A trivia question: can you name the largest country without an active volcano? Here ‘active’ includes ‘dormant’: it is about volcanoes that have access to live magma and could in principle erupt, even if at the moment it decides not to. Monogenetic volcanic fields, if active, also count. Answers through the comment box – there is a ‘ding’ to be won!
One hint: the answer is not ‘India’. Its continental land mass indeed is volcano-free. It has had impressive volcanism in the past, including the Deccan traps. But that was a long time ago, and although large areas are still covered in the ancient lava, it is now dead as a doornail. But in fact India does have a volcano, and one that has erupted multiple times in the last 40 years. This sole hyperactive volcano disqualifies an entire nation from the VA (volcano-avoidance) games.
It is a very isolated volcano, though. It sits not on India’s main land, but on a barren, deserted island far out in the ocean, beyond even the already isolated Andaman islands. It is closer to Malaysia (also a volcano-free nation), Burma or Indonesia than it is to India, and could even be viewed as the northernmost Indonesian volcano. It is the only active volcano in all of continental southeast Asia. The sea it sits in may be the world’s youngest ocean. There is plenty to be excited about. That is, apart from its name. Barren by name, but not by nature.
The Andaman and Nicobar Islands
The Andaman and Nicobar archipelago are an island arc lying between Myanmar and Sumatra, governed by India The islands are among the last pristine tropical islands in the world. There are 572 islands in the archipelago, but only about 40 are inhabited. The largest island, Great Nicobar, is also the closest to Sumatra. But while Sumatra is teeming with people, Great Nicobar is a jungle with fewer than 10,000 inhabitants, although India has great plans for development. The 20 or so other Nicobar islands northward of Great Nicobar are much smaller. North of this group, and separated by the mathematically slightly inaccurately named 10-Degree Channel (the separation is actually 1.3 degree in latitude), are the Andaman islands, with the capital Port Blair.
Tourism here is beginning to grow. Of the manifold of islands, Havelock island is the main destination for tourists. But the white beaches, coral seas and impassable jungle of it and other islands are still largely undiscovered by the traveling hordes. Much remains off limits, in order to protect the remaining indigenous population, who have lived here for 25,000 years. In fact, only 40 of the islands can be visited without a permit. Some islands are absolutely forbidden. North Sentinel especially has a fearsome reputation as the locals are not keen on visitors and have a tendency to shoot arrows at them – and not as a warning. Hovering helicopters get the same treatment. Go there, and do not expect any efforts to be made to recover your body. Effectively, they are independent – even their language is not known or understood.
Geographically, the islands are a continuation of the islands located off the west coast of Sumatra, rather than Sumatra itself. The arc continues towards (and into) the Rakhine mountains in Myanmar in Southeast Asia.
Southeast Asia
The region is very complicated. The main shaker and mover here was and continues to be the collision between the Indo-Australian plate and the Asian continent. India is the wedge being driven into Eurasia. India used to own its own plate but there is no longer a clean separation in the Indian ocean between the Indian plate and the Australian plate, so they are now often considered as a single oceanic entity. (Which one has subsumed the other is a matter of opinion.) It is subducting underneath Southeast Asia. In the process a subduction trench has formed which curves around Indonesia, towards Myanmar and finally reaches the eastern edge of the Himalayas. Along Myanmar the ocean floor has fully subducted and a continental collision is taking over. The entire arc is called the Sunda trench; it has a length of well over 3000 km and achieved worldwide fame from the 2004 megathrust earthquake (and two very large but less publicised earthquakes in 2005).
There is considerable plate diversity here. Much of Indonesia, the Philippines, Vietnam, Malaysia and Myanmar are on the so-called Sunda plate. Under pressure from Indo-Australia, this platelet moves different from the Eurasian plate, but there is no clear dividing line: it is sometimes considered as part of the Eurasian plate and sometimes as a distinct plate. In most places the Indo-Australian plate is subducting underneath the continental crust of the Sunda plate, but south of Sumatra the subduction is underneath oceanic crust.
Source S. Bose et al., Tectonophysics, 849, 229727 (2023) https://doi.org/10.1016/j.tecto.2023.229727
The subduction zone associated with the Sunda trench has the typical appearance for such regions. At the zone itself, there is a deep trench, which at its deepest reaches more than 6 km below sea level. Behind this trench is a ridge of pushed-up material, largely formed from the sediment that was deposited on the ocean floor of the Indo-Australian plate and scraped off by the overriding plate. Behind the ridge is a fore-arc basin, a deeper region which may also have extension. Finally, even further behind is a line of volcanoes. This structure, including the volcanoes, is very clear in Java and Sumatra but can also be recognized in subduction zones such as Alaska.
