It is a truth universally acknowledged that any Icelandic volcano in possession of magma must be in want of an eruption. However little known the feelings and innards of such a volcano may be, any volcano in the neighbourhood, no matter how inactive looking, is considered the rightful property of VC. What a fine thing for our readers and commenters!
But volcanoes are not to be trifled with. Who would have thought that Fagradalsfjall, an ancient and eroded plateau on a peninsula that had not erupted for 800 years, would do this? That the shades of Reykjanes would be thus polluted? And that the eruption would occupy not the plateau but a small hill within a central valley? And that it would become a major tourist attraction? (That was actually predictable, in hindsight.) Most surprising perhaps, to all but the Icelanders and the Dutch, is that the love-hate relation would develop into a dam building exercise by the Icelanders which turned parts of their country into deep polders within seas of lava. In Iceland’s dispute between people’s pride and volcanoes’ prejudice, and in spite of some set-backs (Laki comes to mind), the people remain ahead.
As volcanoes have no compassion for poor nerves, IMO provides them with a request to provide adequate warning, an admonition paid no regard only by Hekla, leaving IMO most seriously displeased. The Eyjafjallajökull eruption of 2010 was a proper pre-advertised event. There were four weeks of warnings (and in hindsight, almost a year), followed by a small and brief fissure eruption, complete with 200-meter tall lava fountains. So far, so good and on an Icelandic scale hardly worth mentioning.
25 days later the eruption resumed and this time it did not go to plan. It wasn’t really the fault of the volcano. All it did was a medium-size explosion. But it became a VEI-4 eruption (0.18 km3 dense-rock-equivalent) which closed Atlantic and European airspace for 6 days. Whereas the first fissure eruption was out in the open, the second event (14 April 2010) was underneath a glacier. And that made a major difference.
In hindsight, three things happened together to make the eruption so impactful. The first one was that the eruption melted the glacier, and rather than flowing away, the meltwater collected in the crater. The eruption became phreatomagmatic, the melt water vaporised, and water vapour takes up a thousand times for volume than the water – hence the powerful explosion. The second thing was that vaporising water takes up a lot of heat. The ash cooled instantly and became as sharp and abrasive as Lady Catherine – not the kind of ash you want inside your jet engine. The third thing is that the 9-km tall explosion column reached the jet stream – and this was in a state where it happily transported the ash at high speed towards Western Europe, in various directions, covering all the major air routes in the region. Not quite knowing where and when the ash could turn up, there was little choice but to stop flying; many airports were closed and re-opened and re-closed repeatedly. The two European countries least affected by the ash were Portugal – and Iceland!
The jet-stream driven ash plume of Eyjafjallajökull
Not all things glacial were bad. Eyjafjallajökull is a known fluoride hazard: previous eruptions have led to deaths among animals from grazing the ash-covered vegetation. The 2010 eruption avoided this, probably because at the lower temperature of the phreato-magmatic phase, fluoride does not attach to the ash surface as efficiently. The subsequent magmatic eruptions did contain fluorides but these eruptions were much smaller.
Eyjafjallajökull showed us the need for much better mapping of volcanic ash clouds. But there was another lesson: glaciers and volcanoes are like the proverbial ice and fire. They amplify each other’s impact. Think Baked Alaska, or the Asian version Flame on the Iceberg.
Flame on the Iceberg, a Hong Kong dessert in the style of Baked Alaska
Iceland has several glaciers which overlie active volcanoes: Vatnajökull (covering Grimsvotn and Bardarbunga, amongst others), Mýrdalsjökull (Katla and Eyjafjallajökull). There are several more which cover less active or (perhaps) extinct volcanoes. Mýrdalsjökull with Katla is considered the most dangerous. It hasn’t suffered significant eruptions for over a century, but it is not to be trusted. This is a high-risk volcano-glacier which could put Eyjafjallajökull to shame.
Risks
But what are the risks such a combination entails? Can it do more than create abrasive, high altitude ash clouds? This post will tell. It closely follows a paper by Barr et al, Volcanic impacts on modern glaciers: A global synthesis, published in 2018.
A tour of Iceland quickly reveals the risks. The region southwest of Öræfajökull was once a fertile plain, with twenty or more farms and several churches called Litla-Hérað . To the southeast was another wealthy region; the landscape was prairie-like. But in the eruption of 1362, it was destroyed and lay fallow for 40 years. The region never fully recovered: parts remain a sand desert even today. One of the causes of this were the massive jökulhlaups which variously removed and covered the fertile soil. It was not the only cause: the massive ash layers from the 10km3 eruption did not help (and gave ammunition to the floods). We have posted on this ancient disaster before.
Glaciers can turn an eruption into a disaster. But eruptions can turn a glacier into a catastrophe. Volcanoes and glaciers affect each other.
Location
Why do volcanoes and glaciers so often go together? There is an obvious reason: volcanoes can grow tall and are often the largest, stand-out mountain in the region. The height means low temperatures near the summit, and the isolation provides a focal point for orographic precipitation from the air rising up against the cone. Enough precipitation at low enough temperatures causes glaciers to form. In Iceland, the best conditions are found near the south coast where the volcanic bulges of Vatnajökull and Mýrdalsjökull provide the height, and the winds from the south bring the moisture. Öræfajökull, at the edge of Vatnajökull, has the highest amount of snowfall in Iceland. In the north of Iceland, glaciers are much less common, not only because the volcanoes are not as tall but also because the north is drier.
Glaciated volcanoes are found in many places. The Pacific coast of Alaska, Canada and the US has many. So does Chile. In between, glaciated volcanoes do exist but are less common because the climate is a bit too warm and dry. But even Equador has some, most notably on Cotopaxi. Mexico has three: Pico de Orizaba, Iztaccíhuatl and of course its connected twin Popocatépetl. The Aleutian islands have several glaciated volcanoes, although there are also many without. The image below shows Umnak Island with the (patchy) glaciers of Mount Vsevidof (2100 meters) but the non-glaciated Okmok caldera (1000 meters). Height matters.
There are many glaciers on Kamchatka’s volcanoes, not surprisingly giving the local climate. But the Pacific Ring of Fire then has a large gap of volcanic glaciers until Mount Ruapehu, 2800 meters, on New Zealand’s North Island. (Japan has 7 known small glaciers on Mount Shirouma, but the mountain is not volcanic.) Elsewhere, Iceland has already been mentioned, and its volcanic glaciers are supplemented by Beerenberg on Jan Mayen.
Finally, the volcanoes of the Caucasus (Elbrus, Kazbek) should be mentioned. And of course the final mention should be of this most contradictory of examples, Africa’s Kilimanjaro. But if you want to experience its glaciers, haste is recommended because their remnants are melting rapidly. Whilst Cotopaxi is four times closer to the equator than Kilimanjaro and is 2 meters(!) taller, Kilimanjaro retains the ‘wow’ factor.
This list is not exhaustive, but it shows where to look for glaciated volcanoes.
An incomplete overview of glaciated, active volcanoes. Source: I. Barr et al., Earth-Science Reviews, 182, 186 (2018)
A definition of what counts as a glacier may be useful. It is not just a snow field that can survives the summer sun. To be a glacier, it also has to flow. The glaciers in Japan were originally classified as snow fields, before they were found to move by tens of meters over the year. Strictly speaking, Antarctica and Greenland have ice sheets (or ice caps), which form glaciers where they flow through the mountains. Therefore, an ice-covered volcano deep down in Antarctica is not strictly speaking a ‘glaciated’ volcano – but this quickly becomes semantics.
What does a volcano do to a glacier? What is the effect?
Cauldrons
Volcanoes are very good at producing heat and may do so even when not erupting. Ice and heat don’t go together too well: the heat melts the ice from below and the water forms a lake underneath the ice. Once this lake begins to drain (typically when it gets so large that it physically lifts the ice barrier), the ice above is no longer supported well and begins to sink. A sink hole in a glacier may be the second indication of volcanic activity, the first being the melt water coming out from the glacier.
