Severe weather forecasting is an exciting science and hobby of mine. Beautiful sights and terrifying storms make it fun. Tornadoes and Hurricanes are particularly incredible to me. A lot of the excitement comes from the fact that no one truly knows exactly what is going to happen during the forecasting portion of an upcoming disaster. Correctly interpreting the interaction of a myriad of variables is a hard task even for seasoned scientists. Most forecasters ask two questions for an incoming weather event. “What is the most likely outcome?” and “How bad can this get?” Of all the various natural disasters, weather-related disasters are the most frequent and dangerous to the average man. The world has seen more large-scale weather disasters than geological and epidemiological disasters combined. Meteorologists have a completely different mindset when approaching certain events. Geologists can’t consider every medium-sized earthquake as a possible prelude to a magnitude 7 or every phreatic eruption as a prelude to a large eruption. Meteorologists don’t have that luxury due to the sheer volume of weather disasters that afflict the society. Meteorologists can majorly screw up 10 times and be right 40 times and still maintain a degree of trust with the populace and government. Geologists don’t have that luxury. Due to the infrequency of geological disasters just one or two major screwups have significant ramifications so it’s usually best to play it safe.
The question “How bad can this get?” isn’t asked as much for disasters of little frequency and there are few disasters as scant as volcanic tsunamis. Do we have enough information to answer the question “How bad can volcanic tsunamis be?”
A Derecho that caused severe damage to Houston wasn’t anticipated in the days preceding it
Volcanic tsunamis are notoriously rare with slightly more than 1% of all recorded tsunamis since the 17th century being from volcanoes. Most of these events had only regional or local impacts. Only one volcanic tsunami is definitely known for being a long-distance wave. It was and is still assumed that volcanic eruptions have a harder time producing large tsunamis than earthquakes. To me, this is preposterous and more importantly, dangerous. We have a small sample size of volcanic tsunamis but I believe that we can deduce the truth using history. We will be using two examples.
The 1888 eruption of Ritter Island
On March 13th, an unimpressive intense VEI 2 eruption triggered a large landslide of 1.5 to 5 km3 of material which triggered a large tsunami that would unfortunately kill 3,000 people. The tsunami destroyed villages along the coast of New Guinea to the west and New Britain to the east. Its effects were even recorded in Sydney, Australia, 3,200 km away from the volcano. Most historical volcanic tsunamis are caused by sector or flank collapses and none of these events were long-distance like notably earthquake-driven tsunamis. The issue is that none of these events were large in the slightest. The Ritter Island landslide was among if not the largest historical volcanic collapses.
But it pales in comparison to truly large collapses. Volcanic flank collapses have been known to reach volumes of over 500 kmsup>3 while approaching the speed of sound. ALL of the volcanic tsunamis in recorded history have been from small-moderate eruptions and modest collapses 1, 2 or even 3 orders of magnitude smaller than the true peak of these events. The Valdivia, Tohuku, and Sumatra earthquakes are the peak of earthquakes. Ritter Island is not even close to the peak of what volcanoes are capable of. Nevertheless, we shall approximate the total energy of the Ritter Island tsunami.
The western segment of the Island collapsed into the sea, destroying the circular island.
With a volume of 1.5-5 km3 and a speed of 40 m/s, we can derive a landslide energy of 6-10e+12 joules or around 1,400-2,400 tons of TNT. Only 5-10% of that energy goes into the water, giving us a tsunami energy of 3-10e+11 joules or 70-240 tons of TNT. 2,987 times weaker than the Tohuku tsunami at the absolute best. Despite its far inferior energy, it still killed thousands and was close to the size of the Tohuku Tsunami. Doesn’t sound like volcanoes have a hard time making waves.
Earthquakes tsunamis are broadly sourced but volcanic tsunamis are point-sourced. Hypothetically speaking, if an earthquake were to inject 1 quadrillion joules in the water, the area of transfer would be along the entire rupture zone of the fault which could extend 500 km. The energy will be spread over a colossal area. If a volcano were to inject the same amount of energy into the water it would be concentrated in a smaller area due to volcanoes having an inferior range compared to earthquakes. As a result, the volcanic tsunami will be more Energetically Dense. The volcanic tsunami will lose energy quicker but it will start off larger. Same energy but in a smaller area. Volcanoes are superior tsunami progenitors to earthquakes since they can make disastrous impacts with far inferior energy that earthquakes can’t normally replicate.
How bad can volcanic landslide tsunamis get? A 500 km3 landslide moving 100 m/s will have an energy of 1.125e+19 joules and could produce a tsunami with 5.6225e+17 joules or over 134 megatons of TNT which is around 20 times the energy of the Tohuku Tsunami. Keep in mind this isn’t the maximum number as this isn’t the limit of volcanic landslides in size or speed.
2022 Hunga Tonga eruption and Tsunami
In 2022, Hunga Tonga finally disproved the “Long-Distance Myth”. The tsunami traveled the whole of the Pacific and killed 2 people in Peru over 10,000 km away from the volcano. No landslide or other form of collapse caused the tsunami. The eruption was just a low-end VEI 6 nowhere near the pinnacle of eruption size. However, for tsunamigenesis, intensity matters just as much as size and Hunga Tonga is seen as the peak of eruption intensity. There is also some discussion on how exactly the tsunami came to being and depending on the progenitor, intensity might matter more than size. Was the HTHH tsunami the peak of non-collapse volcanic tsunamis?
First off, the massive pressure wave didn’t cause the tsunami. The meteotsunami caused by the eruption came sooner than the proper tsunami so much so that the signals were segregated by a few hours. Submarine PDCs likely didn’t cause the tsunami, they were too slow, about half the speed of the tsunami. Lacking the intensity, the HTHH tsunami was likely caused directly by the volcanic explosion. More specifically the 5th and largest volcanic explosion with a yield of 15 megatons. The explosion blasted a cavity 6 km wide displacing 6-9 km3 of water. If HTHH is the pinnacle of volcanic intensity then its wave was the peak of the tsunamis born from the same cause. IF.
The Hunga Tonga eruption isn’t comparable to any other eruptions we’ve observed with modern instrumentation however that doesn’t mean that it represents the pinnacle of eruption intensity. Hunga Tonga is often compared to Krakatoa but this isn’t a good comparison either. The HTHH eruption had a volume of 4-6 km3 DRE but most of that material was stuck undersea. Estimating the volume of magma within the plume has been done and that number is a measly 0.1-.0.2 km3 of magma, not even a VEI 5. This was noted in the comment section as the eruption happened but the volcanic plume seemed to be rich in water vapor and there seemed to be relatively little ash. Indeed the ashfall measurements were low, lower than what should have been observed for its size. The steam made the plume even more buoyant and needs to be accounted for before calculating ejection rates. The ejection rates for the eruption were likely around 7-14e+7 kg/s just slightly inferior to the Novarupta eruption. For reference, the Hatepe eruption had a peak intensity of 6e+10 kg/s which is comparable to the ejection rates postulated for VEI 8 eruptions. Hunga Tonga was 2 or 3 orders of magnitude less intense than the most intense eruptions known. Hunga Tonga is definitely inferior to Krakatoa as well. The shockwaves and plume heights were likely comparable but the Krakatoa plume had far more magma within it and as such had far more energy. (Same speeds and height but more mass = more energy),in addition to the eruption being larger as well.
Hunga Tonga’s eruption doesn’t represent the peak of eruption intensity and as such its tsunami is not the pinnacle of tsunamis of that kind. There is a firm cap on how much water a volcanic explosion can interact with but it’s a safe assumption in my opinion that a truly intense eruption could produce a tsunami with 2 or 3 times the energy of the HTHH tsunami.
Conclusion
Events of relatively small size caused all of the historical volcanic tsunamis and are not representative of the peak of what we know volcanoes are capable of. As such it is illogical to assume these events represent the peak of volcanic tsunamis. Energy from column collapse PDC, Landslides, and mass ejection rates can be as much as 100x, 1,000,000x, and 1,000x more energetic than what we’ve observed with modern instrumentation, respectively. This gives volcanic tsunamis frightening amounts of potential. With the numbers calculated, the maximum realistic volcanic tsunami energy could reach is within 6.76e+16 to 1e+18 joules depending on the cause. Truly catastrophic eruptions and collapses are rare, and these events with the idealized setup for volcanic tsunamis are even rarer. There is a massive amount of evidence that suggests volcanic tsunamis can be much larger than assumed. We must ask where are the volcanoes that could deliver that truly devastating tsunamis? That’s a question for another day.
Tallis
Sources:
https://link.springer.com/article/10.1007/s00445-024-01749-1
https://www.science.org/doi/full/10.1126/sciadv.adf5493
https://www.ngdc.noaa.gov/hazel/view/hazards/tsunami/event-more-info/1175
https://academic.oup.com/gji/article/154/3/891/713958
Thank-you for diving into the Tsunami topic, Tallis!
To the comparison of geology and meteorology: They are both good in predicting and working with daily/normal events. The prediction for sunshine tomorrow or the sedimentation in a river delta are relatively well to do. It’s different if we look at disasters. Both the prediction of next of the thunderstorm in London and next eruptions of Vesuvius are impossible. They understand the physical laws that rule the events, but can’t look into the future what happens where in what way.
If we looks at megathrust earthquakes like Crete 365 or Indonesia 2004, they usually happen in subduction zone trenchs. From this origin they move water on the bottom of the ocean. You can see the tsunami on the surface, but it’s like the tip of an iceberg. The real tsunami is revealed when the energy in the deep sea is forced to get out in shallow waters like continental shelf waters. That’s why f.e. the 2004 tsunami killed people in Somalia on the other side of the Indian Ocean.
Volcanic tsunamis often have their origin at the surface. F.e. Stromoboli’s small 2002 tsunami by a partial collapse of Sciara del Fuoco. Caldera collapses like Katkaoa 1883 and HTHH can origin at slightly deeper level, but still remain relatively shallow with dominating action on the surface, but less participation of deep sea. The worst threat are volcanic tsunamis that reach to deep sea. Examples are collapse of Hawaii’s islands that are one of several ways to shrink the islands. Also the Canaries bear this threat of an island collapse into the deep ocean. Both can cause megatsunamis with probably the worst risk for coasts around the oceans, worse than tsunamis by megathrust earthquakes.