The height of the ridge depends on the thickness of the sediment. At Java, there is only a few hundred meters of sediment, so here the ridge remains deep under water. It is much thicker at Sumatra, and here the ridge reaches above sea level in several places. This has lead to a series of islands sitting in front of Sumatra itself, such as Nias and Siberut. These islands are strictly non-volcanic. The same has happened at the Nicobar and Andaman islands: these islands also are situated on the pushed-up ridge. Further north, on the side of India, the sediment is many kilometers thick, and this has given us the high mountains of the Rakhine range in Myanmar. (Visiting those is not for the faint-hearted as it is a war zone. The world has become a dangerous place; humanity seems as fragmented as the plates it lives on, in a struggle for supremacy and survival among the ancient would-be dictators. And isn’t that what tectonics is all about as well? But Andaman remains safe, if you stay away from North Sentinel or other forbidden islands.)
The direction of the subduction is important. North of Sumatra, the movement is almost along the subduction front. This is one reason why volcanoes peter out in Sumatra and are (almost) absent further north, apart from some extinct volcanoes in Myanmar. This transverse motion is taken up by a slip-strike fault. The subduction along Sumatra is oblique, and here too a transform fault runs parallel to the subduction trench, along the spine of a the island. (It also takes up the rotation of Sumatra and Java). It runs along the Nicobar islands. The fault continues towards Myanmar but here it jumps eastward, further from the subduction trench: it becomes the dangerous Sagaing fault in Myanmar. The stepped offset of the transform fault occurs near the Andaman islands. The area between this offset fault and the subduction trench is moving north, in a motion shared with the India-Australia plate even though it is not part of this plate. It is therefore considered its own microplate, named the Burma plate, a defection from the Eurasian plate which adds to the plate complexity in the region.
Source: S. Sokolov, V. Trifonov, Arc Tectonic Elements and Upper Mantle Structure of Central and Southeast Asia: Seismic Tomography and Seismicity Data. Geotecton. 58, 23–40 (2024). https://doi.org/10.1134/S001685212470002X
The Burma plate is best known from a single event. In December 2004, the subduction zone failed close to Simeulue island, one of the pushed-up islands in front of Sumatra. From there on the failure rapidly migrated north, at a speed of 2.5 km/sec. The failure started at the southern extreme of the Burma plate and traveled north as far as Port Blair. This magnitude 9.3 event was the largest earthquake in the world for 40 years: the ensuing Boxing Day tsunami caused devastation across the Indian ocean. And it all came from the subduction underneath the Burma plate.
As mentioned, he Nicobar and Andaman islands delineate the swept-up sediment ridge along the Sunda trench between Indonesia and Myanmar, connecting the volcanic arc of fire of Indonesia to the edge of India wedged into Eurasia. Don’t expect volcanoes here, and don’t look for craters, basalt and pyroclastics, or hot springs. Do expect earthquakes, and on occasion, tsunamis. Otherwise, these islands are a haven of tranquility between volcanic excitement to the south and continental collisions to the north.
The archipelago
The naming of the many Andaman-Nicobar islands shows a certain lack of inspiration. From north to south, the main islands are called North Andaman, Middle Andaman, South Andaman, Little Andaman, Little Nicobar and Great Nicobar. There is slightly more variation, but no more inspiration, among the smaller islands of the archipelago, which include Coco Island, East Island, Interview Island (??), Sound Island, Strait Island, Defence Islands, Passage Island, East Sister Island, West Sister Island. The names sound slightly desperate and do not do the place justice.
The airport is at Port Blair, the main town on the Andaman islands. Although it is called an international airport, it only accepts flights from India, leaving the meaning of ‘international’ unclear. Around 150,000 people live in Port Blair, around a large bay which also hosts the Indian navy. The town is surrounded by tropical jungle. The climate is hot and humid: temperatures are around 30 degree year-round, with a dryer season from January to April and wet to very wet at other times. The larger islands are linked by a single road which winds through the jungle and runs past the mangroves and coastal beaches towards the other towns and resorts, mainly on the east side of the islands. Don’t expect luxuries and entertainment: the tourism is still low-key and alcohol is not commonly on the menu. But the beaches are spectacularly white, the corals undamaged, the fish colourful, the mangroves smelly and the world here still natural and real. On the road, car windows have to stay closed, in order to protect the indigenous population from diseases brought in by the tourists from distant shores.