A good example comes from the Skaftá cauldrons on Vatnajökull. There are two, called the eastern and the western cauldron. The eastern one was discovered in 1938. The western one did not exist at that time but was first seen in the 1960’s. Their meltwater lakes cause jökulhlaups in the Skaftá river: from the volume of these, the geothermal area below the cauldrons is found to be among the most powerful in Iceland, similar in power to Grimsvötn.
The eastern Skaftá cauldron, viewed a week after the 2015 jökulhlaup. The depth of the cauldron reached about 100 meter. The concentric crevasses are typical: they come from ice falling back into the hole. Source: Eyjólfur Magnússon et al. 2021
The melt can affect the glacier in different ways. If a sufficient amount of ice melts, then the glacier may stall, retreat (as seen at Volcán Iztaccíhuatl) or (in rare cases) could even disappear. More common is the opposite effect: as melt water gets underneath the glacier, it acts as a lubricant and the glacier accelerates. This causes the glacier to advance. It can happen after earthquakes, if existing meltwater becomes released through new cracks (as happened at Mount Wrangell after the 1964 Alaska mega-earthquake) but is often caused by volcanic heat.
Several volcanoes have shown acceleration months or years before an eruption. An example is Volcán Michinmahuida in Chile where glaciers showed sudden advances in the year before the 2008 eruption of nearby Volcán Chaitén. (In this case, tephra fall on the glacier may have added to the acceleration.) Mount Kazbek is also an example of this effect. However, it is difficult to establish geothermal melt as the main cause of each advance. The evidence for the cause-and-effect is often indirect. An indication of volcanic heat as the cause is that the movement is not seasonal, as is the case when the advance comes from summer melt.
Ice domes
Volcanic activity can result in the growth of lava domes. If this happens underneath a glacier, then the ice can also deform. This was seen at St Helens (in hindsight) before the 1980 eruption, and again (after the glacier re-established itself) around 2005.
The lava dome may end up sticking out above the ice. There are few cases known of this, but it happened at Great Sitkin in 1945.
Destruction
An eruption underneath the ice can be devastating to a glacier. It is very common because so many volcanoes are covered by glaciers: the effects are well known. At Eyjafjallajökull, a large crater formed within the glacier which destroyed about 10% of the ice in the caldera. This was in effect an oversized cauldron, with no ice left in the centre, a cauldron worthy of Edgar Allen Poe. It did not form the concentric ice rings as were seen at the Skaftá cauldrons, because the ice was not thick enough for this: such rings have been found at Volcán Hudson.
Instead of a crater, a fissure may form in the ice. This may show the path of the melt water. These fissure can be a kilometer or more long. A glacier can also fracture. Fractures are prone to further erosion, and can form pinnacles of ice, vaguely similar to the penitentes seen in snow on Mount Rainier. After the 1953 eruption of Mount Spurr, it was reported that “The southern flank of the continuous ice rim was partly breached, with castellated ice pinnacles standing in sharp relief within the breached zone” (Juhle and Courter 1995).
An extreme case of destruction is glacier beheading. This happens when the feed area for a glacier is destroyed, leaving a glacier without its head. Because the formation region of a glacier tends to be close to the summit, this is not unusual. A prime example is the Novarupta eruption of 1912, when the entire summit of Mount Katmai collapsed into a caldera, with two glaciers losing their heads. Over time (decades), such glaciers will thin and may disappear. The tail end of glaciers may also suffer destruction, but this is rare since the chance of an eruption happening there is much smaller. It has been seen at Klyuchevskoy 1987.
The complete destruction of a glacier by an eruption is exceptional. This has only been seen at St Helens.
Similar to geothermal melt, an eruption can cause a glacier to advance because of meltwater lubrication. This again is fairly common. Glaciers at Klyuchevskoy advanced after eruptions in 1953, 1980 and 2010. The advance ceases after a few years, and over time the glacier (if undamaged) will return to its previous location, awaiting the next eruption.
Mount Katmai. The formation of the caldera in 1912 removed the feeding zone of two of its glaciers. Source: US National Park Service
Lava
Lava and ice are like Darcy and Elizabeth, a conflict waiting to happen. But surprisingly, the two can co-exist and even get along. Lava flowing below ice causes melt, which can be explosive and can create deep channels in the glacier. In other cases deep depressions form but the lava remains hidden below the ice, perhaps because the lava flows in a lava tube.
Lava can also flow (surprisingly) on top of the ice. This sounds like a recipe for disaster but the combination survives remarkably well. The lava can flow for a kilometer or more, as was seen for instance at Beerenberg in the 1970 eruption. There is melt – that is inevitable – and a channel forms that can be tens of meters deep. Lava can even pond on the glacier. What is protecting the ice, apart from avoiding cases with high lava flow rates? There are three possibilities. The first is a tephra fall (or other debris) from the eruption, with the lava flowing on this. But when the lava stands out against the white glacier, the glacier is clearly not covered by tephra. The second possible shield is snow. Snow is very good at insulation due to its porous structure. A deep snow field can protect the ice below well. The third shield is the lava itself. When it solidifies, it can become a good insulator and so the bottom of the lava flow becomes a solid shield over which the lava flows, away from the snow. This may be even more effective if it solidifies in the presence of water (ice/snow) which gives rise to pumice – with lots of pores which stops the heat from flowing across. Who knew.
There are some spectacular images of lava on snow fields in Iceland. I have not found anything similar for glaciers: lava on glaciers is seen mainly from satellite images (Beerenberg, Mount Melbourne).
Lava flowing over snow in Iceland. Source: Jeroen Van Nieuwenhove
The 2012–13 eruption at Tolbachik volcano, with lava flowing on snow, and flowing below snow. Source: Edwards et al. 2014
Pyroclastics density currents
Amazingly, pyroclastic flows can be more destructive to glaciers than lava. They can scour deep channels into a glacier, sometimes down to the bedrock. Mount Redoubt scoured a section of Drift Glacier to bedrock during the 1966 eruption and again in 1990, effectively separating the glacier from is head twice. This effect is strongest on the steep, upper parts of glaciers. On the shallower lower part of the valleys (the piedmont part) the pyroclastic density currents incise channels but don’t scour as deep: this happened on the Drift Glacier (him again) in 2009.
PDC channels incised on the Drift glacier in 2009. Source: Barr et al.
Tephra
Volcanic eruptions have a tendency to deposit tephra, and being nearby, this can affect in particular any glaciers on a volcano. What does this do a glacier?
In most cases, not a lot! If the tephra is hot, it will melt some ice. If it is thin (and basaltic, i.e. black), it will later absorb sunlight, and begin to melt the ice below, at least until it becomes covered in snow. If it is thick, it will instead insulate the ice. In most cases, the tephra becomes a dark layer embedded in the glacial ice. There may be several to many such layers in the glacier, one for each eruption. They can often be recognized decades to centuries later, looking delightful like a yummy frozen desert. Baked Iceland, anyone?
Tephra layers from Katla and Eyjafjallajökull embedded in glacial ice
Lahars and jökulhlaups
Early in the post, the damage caused by jökulhlaups was mentioned. This is in effect an indirect result, where the volcano affects the glacier and the glacier in return threatens its surroundings. Perhaps another post, another day.
For now, let’s celebrate the resilience of ice against the pride and prejudice of fire.
Albert, September 2026
(With apologies to Jane Austen: any similarity to her Pride and Prejudice is entirely intentional. The book was published two years before Tambora and Austen died in the dark and cold years that followed the eruption, so a certain volcanic connection is not to be dismissed.)
Fire and Ice
Some say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favour fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.
(Robert Frost)
Nice piece with beautiful poem by Robert Frost.
This might be pretty unique to watch: A new glacier on the crater rim of Mount St. Helens, being born after 1980:
https://en.wikipedia.org/wiki/Crater_Glacier
Maybe glaciers need good soil like coffee does.
