most have been huge.

      Taal (may be considered a basaltic Toba, in that there’s no elevation to speak of) may be maars writ large–everything happens near the surface.

      Bardy and Kilauea 2018 suggest that there is a synergy between caldera collapse and eruption location/volume/eruption rate, so maybe it’s not so cut-and-dried.

      Anyhow, I’d love to hear your views on where the ‘big’, caldera-forming eruptions occurred. State of the art as far as I know is: 2018 was LERZ, 1924 was LERZ (intrusion), 1840 was LERZ, 1823 was LSWRZ, 1790 was LERZ, and then it gets fuzzy.

      • I think 1955 and 1960 represent a different case, 1955 was when supply was low and might not have happened at all if the rift wasnt open after 1924, it is after all quite unlikely for such a big eruption so far down after only 2 summit eruptions and 20 years of nearly nothing. 1960 was the result of a lot of magma coming in 1959, and then that majorly overcompensated and the deep supply has been going like crazy since then, as Hector explained. 1960 was actually a very big eruption, 0.25-0.3 km3, it was significantly bigger than the old estimate as like 2018 much more of it was underwater than earlier recognised. I think the same applies to 1840, Kilauea LERZ eruptions it seems are uniformly of large scale. Eruptions on the Puna ridge are probably Veidivotn scale events, hence why Kilauea has a wider caldera rivaling the biggest in Iceland.

        I am going to wait until Hector posts part 3 of his series though, he understands Hawaii better than I do.

      • Probably back in 1960 not enough of the magma chamber was fluid enough, it needed heating up, the very hot magma of 1959 likely helping in that. Now it is superheated to 1300 C crystals suggest.

        Perhaps when the main magma body is sufficiently molten to remelt some of the olivine cumulate is when a caldera forms, losing the solid support, the summit falling in and forcing magma out of anywhere along the ERZ it can. The 2018 collapse didnt have a ring dike so was an inward dipping collapse, while if the collapse happened deeper and drove the eruption instead then it would probably be an outward dipping fault, letting magma go into the fault, where it can erupt violently as it did in 1500 and 1790, maybe also 1650.

        Also would like to add apparently Mauna Loa has gone caldera in the last 500 years, in the early 1700s.

      • By my research 1823, 1832 and 1924 were not proper caldera collapses, the first two actually were just lava lakes a lot like the one right now but much bigger draining, no ring faults or collapse. 1924 was really not big enough to count. 1840 started where Mauna Ulu is now and dikes went both east and west, a tiny vent was recent found deep within the Koae faults, so technically a upper ERZ eruption that got lost 🙂

        1500, 1650, 1700, 1730, 1745, 1750, 1760, 1776, 1790, 1840, 1955, 1960 and 2018, LERZ eruptions. Maybe also 1885 and 1924, but also maybe not.

  11. Shame on google for only having 1 Chinese website find, using the quoted 2 words “earthquake moraines”, in regard to the seismic gap in the west coast of the USA for great quakes.

    • So, then tell the Chinese to publish more, and put it out for the world to see!

  12. To satiate my dark desires, I have compiled a subreddit discussing potential and present disasters. Safe to say that volcanoes will be mentioned so feel free to come visit!

  13. Brilliant. So Anchorage will probably have its peace until around 2100. The way it is explained and the plots show that the ruptures move east to west like the Pacific plate. And then they seem to return, and the process starts from the beginning.
    What happens after 80 to 100 years, Albert? Could it be that there is an obstacle in the West? Could it be that mountain chain bordering the Bering Sea?


    • The trench extends for 3,400 km from a triple junction in the west with the Ulakhan Fault and the northern end of the Kuril-Kamchatka Trench, to a junction with the northern end of the Queen Charlotte Fault system in the east.

      Read more :

      Triple junction with Ulakhan fault the reason?

  14. This map showing the whole area might be useful as well:

    Very far future, at least 50 My, suggestion: High mountain range up north between Alaska and Sibiria. Height like the Himalayas. The island arc with subduction is typical for the phenomenon. Closure to the Arctic and therefore to the Atlantic Ocean. Large opening north of Iceland. Different currents. Climate?
    Gondwana’s climate is supposed to have been mild. There were numerous orogenies. When the Iapetus Ocean formed north of West Gondwana the Cambrian explosion of life started (around 500 mya).

    Alaska will always have quakes, of course. Thank God it’s not as busy as the Philippines. All together: Vision. Mine.

  15. Saturday
    31.07.2021 12:53:27 63.621 -19.136 1.1 km 2.6 90.06 4.9 km NNW of Hábunga
    31.07.2021 12:53:27 63.641 -19.115 0.1 km 3.3 99.0 6.7 km E of Goðabunga

  16. For those who still like to watch flowing, red lava (even though it gets a bit repetitive):

    Whenever the fog isn’t too dense, either red, glowing fog or even a few lava splashes can be seen.

    • Yep – pleased to confirm Fagradals is back on stream! Dash the fog, though.

  17. Something a little different from Ingenuity Flight 10. Scouting out Perseverance’s next target area and currently over 400 metres ahead of Percy.

    Get out your old 3D cardboard glasses 🙂


    post Jul 29 2021, 09:01 PM
    Post #422

    An aerial wide-baseline stereoscopic image.
    Interesting shapes here and there.
    The distortion in the lower right corner could not be compensated, beware of headaches.

  18. Two Cents….

    “Others have had time off. But in a “way, that can be more dangerous. They will come again, and people may no longer be sufficiently prepared.”

    “Sufficiently prepared” is the most important point.
    One of the primary items under the “Black Swan” criteria, is erroneously assuming a zero probability of low probability scenario.

    It’s a low probability, but non zero. Meaning, it “WILL HAPPEN”…. eventually.

  19. Because of the fog the still cams sometimes pictures a surreal landscape.
    Imagine the damp cold air and the silence that surrounds this landscape.

    • More foggy days to come in iceland.

      GFS prognoses sea level pressure plus 500 hPa.

      • The fog in the mountains here was down to 700-800 meters. So it is also over big parts of Europe. For me, in my area, it’s almost a year without summer, apart from a few days. It wouldn’t show up in ice cores though. On the south side of the Alps it’s slightly better.