“The ‘Ālika 2 landslide may have produced a giant tsunami that swept Lāna‘i about 105,000 years ago.” https://www.usgs.gov/volcanoes/mauna-loa/science/geology-and-history-mauna-loa
And you have the Storegga slide with 5600 km³ of continental shelf.
https://royalsocietypublishing.org/doi/abs/10.1098/rsta.1988.0055
Yes, this is a landslide that hits from the shelf into deep ocean. It’s a rare tsunami that was neither caused by (mega)earthquakes nor volcanoes, but probably the effects of glaciation/deglaciation on the continental shelf. Something that perhaps can happen around Antarctica if melting of ice destablizes a continental shelf.
Several years ago Hawaii’s university published this map with mega landslides:
https://hilo.hawaii.edu/~kenhon/GEOL205/Landslides2/default.htm
That’s in fact the worst possible threat by Hawaii.
Isn’t the Hilina slump considered the most likely to go, for the big island?
Yes, it is a dangerous part of Big Island. Hilina slump is slowly and steadily moving towards the sea and does occasionally events like 1868, when an earthquake caused a landslide and deadly tsunami.
Many mega landslides and tsunamis on Hawaii occur at or after postshield stage, when the volcano is slowly dying and moving away from the hot hotspot. Kohala f.e. did one of the last big landslides 250,000-300,000 years ago
They happen when the volcanoes are big enough, Mauna Loa is still very active and has had two collapses. Kilauea isnt big enough yet, maybe in 100,000 years. Mauna Loa is likely to do so again before then. Haleakala and Mauna Kea might also, although its not really obvious what sets off the biggest slides or if it is consistent.
Thanks! I do believe HTHH Tsunami had a deep sea component as I don’t believe a shallow tsunami could travel so far. There is a lot of debate concerning the effectiveness of landslides for tsunamis but I do believe that the threat is there.
The far-off precise predictions for weather events are indeed impossible just geological disasters.but we know that there is almost 100% chance of an EF4 tornado or category 5 hurricane occurring in the next 10 years but definitely not for a VEI 6..
The collapse of the HTHH caldera and phreatomagmatic explosion probably happened predominantly at 1-2 km depth. I would consider this as a shallow to medium deep sea level. The energy is still enough to travel far. How big were the tsunami waves in the Americas?
Weather/meteorology has an advantage that it can observe the conditions for predictions much more better with f.e. satellite (or even a barometer) than geologists can observe the conditions in the volcanic “hell” deep below our feet. It is nearly impossible to observe the important tipping points that decide between eruption or no eruption.
The largest known tsunami was caused by a rock collapse into a bay. The rock volume was less than 0.1 km3 but the shape of the bay focussed the wave which reached over 500 meters run-up height. Five people died. That was caused by an earthquake but a volcano could have triggered a very similar event. It was one of the reasons we were concerned about Lake Nicaragua.
https://www.iflscience.com/the-tallest-tsunami-on-record-hit-alaska-with-a-524-meter-wave-in-1958-72215
One problem with volcanic tsunamis is that the volcano does not even need to be erupting. An unstable flank can collapse at any time. For instance Krakatau 2018, where the collapse happened hours after an eruption. Mount Unzen in 1792 is another example. An eruption had build up an unstable dome, which collapses a month later after an earthquake. The death toll was almost as high as that of the 2011 Japan mega-tsunami.
The fact that these moderate collapses are as deadly as some of the worst earthquakes tsunamis is telling to just how dangerous volcanic tsunamis are. Unzen and Anak Krakatoa are almost always unstable. The past eruptions at Krakatoa and Unzen were probably the straws that broke the camel’s back.
Lakes and bays allow a higher concentration of the tsunami force in a closed water system. The huge landslide of Mount St. Helens into Spirit Lake caused a 180m high tsunami. If the same landslide had happened at an ocean archipel, the tsunami wouldn’t be as high.
You can’t discuss volcanic tsunamis without discussing Etna:
https://ciesm.org/news/mscience/12.htm
Curious thought: might that event have caused the Black Sea entrance to erode enough to open the path into the Black Sea basin, and started the Noah legend?
Hmm. Musing only.
I think that event is thought to be earlier than Etna Valle del Bove collapse, but it is still something to think about.
Watching an ‘ocean flood’ where the ocean breaches into a low elevation area, is something I want to see more than most volcanic events really. Its an event that even the biggest volcanism possible struggles to compare to. The Zanclean flood had a flow rate of the entire planets water cycle through the Gibraltar straight. Its also likely to repeat as Africa creeps north, maybe multiple more times until the isolation is permanent.
The two places that we might get a tiny glimpse of this within the next millennium are the Eyre basin of Australia, and the Caspian Sea. But neither if those will happen in the 21st century naturally 🙁
A relatively small future event might be a potential flooding ot the Dead Sea & Jordan valley if sea level rises high enough or the Jordan Rift Valley extends more.
Tallis:
Thank you for the write up. Volcanic flank collapses can create huge tsunamis. I heard that Lanai shows evidence of such a tsunami caused by a flank collapse. Hawaiian bathymetry, just as a previous post by Volcanophil shows, proves numerous landslides around the islands. You can see this along the Hawaiian chain, as a matter of fact. I did come across this interesting paper https://www.sciencedirect.com/science/article/abs/pii/S0025322703003062 which shows that the science is still out on how coral deposits get deposited so high up on an island, presumably by the tsunami wave. The Cape Verde Islands and Canary Islands also display ample evidence of mega-tsunamis.
The mere fact that there is still evidence of the waves after so long is a testament to the strength of these events. it’s been known that these collapses can cause megatsunamis but it was controversial if they could go long distances. These collapses can inject large amounts of energy into the water and that energy has to go somewhere. If the Ritter Island collapse can have significant ramifications over an entire region then it’s not unlikely that far larger and faster collapses could have significant long-distance impacts.
10 years ago Askja did a major landslide and tsunami, accidentally one month before Holohraun. https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016JC012496
The “tsunami that traveled about ∼3 km across the lake and inundated the shore with vertical runup measuring up to 60–80 m.”
This shows that volcanoes can cause tsunamis without an eruption. Crater and Caldera lakes are very vulnerable for local mega tsunamis.
https://en.vedur.is/avalanches/articles/nr/2929
Many thanks for your fascinating article, Tallis!
Thank you.
Was there a collapse of the new vent? On live from Iceland I see some lava flows that I had not noticed before. I usually watch MBL is.
Mac
One cone continues to do Strombolian lava fountains, while the other erupts heavy steam: https://www.youtube.com/watch?v=Hia5Ejq2778
When the Hunga-Tonga Hunga Haa’pai volcano blew up, it was not a steam explosion of hot magma hitting ocean water, there actually was a sudden release of gases from a phase change which occurred almost at once, which is the only possible scientific explanation for the extreme shock waves which hit the area. It would have simply taken too long for normal sea water to hit the large magma chamber and explode in milliseconds. See https://www.cbc.ca/radio/quirks/record-smashing-tonga-volcano-1.7096003 in particular the underwater mapping of the cone. If this had been a conventional phreatic explosion, we’d expect the cone to be shredded. It is not. Instead we see the center neatly blown out, a low level 6 explosion. We have more to learn about how such volcanic explosions like this create mega-tsunamis
I agree that water interactions didn’t cause the intensity but the eruption did have significant water interactions especially in order to get all of that water vapor into the atmosphere. I’ve heard some rapid caldera collapses are capable tsunami progenitors. There is a variety of ways volcanic explosions could create tsunamis. Column-Collapse PDC. rapid caldera collapse, lateral blasts, or just a big boom
Here is a scientific paper which has the best explanation from all those that I have heard. See https://www.sciencedirect.com/science/article/pii/S0377027324000696?via%3Dihub basically hydraulic failure of the rock occured allowing a compressed gas explosion to occur within milliseconds. The sudden shock events as recorded in the debris are a very strong evidence of this process taking place. We had not one, but several of these decompression events taking place.
Thank you.
Reminded me of when our sprawling site’s steam safety disk blew. Jet was so loud we literally could not hear it. A quarter-mile away, we were ‘struck deaf’…
IIRC, wary analysis of the disk petals suggested corrosion by sea-bird droppings.
This seems to favor Carl’s supercritical water hypothesis, wherein the explosion would have originated in the conduit below the cone and not at the cone/seawater interface above. Thus it was more strongly directed upward, like a nuclear-sized shotgun blast. The resulting upward kick to a sizable chunk of the water column is precisely the kind of thing that generates tsunamis …
I partially agree with Carl, on supercritical state, but we don’t have the water above the magma chamber all of a sudden releasing pressure to enable the supercritical state change.
Hunga Tonga was very busy where we couldn’t see it.
Tonga volcano unleashed fastest ever undersea flows: study (Phys.org, 7 Sep 2023)
Sounds like an underwater lahar or pyroclastic flow: a fluidised stream of volcanic rock and ash.
I’ll add the accounts of the tsunami from Krakatoa in 1883 are fascinating – they’re recorded in the 1888 Royal Society report on the eruption, which is available online. The recent Anak Krakatau flank collapse which Albert mentions just underscores how dangerous that volcano is.
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021AV000627
Kabooom… the Chicxulub tsunami
Rampaged up the ‘Western Interior Seaway’, yes??
Upside, deposited a ‘snapshot’ of flora and fauna.
Downside, ‘Dinosaur Smoothie’…
https://youtu.be/d0-Xj0zJOxQ?si=PZNmW5aas4MrvqPf
Well there is a prediction now, 2026 or before.
Probably a VEI 3-4 eruption followed by up to 0.5 km3 of lava. But a smaller eruption is also likely. Maybe less likely is a bigger eruption or a rifting event outside of the central volcano. The latter would probably look like the Sundhnjukur eruptions but with taller fountains.
Will also be interesting if the magma is andesite again or more mafic like in the late 20th century.
And of course if the 60 minute warning is still true.