Robert Frost’ poem is a dark one, with both desire (fire) and hate (ice) destroying the world. That was in the 1920’s. Now we are in 2020’s and history repeats.
In 2011, during the icelandic volcanoes hype, Grimsvotn erupted. No cameras were available at the site. But I was watching Jokulsalron on one of the Mila cams. Suddenly, a dark cloud showed on the background. For a while, the beutiful chunks of blue white ice were imersed in darkness. Once it cleared up, there were no more pristine white icebergs, but black boulders as if they had been painted black I remember Mike Ross commenting “This is the true thing”. We are watching Grimsvotn’s ashes. A scene never to be forgotten. Cheers!
Jealous
Fourpeaked Mountain and Glacier, Katmai-NP, Alaska, pic found on wikipedia, originally from USGS though:
Considered dangerous:
The most deadly (Nevado del Ruiz, 1985) and the most costly (Eyjafjallajökull, 2010) eruptions of the last 100 years were both glaciovolcanic.
https://www.sciencedirect.com/science/article/abs/pii/S0377027316303298
245 Holocene volcanoes have glaciers (2584 total) with a 5 km radius.
https://www.sciencedirect.com/science/article/abs/pii/S0921818120302472
This is likely similar to hot sillicate lava flowing over sulfur snow on Io s surface
Like.
Thanks Albert!
Another possible indirect result added to Jökulhlaups and Lahars, but coming from icy stuff, are mudflows caused by melting Rockglaciers. Not very common I guess, in the Andes exist rockglaciers on volcanoes I read. The results might be minor though.
Active rockglacier near the Bliggspitze, Kaunergrat/Austria.
I have seen it at Mount Rainier, although not at the level of your picture!
I believe it is Bliggspitze, here in the middle:
It has several Ferners (glaciers). This might be Bliggferner which is known to slide down with rocks involved since ~ 20 years ago.
The whole chain is facing south, and it is hot and dry there in summer. In winter there is skiing. In case you want to see it well, you best come down Timmelsjoch, mountain pass, and then take to Reschenpass and go up Kaunertal which is no mountain pass, so you have to turn around. Nice walks everywhere.
I think the problem is worst in the Himalaya – after what I keep reading – then the Austrian and Swiss Alps. The Rockies and Sierra Nevada and the NZ Alps might be slightly better off together with the Karakoram.
I am wondering whether it has s.th. to do with the flight routes at all. It’s not astonishing though as glaciers react quickly. The so-called little glaciation wasn’t really a glaciation, but an era with around 1,5 degree Celsius less, and the glaciers grew. Now we have about the same amount more, and there are problems.
I would rather call the mass on Rob’s pic sediment, and you can see this kind of sediment all around the Alps everywhere, so sometimes on glaciers. This is basically nothing new, it 1. gets more attention and 2. seems to happen more often and possibly faster.
It is a little bit comparable to cancer which 1. gets more attention and better diagnostics, so 2. seems to happen more often, compared to the 19th century.
These things need very cold blood, good geologists, no media coverage by those who have not read geology or geophysics and possibly some rethinking concerning hydropower (involved here) and possibly some resettling.
To be added:
The slope of the Bliggferner slid 20 centimeters per day in 2007, gradually tearing apart the glacier-covered hillside. This increased the likelihood of a sudden landslide into the reservoir. As a result, a flood wave could be expected to breach the dam, and in the worst case, the dam itself could be damaged. A similar disaster happened in Italy in 1963 when a landslide ripped into the Vajont reservoir, triggering a flood wave that killed over 2,000 people.
Translated correctly by ggl from
https://de.wikipedia.org/wiki/Gepatschspeicher
1.5C difference is a massive change. It is roughly the difference between London and Milan
I guess you weren’t thinking of this past summer though 😂
England slowly becoming good old England again.
In the interglacials, temperatures in England were about 0.5C warmer than at the moment. That was enough for hippos to flourish. We are already 3 quarters of the way there, compared to 150 years ago. Of course, sea level was 5 meters higher than today. London should take note
Where I live should be OK, provided it does not end up as an island. Perhaps coracles will be the next fashion accessory?
As late as the Anglo Saxon period, we should note that Lundenwic was a port; its location was near where Covent Garden is now.
Hi Denali,
Yes the Bliggspitze is the highest peak north from the rockglacier, the Kaunergrat ridge lays north-south orientated and slopes on your and my pictures are facing about west. Glaciers drawn on maps doesn’t show the present situation. Since the last topo map was published early 2000 years, half of the glaciers surfaces, westfacing melted. At least for a decade no or very little accumulation of snow takes place at that altitude anymore (up to 3500 m.). In August there is only bare ice left, it really is a heartbreaking sight to me. I know the area well because I lived in the Kaunertal past 5 years and did tour the area from about 1978.
The rockglaciers from the Kauner Valley are described in “Naturpark Kaunergrat- Gesteine, Gebirgsbildung und Formung der Landschaft” by Karl Krainer. On the west facing slopes of the Kaunergrat were found about 30 blockglaciers of which 11 are still active. The one I pictured is the Innere Ölgruben rockglacier. It can be reached from the mountain cabin Gepatschhaus in about 1,5 hours. The Nature Park has no Alpine skiing, tour skiing is possible. The walks are for those with good physical condition.
I find your comparing with cancer very disturbing. It does not make sense to me to compare a life threatning disease to something common, but beautiful in nature areas. Please think a bit more carefully before you write.
The valley north of the Bliggspitze was closed many years, the hike to the neighbouring Ma darfen- Pitztal through Wurmtal wasn’t possible because of rockfall caused by diminished permafrost. High alpine hikes/climbing in july-august are getting more dangerous because of rockfall and sometimes larger avelanches. Many rocky, steep slopes are not stable anymore.
An example of a repeating mudflow, or debris flow better, from an area with former block glaciers is the “Murgang” originating in Hüttenkar in the Austrian Radurschl – Valley.
Luckily in higher altitude, no human harm, fun side of the debrisflow was the forming of the Smaragd lake. The lake and its surrounding is monitored well, because of potential fast emptying and possible danger for downstream habitation.
And writing about mudflow. 😀
In june in the higher part of the Kauner Valley I nearly was caught in a mudflow caused by a heavy thunderstorm, not a nice experience, had to turn back to a cabin. With more than 100 others I was trapped, because there was one way out only… Next day we were evacuated by rescue helicopters, because the road had been interrupted by trees, debris and mud at four spots. Big thumbs up for the locals, rescuers ans civilians, all was organized smooth and professional. They dealt with such before, clearly!
Some days later I could fetch my car I left behind, workers had created an emergency road. Very impressive to drive through these up to 4 to 5 meters high walls of stones! And also in this case, luckily no harm for humans.
Did lit a candle in the Gepatsch cabin chapel Maria im Schnee afterwards.
The second pic doesn’t show up. To large i guess. Another attempt, smaller.
Very detailed description, impressive, thank you.
I assume you speak or can read at least German. Albert possibly as well. Others – if interested – have to translate this, article doesn’t exist in English which is a problem of Austrian Geology, and the same has to be said about Italian Geology. So:
“Das Tal ist (ohne Oberes Gericht) rund 90 km lang und von bis zu 3000 m hohen Bergen umgeben. Es trennt die Nördlichen Kalkalpen von den südlich gelegenen höheren Zentralalpen. Im Gegensatz zum Unterinntal ist das Oberinntal schmaler und an manchen Stellen durch Schluchten gebildet, etwa bei Zams und bei Roppen, oder bildet eine Bergsturzlandschaft am Eingang des Ötztals.”
https://de.wikipedia.org/wiki/Oberinntal
https://de.wikipedia.org/wiki/Bergsturz
So, what we have here is a Bergsturzlandschaft (landscape of rockfall), north is Tschirgant and Fernpass with a history of huge rockfall, precisely south are The Ötztaler Alpen with Kaunertal.