        • Meanwhile, here in Northern California, Redding just set new records for the most 100F+ temps through July.
          “With July just wrapping up, will note that Redding Area observed
          27 days in July at/above 100 deg F. With a period of record going
          back to 1893, July 2021 recorded the third most number of 100 deg
          F days of any month, behind only July 2017 (29 days) and August
          1967 (28 days). Interestingly, no individual daily record highs
          were broken in July. Furthermore, Redding Area`s total number of
          100 deg F days so far this year is 47, which year-to-date is the
          most observed, surpassing 2017 which had 42 through July 31. The
          annual record for the most number of 100 deg F days for Redding is
          72 days…set back in 2017”.

          Edited as requested by the commenter – admin

          • It doesn’t seem like it, but Redding California is on the latitude of Naples, Italy. Also New York City btw. Northern Europeans including the Britons go to the Amalfi coast south of Naples since decades to get some sun. Reliably. No rain, please.
            Damascus and Casablance are only around 7% lower concerning latitude.
            The Canary Islands are around 28° north and have the best climate in Europe, warm, moderate, often windy. On the other side of the Equator there is are corresponding islands: Mauritius and the Seychelles.

          • In addition to that it is one large bulk of continental mass already. The American plate ends under Sibiria, the African plate under Eurasia. So basically it is one big bulk from Oslo in the West over Vladivostok to Halifax in the East and Capetown in the south.
            Whatever car we drive or energy we use I only expect it to cool down with a row of VEI 6 and a small glaciation.
            It seems to be a very lovable place, otherwise people near the equator would not have so many children.
            For explosions among animals there was the same rule: It was always warm.
            So, I won’t go with the sinner version. But it has gotten warmer. Climate warming is not the hoax. The hoax is to sell people new products, but refrain from doing something in the sense of protection against future warming. Or flooding for that matter.

          • Albert explained in one post how mankind could be capable one day to set the earth in another place. I believe that.

            And I also believe that NASA would be able right now to simulate the effects of a VEI 6. If not tell me why not, please.

          • Dragons please help! Please remove the link posted above.
            It is for the weather blog I frequently post on.
            Not sure why my C&P spit out this link?

          • Tripoli, Libya=San Diego, latitude. For many people, also in Europe (I do like Americans) this might not be too obvious. I once read, about 5 years ago, that California doesn’t build enough reservoirs. I also read that LA does not have a warning system for landslides, that they come down in the east, are collected in a basin and then transported by trucks. If I hadn’t had any names in there and had had to guess I would have said Middle America or Africa. Don’t worry, the German floods showed that we are gliding back into medieval times as well. Your bridges over the Puget Sound might collapse with an earthquake and huge tsunami. Our bridges don’t even need a tsunami, they just come down, see Genova and take everybody into the abyss.

  20. The flow into Meradalir no longer flows towards the camera: the flows from the last days there are too thick. It is now flowing to the far end. I wonder whether this is the flow which will escape from Meradalir. It could be close

    • I dont think it will escape this time, but will fill in the gap, so maybe next time it will. That might be in a few days or a few weeks but its lookign inevitable now.

      Must be serious flow rate to sustain a channel so far over flat ground too, a 3 km channel is pretty easy on a slope but flat ground they tend to stagnate.

      • It is no longer flat. It has build up a lot against the slope

      • It is ony about 1km (the flatter part), and since a while the main “lake” is no longer flat like a lake, but significantly sloped. There is no underground displacement any more between the western and the eastern part of lower Meradalir.

        That being said, within the eastern part there still is some underground displacement activity. So after this new flow ended a bit shot of the eastern edge, it settled down, and pushed the level close to the exit up by quite a bit. There are still a few meters missing though.

        Now that most of the lava is flowing on the surface and also with those large gaps between flows leading to lots of energy loss, most of the mass will continue to stay in the western part of Meradalir, and I believe it will take quite some time until the exit is reached.

  21. What is going on with the eruption? The tremor is as high as I’ve seen it () but the cams show no activity. It was going like gangbusters about 10 minutes ago.

    • Maybe it is intruding, possibly a new vent or even a whole new fissure will open soon 🙂

    • The tremor has just paused again. I think this was the end of today’s episode.

      • The cone stops spewing before the tremor drops? I’d have expected it to be the other way around, or simultaneous.

        • The tremor ended 12 minutes before the comment. But the observation may have been earlier – I don’t know when the lava stopped. It would be useful to compare the times

          • I’d reloaded the tremor graph right before making the comment. The cone had gone quiet only a few minutes before that. The tremor graph had shown no drop yet at that reload.

          • Thanks. The tremor chart does not update instantly. When you reload, it may still show data that is out of date by a few minutes, while the camera shows live events. It would be good to note down the time when the lava disappears, and afterwards compare this to the time the tremor plot goes flat. That should tell us what goes first, the lava or the bubbles

          • The tremor stopped again and I had a chance to compare it against the lava in the Langihyryggur camera

            The camera showed a collapse of the inner wall at 11:09:22. The lava bubbling became rapidly less and no lava was visible by 11:10:00. At 11:10:30 there was one more lava bubble. It was gone by 11:10:50 after which the lava episode ended.

            Compare that to the tremor below. The first vertical red line shows the wall collapse and the final red line shows the termination of any lava. This is exactly when the tremor fades and stops. From this, we can decide that the tremor is the bubbling of the lava. It seems plausible that the bubbling stopped because of the wall slide. The wall is a tephra plaster and when it slid down it would have insulated the top of the lava and plugged the hole. This stopped the degassing, without the gas the lava retreats and the pond is empty.

            I have previously suggested that the conduit was the location of the action. It has also been suggested that it is the magma supply from the mantle that varies. But these data show that at the current time, the source of the interruption is in the lava pond at the top.

            The restart tends to be slower, as shown by the harmonic plot. Once degassing begins again it goes very fast for a bit but then slows down, perhaps when the rising lava begins to enter the pond.


  22. How tall is the volcano now? The cone looks not that big but it is surrounded by a growing shield, at least on the side the cameras are. It must be getting close to 200 meters above the ground that was there before it all started. At what point is it just too tall and a rift opens, or the eruption just moves entirely to a new spot nearby?

    • Reykjanes Ridge. Earthquakes there are quite common. It is a volcanic region (spreading ridge) but normally not a volcanic earthquake

        • Yes, there are quite a few. I though they were just aftershocks but a bit too many and too strong for that. Still likely tectonic but if this continues for days then I might reconsider.