The Andaman sea
Between the Andaman Islands and the Malay peninsula lies the Andaman Sea. A depressed continental crust should allow for a depth of hundreds of meters. But instead, the central basin has a depth of over 2 kilometers which requires oceanic crust. Indeed, there is oceanic crust here, some old and some young. The young crust is related to the steps in the transform fault that runs through the Andaman Sea. Each of the steps acts a short spreading ridge creating new oceanic crust.
In the annotated google-map map above, the dashed lines show the young oceanic crust in the Andaman Sea, coming from the so-called Andaman Sea Spreading Centre. The spreading centre started some 4 million years ago in the east and has been expanding towards the west. It is currently spreading at 3.7cm/yr. The young age may make it our youngest -and smallest- ocean, from a split in a microplate! It is not likely to last though.
With oblique subduction, as is the case here, it is common that the transform motion is taken up by another fault a bit further downstream. Having it develop into a spreading centre is more unusual. The Andaman Sea is now considered to be an extensional back-arc. The ‘back-arc’ part means that it is located behind the line of volcanoes – which in this case involves just one active volcano and some submarine cones. The west side of the Andaman Sea is by this definition a fore-arc, and the east side a back-arc. Such is semantics. The eastern third of the Andaman Sea is continental crust from the Sunda plate and is shallow. This is also true close to Myanmar: here the depth is even less, due to silt brought in by least-known of the great rivers of South Asia, the Irrawaddy.
The Andaman Sea has a thinned crust, indicating that is undergoing extension: the sea is growing. The spreading centre is responding to this by creating new crust. The spreading centre is oriented east-west, requiring a north-south pull to have broken the plate. But what is doing the pulling? Options are that the Indo-Australian plate is dragging the Burma plate along in a drag race towards Myanmar, or that the compression of the Eurasian plate by India is pulling the Burma plate in, with the other end of the Burma microplate kept in place at Indonesia. Either way, the rule of thumb in Asia is that everything is India’s fault – geologically speaking. (For such a large country, and apart from the Himalayas, India itself is remarkably fault-free, although it does sometimes get large earthquakes in unexpected places, such as the destructive Gujarat earthquake of 2001.)
The northward extension is not the only effect. The Andaman Sea is also growing in the east-west direction. This is at a third of the rate of the north-south extension. The cause is in the transform fault, which is somewhat oblique and therefore also shows a bit of extension, at a rate of around 1 cm/year. Back-arc extension is often caused by rollback of the subducting plate, but that does not seem to be the case here.
But although the Andaman and Nicobar islands are non-volcanic, the Andaman sea does have active volcanoes. One, to be precise: Barren Island.
Barren Island
About 80 km east of the main Andaman islands sits, all alone, Barren Island. It is not large, at just over 3 km across, and it mainly consists of a crater wall around a central depression, with a cone at the centre. (In fact the central cone itself also has a crater.) The inside of the crater is 1.5 km across. The crater wall is breached to the west and lava has at times reached the sea through this breach. Elsewhere, the outer sides of the crater wall have an eroded appearance. As the name suggests, the island is uninhabited. As the name does not suggest, the outer slopes are densely wooded.
The best way to see the island is with a boat tour from Havelock Island. The island is a protected territory, where landings require special permission (don’t expect this during the tour) and overnight stays even around the island are not allowed. The journey takes three hours and the boat needs to return to Havelock afterwards. This leaves around 6 hours at Barren Island, much of which may be spend snorkeling on the pristine reefs. The season for taking such a tour is quite short, from December to March. April to November is much wetter with tropical storms, making this long sea trip potentially unpleasant and on occasion hazardous.
The cone is almost the highest point of the island. Its height was last reported as 335 meters above sea level. A drawing from 1789, around the first report of volcanic activity, shows the cone but smaller than it currently is, with the highest points of the island on the crater rim. The rim is up to 355 meters tall and this is the commonly stated height for Barren Island. Recent eruptions have added height to the cone. The eruptions also extended the western shoreline. The sea is 2200 meters deep, making this a substantial volcano. Over 95% of the volume is hidden below water, making it worse than the proverbial iceberg – a poor analogy for a volcano anyway.
Source: wikipedia. Barren Island in 1789
Nowadays the volcano erupts regularly. There are reports of eruptions from 1787, 1789, 1795, 1803-04, 1832 and possibly 1852, but this followed by a quiet time lasting more than a century. The volcano came back to life on 28 March 1991, with an eruption from a vent below the summit. The surprising eruption was reported by a ship in the area and was confirmed by overflight a week later. By July, the eruption had become much more intense, with explosions from the summit crater and a plume 1 kilometer high; the eruption tapered off in October. The peak of the eruption coincided with the peak of the rainy season: the eruption may have been strengthened by rain water percolating to the magma conduit.