We therefore have a very well known old situation here which has been mitigated by glaciations.
A similar situation can be found in Switzerland, Kanton Wallis, here not Inn-Valley, but Rhone-Valley.
There might be Graben-like setting like in Rhine Valley near Basel.
https://www.volcanocafe.org/the-basel-earthquakes/
It is all south-west facing, btw, also Tschirgant. It gets the maximum of sun and rain and also snow and is therefore heavily eroded. This guy was found in the area:
https://en.wikipedia.org/wiki/%C3%96tzi
Thank you for the Karl Krainer literature, might try to get it.
I haven’t found anything like this so far. This map was dug out by Albert and is about faults in the Basel area. We can see the River Rhine take a 90 degree turn from an EW to a SN flow and the according faults, SN and reverse faults perpendicular to those.
But I discovered sth different, the Periadriatic Seam. So, that part of the Alps, including the Rhone Valley is located north of a continental-continental collision zone. It is not as forceful as the collision Zone bordering the Tibet Plateau, but I guess it shouldn’t be underestimated.
https://en.wikipedia.org/wiki/Periadriatic_Seam
This is also interesting:
“Tectonic compression isn’t the only force pushing the Himalayas upward. As glaciers across the range melt and lose mass, the underlying crust is rebounding, similar to how a mattress springs back when you stand up. This process, called glacial isostatic uplift, contributes 0.5 to 2.0 millimeters per year of rise in the Himalayas. That accounts for roughly 10% to 40% of the total observed uplift of 5 to 6 millimeters per year.”
https://scienceinsights.org/why-are-the-himalayas-still-growing-taller/
Okay, this is the Himalaya with a net growth of 4 (Mt. Everest) to 10 mm per year.
The Alps have a net growth of only 1-2 mm per year, but the same mechanism would probably apply to them.
So, a bit OT as there is no fire, just ice and rock. The Langtang Lirung rockfall gripped me though, poor people. The survivors did get enough food, tents, clothes and blankets, but in some parts it was impossible to deliver them as all streets were broken down and monsoon made enough helicopter flights impossible. So there was and probably stil is also famine. Poor guys.
Last but not least this deserves mentioning as well:
https://www.geopraevent.ch/project/sophisticated-monitoring-system-at-the-simplon-pass/?lang=en
Mountain concerned:
?utm_source=en.wikipedia.org&utm_campaign=index&utm_content=thumbnail
https://i0.wp.com/www.volcanocafe.org/wp-content/uploads/2026/09/word-image-19072-9.jpeg?ssl=1
Lava flowing over Sulfur snow on Io surface : D
1996 to 2011 Iceland did five “glacier eruptions” beneath a glacier: First Gjàlp, twice Grimsvötn, then Eyjafjallajökull and finally the third and final Grimsvötn eruption 2011. These 15 years were unusually explosive and active for Iceland (including Hekla 2000). But the public attention cycle lost the memory of the 2004 Grimsvötn eruption, when Eyja exploded 2010. Six years is too much for the public to keep something in mind, although it is a short timespan for volcanoes and Iceland.
Compared to this, 1980 to 1995 was only one minor eruption of Grimsvön 1983 and some uncertain subglacial eruptions (f.e. Loki-Fögrufjöll 1991). Also after 2011 there didn’t occur any explosive glacier eruption on Iceland.
The Pleistocene Tuya fjells of Fagradalsfjall are an example for effusive subglacial eruptions that likely also occur sometimes on Grimsvötn. If water and ice pressure is strong enough, they can contain lava calm on the floor.
After a pause, overflows have restarted. Atmospheric, between the clouds
V1cam only at the moment, the others can’t get through the clouds
Is the inflation caused by the weather ? the hurricane passing by
Good question! The tilt has been increasing since a day or so. There may be an effect from rain or it could be intrinsic.
The actual overflows show that pressure must be high, so there must be actual inflation. But the hurricane rain adds a phreatomagmatic element to the ongoing small-scale eruption. This likely causes vibration of the tiltmeters. The webcams show during daylight steam activity on the whole 2020-2023 Halema’uma’u lava lake that’s only on the surface solid.
Interesting typhoon-story, found while checking on Nolo, very tragic:
https://www.msn.com/en-us/video/news/1430-passengers-on-board-when-a-typhoon-sank-japan%E2%80%99s-largest-ferry/vi-AA1XvV4z
https://www.youtube.com/watch?v=x7M8sAf5Ums
What do you make of this? The locations actually look similar to the previous vents pre-1883: Perboewatan & Danan
I was on holiday with my family in 2010 in Portugal when Eyjafjallajökull erupted. It was all a bit hysterical, people were on about driving to Valencia and getting a ship home, nobody knew how severe or not the impact was. Everyone who had booked to stay in the hotel had their additional time paid for and sorted by Thomson (now Tui). Unfortunately as we had booked using separate airline and hotel companies we couldn’t get immediate compensation, and had to keep receipts (as well as staying at the hotel for an additional unplanned week). As you can imagine this set us back financially for a year or two until we were compensated. Fortunately some of the other guests took pity on us and got us food (they were all inclusive, we were self catering). The second week was actually lovely hot weather!
Iceland liked this article and did swarm out of respect.
whereabouts?
The caldera to the north of katla
I think.
Torfajokull
A series or swarm of earthquakes on the Ring Fault of Torfajökull! The earthquakes appear(ed) on the NW side of Torfajökull towards Hekla.
https://skjalftalisa.vedur.is/?from=2026-09-20T16%3A38%3A04.264Z&to=2026-09-27T16%3A38%3A04.264Z&split=EQWwhgDsQ&lat=63.955411981997315&lng=-19.19000800518711&zoom=9.84460754722948
Torfajökull is “the largest ring fault in the volcanic zones of Iceland” https://www.researchgate.net/figure/Torfajoekull-Caldera-the-largest-ring-fault-in-the-volcanic-zones-of-Iceland-has-a_fig5_269227357
Yes, it has been more active in the last year or so.
Kilauea overflow looks more serious at the moment. 2.07 hst.
The overflows are more frequent at the moment and one of the higher vents is now also leaking
The current overflow has already lasted for more than 30 minutes
Pu’u O’o has longterm deflation:
ESC (Chain of Craters) has strong short term deflation since September 24th:
Kilauea Iki has significant inflation:
Does all this mean that magma is – overall – flowing from ERZ to the summit? Pu’u O’o today had a M3 quake. The southern summit region had a number of earthquakes today, maybe an indicator for increasing pressure.
Correct: ESC has had strong deflation since yesterday (September 26th), but coincides well with inflation of Kilauea Iki and SDH.
The changes over the past days at ESC and IKI could be rain related – wait and see. The Pu’u’O’o change seems large, but over the past week is small. The JCUZ GPS shows continuous deflation in the ERZ. That is a better measurement than the tilt. The deflation is seem across the entire region, including south of the caldera, by about the same amount. I am wondering if this is just the southward slide of the flank of Kilauea. There may also be a contribution from cooling of the 2018 magma. Only Kilauea itself is not showing deflation: the GPS around the caldera have been flat. There is no magma movement into Kilauea: the eruptions here aer driven by magma moving up, not in.
These are tiltmeters, what does gps say?
After all a tilt can be cause by either side moving.
Can Hofsjökull – the central glacier of Iceland – do a big explosive eruption? During Holocene it only did effusive basaltic eruptions. But they say that the magma type of Hofsjökull is both basalt and silicic (rhyolite). It didn’t do any during Holocene, but maybe it’s a volcano that can do this every 100,000 years or so.
It looks like the Kilauea frog barfs every 1.5 hours, sorry about the immaturity but I can`t unsee the image on V3 cam. I wonder how long this will continue.
Now that the V3 webcam image is useful again, you can see what looks like a new vent between the south and west vents. Lava overflows from the new vent, which is higher than the south vent, pour straight into the south vent, usually getting no farther. But, around 6:31 HST lava from the new vent filled the south vent, which then overflowed briefly.