It’s a tad hyperbolic, some of his stuff is. But we won’t know for sure until there’s some measurable inflation data and/or an uptick of quakes to a notable level.
I think thats youtube and clickbait culture more than his fault really. To be honest its far less hyperbolic than most of the open predictions made about Hekla or other Icelandic volcanoes on VC, especially earlier on, which I think personally have aged a lot worse than they could have because they were structured as expectations rather than predictions.
Stuff like 4-5 unrelated major to possible Laki scale eruptions beimg simultaneously imminent or that Holuhraun was somehow an average eruption when it was 5th place in the islands 1000 year history.. Or that standing on top of Hekla is uniquely dangerous for lack of warning. Personally I would climb Hekla 100 times in a row before ever considering climbing into Halemaumau, or ever going near any peleean stratovolcanoes.
The cinder cone at the current Iceland eruption site continues to build upward quite rapidly. Only a three or four days ago it was entirely below the level of the power lines visible in the Vogar webcam: https://www.youtube.com/watch?v=hGUELw4j6gQ.
At that time the little bump between the two bigger bumps was the highest point.
Great timing for this article Tallis, as those along the coastline of the Southern California Bight are anxiously monitoring a huge and worsening landslide near the very-upscale Rancho Palos Verde along the Palos Verde Peninsula. As of now, power and gas have been cut off as a massive landslide is accelerating at unprecedented speed…which in some places have been reported as high as 4 feet/mo. At present, the slide has become massive…and in fact, now for the first time represents two separate slip planes. For decades since the first signs of earth movement was noted in the 1950’s, the slip was miniscule (~ 1″-2″/yr) with sedimentary/aluvial layers sliding down a steeply sloped plain of evolved volcanic ash that’s forming an impenetrable layer of bentonite (think “slip n slide”) about 150-200′ down.
Now, a second slip plane about twice as deep has developed which geologists (according to the LA Times) believe is along the ancient Altamira Landslide complex, for which movement has never before been recorded. What is most worrisome is the deeper slip is by far the most active currently with over 13″/wk being mentioned around Portuguese Bend.
Aside from the danger of land cracking and movement from the landslide, there is a very real possibility now of a catastrophic failure/landslide of the coastline with the potential to trigger a significant tsunami that could impact much of the SoCal Bight coast. In 1812, there was a reported large tsunami that hit the Santa Barbara channel, which recently has been hypothesized to have come from a massive landslide near where the current crisis is evolving (of which several ancient and slides have been revealed by bathymetry).
In this current event, the trigger is likely coming from the heavy rainfall the area saw during the last two Winters that’s now made it down to the deeper slip plane and has started lubricating the lower bentonite surface. IMHO, with the land uphill now cracking down to depth, more and more surface water will now be free to penetrate down and further both add weight and mass to the surface crust but also decrease the stiction along the sliding slope…a very precarious setup just ripe for complete failure scenario should even a moderate size earthquake occur in this very earthquake-prone area.
https://www.science.org/content/article/tsunamis-threaten-california
http://www.appliedfluids.com/tsunami.html
https://laist.com/news/climate-environment/rancho-palos-verdes-takes-first-big-step-towards-possibly-slowing-portuguese-bend-slide
I wasn’t aware of the gravity of the situation. There are some measures to slow it down but it’ll have to happen eventually. Hopefully, we’ll know when that time comes.
It just makes me wonder how many non-volcanic collapses are in the making that could trigger devastating local tsunamis
There have been mitigating activities going on for years to help slow the landslide…but now that the deeper slide has started, those efforts that focused on a shallower slide have now been suspended since they’re no longer of much help.
As said, all it’ll take is a moderately strong nearby Earthquake to set it all loose.
Regrettably, SoCal has also been seeing a spike in lower level activity..but still enough to raise a few eyebrows among geologists if a bigger quake may be in the offing?
If this event is unstoppable now, and could become acute with basically no warning due to a sufficient quake in the area, then it’s best to ensure it happens at a time of our choosing.
Evacuate the area, including anywhere a tsunami might hit, and then drop a bomb on it. Get it over with. Once everything has settled down, rebuild. Or if the area is going to be prone to these things on a frequent enough basis, set it aside as a national park or something. Obviously, people will need to be compensated. The legal and physical tools exist though (eminent domain, air force bombers) and it would likely save hundreds of lives compared to the alternative.
Your point is well taken…and were it not for the chance that a major tsunami could wreak 10’s of billions of dollars of coastal damage, with the financial responsibility falling on the backers of the bombing…a few well placed bunker-busters could break up the slide into smaller, less damaging pieces.
There is a quasi-similar setup in Hawaii…the Hilina Slump, which moves about 3-4″/yr. Like Hilena, it’s possible that this landslide will just continue to creep along at a steady rate (albeit at 140″/yr not 4″ like Hilena) and not create a tsunami. But as mentioned, bathymetry does indicate there are other nearby large debris deposits/flows seen extending from the coast…but it is unclear to me if these debris were deposited in single catastrophic events or an accumulation over time of smaller/slower events.
It’s also possible that this year the rains will not be nearly as intense with SoCal going back into drought conditions thus cutting down on the water “lubricant”.
So while the risk is certainly there, IMHO a catastrophic event is not necessarily inevitable with a range of other outcomes possible…including a tsunami that isn’t high enough to cause massive damage.
What is inevitable though, is those people/property most at risk will eventually be forced to abandon this section of Palos Verde, with the rest of the SoCal coast staying extra-vigilant. Keep in mind tsunami threats anywhere in California are well known by the locals, with authorities already pre-conditioned to respond to a tsunami possibilities after a strong quake.
The BBC has picked up on the situation, albeit not the impact a collapse would have
https://www.bbc.co.uk/news/articles/c2042yx1xz1o
I find it kind of funny. Media always hypes non-existent, unfeasible, or far-future events, while downplaying genuine threats. Some powercuts should be least of anyone’s concern
So, GeologyHub just published a video on Hekla, where he makes a point about the “Ragnarbotn river” drying up and that that is a sign that Hekla is getting ready for a show.
We all know that Hekla needs no prelude before the concert begins, so I find the fact about this river strange. Google searces with the spelling he used gives nothing. And the pages here on VC about Hekla gives no mention.
Is he making things up or am I just rubbish at searching?
There were some references to it on the last article on VC, with links to a couple of articles. I often struggle to find locations in Iceland when searching, unless it is towns.
Geologyhub doesn’t give precise sources for his information some (too many) times. I’ve seen no mention of a river or stream drying up on IMO. It’s probably worth an inquiry. I wonder if he visits this blog, if he’s reading these comments, we need the data!
There is a small spelling mistake and it’s not a river. The information originates from a facebook group. Rangárbotnar are a number of springs that feed the river Ytri-Rangá. It’s not the entire river that dries out. Drying of the springs can be a sign that an eruption is getting closer, but it has also happened before without any eruption following, so it’s not a sure sign.
Thank you
There’s a nice page about the area here: https://icelandphotogallery.com/rangarbotnar-ytri-ranga-iceland-photo-gallery/
Thanks for sorting Geology Hub’s mistake, Tomas!
It doesn’t fill me with confidence about the rest of their speculation.
Today Hekla has answered with two quakes. During the whole year 2024 Hekla has done 43 earthquakes until today. Most happened on the NW flank of the volcano. Maybe the location for next eruption? Each eruption of Hekla choses a unique place for ash plumes and lava flows.
https://skjalftalisa.vedur.is/#/page/map
1980-1981, 1947-1948 and 1845-1846 lava flows ran towards the NW. These eruption were either longterm (up to one year) or a pair of close eruptions like August 1980 and April 1981.
Hekla does do small (~0.5), shallow (1-2 km) earthquakes on occasion. The other event was very deep. So neither indicates any development. Wait and see! And wait some more..
How explosive were the eruptions 1980 and 1981? Did they follow (on small scale) the typical Hekla eruption type or were they more effusive?
1980 was like the other 1970-2000 eruptions, fast fissure eruption but over quicker than most. 1981 was non explosive though and maybe better considered a really late second part of the 1980 eruption although technically that isnt really correct to convention. The fact it hasnt happened since, especially after 2000 that was a just as fast and short fissure eruption as in 1980, probably tells how it was an unusual event.
1980 had previously a short break of ten years. 1947 the break until the previous eruption was 33 years (1913). Now we’ve had 24 years since last Hekla eruption. The break is getting increasingly big. Shall we take into account that Hekla can do one of the longer lasting eruptions next?
Here is the Wiki descpription of 1947-1948 eruption: https://en.wikipedia.org/wiki/Hekla#1913_to_1948
It had nearly six months of explosive eruptions (first Plinian, later Strombolian), and the whole time lava effusion that covered 40km² and had a volume of 0.8km³. Interesting that Hekla’s intermediate lavas did Pāhoehoe and lava tubes like Hawaiian volcanoes.
I had a look at the ground deformations around Svartsengi and it looks like it has been pretty much at steady state since around August 25, so the outflow is pretty much balancing the supply. For a while, it looked in the GPS trajectories like inflation had resumed, but that was probably just some bias in the measurements.
Now there are new interferograms covering the periods Aug 24 – Aug 31, and Aug 25 – Sep 1 and they show no significant changes. With knowledge about the location of the sill, you might be able to trace one contour of subsidence around the sill, but if you were just given the interferogram without reference you wouldn’t be able to tell.
IMO have issued a news article about annual checks on Askja. Inflation is continuing and the estimate there is around 44 million m3 magma at around 3 km depth.
https://www.vedur.is/um-vi/frettir/arlegar-maelingar-voru-gerdar-i-oskju-i-agust
Off topic but is there a way to get auto-translate through a mobile browser?
What browser are you using? Using Chrome on Android it automatically asks me if I want to translate from Icelandic to English. If your browser does not have a translation option then visiting https://translate.google.com/ and selecting “Websites” should allow you to to past the URL and get it google translated.
10 years ago and one month before Holohraun Askja had this tsunami: https://en.vedur.is/about-imo/news/nr/2919
https://en.vedur.is/about-imo/news/nr/2930
“The slide triggered a tsunami in the lake that washed up on the lakeshores all around the lake, reaching up to 20–30 m and even higher in places. The wave travelled farthest around 400 m into the flatland SE of the crater Víti.”