          • You must be right, in the meantime I found the Icelandic MET office, and on there site those quakes were less strong and today I couldn’t even find a small follow-up.
            But talking about tsunami’s what about all those earthquakes these days in the Dodecanese Islands regio and Crete. Earthquakes in those regio’s started historical tsunami’s. About every two centuries happend a tsunami in the eastern part of the Mediterranean Sea, but that was long ago……… maybe a nice article?

    • ZZDoc, thanks for that link. Completely unexpected topic. Naive perhaps I am.

  23. While admittedly O.T. (well sorta considering some recent posts), here’s a preliminary paper from, (a branch of NOAA) that goes into the severity of the great Pacific Northwest Heatwave in late June that drove temps to an insane 121.5F in Lytton (above 50N) in British Columbia.
    The paper notes the statistical and physical rarity of the event which puts it at a 1:1,000 yr. event (based on a comprehensive analysis by an international group of weather and climatologists as part of a project known as the “World Weather Attribution” project).
    Note a key takeaway is that the WWA members acknowledge that there is the possibility that a climate threshold (unknown at this time) has been exceeded, since a physical explanation (under currently understood parameters) is almost unbelievable/impossible?
    If so, then the GPHW may not have been a 1,000 yr. event…but rather a harbinger of climate change that now allows for these type of events to occur, possibly as frequently as ~50yr.

    • Could tens of thousands of wind turbines harvesting summer breezes in the PNW be a big part of the problem? Maybe we should “reverse them for awhile” and cool things back down?

      • Possible. There’s at least some discussion about the matter. besides, concerning flooding, they are sitting on huge platforms of concrete.

      • The heat wave had little/none to do with surface conditions.
        The principle forcing mechanism was what’s known as an “anticyclonic wave break”…which sources in the upper atmosphere then propagates towards the surface in the form of subsiding air. As the air flow is driven downward, it compresses and adiabatically heats up. In the case of the northwest heat wave, heights at 500mb were over 600 dm..virtually unheard of in that part of the planet this time of year (or any time of year for that matter).

      • I’ve wondered about the same thing for a while now.

        There’s only so much (fixed amount) of energy in the wind – if you extract some, there must be consequences downstream…something to do with the concept of ‘conservation of energy’, I believe the term is.

        The same applies to solar panels, used in large/very large arrays.


    • Funny how the local weather geeks for years have been complaining about never breaking above 107 in PDX. Then the freak high pressure setup and blew past 107 by 1, then 4, then 9 degrees in three successive days?! Driving to work June 28th at 1856 and the temp was still 113…Guess Arizona misses me.

      Last year a freak early fall high pressure setup north and east of us, driving the east winds to ludicrous levels, nearly burning down the PNW in the process.

      I’m no anthropogenic climate change advocate, but it sure seems these outlier high pressure events are happening more frequently. I do believe in natural climate change, cause it’s always changing. The mechanism of the change and rate is what I seek to understand.

      I have firmly in my target sights the giant plasma ball in the sky and it’s associated interplanetary magnetic fields. Our power to control these sorts of things is superficially insignificant at best. The local solar environment, in addition to the local galactic position of the solar system? Now that’s intriguing.

      • I don’t think the global warming needs advocates – it is doing quite well, and is continuing at the predicted rate. That is not a major surprise since the physics has been known for over a century. The first paper on it was around 1895(!) and the heating it predicted for doubling of CO2 was within a factor of 2 of the value we have today. Of course, in those days it was just a theoretical exercise and the paper actually said that we would never burn enough coal to make this happen. That prediction was wrong. But I am not in favour of attributing every extreme weather event to global warming. You should predict what kind of weather becomes more probably before it happens, not afterwards. Heat waves will get hotter, but changes at the level seen in Canada were not predicted. Flooding was predicted to increase but the German disaster was not predicted.

        People have been arguing about solar influence on climate but those discussions have ended because the predictions they made a decade ago (that a quiet solar cycle would stop warming and cause cooling) were so far off the mark. But the IPCC reports have all the different effects in there, with their contributions and uncertainties. It is an honest assessment which includes solar variability. You can look up there the current state of knowledge in the WG1 report of 2018: The relevant table is number 5, where you can see there is a solar effect but it is very small compared to the atmosphere.

        • I am not convinced that the sun is a slow variable star.
          However what we are going to the planet pretty well overrides all of this. The tropical rainforest is being cleared, we are putting GT of CO2 into the atmosphere and we are changing the planet’s ecosystem.
          Sadly the major payers are outside ‘the west’ and they run their own counties.
          They will go for cheap growth which is oil/coal. In a way who can blame them.
          We are headed for global warming and I am afraid it will be worse than predicted.
          Best places are islands (high latitude) but these tend to be short of soils due glaciation.
          Times will be tough, billions will die. I never thought I would find myself saying this even 10 years ago.

        • The amount of ejecta from Pinatubo was in the PPT (probably even less) if averaged across the entire area it contaminated….yet such a miniscule amount was able to skew NH temps by up to 0.6C. The reason of course is that the ejecta was ideally located in the stratosphere and contained gasses that led to aerosol formation….so IMHO, it isn’t always a matter of quantity but a matter of quality.
          The atmosphere and our climate is an extraordinarily sensitive/complex system where all things weather-related are inextricably linked….and what may seem on the surface to be a “minor” or negligible effect does not rule out the possibility that the variable may have unknown secondary consequences.
          Lastly, I note that your table does not include the effects of insolar changes as the they are related to the height of the tropopause. There has been a lot of backroom chatter that’s trying to explain a general trend of subsidence in the atmosphere that seems to enhance H.P. development and conversely suppresses run-of-the-mill cyclone formation. The point is, while the insolar changes directly related to temperature are indeed negligible, that does not preclude other changes in the upper atmosphere that can have a greater impact…i.e. no different than a small amount of CO2 that directly may not raise the temperature that much, but enough to melt hydrates and permafrost that releases methane and increase water vapor content of the atmosphere…both of which are far more potent GHG than the original CO2.