To me it seems like the whole structure around the south and west vents is slowly falling apart. At night time the luminosity changes in both vents are almost synchronized so I think they are just separate openings of one vent. Eventually the will merge to one big opening. Perhaps the whole structure is slowly inflating like a lava dome and the solidified lava cover is cracking apart slowly.
Can there happen a collapse of the vents that opens a visible convecting lava lake?
At this moment, a collapse will open the floodgates
Krasheninnikov, Us-India-Satellite timelapse:
https://phys.org/news/2026-09-india-satellite-captures-lapse-video.html
Shiveluch, Jan 2011, Fire and Ice
Plus Klyuchevskoj
https://tse3.mm.bing.net/th/id/OIP.8YHSLtDCa9FpXxsT0To_dAHaE7?r=0&rs=1&pid=ImgDetMain&o=7&rm=3
Plus Great Sitkin, much ice, little lava
https://img-s-msn-com.akamaized.net/tenant/amp/entityid/AA2cXABK.img?w=534&h=300&m=6
The Starship launched successfully but there was a problem afterwards. Not clear year whether they will still make orbit.
So it did the job of getting in orbit and pushing out the satellites. But it was cut short after 3 hours (I guess because the orbit was too low?) and after re-entry the starship blew up ( deliberately or not?).
To my understanding, Starship blowing up after a water landing is intentional (see all prior successful IFTs). The failure of that to happen on the previous launch was an anomaly.
It seems the mission was cut short because of a failed Raptor engine. They had to poll to go orbital (it would’ve remained in a suborbital trajectory if it wasn’t go for orbital, and the Starlinks wouldn’t have been deployed, then, either) and I figure they rather not wanted to take their chances and do the full nine hours. Starlink deployment was successful to my understanding, which wouldn’t have happened if Starship didn’t reach the target orbit of 275×275 km, with some margin. I recall it ultimately ended up at 273×278 km or so, pretty good if you ask me considering the Starlinks have to maneuver themselves into the appropriate orbit anyway (note prior Starlink trains shortly after a launch, for example).
The explosion at the end was not announced and it seems they would have preferred to recover it. I wasn’t sure about the orbit: as the starlink satellites have a fair amount of fuel for orbital manoeuvres, they can make their own adjustments. They need the fuel though for the rapidly increasing number of evasive manoeuvres to avoid collisions. The reason for the early termination ws not clear to me. Were they concerned about the engines not firing for the de-orbiting? Or was there a fuel leak with a risk of explosion?
This is always interesting, but nothing really new, so I hope a Q that popped up in my brain might be answered by you. Reading Th. Harris’ novel Agrippa (boring till page ~180, then getting more fascinating) I followed some biographies and saw that those raw emperors islolated several women on Ventotene, then Pandateria.
Ventotene lights up volcanism of course. Seeing the age of volcanism on 1) Ponza (~4Ma) and then Ventotene (0,8-0,3 Ma) and the direction of the African Plate (NNW here) I was wondering whether this could be mantle-plume volcanism, going Ponza – Ventotene – Bay of Naples with C.Flegrei, Vesuvius and Epomeo.
Just wondering.
The other thing I realized reading is that they knew Stromboli quite well from their war against Sextus in Sicily. So, absolutely amazing that they never checked on Vesuvius, but maybe they were just two busy with warmongering and killing each other, poor souls.
Scott manley on youtube is a good science communicater for all things rocket related.
Thank you. I prefer written stuff though, s.th. like this:
“The main result achieved concerns the identification, at depths greater than 16-20 km, of a layer characterized by “very low seismic wave velocities.” This data suggests that up to 30% of the rocks in that area are in a molten state. According to the authors, this area represents the source of the primitive magmas of Campi Flegrei, which, as they rise through the Earth’s crust, cool and evolve toward more silicon-rich compositions.”
https://www.ilmattino.it/en/deep_magma_pathways_revealed_beneath_campi_flegrei-9548531.html?refresh_ce
or this:
“reveal the spatial distribution of melting. The B-B’ profile shows a broad zone of partial melting between 20 and 30 km”
https://www.nature.com/articles/s41598-026-51786-3
Which doesn’t answer my Q I guess. How come there seems to be progression?: Progression is a sign of a mantle plume. Looking at Ventotene east and Ponza west these two also remind me of caldera rims.
It is the same as with Marcus Agrippa: There are distinct signs that he might have been a son of GJ Caesar who ruminated in many beds, but there is no proof.
Well this is Italy. Fascinating history and geology, open to some speculation.
But one thing is sure:
The Romans BC made the best concrete ever with the help of their surroundings:
“The harbor concrete, a mixture of volcanic ash and quicklime, has withstood the sea for two millennia and counting. What’s more, it is stronger than when it was first mixed.”
https://www.washingtonpost.com/news/speaking-of-science/wp/2017/07/04/ancient-romans-made-worlds-most-durable-concrete-we-might-use-it-to-stop-rising-seas/
Fascinating country, historic and geologic marvel.
We have some lava flowing out of the south vent.
Well that was short. started at around 10:33:55 HST -ended 10:37:30 HST
It looks like the south vent has not stopped. They are short, but they are fairly frequent, maybe every 10-20 minutes and it seems that at each end of the overflow the gas jet has become more violent. The north vent seemed to be heightening its activity with it too.
Well, now the south vent is going nuts.
The cone seems to have grown too high for its own good. The other vent may now be lower
I think the cone identifies as a flame thrower now 🔥
Those overflows are really pretty.
A small vent has opened at the base of the cone, throwing a bit of spatter around.
It looks as if the southern vent has got a convecting lava lake, that from time to time rises above the rim of the vent. After 18:00 HST yesterday you can see the rising lava lake, in which gas bubbles are bursting. The magma that is in the vents, is relatively gasrich, so it does lava fountains and exploding bubbles.
Yesterday the southern vent became the dominant vent. Maybe this is the dominant vent of the future? Half past 7 p.m., the first short lava flow was visible. Around 8 p.m. several bright glowing lava floods escaped the southern vent. During the night, the southern vent did many cycles of lava floods and dormant minutes.
One aspect is clear: This is the highest standing lava lake of Kilauea since at least the 1920s. The altitude of the southern vent is much higher than the 2008-2018 lava lake. The summit eruptions of the 1970s were rather fissure eruptions than lava lakes. According to the summit reference map of September 8, https://www.usgs.gov/maps/september-8-2026-kilauea-summit-eruption-reference-map the vents have reached an altitude of 1080m above sea level. The lava lake in the southern vent is close to its summit, so not far from 1080m above sea level.
You can see a drone flying around on v3 and V2 cam at around 3:12 am HST. Starts in the foreground over the lava flow at the bottom left of the screen, then later around the north vent.
GPS of two stations near Chain of Craters show a strong S and E movement: 1. “Devil’s Throat” near Hi’aka Crater, 2. PUHR near Ruhimau Crater
The opposite movement happens at UWE (near Uēkahuna bluff and K2 webcam). There the station moves N and W:
?fileTS=1790630784
one image removed as requested – admin
The second UWE graph can be deleted, it was added once to often.
It’s the same pattern as between every episode, meaning that it’s still inflating. Eventually, something has to give. New episode, new fissure, magma migration to one of the rift zones, who knows? Exciting times…
One option is that the summit gets a “flood basalt episode” that resembles episode 48 of Pu’u O’o (July 1986 to 1991). An eruption like this would have no high vertical lava fountains, but a quick flooding of the whole Kilauea Caldera until “Byron Ledge Trail” that lies on the hill between Kaluapele and Kilauea Iki.
The pressure needed to create a “lava flood eruption” is maybe higher than the pressure needed to start one of the past 54 episodes.