The intra-caldera tsunami would have been a threat to Askja tourists. It happened during summer and tourist season, but fortunately at night.
Good day…
On my Island, (Tenerife) I suprise of the level of “volcano/Landslide” discovered…
https://www.mdpi.com/2624-795X/2/3/13
Not bad is someone can digin and build a comprensive landslides on tenerife, canary islands
Great article. I find the review of prehistoric and historic events around the world useful. It shows that mega-landslide-related landslides are exceedingly rare but that Ritter Island-like events are a very realistic threat. And a volcanic landslide does not need to reach the ocean to be devastating either.
All the Glycymeris coral dating from different locations seem consistent with the age of the 170 ka, 200 km3 Icod landslide in Tenerife, which seems to have sourced most of the megatsunami deposits. The other Tenerife landslides seem much older >500 ka, and I personally doubt La Orotava had recurrent landslides unless they were very closely spaced. Surprisingly, they do not find deposits of the 40-80 ka, 150-180 km3 El Golfo landslide in El Hierro.
Looks like Sundhnukar is wheezing to a close.
Here is a good article regarding Rancho Palos Verde (and a map of the landslide). Also goes into detail regarding the legal ramifications of a house moving from one place to another! I say let’s build houses on top of giant roller blades.
https://www.latimes.com/california/story/2023-03-06/a-big-chunk-of-palos-verdes-peninsula-is-sliding-into-the-sea-can-the-city-stop-it
In all seriousness, even if the people there wanted to move they’d probably struggle to sell their homes for any value. A humanitarian crisis in an upmarket location.
Of course the problem of your entire house moving location is a familiar one for Australians. Their whole continent is rushing north. At some point they will enter territorial waters of Indonesia. I can see that ending up in court. Presumably Indonesia will want to send them back as unauthorised migrants.
An annual examination of Askja leads to the results:
– Inflation continues with 12 cm since last year (4.4 million cubic meters)
– Magma accumulates at 3km depth
– No sign of movement of magma towards the surface
1961 signs for the coming eruption were increasing seismicity 20 days before the eruption and a significant rise of geothermal activity. Between 6 and 12 October occured six earthquakes of 3 or 4 magnitude. Additionally hot springs occured.
https://www.vedur.is/um-vi/frettir/arlegar-maelingar-voru-gerdar-i-oskju-i-agust
This map shows the latest (1st September) lava flows of the Sundhunkur eruption with yellow color. The eruption is at present in balance between what flows in and what flows out:
https://www.vedur.is/um-vi/frettir/jardhraeringar-grindavik
In Isak’s livestream presently there is a great view of the lava and it is forming shiny pahoehoe and glassy surfaces, and the lava is that characteristic bright red orange. After 2021 and up to April this year the lava was very fluid but it never looked like this. Same for Holuhraun, it formed lots of pahoehoe but it wasnt very shiny in nost places. But now we see it again. If the eruption lasts for a while lime this it could form a lava tube and advance slowly north.
Im surprised it is so open still, this vent is presumably many km down a thin dike from the permanent magma system. So if this stays open for a long time it might mean the magma system is more complicated than it was a few months back.
The lava flows have already reached half way towards the northern coast road. The landscape there is nearly horizontally flat. This brakes the speed of lava flows. The possible next eruptions will have difficulties to cross the whole distance.
That laminar flow from the southern vent looked awesome. A shiny thin skin, moving on top of the lava in perfect unison. No cracking up, no ropiness. Zoomed in without the sides as a reference it looked as if it could just as well have been standing still.
The previous sustained high fountaining has built up a very wide mound compared with previous eruptions that built steep spatter cones. Now that it has switched into spattering action it has started to build the usual spatter cones on top of the mound.
Ground deformation measurements indicate that the dyke widened quite a bit during the opening of the northern part. Compared with the radius of a more cylindrical conduit it might be narrow, but the height of the dyke is probably in the kilometer range, making it a conduit with a very large cross section. As such, I don’t think the projected distance at the surface makes much difference.
Yes it was almost like a sheet of metal. It reminds me a lot of some if the videos from Hawaii, around 2007 or so. Or the lava in Kalapana in 2010 that first got me into this hobby 🙂
It also means the lava must be basically coming right from the deep source now too, even if it is still collecting in the sills it isnt stuff that has sat there for years but probably all magma supplied since May, and ongoing. The lava flood we had at the start was also the most extensive even though most reports dont give higher output than in May, so either that is incorrect or this lava was more fluid. Im inclined to say a bit of both.
But certainly things could get very scary next time. And now we know that potentially the entire November dike length is eruptable its pretty much a certainty it goes just as far south evebtuually. Only thing that saves Grindavik is the supply dying but theres no way to predict that. This eruption was harmless but I fear it is a warning in disguise.
Recent GPS movement near Askja
Looks like it was a temporary glitch. It’s back to its previous trajectory now. This is very often the case with gps data. You need to look at several stations and the deformations in all three dimensions to tell if something’s going on. The problem for us is that there is too little publicly available 8h data around Askja. One hint is that the inflation trend for station DYNG is to the NE, so a sudden shift to NW would be unexpected and would probably not happen without some moderate earthquake activity.
If you take a look at https://strokkur.raunvis.hi.is/gps/8h and look for Askja, you can see 3 GPS stations that display this glitch, so it’s not just one station. That was the original reason I posted. It appears to be some glitch in all 3 stations.
16:31:12 2024-09-03
MAGNITUDE 4.97 mlw DEPTH 1.665 km
AREA: Miðhálendið – Vatnajökull – Bárðarbunga – Bárðarbunga
IMO website
Tuesday
03.09.2024 16:31:12 64.656 -17.378 1.7 km 5.0 99.0 7.3 km ENE of Bárðarbunga
And has a 99% ‘quality’ tag.
The recent quakes look to be tracing the ring fault.
This paper seems to be open access
Ring Fault Slip Reversal at Bárðarbunga Volcano, Iceland: Seismicity During Caldera Collapse and Re-Inflation 2014–2018
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021GL097613
From https://vafri.is/ (Live from Iceland)
Are they still related to sinking of the Caldera?
Has Bardarbunga ever done ring fault eruptions?
I would think it was more likely due to continued reinflation.
This is a GPS that is east of Pu’u O’o, starting to show a response to the activity further uprift. Its going a little slower than a month ago but seems things are still filling up. Kilauea is currebtly quiet, which it usually does a stronger swarm following such a pause. We will see soon but if it intrudes in the Pauahi area again it will probably erupt, otherwise the middle ERZ will inflate again and probably quite fast.
Kilauea seems a bit sleepy right now. I don’t see any GPS or tiltmeter with very fast inflation. I think the UERZ is where most magma is going right now, with PUHR inflating fast but not as much as in some of the episodes earlier this year.
Whenever Kilauea looks sleepy is when it tends to erupt soon after. I think I have been looking at it the wrong way, persistent elevated quakes seem to not actually be very likely to end in eruption. But when the volcano is quiet, the next time it wakes up seems to be likely to do a more significant intrusion. The big intrusion in January was after a quiet gap, and the activity in May was pretty low too before erupting in early June.
Its not completely reliable, the first Pauahi intrusion was in an active time. But still it seems to be a bit of a trend.
My best guess is that magma is building pressure in the deeper system and not so much in the shallow area that is easy to detect or set off quakes.
Svartsengi seems to follow a similar pattern of a period of quiet just before the intrusion into the dyke.
After last summit eruption September 2023 we’ve seen a number of intrusions. If we assume that each intrusion has an average unkown probability to erupt, we can expect that next one shall erupt.
I think there is a big misconception that intrusions are random, I dont think they are at all. Svartsengi is a great example, first intrusion was in November 2023 and didnt erupt, all this speculation and then it erupted now 6 times and maybe one failed tiny dike and all of them in the same exact line, and initially was even within a day of reaching the trigger of the November event.
Kilauea is the same, June dike and tiny eruption was almost in the same spot as the intrusion in January. Both intrusions in recent weeks near Pauahi have probably only failed to erupt because of the elevation of the ground above it, the volume of magma involved is small only a few million m3 on 22/8 but Chain of Craters road was cracked up extensively.
I also will make a bold claim that at least in Hawaii I dont think it is possible for a dike above a certain size to intrude without erupting. Far as I can find, there are actually only 2 examples of dikes on the ERZ proper that didnt erupt, at least since 1950, that being in 1955 east of Napau in between the two eruptions in time. And a dike that intruded east of Pu’u O’o in end of 1983 after a high fountain. Literally, in the modern era every single time a dike has started from where Mauna Ulu is now eastwards, at least SOME amount of lava has surfaced, and in nearly every case the low output events were succeeded by one or more much more voluminous events in the same place.
Im actually not sure if anyone has considered this at all before, certainly the way HVO talks about it makes it sound like intrusions usually fail, which apparently is very incorrect. Strictly speaking, it would be extremely weird if we get a dike starting further east than Pauahi and it fails to erupt. The only part of the ERZ that seems to have trouble erupting is the upper part that starts from the connector, but as seen clearly recently it is very rare to get big intrusions starting here.
Since 1950, about 50% of Kilaueas supply has erupted, which is pretty crazy really. 1983-2018 was over 90%, it was basically a clean hole in the crust.
The 1993 Kilauea dike did not erupt, though, which was east of Mauna Ulu:
https://www.sciencedirect.com/science/article/abs/pii/S0377027317305425
The 1924 dike is also not known if it erupted or not.
Interesting I wasnt aware of this event being an actual dike, instead of being the connector flaring up (“inflationary intrusion” in old papers).
It also is a bit of a technicality I guess, and I guess its still only 3 out of the total still, which is pretty good odds.
Sometimes intrusions can accumulate towards an eruption. 2020 first there was an intrusion on 2nd December that failed to erupt, but some weeks later on 20th December the successfull second intrusion commenced the first eruption in Kilauea’s summit since 2018.