          • Aerosols are included in the table and models. You will also see that this aspect has the highest uncertainty. The new report should be out this year and may have updates. IPCC is conservative, so gives most weight to what is scientifically established and less weight to new results that need validation by further studies. The listed uncertainties are fair. You mention methane but that is included in the models. It is significant but CO2 has more effect. Volcanic eruptions are also included although obviously on a statistical basis only. Even a major eruption only affects the atmosphere for a few years, and therefore doesn’t change the overall trend line. I am not sure what you mean by contraction of the troposphere. Are you referring to the temperature change at high altitude? Because CO2 is stopping ground radiation from getting out, the upper troposphere and stratosphere have lost a bit of heating: they get some energy from absorbing ground radiation. One of the predictions of global warming is that the stratosphere cools and that has been seen. That makes convection a bit more important for energy transfer. This is known physics. Of course, many global warming models don’t calculate the physics but used fixed parameters to describe what happens. IPCC will give higher weight to models that do physics. The third way to calculate changes is by seeing what happened in the past with changing CO2 levels. That comparison tends to predict stronger warming and higher sea levels than direct models. None of the models or past comparisons show evidence that anything major is missing from our understanding. And none indicate that the sun causes significant variations. A lot of that originally came from the idea that the Mauder minimum coincided with the little ice age. Now we know that little ice age lasted much longer than that. The most likely explanation for the little ice age is that it wasn’t little. It was the beginning of the real ice age.

          • Albert.
            When I say the sun may be a long period variable I am talking about ~100ky timespan, which is about the time it takes a photon from the suns core to reach the photosphere. This would suggest the core nuclear reaction is cyclic, basically exploding and the heat decreasing the density, switching the reaction off, until its restarted by cooling and compression.
            You will note this means the low-level irradiance is probably where we have been for a while, so doesn’t make it better, necessarily.

          • There is a reason in physics why the nuclear burning in the core of the sun is so stable. The response to any change in nuclear fusion rate would be instant, and drive it back to where it was before. Since the energy production is stable, the only way to make the energy output vary is by temporarily storing energy in the outer layers of the sun. That happens in variable stars but the sun does not have the parameters for this – it is outside of the ‘instability zone’. Good for us. The solar cycle causes a change of a bit less than 0.1% in the total solar irradiation over the cycle. You do get a slow change as the hydrogen inside runs out, but over 100 kyr that amounts to a fractional change of 0.001%. You need a thousand times longer to see that change. That only leaves the convective region in the sun. The time scale for variations here is indeed 10^5 yr. But there is no indication that this convective zone is not stable. It has been well studied using solar seismology. We are very lucky that the sun is so stable. A good overview (now a little old) is at

          • The stability of K, G and F type stars is why they are the preferred places to look for planets with potential. A-O stars dont really live long enough to evolve planets , actually O stars probably dont live long enough for planets to even form around them. M stars are way too violent and energetic too, which is something that a lot of sources seem to forget thinking that smaller stars are more calm, red dwarfs are very dangerous for life… Proxima b and the Trappist planets probably have habitable surface conditions but beyond lethal radiation, at least certainly that is the case at Proxima Centauri.

            Even life around brown dwarfs in a habitable zone is unlikely, they are basically Jupiter on steroids, hypermagnetic 1000 C hell planets that have gravity so strong you cant leave without an orion drive… You wouldnt last an hour on a planet (moon?) around a brown dwarf.

        • You recently said that industialisation ended the Little Ice Age. Before the Little Ice Age there was the Medieval Warm Period from 950 to 1250 roughly.
          What we don’t have, therefore, is a double blind study. We don’t know how warm it would be without industrialisation. There are cycles going on on Earth and on other planets in the solar system that are not fully understood.
          So, instead of giving people trouble with a ridiculous form of energy should go into capture as capture would cover all reasons for higher CO2 levels and warming.
          I have the pessimistic feeling that creating new expensive industries will have the following effect: Poverty as Tallis suggested, aside from that: No change.
          So, indeed, if CO2 is the main problem it needs to be captured and also Methane. If not, we are being lied at. Grossly lied at. I donate for forestation sometimes.

          • Please note that the medieval warm period was a localalized effect, not global.
            Forestation is a good idea, but too slow and too little to cover the huge amount we’ve emitted (and still are emitting).
            CO2 capture is an interesting idea, but this also needs a huge amount of energy which has to come from somewhere.
            It’s scientifically well established that CO2 is the main driver of global warming.

      • The mechanism is the greenhouse effect which is enhanced by our release of CO2, and the rate of change is entirely governed by how much excess we put in the atmosphere. The sun’s output has not changed in any meaningful way in the past 150 years, so is not relevant to the effects of AGW we see today. None of this is in any way in dispute – we’ve understood the science for decades now. If you’re interested in the science behind it, most of it is easily understandable at roughly the 5th grade level, and is quite easily accessible to the general public via the beauty of the internet (see for example). If you’re not interested in the science, that’s totally fine, but I kindly ask that you take the extremely respectable “I don’t know enough to have an opinion” stance, which I’ve personally used many times for various topics.

  24. Quite good, indeed, Craig. Very sober. While the heatwave hit California (that must have been awful) it got really rainy in Europe and still is. I wonder sometimes whether there is a connection.
    The last flood in the same area was in 1910 and before in 1804. Albert has written a piece about the “Magdalenenflut”, it is in the index.

    It might be interesting to check Californian or the West coast’s temperatures for those years. If there is no correlation it most likely has to do with the meandering Jetstream.

    Sorry for the sort if rant. Some of us are getting upset with politics. Covid politics was the trigger. I also think that it has a taste when people sit in lockdown while milliardares take an excursion into space.

    • What do you want the world to do? People don’t understand that this world can’t function without fossil fuels, Solar, wind, and geothermal are not viable for all of the people on this Earth. Going off of fossil fuels without a viable alternative will kill billions of people in the most horrible ways. You can’t expect the poorer countries who are poor because of the direct actions of the major powers to suddenly condemn themselves to endless poverty at the behest of those same major powers.
      I believe there should be a focus on finding new scientific ways to capture carbon and finding a better way to get energy beyond renewables. All I have been hearing is that “it’s too late” like humanity and animals haven’t survived dramatic climate change before. They’ve been saying that for the past 20 years and if there was more effort into finding a viable solution instead of clinging to unrealistic ideas, I am sure ACC would have been distant thought now. The more pressing matter in my opinion is the fact that pesticides are killing off insects at unsustainable rate, and plastics are decreasing male fertility. Ecosystem collapse through these poisons will be much worse then through current projections of climate change

      • Not sure about your ladder logic, Tallis.
        For example, fossil fuels can be replaced (eventually) by non-polluting fuel cells…and on a local level instead of building/maintaining massive grids or other energy-storing technologies. These type of localized power sources can be invaluable to impoverished nations to help them cope with the effects of a global climate change they had little part in creating. So yes, we can survive without fossil fuels…all a matter of will and somebody willing to make a buck off all the new jobs that will be created. 😉

        • A sustainable replacement of fossil fuels would be a Multidecadal process, but some scientist and most politicians are not trying for the most sensible solution, instead they are going for ridiculous or short-term solutions which will only delay and/or bring suffering to the majority of the populace.