Last night I watched the south cone suddenly flood and a drone was sent out around 8:10 pm to fly in close and check it out. Tonight the jet has gotten very energetic and spewing lava at high velocity sideways around 40 degs or so but there seems to be a hot spot to the left of all this and a couple of times it flared up when the jet was the strongest. An eye needs to be kept on this. The back side did grow stronger while all this was going on around 8 to 9 pm Hawaii time
At 10:57:12 pm hawaii time a new jet broke through to the left as expected on the V3 cam Tuesday Sept 29 for the south cone activity.
thank you
At around 2:40 am HST the South vent started a flow. As that flow started to diminish the west vent started to clear its vent.
Oral & Visual summary: https://www.youtube.com/watch?v=_fa-EjXMWcA
They say that it’s impossible to predict with certainty, to what the high pressure in the summit region will lead.
HVO says: ” the two most likely possibilities are that activity continues at the north-south-west vent complex, or it activates another existing weak crack system in the summit region. Neither of these events are likely to produce a strong seismic precursor” https://www.usgs.gov/volcanoes/kilauea/volcano-updates
They don’t predict whether there’ll be an “ultra-effusive” episode or a steady continuous longterm eruption. Both options seem possible to me.
I think there is already another crack which acts to keep the magma level stable in the cone and other vents. It may be feeding into a lava sheet below the crust in the caldera
It seems to be in a stable state now. Is a lava flood episode possible or shall we exclude it for now?
I’m thinking about how the continuous stage of the Summit Eruption may unfold. Pu’u O’o did it suddenly in July 1986. Mauna Ulu did it gradually and slowly in 1970. Do longterm Summit Eruptions behave like Mauna Ulu or Pu’u O’o? Mauna Ulu is more close to the summit, so it likely has a more “summit-like” behaviour than Pu’u O’o that is on the lower MERZ.
If it was doing that there would be breakouts and spatter cones elsewhere in Halemaumau, the supply of magma to the vents is just low and its likely there is a lot of pressure building somewhere deeper down
The crack with the leaky vents stopped on Sept 16, per HVO. The highest vent on that dike was explosive and strombolian, probably degassing the rest, and probably would still be active if lava was still moving through
This may be bigger than we realize. Tonight the V3 cam is set to wide pan because in front of the camera the ground is steaming and it is a long ways away. Also on the V2 cam there is a glowing hot spot way far away from the two vents in the caldera floor and it is noticeable too in the darkness.
I’ve seen several references to the West vent lately, which actually are describing the new vent that I mentioned several days ago. This new vent is much closer to the south vent than the west vent, which has been inactive lately. The west vent has been visible only occasionally. You can see it above and to the left of the north vent in the V2 camera view around 20:52, Sep 29 HST.
On V3 in the best conditions you can see five vents or openings. The newest one is maybe just an opening at the base of the north cone, but it is stable and does some spattering. The other four have their own cycle, independent but correlated, I think that it shows that a vulcano has a fractal topology and the number of vents depends on the scale. Interesting episode this one.
Vito
You can find in this report the USGS refering to the 3 dots on the map as North, South, and West vents.
USGS Volcano Notice – DOI-USGS-HVO-2026-09-15T03:18:09+00:00
https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-09-15T03:18:09+00:00
In this publication are references the activity of the different vents for the episodes, but does not mention the west specifficly (towards the end of the article).
https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
That report is too old; I noticed the new vent on Sep 27, 2026; and the latest HVO reports don’t seem to notice it as a new vent. I remember older views of the west vent, and they showed it much farther away from the south vent.
From what I can gather from HVO’s reports (and especially the article on the summit overflight yesterday, https://www.usgs.gov/observatories/hvo/news/photo-video-chronology-kilauea-summit-monitoring-overflight-7, final image), they consider the vent to be part of south vent. Thus the vents are north (two subvents – cone and base), south (two subvents, assuming one has a bridge in the middle) and west (two subvents). Assuming fountaining does occur, the subvent structure will be completely destroyed in the fountaining vent(s), so it’ll be a gaping hole until spatter fills it in again.
Regarding south’s new vent (which I’ve been referring to as “wall south”), I believe – because north vent filled south during E54 – there’s a parallel to be drawn from when south vent completely filled north vent during an episode in the 20s. Next time north vent fountained, it erupted from anywhere but the center; even from a prominent pillar in front of it. I believe south vent is undergoing that now with it opening new vents around the crater wall. Wall south is in any case a prominent flamethrower, so if south fountains at all in the still-anticipated E55, it’ll be my prime suspect for initiating it.
At around 5:38 am HST the sound from the microphone on V3 camera appears to change, possibiliy picking up the spitting spatter before the flow that follows.
On the longterm perspective what options does Kilauea have? I propose three:
1. A shield eruption like Observatory shield that constructs a volcanic shield inside and upon the current caldera
2. A caldera filling process that ends before an outflow of lava from the caldera
3. A return to a period of explosive eruptions.
What else proposals are realistic?
Magma migration into one of the rifts. Possible rift eruption.
Convecting lava lake.
Maybe one leads to the other. Imagine this: Magma migrates to a rift, the magma level in the conduits reduces by so much that the current vent complex loses support and parts of it collapses down into the conduit. The magma column is disturbed by the debris and explodes violently, excavating parts of the vent complex and leaves a big gaping hole. After a short hiatus, magma returns to the summit and fills up the hole with a convecting lava lake as a result. Pure speculation of course.
I think it’s very hard to predict what comes next, but one of the rifts will get involved sooner or later if the summit keeps inflating.
Or a very cool looking dome fountain on top of the cone, draping the cone with lava so it looks like cousin It made of lava.
It’s quite intense. Could this turn out to be the next episode?
Nope, it stopped. Well, well, time to go to sleep anyway…
We haven’t had any shield building eruption in the summit comparable to Pu’u O’o or Mauna Ulu during European-Hawaiian history. But I’d assume that the summit is capable to do something like this, too.
From the USGS:
Kilauea Message 2026-09-30 16:55:03 HST. Kīlauea summit seismicity has increased. Tremor began increasing around noon today. A swarm of small earthquakes occurred beneath the vent area between 2-3 PM. Summit tilt accelerated around 2:30 PM with inflation centered near the vents.
V3 cam was zoomed out a while ago so apparently something interesting is expected to happen.
Like the steaming ground right in front of the camera?
The sudden increase in summit tilt is insane.
https://imgur.com/a/9WWLfGf
SMC, 2 day, live.
This tiltmeter is dropping. Something strange is happening…
UWD tilt slowed some, but it’s still climbing.
Either the tilt meter is falling into the crater or the build-up to an ‘event’ has started
Kilauea Message 2026-09-30 21:49:15 HST
There has been an marked increase in shallow deformation and seismicity centered beneath the current vent region in Halemaʻumaʻu. Patterns of inflation and earthquakes suggest that a shallow east-west dike is being emplaced in this area.
https://www.usgs.gov/volcanoes/kilauea/volcano-updates/volcano-messages
Looks like the UWD tilt has begin to slow. Something might begin in about an hour to three…
Yes, seismic noise is way down again. The m most recent quakes are at the north end of the caldera, some 500 meters below the surface. I am not sure that the cameras are pointing in the right direction. The dike came quite close to UWEV, which is why it responded so wildly.
Okay, the north vent became hyperactive a few minutes ago before part of the cone collapsed and became inactive…
And the north vent has become active then less active again. Build up to episode 55?
We have a summit magma intrusion. We might see a fissure open across the caldera wall or under the caldera lava fill anytime now. If this intrusion extends into the southwest rift zone we could see a catastrophic draining of the lava ponded inside the caldera.
Judging from the tilt the intrusion is propagating from west to east, I’m not sure if along the usual dike swarm that runs to Kilauea Iki or following the 2018 caldera fault, in any case with this propagation direction it seems unlikely to extend into the SWRZ.
It is going northeast. However, this becomes uphill, and if it stalls it may then go in the opposite direction!