Eruption history 2020-2023: https://www.usgs.gov/volcanoes/kilauea/science/december-2020-september-2023-kilauea-summit-eruptions
On the first intrusion: https://www.usgs.gov/news/volcano-watch-a-small-notable-magma-intrusion-kilaueas-summit
What you said is exactly what im talking about, that intrusions tend to happen in the same area after an initial often large one.
Update on the Rancho Palos Verdes situation.
On Monday 2nd September the California Governor declared a state of emergency for the area after significant land movement and officials had to cut off power to 245 homes, citing a risk of igniting fires.
https://www.theguardian.com/us-news/article/2024/sep/03/california-power-outages-landslide
From https://www.latimes.com/california/story/2024-08-09/california-landslide-accelerating-residents-fight-back-rancho-palos-verdes (wants you pay them, but luckily found this map on Google images)
Looking on this, it does seem fairly big…
That’s a lot of slip in a small timeframe. Picture it in terms of pipework in houses, exterior walls etc.
It’s actually a good job a lot of these houses are constructed of timber…
However, there are a few that are not-so much constructed from timber that are pretty unlucky. Honestly, it reminds me of how a few conspiracy nuts would think of when San Andreas will sink California into the ocean…
These are the roads affected by the slide. Makes the Grindavik November 2023 dike event look fixable.
And then there is this, I don’t know the importance of this beach, maybe it sunk due to the landslide…
https://www.mbl.is/frettir/innlent/2024/09/03/myndskeid_setti_sig_i_storhaettu_vid_gosopid/
Well, looks like another Darwineer climbed up the volcano yesterday…
(I don’t know what’s with a few people these days, either courageous, idiotic, or both)
RÚV now has an article up on the Bárðarbunga M5.
Quake swarms but no eruption (4 Sep)
Doesn’t say much, but I suspect the public would’ve wanted to know…since a Richter 5 is often the opening pitch of a new ball game. I like the photo they’ve included, Iceland is such a photogenic place!
Oops, sorry the link didn’t work. Try again:
Quake swarms but no eruption (4 Sep)
Is the Iceland fissure eruption over?
It looks like it’s over on the webcams, and the HSO2 4 hr GPS shows the beginning of an upward trend:
.
Hekla: https://www.volcanocafe.org/hekla-of-history-the-1104-eruption/
If I understand it correctly, Hekla began its life as a Rhyolite volcano. Did the first Hekla eruptions cause a volcanic depression (caldera/crater) by explosive eruptions?
I havent ever seen anything about Hekla having a caldera. Its central volcano is Holocene age although the area is active a lot longer based on all the subglacial features.
To be fully honest, a lot of the speculation with Hekla on here has never really sat right with me. Im not convinced it is all that abnirmal, its just that it is the only Icelandic volcano that is in the intermediate stage between a fissure swarm and a defined central volcano. The volcanic system of Vatnafjoll nearby I think is a part of Hekla, magma composition difference isnt an unbroken law defining two different volcanoes, literally Sundhnjukur this year has gone from mildly transitional Fe-Ti basalt to tholeiite basalt. Just means the mantle source is variable. The tectonic setting and the fact the large basaltic eruptions and rhyolite plinian eruptions of old have simultaneously changed to mixed large volume intermediate lava eruptions and small basaltic eruptions is very hard to explain without a connection directly.
The wide area of influence and the large size of Hekla eruptions do siggest it will evolve into a caldera in the future though.whether it will be a mostly rhyolitic caldera like Torfajokull or a mostly basaltic caldera like Katla isnt very clear. Im inclined to the latter more.
During its early eruption history Hekla was mainly an explosive silicic volcano. The explosive eruption must have build a very different shape of the volcano. Only during more recent history Hekla got basaltic andesitic magma and changed to “mixed” explosive-effusive eruptions that built the strato volcano cone.
1104 was the last Rhyolite explosive eruption. Did it leave an explosion crater behind? Or did the silicic eruption fill up explosion craters with lava domes?
Irpsit said there was no indication of any caldera fault in the area. Evidence that there was an early caldera is based only on a study of tephra, I don’t remember where published. Still, big explosions leave big holes! The 1108 eruption would have excavated 1 km3. That is a substantial part of the mountain. It has erupted enough lava to fill the hole since, but much of this was erupted on the flanks and presumably (!) the 1108 explosion was on the summit. The hole could have been filled up by non-erupting magma, possibly in the dikes near the summit that feed the summit rift eruptions.
The magma chamber is deep, that 1 km3 of space could have been distributed over a wide area, possibly even bigger if a lot of basalt rushed in. The subsidence would be obvious in instruments today but not at all visually.
Same thing happened at Kilauea in 2018, the actual collapse at Halemaumau was only about half the volume of lava erupted, the rest was subsidence of mostly the south caldera area but also the middle ERZ. The crater is permanent and needs to fill with lava and did so quickly but the rest fills quietly. When it is filled up again, eruptions will resume and likely on a large scale, the same thing from 1975 to 1982 was terminated by Pu’u O’o starting…
I think Laki might also have been this way at least in part, although Grimsvotn probably did collapse during that rifting sequence too, its hard to see it surviving unscathed.
2018 was effusive, so a different beast. It is hard to see how a big explosion can be sourced from a deep wide chamber. There was certainly major damage to the mountain from the 1108 explosion, but it is now filled in, covered up, or (like a tommy button during pregnancy) pushed out
Im not really sure why it would be any different, the eruption was big but not enormous. Lots if explosive eruptions happen without excavating a big hole, St Helens didnt actually make a collapse caldera but was a VEI 5 separate to the landslide. Ruang just this year did a VEI 5 or close and didnt collapse. More directly the 1947 eruption of Hekla was a VEI 4 and though mostly effusive it wasnt quiet and it didnt leave a big hole.
Its mostly buried now but there is a thick silicic flow on the south side of Hekla from 1058, it probably comes from the sane area as the 1104 eruption. It is much more of a dome than later Hekla eruptions have been but it also looks like it flowed down a slope rather than filled in a hole, lava domes dont form flow ridges unless they flow away from the vent area.
st helens left a big hole in the mountain which is still there. It is conceivable that Hekla 1108 was on the steep flank rather than the top, but the cubic kilometer of rock has to come from somewhere, and Hekla is not that large.
1158 not 1058
Im talking about the plinian eruption after the landslide, that was at least a high VEI 4 to a 5, and that was not related to the volume of the landslide. Again, no collapse caldera or anything. Plinian eruptions are like lava fountains but it is faster, maybe a transition from subsonic to supersonic flow.
The 1 km3 ‘void’ left is dispersed as wide imperceptible subsidence. Tarawera was a VEI 5 as big if not bigger than Hekla in 1104 and it didnt form any particularly big craters by magmatic action, nor destroy the mountain that is a similar size and shape. Dubbi in Eritrea also had done huge eruptions with no collapse, and is actually extremely similar to Hekla in every way. 1861 eruption was a VEI 5 bigger than any eruption Hekla has done historically and it was inbetween two massive basaltic eruptions, the total is at least 3 km3 of lava, and pyroclastic flows 20 km distant even directed blasts reported I read somewhere. And yet there are no big craters on Dubbi at all let alone huge holes in the mountain.
Did the 1108 eruption involve a lava dome activity? Rhyolite can do it, and it would be an activity that could have happened unnoticed by humans. Rhyolite lava domes or flows are able to fill an explosion crater.
Some “normal” Ryholite volcanoes often first to the gasrich explosive eruption before second the lava flow or lava dome can appear on the surface. Did Hekla during the silicic explosive eruptions behave like an ordinary Rhyolite volcano or did it follow its own extraordinary type of volcanism?
Yes, that seemed one possibility: explosion of a large lava dome, blowing the top off the mountain. That would imply that Hekla had a rather different shape before the eruption. It may also have been quite a bit smaller (lower) than it is now.
If it did the direct evudence is gone. But the fact the 1158 lava is a dacite coulee and looks like it flowed down a slope might support that a dome or a cone was created in 1104.
Considering how well known the last century of eruptions at Hekla is the prehistoric stuff is really poorly understood. Most of the lava is basically undated, only with tephra statigraphy that gives huge range. Im personally a little sceptical the major Hekla tephra eruptions are entirely explosive, the area is a rift zone, there is a reasonable logic that the eruptions were bimodal fissure eruptions, especially as the most dense concentration of visible fissures is an extension of Heklugja and there are many craters along it. There are a lot of lava flows around Hekla some very large and a lot of them appear to originate from the area that is underneath the mountain of Hekla now, buried by historical flows. Carl said those flows (“keldnahraun” inland of Hella) are from Vatnafjoll but the only map I have found doesnt show that. And Vatnafjoll is I think a part of Hekla anyway.
A difficulty of Hekla is that the eruptions along the summit ridge are voluminous. They can fill gaps very fast. They happen everywhere along the ridge. It’s possible that pre-historical craters are buried below 100s of meters of lava. We don’t know how large the crater of the 1108 or 1158 explosive eruptions were.
Was Hekla able to do dacite lava flows? Dacite is the most viscous of classical (sub-alkali) magmas. But if Hekla has more hot Dacite, it maybe can behave more effsuvie than Pinatubo or St. Helens.
I agree that Dubbi 1861 is a good model for big explosive Hekla eruptions, since morphologically the two volcanoes are extremely similar and the 1861 eruption left similar deposits, first silicic tephra, then basaltic lava flows.
If Hekla is rhyolitic you’d also have to ask the question if Katla, Eyjafjallajökull, Tindfjallajökull & Torfajökull are. It’s more so about the area of the crust (triple junction) where long lived magma chambers seem to have popped up, not necessarily quite so constantly active as the volcanoes under Vatnajokull, which has allowed the magma to fractionate. We can see with Katla which is in an active period, that most of it’s recent activity is basaltic-andesitic, as there is no long dormant period to allow for anything evolved.
Hekla is the only one to regularly erupt rhyolite, although when it does it is quickly followed by more typical basalt. Other Iceland volcanoes may also produce rhyolite but if they erupt say once per thousand years, we would hardly know.
But Hekla is young. We don’t know what it will be like when it grows up.