          • Yes, but ‘politically acceptable until the next election’.

          • Thanks as always for your comment, Tallis.
            If it can be shown that we can make money by designing, building and selling commercially viable fuel cell generators (or a viable alternative) that can provide and store power with a zero carbon footprint, that will be the true driver for a green changeover (and not political will/whim). In the beginning, there will likely be a massive investment (either public or private) required to fund the changeover…but then once profitability is achieved, free enterprise would take over. This seems to be the model that China is following. It is now a world leader in GHG mitigation (but they still have a looooong way to go), but in the meantime using both public (gv’t) subsidies/investment plus private funding, they are well on their way to building a new energy infrastructure and developing the machines and technology that eventually will get sold to the rest of the world… a huge profit, I might add.
            At present, the limitation with fuel cells seems to be the best method to crack water vapor into oxygen and hydrogen (which takes power…ideally renewable such as solar and wind). Electrolysis is the current choice, but it’s still too inefficient as far as how much hydrogen is produced per watt of power used in the electrolysis process, plus there are supply/disposal issues of the electrolyte itself.
            But there are many other options to create storable power…some pretty far fetched and mostly theoretical, while others are close to becoming viable as data from prototypes that already operate on a limited scale start trickling in.
            For instance, I’ve personally worked (designed/patented actually) an RF based plasma torch that we used to crack water vapor into OH+ and H…of which the OH+ was used to make extraordinarily high quality SiO2 (<20 angstroms) using atomic oxygen (instead of O2) as a reactant, (with the residual Hydrogen becoming a waste product that could be captured and stored).
            (as a sidenote: for semiconductor fabrication, SiO2 formed using gaseous H2O (wet-ox) or O2 (dry-ox) results in a more porous oxide with poorer dielectric properties than oxides using monatomic oxygen to grow the glass).
            While the concept of creating OH+ to deliver the monatomic oxygen worked nicely for the limited quantity of gas it produced, it would probably not be a good choice for mass use due to the processes complexity. However, if a simplified, perfectly-tuned microwave-based "cold plasma" can be perfected (they exist today in the form of atmospheric pressure cold-plasma "pens" used primarily in Medicine), the improved power coupling to the plasma could substantially increase H2 production with a lower power draw than the electrolyte process. Again, more R&D is needed if the process can be scaled up to create enough H2 to provide a sufficient amount of stored hydrogen.
            Another interesting option that is being actively explored is to thermoelectrically convert flowing heat directly into electricity (TEG), which in turn could power hydrogen generators. This process uses solidstate thermoelectric technology (also known as the Seebeck effect), which is always evolving….plus heat is free. IMHO, there is a lot of promise in this concept since the Seebeck effect is well understood. Again, a few billion dollars in R&D could help bring this technology into the realm of reality.
            These are only a few of the many such areas of power-generation interest, and given the continuously increasing costs of staying carbon-positive are biting us in the arse, at some point the market (and not politicians) will indeed respond with a viable alternative.
            Call me a Pollyanna, but there's too many billions /trillions of dollars to made in building an entirely new, fossil fuel-free energy producing infrastructure….and at some point in the near-future, the next Elon Musk is just lurking in the shadows waiting for a suitable technology to emerge and then get exploited.

          • True with the timing. They do it to catch voters knowing it’s wrong.

        • Craig, you exemplify the view held by the majority. That is for magic solutions that ignore the law of conservation of energy. Non-polluting fuel cells need fuel, which comes from ??

          • The power to run say, an electrolysis-based H2 generator, would need to be green to start with…preferably solar or wind or as mentioned, thermoelectric that converts heat that already exists into electrical energy… there indeed would be an energy input…. hence conservation of energy is preserved. The fuel (H2) for the fuel cell can be extracted from cracked/dissociated water molecules in the air (as well as oxygen).
            Regardless, the key challenge for a localized/economical green-power conversion infrastructure is how do you store (or produce) power when the sun doesn’t shine or the wind stops blowing? That’s been the biggest (but not the only) roadblock to mass use of green energy (aside from huge up-front costs).
            Batteries are cumbersome, energy-intensive to manufacture, and very expensive with a finite lifetime. But a simple tank of hydrogen could be cheaply made and easily maintained.
            The point/beauty of the fuel cell technology that I’m most optimistic about, is that it utilizes latent heat (pre-existing energy) from gasses that get’s released during reactions between air (oxygen bearing) and H2 that can supply electricity 24/7…or as long as a supply of Hydrogen is present. Plus, the fuel cell’s “waste” is pure water (as an effluent) which as we know, is as good as gold in many places.

          • The problem with hydrogen is that it’s so tiny it slips between the molecules of any pipe or canister you try to keep it in. So, either you use it close to the source in space and time; put up with a high level of leakage; or incur the giant added expense and complexity of surrounding the hydrogen with serious cryogenic equipment to keep it frozen.

            Well, that’s one problem with hydrogen. Another is that any pipeline or container of hydrogen is a very powerful bomb, more so even than with natural gas. All those Hollywood movies where cars, trucks, and things explode after taking a couple of bullets or crashing into anything not Nerf-branded? Bogus for gasoline, which is quite stable actually, though a fire hazard if an open gas container is around sparks; truer for natural gas; very true for hydrogen. Even cryogenic hydrogen is not immune, as seven astronauts found out to their chagrin back in the 1980s. Now picture having that explosion go off in your neighborhood at some gas stationesque facility. Or in your backyard. Or your kitchen. You could well unexpectedly become an astronaut for the last few seconds of your life in that case.

            Given the problems with storage, transport, and safety, I wouldn’t look to hydrogen as our savior. Battery storage is more likely to be our key innovation here, with a lot of work being done on iron-air, zinc-air, sodium-ion, and vanadium battery technologies. Good enough batteries might even give us better long-distance transmission: power delivered by sneakernet instead of wireline infrastructure. For last-mile transport that wouldn’t be the case, but transoceanic? That could allow us to generate power by paving a chunk of otherwise useless Sahara with solar panels and then just bottle the energy and ship it everywhere.