The earthquakes have the direction between Halema’uma’u and “Kilauea Military Reserve”. This area was last flooded with lava 1919. It was not covered by lava afterwards. Was 1919 the “Postal Rift Eruption”?
On the V2 cam at 10:26 pm Hawaii time you can see a new vent beginning to open up behind the north cone, looks like the wall of the caldera?
Sorry, I can’t see what you mean. What I do see is a flaming frenzy on the V1 cam. All the vents are in flamethrower/blowtorch mode at the moment.
Interesting M3.4 at the edge of the down dropped block in the middle of the caldera.
21:51 pm on the V2 cam you can see it
I think that’s the west vent.
Zach:
You might be right.
That was very impressive. I am wondering whether it was the back flow from the stalled dike. It lasted about 5 minutes
Plot of the main bunch of quakes north to south. UWB is in the top of the plot, it starts east of KW2 cam.
There was also a M3.4 earthquake in the summit on the border between the 2020-2026 lava field/lake and the old cold lava floor:
https://earthquake.usgs.gov/earthquakes/eventpage/hv75046747/executive
It was strong enough to be felt by humans.
V1 cam shows the “happy volcano family” of four vents now. Sometimes lava from the northern Hornito runs down in the 4th vent below it. At other times this 4th vent does spattering at is own:
More than 100 earthquakes today, many of them in the caldera:
HVO says that “a shallow east-west dike is being emplaced in this area”. Maybe the next vents appear in the northern “dry” zone of the caldera that wasn’t covered by lava since 100 years. 1919 this northern part of Kaluapele Caldera was flooded with lava. This zone is blue in the old (pre-2018) summit lava flow map:
The summit vents have a mid-1800s look about them. Mark Twain would feel at home.
Seems like eruption rate everywhere is on the rise. All three main vents in full discharge mode now (15:49 GMT, 05:50 HST) including a newish vent on at the base of the north vent.
Massive gas/torching going on, with lava overflowing/cascading over the south vent.
In my estimation, this current spike over the last 24 hrs. or so is the most vigorous considering the number of vents concurrently being so hyper-active. Not sure about any flank-wall flows as the camera’s may not the pointed in the correct direction(s).
Curiously, the north vent cone has “healed” the holes in the side walls we saw several days ago despite massive overflows since then which I would think would have further destabilized the cone? Note also the relocation (westward) of the lower vent at the base of the cone. IMHO, I agree with other posters that the eruption is now in a building phase that most likely is leading to another major change in the eruptive behavior..especially considering a possible new sub-aerial dike forming and erratic tilt signals.
at 1:00 local time you can watch the cone partially collapsing on V3, the wall facing the camera slumps after a big overflow, leaving the cone visibly smaller than before.
very cool. thx.
Looks like the earthquake activity has reduced yet not stopped. UWD has plateaued after uplift, but the SMC, IKI and SDH showed continued to drop, with SMC being the most significant.
UWD, 2 day, live
SMC, 1 month, live
SDH, 1 month, live
IKI, 1 month, live
Now, I’m not much of an expect here, but how I interpret this, based on previous examples of dike intrusions, is that the UWD is on the northern “bulge” of this butterfly deformation, while the SMC is closest to the sinking caused by the dike. Now, I think that the intrusion is still ongoing because all the summit tilt meters, except for the UWD, has continued to drop, with the area at UWD reaching equilibrium.
I think the reason why the dike has stopped might be because of the psuedo-magma chamber within Halema’uma’u, created by other eruptions prior to the eruption we have now. The dike intruded into this body, adding more magma while causing minimal earthquakes. If that’s the case, this other eruption could appear almost without warning within Halema’uma’u in the next few days.
Thank you. I kinda know the jist of it, like moving away means inflation and towards meaning deflation. Anyways, here is a inferogram map here:
https://www.usgs.gov/observatories/hvo/news/volcano-watch-intrusion-during-eruption-summit-kilauea
Looking at the map, it doesn’t go past the 27th of September, but it’s enough to contain some info. Looking at the red arrow, they said a fault slipped and, oddly enough, it kinda aligns with the new fissures from September 14th.
Note this interferogram does not cover the current intrusion, only reaches to the 27. Nonetheless it does show what’s likely happening given the earthquakes happen in this same line that was already rupturing before the 27, possibly as a consequence of the intrusion of Sept 14 that erupted from the cadera fault near the vents. What’s happening is that magma has intruded what was a caldera fault that started to deform towards the end of the 2018 eruption but never collapsed. Minor slip is happening in this fault at the same time as the magma intrudes, judging from the M3.4 that caused the caldera rim to rebound, though most of this slip is probably aseismic as the fault is now lubricated in magma. At present the intrusion continues very sluggishly and continues to propagate northwards judging by the change in tilting direction.
HVO is in the “fog of war” and just says that anything is possible to occur now. They don’t predict a certain outcome of the present situation.
That is the usual situation at volcano observatories. Active volcanoes don’t respond well to predictions. (Dormant ones are easier.) The last year has been unusual, in that the activity so closely followed a single tilt meter. We are back to normal.
I predict that Kilauea will erupt. Or not.
And talking about tilt, UWD is increasing notably again. We need a word from Tomas.
The GPS at this location may be showing a small uptick but it is not large. The dike is confined to the caldera
Just a new 3.49 M earthquake at 0.3km depth on the northern end of the 2020-2026 lava mass. Many earthquakes are close to the boundary between this new lava mass (partially molten and partially solid) and the old aged caldera floor that didn’t collapse 2018.
As Hector mentioned in his post “magma has intruded what was a caldera fault that started to deform towards the end of the 2018 eruption but never collapsed.” Perhaps magma can cause a new fissure eruption in this old aged basaltic rock of the caldera floor. 1919 was the last lava flow in this area. I don’t know where 1919 was the fissure. Can it be used again after more than 100 years?
Remember one thing: tilt meters don’t measure up/down. They measure change in slope. If both ends of the instrument go up, nothing happens, same if both go down.
The tilt meters used at Kilauea are 2D. They measure tilt along two perpendicular axes, aligned with the placement of the instrument. The measurement is then transformed (rotated) according to the instrument’s alignment relative to compass direction, to show tilt along true north and true east. Finally, it’s transformed again to get the tilt in the radial and tangential directions, relative to the inferred magma body under the caldera.
When the summit inflates, it will do so as a bulge. The tilt meters sit on different sides of the bulge and with the arrangement described above, we should get a positive change in the blue (radial) curves and no change in the green (tangential) when the magma body inflates.
In other words, the tilt curves are tailored to show inflation of the magma body below the summit. Other deformation sources will not give as straightforward signals. It all depends on the gradient of the deformation relative to the directions that the tilt meters are tuned to.
So for a dyke intrusion with the classical butterfly deformation, two bulges and a depression in the middle, the sign of the change in tilt meter depends entirely on which side of a bulge the instrument sits. Two instruments can be on the same side of a dyke and show different signs because they are on different sides on that bulge. Or, they can be on different sides of the deformation they are tuned to measure and show opposite sign for the same slope. As an example, UWD and IKI have their radial directions opposite to each other. Suppose there were a new sill inflating to the east of IKI (hypothetical). Then UWD would show inflation, but IKI would show deflation, since they are on opposite sides of the summit inflation they are designed to pick up.
Tilt meters are good at measuring exactly the thing they were set up to do. In other situations, they should be handled with care.
I think a useful reminder of tiltmeter output.
As you know I often fear tiltmeters are taken too simplistically rather than as combined as a group to provide a coherent answer. Consequently I tend to ignore comment unless it takes this into account. It has to be said that I do not know each meter personally and rather hope expert opinion gives the analysis of many as a conclusion, rather than one or two with a graph that on its own mean very little.
Thank you (deeply) for your brief exposee above.
PS Albert thanks for the pix.
Looks like the deformation on UWD is starting to pick up again ever so slightly
For those who are keeping an eye on Iceland the IMO has an update out.