Torfajokull is bimodal basalt and rhyolite mostly, although the majority of its surface rocks are rhyolite, basalt is from vents outside the caldera. Tindfjallajokull seems to be the same but it is inactive, theres a strombolian basaltic cone on the caldera rim.
Eyjafjallajokull seems to not really have any magma chamber, it also seems to be really old too like maybe over 2 million years old based on rocks at its base. Maybe the modern volcano is more recent and erupted through an old one. But it kind of erupts everything, 2010 was basalt then andesite, it has rhyolite too.
Katla is mostly basaltic, it has one large rhyolite eruption in the early Holocene, but no rhyolite or anything evolved beyond basalt for a few millennia and theres nothing particularly notable about the size of rhyolite eruptions there only that they stand out a bit, they arent unusually big. Katla might be best considered a pyroclastic shield volcano like Ambrym and Okmok, although its probably been a long time since it did any shield building as such. Katla might be really old too, maybe the caldera there now is just the most recent of many central volcanoes in this particular spot.
Hekla was during its early times rhyolitic. Later rhyolitic eruptions became more rare. But there are supposed magma chambers that still can breed evolved rhyolite.
The normal magma chamber of Hekla – that we usually see in action – contains mixed magma: At the bottom its hot basaltic andesitic magma, but at top of the magma chamber it’s evolved andesite to dacite (like the cream on milk). The eruptions begin explosively and erupt the viscous top magma first, before the hotter and predominantly effusive magma can follow.
Tindfjallajökull (short “Tindfjöll”) has a peak made of Rhyolite Lava Domes. Maybe this shows that also Hekla can do lava domes during Rhyolite eruptions, that are hidden by later lava flows.
It would probably need to sleep for a few centuries to have a big felsic eruption, there probably isnt much down there, unless there are pockets of isolated granite, but its hard to see that. 1970 was 22 years of quiet and mostly effusive.
So I dont think any of us will see a rhyolitic Hekla eruption unless immortality is perfected… 🙂
Askja showed 1876 that isolated pockets of Rhyolite magma can erupt that were ignored during centuries of basaltic eruptions. Hekla may similarly have isolated Rhyolite pockets that usually not erupt, but can surprise in future.
Just as we talked about the region, Torfajökull has had an earthquake swarm today close to the caldera rim. It currently belongs to a line of earthquakes from Arnes of Hekla to Torfajökull. Also close to Prestahnúkur a small swarm.
Askja also is a caldera and an old mature system, and its only had a handful of eruptions that werent basalt in the Holocene and the two biggest were during caldera collapses that were set off by rifting. I cant find it right now but I saw something that the 1875 explosive eruption was not very voluminous just very powerful, probably more due to water interaction than magma composition. Oskjuvatn isnt a maar it is a ‘passive’ caldera like Bardarbunga or Kilauea, just this time a little less passive. Outside of calderas Askja is an effusive basaltic volcano completely, although it is big so eruptions can be intense and voluminous.
Hekla is still at the early fissure stage, the only other possible comparison of a fissure with central volcano status in Iceland is Heiðarspoðar near Myvatn, source of the massive Laxahraun flood lava. But I think that is the south rift of Krafla not a separate entity. However outside Iceland there are lots of friends for Hekla, stratovolcanoes that have built on fissures.
Dubbi in Eritrea, is basically identical, it even looks almost the same, but in 40 C desert not the arctic. And Dubbi also does massive bimodal eruptions without a shallow magma chamber, like Hekla probably did before (maybe even in?) 1104. Theres a few uncertain dated lava flows near Hekla maybe some were from 1104 and missed because everyone left.
Still, I think if a pocket of rhyolite did exist it isnt really going to be important, Heklas normal eruptions are plinian at the start without it, only difference would be some white ash in places. Im not sure it would even form a dome, the lava at Torfajokull doesnt really, it can still flow just not that far. And Hekla already has fluid lava for its composition.
https://phys.org/news/2024-06-reveals-comet-airburst-evidence-years.html
https://www.nytimes.com/2024/03/05/magazine/younger-dryas-impact-hypothesis-comet.html
I had seen that. Nonsense is hard to kill
I thought it was long established (with evidence) that the Dryas was caused by the collapse of ice dams as the last ice age went through its closing years? The giant flood of icy fresh water into the Atlantic (and Pacific) reversed the warming trend for a max of a thousand years or so.
Which still makes me grumpy when poorly researched science says a few icebergs drifting down the Laurentian see, and some Greenland meltwater can cause the same to happen (The Day After Tomorrow, I’m frowning at you…).
Heads off muttering about coriolis force…
The idea of an impact as cause of the Younger Dryas never did make much sense. But once a misconception is around, people try to put all kind of ‘evidence’ on it. And whenever a disaster needs an explanation, sooner or later a comet will be mentioned. After all, they were the ultimate bad omens.
Aaannd we’re off again.
Fun how it’s exactly tracking the lead up the current eruption, which would make the next eruption a Christmas present!
(From IMO’s latest update 5 Sep.)
Except that the length this eruption went, if it goes the other way will go into Grindavik. Actually, it would erupt right in the harbor. Its not a certain outcome, rifts dont always flood the whole initial graben with lava, but the north direction is both uphill and extended less than where Grindavik is, so if it can go that way it seems inevitable it will go south unless the magma supply stops.
And the supply stopping also assumes this is all driven by pressure. If it is instead driven by filling in a gap, then the gap isnt filled under Grindavik, and the magma supply will basically never stop… 🙁
I’d estimate the subjective probability as 50% that the next eruption still happens in 2024 = 50% that the next eruption will begin 2025.
Depends on whether the deep supply rate remains as high as it has been, there was some evidence to suggest it had slowed down slightly. Recovery is going to take minimum 2 months, maximum 4 I’d say.
The diagram posted by Bruce shows that three of the eruptions began when 20 million cubic meters were accumulated: December 2023, May, August. August needed more than 20 millions, and this probably is the minium value for next eruption.
If we sum up all of the intruded magma volume since November, we’ve got > 0.1 km³ (100 million cubic meters) if I don’t do a mathematical mistake. End of October we can get the sum for the annual magma inflow in Svartsengi. Probably something around 0.11-0.12 km³.
Volume of lava erupted by Svartsengi was 0.15 km3 before this eruption. I havent seen a number for this eruptions volume yet but if it is the largest then the total is almost certainly over 0.2 km3 now, and 0.35+ km3 since 2021. Thats only lava too, the intrusion in November was about 0.1 km3 and mayne about that much in total subsequently. And Fagrafalsfjall too. The full total is probably much more than 0.5 km3 since 2021.
For comparison, the Krafla fires was 0.3 km3 of lava in 10 years, although most of that was after 1981. But in only a single year Svartsengi is more than 2/3 of that… And at 0.5 km3 in 4 years that is 0.12 km3 a year, or 4 m3/s, which us actually a bit less than the 4.5 m3/s I have seen showing up so the real number could be even more.
Im increasingly inclined to think this will be a much bigger event than the fires of the middle ages.
The first inflation of Svartsengi began on October 25th 2023. From this we have to wait for October 25th 2024 to get the annual sum of magma inflow.
The Medieval Fires began with Afstapahraun (Krysuvik). If we look at the historical (after 870 AD) Krysuvik lava flows (map layers in Catalogue of Icelandic Volcanoes), Krysuvik’s lavas go the whole way from Hafnafjördurs northern coast to the southern coast of the peninsula. Maybe the first part of the Reykjanes Fires are more extensive than later parts. This time the first serious part begins at Svartsengi and Fagradalsfjall. During the Mediaval Fires the Svartsengi (Eldvörp) eruptions happened very late 1210-1240. It was a different stage than the initial part.
The eruption is over: https://www.ruv.is/frettir/innlent/2024-09-06-goslokum-lyst-yfir-421292
https://www.vedur.is/um-vi/frettir/jardhraeringar-grindavik
The last signs of the eruption near Stori-Skogsfell were noticed yesterday afternoon. The eruption was the third longest of the series (14 days). Calculations by IMO indicate that it was the largest eruption. Renewed heaving (=inflation) of the ground coincides with the end of the eruption.
Interesting how the eruption in 14 days was larger than the March-April eruption in 54 days. It shows that the first days count, not the duration of the eruption.
I seem to remember an estimated eruption rate of 2000-3000 m3/s at the start.
Yes, this could be true. I’m wondering how big the rate at the peak of this eruption cycle will be and when it will be. Will there be a peak of activity or will we get a long period with regular behaviour with constant dormant periods and identical rates at eruption starts?
I just checked. On August 28th, IMO stated the the estimated extrusion rate at the start was 1500-2000 cubic metres and had dropped below 100 cubic metres at the point of writing. They also stated that it was the largest eruption so far and the lava field was 15.1 square metres.
Typo in the units of the lava field ..
It was a very small field 😛
completely unrelated but one would be very curious:
Volcanic beads in the Chang’e-5 soils indicate lunar volcanism is active 120 Ma! Remote sensing found young lunar volcanism (<100 Ma) for years but in debate without samples, this is the 1st time extremely young lunar volcanic products discovered!
https://www.science.org/doi/10.1126/science.adk6635
Many thanks, this is very interesting. Now I must wonder where it came from. I guess I will start looking lunar maps like crazy.
I do wonder if the glasses could come from Olympus Mons in Mars though, since the age would match with that of Olympus activity.
I haven’t seen details of the analysis, but Martian rocks should be identifiable from Lunar ones based on abundances and isotopes. It seems likely that this is from the Moon. But maybe not from this location: impacts tend to throw local material out to far distances, and anything lying on the surface may have come from a large distance away.
some more pictures in these tweets.
https://x.com/YuqiiQian/status/1831870166382383172
Wow, I can’t believe I had never heard about these landforms. It’s the weirdest stuff I’ve seen in a while, I can’t wrap my head around how it formed.
https://jatan.space/ina-irregular-mare-patch/
Topography of Ina, I marked the boundary between the young lava and the old cratered ground. The lava is supposed to be 30 Ma old based on crater counting. It’s a shallow depression 3 kilometers wide and 60 meters deep.
https://quickmap.lroc.asu.edu/layers?camera=1642263.9955%2C152420.8245%2C556804.0752%2C-0.9434%2C-0.0876%2C-0.3198%2C-0.3185%2C-0.0295%2C0.9475%2C60&showTerrain=true&queryOpts=N4XyA&isCesiumEntityDetailsEnabled=true&showCompass=true&trailType=1&wideTrail=true&layers=NrBsFYBoAZIRnpEoAsjYIHYFcA2vIBvAXwF1SiykBmAJjgHYZEERrqAOJhHyHfIgCIATgENMAcwCmggFzAAtOygLaoBhRHjpABVG4pAF0MzZggA7Zh5gwuFSAJgoDOh4QEtzU54LIUS5EA&proj=22
Check out Tycho. It has a similar age. You are looking for a crater (likely) which caused local lava, followed by a later smaller crater which threw out the debris
This would mostly have been caused (or jump started) by an impact event? Just speculating.