      • The reality is that the world will not accept the drop in living standards required for a carbon-free economy. Some countries can do it, small populations and high renewable energy sources, but the overwhelming majority cannot. If there was a world government and peace worldwide then there are a few possible solutions but that’s just a pipe dream. Yes billions will die, and possibly the world will return to the middle ages and a stable, autocratic and impoverished population or 500M to 1B.
        Reality doen’t have to be fair and nature never is.

        • What drop in standard? A car that has twice the efficiency is just as comfortable/large/american. An LED gives just as much light as an old type bulb but at 20% of the energy use. (The ‘energy saving bulbs’ used before in were not very good at giving light – not all innovations work.) And they work our cheaper to buy because they last – the old bulbs were made to be replaced every year, good for the manufacturer but not for the user. How does you living standard drop from insulating your house? The only one it hurts is the energy company which sells you the energy. Your argument is just industry wanting to maximise income by not changing anything.

          • You are right, Albert. But: Many people in my country don’t have the money any more to pay the then higher prices for homes, neither for purchase nor for rent. Besides there is a problem with mold.
            I am with Tallis: Carbon capture.
            And Tallis is right with poor countries. And semi-poor countries like the BRIC states won’t go with it. That’s at least half the world population. China is building airports and coal plants.

          • The part “they” avoid saying is that the drop in living standards will be for the billionaires, not for us. OK, we might need to drive individual cars less and use transit more, or a few other minor things, but it’s the billionaires whose lifestyles would have to change drastically. So of course there’s lots of FUD and propaganda to try to obfuscate this fact and gin up opposition by convincing Joe Sixpack that he’d have to go back to a wood-heated candlelit 1800s hovel. (Which would actually be terrible for the environment anyway. There’s no turning back the clock.)

          • Albert I agree, although we are beginning to get close to maximum realistic efficiency for the ICO, we are at max efficiency for electricity (pretty well) and the change from petrol to diesel has no further efficiency steps. Light bulbs are not a major power user anyway, and most high-volume (ie non domestic) was fluorescent anyway which is actually as good as LED (efficiency-wise). What would help would be two standard car types, the rest with punitive taxes. One equivalent to 750cc turbo diesel (small car) the other 1200cc (larger car), electric to match allowing for generation CO2 production. Cities domestic a 2 person max 30mph 20mile range electric those with families are allowed a 4 seat version. That could have been done 10 years ago, and still not on the drawing board.
            PS All houses where its practical to insulate have been done when there were very favourable grants. For the millions of solid wall victorian (and earlier) dwellings its very non-trivial to insulate effectively. Basically outer insulation covered with composite render at a cost of circa £30k/house (£70k for the larger ones).

          • Twisted one sadly what you say is what some want to believe but there are so few billionaires that if you removed all of them at a stroke it would make absolutely no difference. In the west its everyone who needs to cut their total energy use by circa 50%, this includes the energy in everything you buy (and throw away), in the energy cost of entertainment, material objects, clothing, building etc because basically 10-30% of the cost is in the energy used to produce it.
            PS Icelandic volcanoes are still at it …

          • I lived second home in the UK for a while in a house that was 100 years old and had some of the above issues.
            The reason was though that next to no sun could get in in the summer, so the house never heated up sufficiently, because the owner wasn’t allowed to take the row of 100 years old oak trees south of the house down and replace them with some newer trees in the north.
            The oaks were nice and dense, but ate up all the sun, the house was permanently cold. The walls were fine, and the owner had recently replaced all the windows. In winter it was sometimes warmer than in summer.
            A house like that wouldn’t take advantage of insulation, but instead of more flexibility in preservation. Insulated, that house would become mouldy. I swear you.

        • TwistedOne – why should the billionaires accept a drop in living standards?

          “Eat bugs, live in pods, don’t have kids” is a ‘planet-saving’ solution for us, not for them.

          Albert is right that a lot of energy saving solutions are pretty painless, although a fully insulated house will still need some fresh air.

          But in the very long term, even ignoring the greenhouse effect (say thorium nukes were developed tomorrow with no long-lived radioactive byproducts), we cannot increase
          energy production indefinitely. The earth has to get rid of that heat.

          • In the UK, housing stock could do with some insulation. A bit of fresh air is essential, but I have seen houses here where you need to nail down the carpet to stop it blowing away in the fresh air blowing in through all the holes. The UK government keeps promising schemes to get this sorted but somehow the money never arrives. Carbon capture is good, but not emitting the excess carbon in the first place is better. At least half our task lies in energy efficiency. As farmeroz keeps telling us, it is hard to make the energy budget balance with renewables at our current rate of use. The other half is in renewable-energy infrastructure and the third half is carbon capture. It will be expensive but inaction will cost even more. There is a lot of talk of population growth. But in fact we have done 80% of the work to bring birth rates down to replacement levels. In comparison, for our energy efficiency we have done about a third of what is needed.

          • Regarding fresh air for a well-insulated house, haven’t the Brits heard of air-to-air heat exchangers? We had one installed in our well-insulated new house in 1985, in Vancouver, Canada.

    • They are indeed often related…especially when a high-amplitude hemispheric event like an El Nino (or La Nina), or SSW/PV event is present.
      Here on the west coast of N.A. our principal source of weather is from the Pacific.. i.e. W-E.
      When the jet stream (storm track) gets blocked by a ridge over Greenland (for example), or over the NorthPacific, the upstream flow starts to back up like a toilet plug with very little “meandering” in the jet stream. Usually this creates a predictable pattern/teleconnections between Europe and here in California (with local details ignored).

  25. Etna was extremely impressive last night. 52 and counting this year?

    • Thanks for the reminder that there is more going on in the world!

      • I think Etna really deserves a post on here, 2021 has actually been an extraordinary year there. Of course it has erupted a record number of times but even more than that is that most of these eruptions have been bona fide subplinian eruptions, a lot of the 40 paroxysms in 2000 – the only comparable year recently – were much less vigorous. The fluidity of the lava too right now is also notable. Not like Hawaii but it moves very fast on the steep slopes that Etna has, and at high rate it moves fast anyway. All of the summit craters are actually erupting not just the SEC complex, the magma stand is very high and a flank eruption seems inevitable soon. I expect the worst really, it seems unlikely an eruption at low altitude of any sort can be harmless, especially not a lava flood like a repeat of 1669.