Eruption risk remains unless land subsides for six months (RÚV, 1 Oct)
My impression is that there’s been a little bit more tremor activity lately to the east of the crater row, around (lake) Kleifarvatn. But it may just be my imagination.
I’d assume that the probility for an eruption of Svartsengi within the next three months is as high as Hekla, Grimsvötn and Bardarbunga for this moment. It is one of the currently most active volcanoes of Iceland.
Compared to this the probability is much lower that one of the other volcanoes on Iceland will erupt in the next three months (f.e. Askja, Katla, Krafla …).
17.55 utc, M3.5 Kilauea and another push on the tilt devices. No sign of surface activity change.
UWEV GPS with clear positive path or 2mm per day upwards:
As said below, the situation mirrors a bit the 1919 situation and the 1800-1825 development.
Mauna Ulu’s GPS has a significant East and South movement, it moves ~2cm away from the summit:
Maybe a slight increase in tremor as well? Hard to tell
1919 the “Postal Rift” eruption in the caldera occured, when the tiltmeter was very high. 1919 was a strong positive jump of the tiltmeter … maybe very similar to the current situation. 1919-1924 was a high pressure period in the summit area. Maybe we’re in a similar moment like 1919, when the period of high magmatic pressure in the summit region began. It was also a time, when the major SWRZ eruption happened 1919-1920.
Until 1918 the filling rate of the caldera was 0.0045 km³ per year. 1918 to 1924 it jumped to 0.0239 km³ per year.
But 1823-1825 the filling rate was even higher: 0.322 km³ per year.
2025 were 36 episodes. They had an accumulated volume of 0.1986, so nearly 0.200 km³/year. So the level of the filling rate until August 2026 was much higher than the level before 1918. But it is still lower than the >0.3 km³ per year around 1824. Is the current high pressure in Kilauea’s summit a sign for accelerating filling rate towards the 1823-25 level?
Supply rate in 2023-2024 was probably even higher than in the 1820s. The 2018 eruption was 1.5 km3 of lava, only half of which is accounted for in the caldera created, and even DRE finds a significant amount of extra lava above the collapse volume. Elastic deformation accounts for close to half of the 2018 collapse, the majority of that in the summit and upper SWRZ, and that was all almost entirely repressurized in under a year by mid 2024… with pressure falling again after the current vents opened.
Basically the supply rate in 2023-2025 was probably on the rate of 0.5-0.8 km3/year extrapolated although it was only this high relatively briefly. Supply rate during the 1st year of the current eruption was 0.25 km3/year erupted, alongside extension of the summit indicating additional magma though no distal inflation. Supply rate in the 2nd year up to present is rather lower at 0.15 km3/year extrapolated from the fountaining episodes and possibly much lower in the last 2 months, and probably results from pressure being much higher in the magma system which prevents new magma flowing in. This is the same supply rate as before 2018, and the vent elevation now is significantly higher probably around 1100m elevation or even more.
It looks like Kilauea is really degassing today.
The tilt change is spectacular. Good explanation of the earthquakes (offset from the dike).
USGS published this overflight of the vent complex:
https://www.facebook.com/share/r/1KYnk4R7hX/
The vent pointed out by Randall is clearly visible and is what they refer to as the west vent.
I have been trying my best to understand the deformation patterns, but with so few data points it’s difficult. The tilt is a local gradient of the ground elevation, and trying to extrapolate a deformation pattern is like solving a multi dimensional differential equation without boundary conditions.
What we can note is that before the latest M3.5, the tilt was slowly increasing for the blue curve. More interestingly, the green curve was also changing. That tells us that the source is probably not inflation of the magma chamber, and the earthquake seems to confirm that it was related to the shallow intrusion. Without a good InSAR picture, covering the time period of the intrusion, it’s hard to draw any further conclusions.
I think it’s clear that the current vent activity is not enough to keep up with the magma supply. Inflation continues, and the intrusion is a clear sign that something else has to give. I think a new eruptive fissure inside the caldera is the most likely scenario among the many possible scenarios. Episode 55 is of course another possible outcome, but it seems less likely the longer this goes on.
Would a new eruptive fissure happen inside the 2020-2026 lava accumulation or outside of it?
Interesting is at this moment the opposite horizontal movement of UWEV and PUHR GPS stations, while they both are positive. The stations sit on opposite sides of the caldera:
UWEV jumped dramatically NW, while PUHR moved SE.
They are on opposide sides of a dyke intrusion. That’s exactly the deformation you’d expect. It’s a very good question. What would happen if it intrudes into the accumulated lava inside the collapse pit from 2018?
It is a large movement which I assume is from the earthquake. The vents have been much more quiet since the quake so it seems the movement took the pressure off a bit
You can see Kilauea’s deformation even on Mauna Loa’s eastern flank. This station sits next to the KP webcam on Mauna Loa’s Strip Road and watches Kilauea from there:
https://www.usgs.gov/observatories/hvo/kpcam-kilauea-summit-mauna-loa-strip-road
Just to clarify: the USGS video clearly shows 3 vents to the left of the north vent, and the top one is the one that was earlier named the west vent but has lately been very quiet. The more active middle vent has recently been called the west vent by HVO and other commenters; they don’t seem to realize that it is a new vent and not the older west vent.
Habunga seems a tad unsettled:
Date Time Latitude Longitude Depth Magnitude Quality Location
Saturday
03.10.2026 21:51:09 63.638 -19.104 0.0 km 1.9 50.0 6.4 km N of Hábunga
Saturday
03.10.2026 21:44:07 63.635 -19.088 0.0 km 3.0 50.0 6.1 km N of Hábunga
Saturday
03.10.2026 21:27:32 63.642 -19.100 0.0 km 2.9 50.0 6.9 km N of Hábunga
Earthquakes at Langjökull have migrated over past year from just west of Thórisjökull to the northeast, south of Eiriksjökull but still under the ice cap. There are 3 main clusters along a southwest/northeast trend.
They were initially anywhere between 0-18km depth, but the most recent northward quakes are now in the upper 6km going off Skjaftalisa, including the 4.2 on 15/09/26.
That is an interesting observation!
https://relief.bertspaan.nl/world?lang=en
Awesome tool, thanks! Played with it a lot, the dynamic color range does a lot for the ability to visually see the shapes and different scales. In the Bavarian alpine foothills you can see geology at a single glance, all the terminal glacier basins including the former lakes like Rosenheim (Inn River, which has the Danube as a tributary), Salzburg, the sandur plain on which Munich is built upon.
And, oh my, look at these crater fields surrounding my city!
https://postimg.cc/06hzcg3V
https://postimg.cc/BPpQWRYs
Nothing volcanic I’m afraid, just a series of explosions that happened around 81-86 years ago… Didn’t think there were still so many of them.
Some days ago two news islands appeared near Anak Krakatoa. Are they a sign of inflation? https://www.scmp.com/news/asia/southeast-asia/article/3369497/2-new-islands-appear-near-indonesias-anak-krakatoa-volcano-after-eruption
A different topic related to Krakatoa: The old Krakatoa/Krakatau that collapsed 1883 consisted of three volcanoes: Rakata, Danan and Perboewatan. Can Krakatoa build a group of active volcanoes like this again? Rakata survived the collapse 1883, so it is perhaps able to erupt again. But it appeared calm after 1883.
TIm Catron, GeologyHub just issued a recent video, claiming that an area near the Kilauea crater has been restricted off limits. See https://www.youtube.com/watch?v=xvRPpx8fEBk. Is this something to be concerned about?
Watching the cameras tonight, V1 cam shows the small flaming has resumed now, just to the right of the base of the north cone hornito. This was not visible last night but it was very noticeable the evening the the dike emplacment. And the V2 cam shows some new flaring at the right part of north cone, on the ground in front of it, as best as I can see. It flickers, but does catch your eye at 21:11 local Hawaii time. It seems activity has picked up slightly.