Anyone know what is causing the glow circled? Is it old lava glowing?
Source: https://www.youtube.com/watch?v=Hia5Ejq2778
It’s probably smoke glowing from some incandescent lava below it and not directly visible.
Very slow ballet.
Witness 1.8 billion years of tectonic plates dance across Earth’s surface in a new animation (Phys.org, 6 Sep)
https://youtu.be/_LJG68AmZxI
Earthquake swarm at Skjaldbreið shield volcano near Langjökull: https://en.wikipedia.org/wiki/Skjaldbrei%C3%B0ur
https://volcano.si.edu/gallery/ShowImage.cfm?photo=GVP-05768
There were quakes in this same spot here earlier in the year or late last year too. Its probably tectonic but the orientation is correct for it to be a dike or that one could form here in the future.
Seems like potentially this whole part of Iceland might be about to move. Þingvellir and Langjokull arent the primary plate boundary but some of the spreading dies take place through there, and it has been around 235 years since the last movement. Þingvellir spreads around 4mm a year, so we are due about a meter of rifting there now and only more going forward. Its also been about 1000 years since any eruption around Langjokull, and the last one was concurrent with the Reykjanes eruptions last time as well as Ljosufjoll that is also waking up.
It is also notable, the last eruption at Langjokull was around the same time as Vatnaoldur and Eldgja, and both when Reykjanes was last active and not long before Hekla became highly active, so a lot of novement along the primary plate boundary. The last time Þingvellir rifted in the late 18th century was not long after Laki, it probably isnt unrelated. There was no magma cycle at Reykjanes in that time but an eruption still happened out at sea on the ridge, and presumably a dike started from Hengill or Brennisteinsfjoll, or maybe even north of the lake, though the supply wasnt sustained into eruptions.
But now it us clear there is a lot of magma available, if the area does rift in future it probably wont stay underground. At the same time Hekla might be close, and Torfajokull is inflating, and so is Hamarinn south of Bardarbunga, between them is Veidivotn. So that area seems quite likely to rift in the coming decades and bring a major event. And Reykjanes is already in full swing as we speak and likely will be for the rest of our lives.
Western volcanic zone to me really is more interesting than Vatnajokull area, its kind of mysterious. Snaefellsness too, its the part of Iceland that seems to be firgotten and like it was already made not is being made now like at Vatnajokull, and eruptions there are quite different to historical eruptions at Vatnajokull too, shield volcanoes and cindercones with tall fountains. That both of these forgotten areas might plausibly erupt quite soon is exiting. If an Icelandic Pu’u O’o started in a not hazardous spot that could be a huge tourism boom 🙂
The earthquake swarm is either a lifesign that there is a living volcano or something like the 2000-2020 quakes on the Reykjanes Peninsula. Volcanism there is related to tectonic rifting, because the diverting plates invite magma to come up and fill the gap.
It is – from human perspective – a bit random which neighbouring part of Iceland participates in over-average activity during the Reykjanes Fires. It can be something on SB system or WVZ or Katla. After the 900 start of the Reykjanes Fires (Afstapahraun) there were eruptions both on Katla, Losfjöll (Snaefjellsness belt) and Langjökull (WVZ) during 10th century. Hundred years are long. If all of this would happen on the same timetable during 21st century, we would miss most personally.
Think the quakes are most likely tectonic and are occurring across Iceland. The crust may be accommodating the ending of the latest eruption on the Reykjanes Peninsula. That is not to say that there isn’t any associated magma movement as part of the process.
Something similar happened after the other recent eruptions. It looks bigger this time but that is from memory; I could be wrong.
Forgot to mention, there may be independent magma movement as well.
I guess its a bit of a mystery what sort of volcano Langjokull is. There are two central complexes that have evolved rocks, long dikes and rifts, and maybe a caldera. But there are no eruptions near it that are long fast fissure eruptions, all the eruptions in the Holocene are either shields or slow fissure eruptions (‘wandering eruptions’) that are fed from deep sources, not from dikes in the crust over long distances that need pressure to stay open. That is probably why Holuhraun stopped pretty quickly, and the recent vent just now too, after being at low but stable activity for a while.
If I had to guess, Langjokull isnt a central volcano anymore, those are dead or inactive but the deep system is voluminous, leading to rare massive eruptions. If the rift was more active there might be flood lavas, but the rifting is very low at the glacier. At Hengill and Þingvellir rifting is faster and there are actually fast flood lavas, although Hengill is much smaller and eruptions there are a lot smaller than at Langjokull.
Langjökull prefers to do fissure swarm eruptions (15-17 in Holocene) over central volcano eruptions (two in Holocene). Many eruptions were longterm slow shield eruptions close to Fagradalsfjall’s eruption rate (5-10m³/sec), but over a span of 40 to 80 years.
On Reykjanes Peninsula the volcanic systems have no visible central volcano, only a fissure swarm.
On EVZ many volcanoes have a dominante central volcano and a relatively seldom active fissure swarm.
Langjökull prefers less central volcano activiy than EVZ, but more than Reykjanes Peninsula. So it looks like a medium volcano between both types.
More what I mean is that I think the central volcanoes are inactive, meaning eruptions are from the deep magma system directly and not specific to one of the old central complexes. So like at Reykjanes but far apart and big. I would argue Svartsengi is more of a central volcano than Langjokull actually, because it stores magma in the upper crust right now. Krysuvik also does this presumably when it is active, and so does Hengill. The last also has some evolved rocks too, but it has only done basaltic fissure eruptions in the Holocene so I think it isnt a true central volcano presently, no more than Krysuvik and Svartsengi are.
I guess then, the only likely active central volcano in western Iceland right now is Snaefellsjokull, the rest are various forms of basaltic fissure swarm and monogenetic eruptions.
I don’t know the distant past of Langjökull. Did it have a longterm development with changing behaviour? During Holocene it only did two central eruptions. But I can’t exclude, that during Pleistocene or Neogene there was different behaviour.
Contrary to this the Reykjanes Peninsula probably always followed the same pattern with fissure swarm eruptions without a visible central volcano (only a temporarily one).
Prestahnúkur even had no Holocene eruption at the central volcano. The central volcano there has a 60,000 years old rhyolite peak (dome?).
Would be nice to get another interferogram of Kilauea. The summit isnt inflating anymore but the constant background quakes are at levels similar to before and go down to the middle ERZ.
Only problem is the tiltmeters on the ERZ arent really set up well to detect uplift there, they are on the rift axis so if magma is under them it looks like nothing. That might actually be why Pu’u O’o isnt doing anything now, the magma has gone past it.
Abd all the GPS plots are frozen now for a while, it might be from ongoing maintenence or upgrades to the system but its still leaving a lot unanswered and the updates never really say much if an eruption or intrusion isnt ongoing.
Without any more info, and based on the GPS at RKAR east of Pu’u O’o looking like it might have started noving, it looks like pretty much all of Kilaueas supply is going into the middle ERZ now, and it is doing so with no resistance. It might take a while to fill, maybe the rest of the year with nit much change from how it looks today. But when the summit starts uplifting that is the sign we get a Pu’u O’o 2.0 within a few months. But all this night be outdated very soon too.
The Bulletin Reports allow to follow the development 1982-1983: https://volcano.si.edu/volcano.cfm?vn=332010#bgvn_198211
December 1982: Shallow earthquake swarm in the summit region. “Epicenters soon migrated into the upper E rift, to the vicinity of Lua Manu and Kokoolau Craters (1.4-3.2 km from the caldera rim). […] Total deflation was about 5 µrad, suggesting that 2 x 106 m3 of magma from the summit chamber was intruded into the E Rift.”
Observations January 1983: “In the weeks prior to the eruption seismographs recorded increasing rates of microearthquakes in the E rift zone.” On 2nd January a significant earthquake swarm with weak tremor. “The swarm started in the upper E rift near Mauna Ulu, increased in the early hours and migrated downrift about 9 km to Napau Crater […] spread farther downrift to beyond Pu’u Kamoamoa […] until the eruptive outbreak small earthquakes accompanied by harmonic tremor occurred at a nearly constant rate, mainly along a zone between Napau Crater and Pu’u Kamoamoa”
Significant seismicity only lasted one day (2nd January) until the eruption. This shows that we (and HVO) likely only have one day to be alerted for the upcoming eruption.
I plotted the Pu’u O’o intrusion on the IRIS map, the dike that erupted started at napau, the part west of there was the ERZ connector flaring up as it does before most events. I dont think HVO back then and maybe still today actually distinguishes the ERZ connector (or SWRZ connector) flaring up as a different sort of thing. So actually the intrusion likely only takes a few hours really, the eruption rates along the initial fissure at Pu’u O’o were very high, lava flowed 5 km in an hour from one vent at the eastern end. And a similar eruption in 1986 sent a narrow flow 8 km in under 3 hours…
It is also my expectation that the next sustained eruption will be east of Pu’u O’o. Mauna Ulu started when the floor of Halemaumau was at its highest since it was a lava lake, it was like 1100 meters, it lowered in 1971 with that years eruption there. But Mauna Ulu started off at about 930 meters. Pu’u O’o started at 730 meters and Halemaumau was 1050 meters elevation. Mauna Ulu ended when it became taller than most of the caldera floor. Pu’u O’o ended when the lava lake in Halemaumau started overflowing at about the same elevation as above. Now the floor of Halemaumau is 950 meters elevation, it is lower, but clearly it is too much pressure to erupt there now so presumably there is an easier spot. We know the ERZ is moving east of Pu’u O’o, and the land is much lower there, 500 meters elevation at JOKA, if that station starts rising then gravity will rule all, even if eruptions happen further west (likely) pressure will still not really reduce enough. Pu’u O’o itself probably will force this, it has elevated about 10 km of the middle ERZ about 60+ meters higher than it was 50 years ago.