        Maybe most significantly of all though, Etna right now is the tallest it has ever been recorded. That alone is extraordinary.

        • I agree, a lucid article setting the situation out, bit of history, changes over the last decade and so on.
          Trouble is, people have jobs to do and unless its something you keep solidly abreast of, its a lot of work. It is, even if you have, mind you.

        • Chad, sorry, do you think that Lake Avernus (close to Monte Nuovo, Campi Flegrei) could be a Maar?

          • Is this the one in Pozzuoli? Yes, it looks the type, decent size too, 1 by 1km.
            The most recent eruptions of Campi Flegrei were just north east of there also.

            There are quite a worrying number of maar-diatreme and caldera like structures headed up the coast towards Rome and beyond. I’ve been using the circle tool on google earth to outline them, although I think Roccamonfina might be extinct

    • Some pix would be nice as its always stopped by the time I read your posts!

  26. I am starting to get pissed with Phivolcs, they’re not giving any deformation data or anything beyond the same incredibly indescriptive statement. “Taal Volcano Island has begun deflating in April 2021 while the Taal region continues to undergo very slow extension since 2020.” I have looked at the latest insar data that hasn’t been updated since March and it’s incredible. I am not exaggerating when I say that this deformation spans both 20 km east and west and 15 km north and south! Parts of the volcano that didn’t inflate before the last eruption are inflating now and this is after the system lost a ton of magma! Parts of the volcano were inflating at a rate of 30 cm per year and that is NOT slow! If whatever magma is driving this unrest reaches the surface, people will suffer. This isn’t your typical stratovolcano, damn it! this is large caldera with 500 km3 of eruptible magma! if 0.5 percent of that erupts that’s a CRISIS.
    We have two potential sources of a major eruption and both of them could snap at any F@$king moment and produce a VEI 4+. Just because there isn’t a lot of tremor or gas emission (relatively speaking) doesn’t mean it’s over and in fact! It could mean that the magma and gas are plugged and large amounts of pressure is building right now. I don’t need the seismograms, I just want to know how the magnitude of the deformation since March and see a little more respect for one of the volcanoes capable of producing a catastrophic pyroclastic surge!

    • Calm down Tallis – you are suffering a VEI-4. An eruption of Taal is not unlikely over the next 5-10 years but the current deflation suggests it is not planning to do so now. Inflation of 30cm/yr seems unlikely. Even Iwo Jima does not do that. What data are you looking at?

        • Note that the timeframe is since 2018. When I adjust the time slider, it appears that major extension happened nearly two years ago. It was then followed by contraction, until last fall, when inflation started again and then the data ends in March. The extension is no more than it was in mid-January 2020.

          In the long-run, Taal will do something big. However, that data doesn’t particularly suggest a large eruption in the immediate future to my non-expert eyes.

          • I don’t know what exactly you’re looking at but this data shows that there was substantial deformation last year that didn’t get enough attention. There was major subsidence and uplift on the SE and NW sides respectively. some place swith rates surpassing 10 cm/year. I implore you to look back on the past reports for Taal and you will see that they described these impressive movements as slight which is absurd. I have no clue what data they are looking at but they are not giving us any values concerning the deformation of the system which is ridiculous.
            I have no idea what it is inflating and subsiding and by how much. An eruption could be imminent depending on how close the magma is to the surface, how quickly it’s moving, and what’s keeping it from the surface. We don’t know those variables so I can’t say that this volcano is erupt but it would equally assumptive to assume that a major eruption is far off.

      • 30 cm in a year is what Kilauea has been going at after 2018.

    • Extension can mean rifting, not necessarily inflation. The area is a rift zone after all.

      But if the extension goes on long enough the caldera ring fault will collapse, and if Taal has got a ring dike like Hector suggested that ring dike will be decompressed, and also the magma under it will be compressed a bit. Result is a lot of magma degassing and lava fountaining out of the ring fault.

      If it is dry then you get something like the massive fountain fallout around Kilaueas summit, but Taal is not dry, and so you already knkw where that is going. 1756 must have been a slow caldera collapse ecactly like this, 7 months of collapse and eruptions, if it was pressure driven it would not last so long.

    • Thanks! At 3:30 we finally get a look at the gap that the lava will use to exit Meradalir. There is still some filling needed at that end of the valley; the latest flows almost reached it, but not quite.

    • Quoting the post ‘The most notable absence is perhaps the Philippines’ …

    • That’s science. Science must be wrong sometimes to stay vibrant in debate and ideas and correct things with better knowledge.
      The best debates of the past: Richard Owen vs. Gideon Mantell or Dinosaur vs. Lizard. Also Darwin, mostly represented by his “bulldog” Thomas Huxley vs. Owen. That’s progress.
      Science should be ideas that can be wrong and PHD who do the work to prove one or the other. Or ewesome Volcanos (surprise).

      I wouldn’t have thought that Nyarogongo gives up for a while with those cracks in the streets..

  27. The Alaska earthquake shows up nicely in Hawaiian tiltmeters, meant to measure changes in slope from volcano deformation:

  28. The earthquakes of the last week at Kilauea are really showing the magma system nicely.

    It looks like the magma conduit is now pressurized all the way to Pu’u O’o, hence the quakes along it. The south flank is active even further east so it is possible the conduit will also reach the magma chamber under Heiheiahulu too, but even if it doesnt the level it is at now is about what triggered the eruption last year. DI events have also stopped so it seems right now magma inflow is constant, too high for any backflow.

    The fact the magma conduit is also active to Pu’u O’o brings an ERZ eruption into the equation now too, unlike last year the deep pit is filled in, and parts of the ERZ above the active section are at a lower elevation than the new floor of Halemaumau. If it keeps going to the end of the active flank movement then it could get interesting.

    • I won’t be satisfied until I see a flank eruption that crosses the coastline! 🙂 Littoral cones and phreatic explosions FTW!

      • Oh I think that will happen a lot over the coming decades. Hector I think is right about 2018 only making it easier for the rift to erupt, the summit happened first because it was deep but probably by years end not so much, then basically the entire volcano is fair game…

    • Following on from this there have been a lot of earthquakes in the Pahala swarm recently too, in fact most days even more there than in Kilauea. If this really is the part where the volcanoes connect as per Hectors radical theory then it is looking very interesting, really it is hard to justify any reason these quakes are unrelated to the volcanism.

      As for your eruption in the ocean Damon, that will happen, Kilauea is due for a major caldera collapse soon, something much bigger than 2018. Think Veidivotn scale, 5 km3 of lava, plinian fountaining from the summit and a curtain of fire along most of the LERZ, one can only hope the ocean stays out of the dike or the comparison to Veidivotn might well become a lot more literal than just the DRE volume.

  29. Lava reappeared in the cone pond at 23:40 last night, and rose over the next hours but did not overflow. This was also when tremor began to increase. However, the tremor increase has been slower than in previous episodes

    • Faf drumplot signal didn’t increase at all at 23.40.


      At the moment the signal is increasing very slow. But that might be weather related.

        • Yes I noticed. It seemed the degassing wasn’t that strong anymore. No spattering, or at least much less as usual.

          The tremor and drumplot signals have gone down once more again now.

          Change of pattern again?
          Curious about future scientific pieces that describes Geldingadalir’s behaviour.

          • Would make sense if the cone is leaking, the outflow that formed a few weeks ago is actually higher than the original spot now, and the side facing Geldingadalir is way lower and being that area is a stagnant lava lake the cone is probably also more unstable there too.

            If the lava flow is all in that direction it is going to flow very fast into Natthagi, the walls are honestly just not going to stand a chance against flows of the magnitude we have been looking at the past week. Meradalir is a big valley, it is likely even just a single one of the recent flows would have filled Natthagi to overflowing, including the wall at the exit. That big flow that originally flooded Natthagi was when all the lava from the vent was channeled there for a day or two, and look how far it got. Now imagine that but repeating for a few weeks.

            Of course maybe nothing has changed so this is all exiting speculation but it is pretty inevitable in the long term really.

  30. The on-going conversation regarding climate change and ice cores prompts a question regarding the following which have been read and sitting on my bookshelf for several years now….

    David Keys’ ‘Catastrophe’-An Investigation Into the Origins of the Modern World

    Were the Dark Ages Triggered by Volcano-Related Climate Changes in the 6th Century?
    [If so, was Krakatau volcano the culprit?]
    by Ken Wohletz,
    Los Alamos Laboratory LA-UR-00-4608
    Your thoughts and opinions?

    • Please, take your Keys and burn it. Yes, the volcanic eruptions changed the world, as we have written about here as well. No, Krakatau had nothing to do with. It did not have an eruption at that time and in any case was in the wrong part of the world for the eruption he claims. There is not a shred of evidence for it – but you would be amazed at the number of people who have brought this up! Myths are so much more powerful than facts.

  31. I see Öraefajökull is having a little rattle today. Perhaps it is feeling ignored due the the Reykjanes activity!

    • There is still a lot of research to be done regarding the psychology of volcanos.

      • Some require therapy. Some just require a better diet, they’re getting a bit bloated.

    • It is under Skeidararjökull, the neighbouring glaciertongue of Örae.
      Interesting, because of the depth range of the quakes, and because there is no central volcano around.

      Few weeks back there was another little burst at the same spot. I tried to find any info on exsisting faults, no result. But the IMO records show there is a patch of earthquakes, most of them in the years 2002 – 2009.

      • Many of the quakes in the period 2002 2009 were generated by the Grimsvötn Jökulhlaup activity, these were shallow though.

        • There’s been a number of quakes in that area for a number of weeks.

          I’ve checked this out on an ordinance survey map and there seems to be a volcanic entity called skerhóll around 2 miles from that area.

          • Checked the geology, mainly basalt and intermediair, Lower Pleistocene and Pliocene. Some patches Rhyolite, older than 11.500 yrs.

  32. Mods – please can you delete my posts of 22:44 and 22:46? They’re irrelevant due mostly to not being to the Opticians for a while. Thanks 🙂

    • I don’t know Clive – they make for fascinating reading!

      • Oh well, maybe they could stay up! I got the wrong volcano in the wrong place at the wrong time. A new case of volcanic blindness.

    • Sorry, we can’t easily delete comments since it messes up the comment stream. Every time we do that, people find that their replies to comments end up in unexpected places

  33. Just a few questions.

    Lots of seismic activity close to Nisyros, any chance of a fizzle? Most of the quakes seem to be submarine.

    Japan, nice seismic swarm brewing ~130 clicks from Tokyo, thoughts?

    Is a swarm potentially starting beneath Katla?

    • Katla’s seismic activity isn’t even very unusual at the time. It’s just typical summer behavior due to glacier melting, while ice builds up in the winter. That’s also why most volcanoes in higher latitudes erupt during summer or after a colder epoch during periods of warming, often abrupt warming if i’m not mistaken.

      That being said, it’s possible that could trigger an eruption, but we’re already august and so far i don’t see anything that concerns me at all. That could quickly change, but so far it’s not the case.

    • Hi Peter,

      I’m halfway through writing an article on that very subject around the Nisyros area, which is a relatively fresh area volcanically speaking and still developing. I can tell you that some of these quakes are tectonic and volcano-tectonic in nature, as there are a number of grabens and half-grabens in the area due to the stretching and extension of the crust.

      There is a sill intruded into this area and I fully expect another large eruption from the Nisyros/Kefalos area within 100,000 years.

  34. Has the Geldingadalir vent done anything the last 24 hours? Every time I have a look in, it is steaming quietly but not erupting.

    • It’s been struggling through a down period since Monday afternoon local time.

      • It is now on its second attempt to recover. The first one around midnight did not get far. It is now at the point where lava might return in the cone within an hour, although any overflows would take much longer. It hasn’t done much in the last 48 hours

        • Indeed. Eyeballing the purple line on looks like the mean amplitude is steadily decreasing between 25/07 and 4/08.
          That said we have been surprised by behavioral changes in the past.

  35. Best lava map I have seen so far. The link has probably been posted already.

    Contour spacing at 10 meters better than most others I have seen.

    • I can see all the maps, and if I click on this one I go to the original where I can do one layer of zoom.
      I have noticed a big delay in larger pix before, sometimes 10’s of minutes when a starfield default image is then replaced by the posted one.
      I suspect its a delay getting large pix into servers or local caches.

  36. Pity, I’ve tried again.
    Not sure why the link didn’t copy

    • Perhaps because of the size: that map is many mb’s. Might also be because it is not a secure link. In other words, I have no idea.

      I have put a downgraded version here

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