The elevation of 1983 Pu’u O’o is now about where the 1977 vents and eruption was. Only other place might be the bottom of Makaopuhi but an eruption there would make a lava lake and drown itself out, instead of evolving into a shield. or make a huge lava lake that would probably later drain downslope east anyway…
If I remember the 18th century lava flow map, there many eruptions happened in the Pu’u O’o area, but on different locations. Maybe we get eruptions like this on varying places. If we look both at volume and frequency, this part of ERZ is the main part, a lot more active than Mauna Ulu area. So it’s possible that an eruption happens east=below Pu’u O’o, but that the eruptions won’t stay there all the time.
If we look at the GPS 10 yeras timescale, we see that the southern flank (AHUP and MANE stations) have recovered the whole loss of 2018. MANE is even 5cm higher than 2018. Maybe this shows the strong inflow of magma to Kilauea’s system 2024. Isn’t a central feeder below Koa’e fault?
Problem is that the 18th century lava only shows the last eruptions, using that logic now would mean we basically dont know that most of the 1960s eruptions ever happened. I think probably there were a lot more eruptions that happened and that many fissures were active more than once and repeatedly buried the area. That us something which historically has been ignored but it is really obvious now, many fissure eruptions are kind of polygenetic for a short time, Sundhnjukur now showing this. Laki was a bit like it too, and so was Kilauea in 2018, vents dying down but not completely and then erupting again. Not all are though, Holuhraun was only really one eruption. But then there are also truely polygenetic fissure volcanoes, like Hekla, and probably also Mauna Loa as it behaves now too.
Basically though, eruptions on Kilauea apart from low down dont tend to go their biggest immediately, 1961 was mostly intrusive, but 1965 in the same spot was quite voluminous, similar size to last eruption of Sundhnjukur actually… The big flows from the 18th century were a lot bigger than 1965, maybe not huge volume but very intense and extensive.
My assumption really is the activity was moving east. Maybe Heiheiahulu was after a big quake that opened the ERZ low down, and before that was mostly middle ERZ at Napau, although not forming a shield that time. I have mostly refrained from actually assigning a timeline, just that most activity west of Heiheiahulu is probably older than 1750.
Im also not sure what exactly is below the Koa’e area, it is probably deep rift and intrusive complex. The fact the caldera is where it is and offset from the rifts is probably reason enough to assume the main magma path is there, but the deep magma chamber is a bit south of the actual visible caldera too so it is a little complicated.
If I had to guess then the Kulanaokuaiki fault is probably the southern edge of the deep magma system, but it isnt above any of the shallow part that erupts. However it could be at times, and maybe was back when the Pahala ash and Hilina basalts were formed, because those eruptions were a lot bigger than eruptions at the summit today. Kilauea is a pretty mysterious volcano still,we know pretty much exactly what it has done for 100 years but I dont think we know anything really before 1000 years ago, it definitely hasnt just been its recent self since forming, and it could be very different in the 21st century than it was in the 20th.
“Not all are though, Holuhraun was only really one eruption.”
Yes, the 2014-2015 eruption was a single event, but it did erupt through the fissure row of the pre-existing Holuhraun lava field. Very similar to how the current eruptions at Reykjanes happen at the old Sundhnúkur crater rows.
Yes I forgot to add that part. Theres also a proper actual flood lava (Kreppuhraun, or something like that) which flows down the river down even past Herdubreid, it is buried in sediment but most likely erupted from the Holuhraun fissure area too. Its like 6000 years old, so the rift is quite old, far from a recent invasion of Askja by Bardarbunga.
It would be interesting to try to find why some rifts have only a single and often isolated eruption while others have many, often growing in intensity. There isnt anything I can think of that is actually very consistent. Kilauea even does both of these styles somewhat arbitrarily…
Magma dikes in the Holuhraun region can’t easily go any further for topographical reasons, so they will tend to erupt here. So it is not unexpected that the region has had multiple eruptions.
Something I have wondered, Holuhraun is lower, yet there are more confirmed recent eruptions there than in the more obvious part of the rift to the west. Only one historical eruption there is given as certainty but not a date though, the eruption of Frambruni north of Trolladyngja, which was between 1100 and 1400. It was a big eruption similar scale to Holuhraun and probably with higher peak intensity and a rather larger volume of over 3 km3, it might actually be the biggest volume of magma Bardarbunga has erupted historically. It also lasted about a year if it was similar intensity to Holuhraun so I dont know how it was missed exactly, unless it was most intense over winter and slowed a lot by the time it could have been safely seen.
Problem is there is literally no erosion up there outside the glacier, all the lava looks really new, old stuff is just buried in sediment more. The bedrock must be pretty hard, or it doesnt rain enough, snowing instead maybe.
Or the lava really is as young as it looks, so we should get something soon, an eruption just southwest or northeast of Bardarbunga something that is maybe 1/10 the volume of Holuhraun, that is much more likely than a big eruption.
https://eartharxiv.org/repository/view/7656/
Hectors new own geology research have been posted, very strange but edivence based in reality and he have collected the data and done the chemistry and the other complicated stuff, the genesis of alkaline magmas may be of huge intrest here
The solar cycle effect on extreme hail events fits with the CERN Cloud project data.
At the height of the solar cycle there’re fewer high energy ionizing particles hitting the atmosphere since the terrestrial magnetic field is compressed by the more active solar magnetic field. The high energy particles get stuck in the compressed magnetic field. Thus there’s less nucleation in the high troposphere and those nuclei which do form have an increased chance to accrete more supersaturated moisture. Thus they get bigger than during solar minima – when there’re a larger concentration of nuclei, which then form smaller hail since they’re stripping the moisture out of the convection column over more and smaller hailstones.
At least that what it sounds like to me anyway. 😀
Thanks. The pattern is complex, the hail >=6 cm in Spain has a clear peak in the middle of solar cycles. >3 cm hail in Spanish province capitals instead peaks through the whole second half of the SC, as is also true for Sep-Oct rain in Mediterranean in a Gerona station I checked today (data from https://www.ncei.noaa.gov/access/past-weather, I hope to check others at some point), I think applies to major hurricanes too from what I’ve seen on internet posts, and inflation rates in intraplate volcanoes if SC23 is representative (enhanced activity in 2003-2007 spans nearly the whole second half of SC23):
https://ibb.co/vDcR2GK
This matches with the solar wind dynamic pressure peak which is stronger in the second half of SCs, and I think that makes sense with the hypothesis presented in the work. >=400 g hail may have been a poor choice to defend the idea, now that I think more about it, although I partly chose it so that a brief list at the end of preprint could include all the data used.
I’d prefer to discuss anything regarding this on the VC Bar though.
In some cases volcanoes can cause river tsunamis. A famous example is the Laacher See eruption that built a volcanic dam (a temporary 140km² lake) in the Rhine valley. After the dam failed, a “river tsunami” flooded the whole river until Rotterdam.
For events like this, a volcanic debris flow has to block a major river. Can also lava flows, that enter a river, do this? 2014 I tried to watch for rivers blocked by Holohraun’s lava flows, but they likely were too minor to cause any significant “river tsunami”.
It happens a lot at volcanic fields in western North America, seems like nearly all of them have lakes made by lava dams, including in the Grand Canyon. Although obviously the dams didnt fail in these cases.
Maybe lava is too resistant to fail so the dam is just passively eroded by overflow or it doesnt fail at all most of the time. Ash is just sand really, if it isnt altered it wont be very solid. Best examples I have seen of volcano related floods are of calderas filling with a lake that then breaches, which happened at Okmok in Alaska within the last 2000 years. It also happened in New Zealand after the eruption at Tarawera, in the 1910s I think. Taupo also breached a dam and flooded a big area too. The little lake at Grimsvotn draining is quite tiny compared to some of these, really. Im sure there are many more examples.
Iceland does the Jökulhlaup version of river tsunamis. Katla 1918 and Gjálp 1996 with massive floods, maybe also with some impact on the local sea.
As I read about Gjálp, I’ve noticed that there was basaltic andesitic magma, different to both Bardarbunga and Grimsvötn. Perhaps Gjálp is a different volcano?
Grimsvotn has 3 calderas, one is active directly and is where most eruptions are but I think one of the others might be the source of the magma for Gjalp. There have been eruptions at Gjalp before 1996, back in 1934 I think, maybe other times too. I dont know if those were basaltic andesite though. The northernmost caldera of Grimsvotn is pretty much right next to the southern part of Gjalp.
But it isnt a new volcano, just a flank vent of Grimsvotn. Maybe it will one day form a tuya, it was pretty close to becoming subaerial in 1996 and if eruptions here are 50-100 years apart a lot of Vatnajokull might have melted by the next time. Probably make a line of lava fountains maybe up to 1 km high above the ice, something like Etna but as a fissure eruption. I imagine the area immediately adjacent to Bardarbunga and Grimsvotn will see some big lava eruptions in deglaciation, probably some shield eruptions and maybe fast fissures of large scale. Will probably look a lot like the land just north of Askja.
Another jökulhlaup started next to Mýrdalsjökull, the third this summer now. Does everyone think they are continuations of the same event, related to global warming, or Katla warming up nicely?
Katla has registered 242 earthquakes Mag 2.0+ over the past year, it is a bit restless but there’s also the usual glacier-calving/northern hemisphere summer melting activity going on which stirs things up a bit too.
Eyjafjallajökull was showing activity for a decade or two before 2010 so probably nothing imminent.
Ok, that’s interesting. I guess we can only see what happens, 242 M2+ seems a huge number, but perhaps Katla has always been restless.
New post up! The anti-tsunami
https://www.volcanocafe.org/the-aral-sea/