The eruption resumed on 20 December 1994, continuing into 1995, but was less vigorous this time. Perhaps this was because it ended by mid-June, before the peak of the rainy season! Again, this eruption was first spotted from a passing ship. A landing on the island was done in April: it found lava flowing from a vent at the bottom of the cone, and reaching the sea.
The next eruption came in May 2005, developing in multiple simultaneous eruption columns. This phase continued with intermittent events until 2010. Further eruptions came in 2013–2016, 2017, 2018–2022 and 2024. All these eruptions were fairly minor, with VEI of 1 or 2 only. The eruptions are strombolian, with ash and scoria cone formation, but with limited lava flows. The initial explosions in the eruption sequences are likely hydrothermal: in this tropical climate, rain seems to be a driver of eruptions.
The lava on Barren Island is subalkalic basalt to basaltic andesite, on occasion andesitic. Although the thickness and extend of the lava flows of the 1991 and further eruptions are reported in several studies, the actual lava flows themselves were rarely observed. (An exception was in 1995.) One paper even argues that the lava flows seen around the scoria cone come from the eruptions in the 18th and 19th century. However, this is contradicted by the reports on the ground of 1995 and the fact that the shoreline in the western breach moved outward during this time. Short lava flows have also been seen near the summit of the cone. The lava volume has not been large, however.
Sentinel image of 28 September 2018 showing a short lava stream. A very similar lava flow was seen on 4 April 2024
INSAR data has shown deflation during eruptions. The data indicates that the eruptions were fed from a very shallow magma chamber at a depth of 600 meters below the cone, which is not far below sea level. Other papers suggest 5 km depth. A deeper magma chamber seems to exist above 20 km depth.
A 20-meter wide beach at the western breach. Source: P. C. Bandopadhyay, Biswajit Ghosh and Mara Limonta, A reappraisal of the eruptive history and recent (1991-2009) volcanic eruptions of the Barren Island, Andaman Sea. Episodes Vol. 37, 192 (2014). (I have not been able to locate this on the map of Barren Island. It is much too narrow for the main breach and shows no young lava. It may have been an inlet just south of the breach.)
The eruption in July 1991. Source: Bandopadhyay et al., 2014
Older eruptions
The structure of Barren island shows the effects of older eruptions. The satellite image shows the shape of the crater, but also a remnant of an older crater as an outer arc on the southeast of the island. That older crater also shows indications of a breach, towards the southwest.
The two large craters (the central one and the southwest arc) show that the volcano can do much better eruptions than the rather minor recent activity. These were not one-off events. A sediment core extracted 30 km east in the nearby ocean shows seven distinct ash layers, with compositions that identify the source as Barren Island. They are dated to between 70,000 and 10,000 years ago. All seven will have required major explosions. The largest of these explosion is dated to 61,000 years ago, with the next one not until 24,000 years ago, so after a long quieter period. After that there were three further explosions 5000 years apart, but the last one was 10,000 years.
The ash from the explosion that happened 10,000 years ago is also seen in layers exposed in the caldera wall. That means that the caldera must be younger than that, and did not form in that event. It apparently formed without a major explosion. The likely cause is a collapse from loss of magma pressure during an eruption. The current eruptions are at or around the central cone. However, and speculative, eruptions may have occurred on the submarine slopes that could have caused such a collapse. And it cannot be fully ruled out that there were in fact more explosions, but that the wind pushed the ash away from the part of the ocean where the sediment was studied!
The age of Barren Island is not clear. Argon dating on crystals found in the oldest rocks of the island give ages of 1.5 million years. But this may be recycled material, where eruptions brought up much older rocks from below. Old magma may be reheated, leaving the crystals in it unperturbed. The region must have been volcanic 1.6 million years ago, but this activity may have been deep submarine, with the island only emerging from the sea much more recently. The explosion 70,000 years ago must have come from the above water, so at this time Barren island existed. The lack of deeper ash layer may indicate that before that, this was a submarine cone.
Barren Island is normally interpreted as a subduction volcano and this is by far the most likely cause. The alternative is that it is related to the spreading centre, however it is located some distance from this. Barren island sits just west of the region affected by the spreading centres, and so in unaffected (or less affected) by the northward motion. This may have allowed it to remain at the correct distance from the subduction zone for the volcanism to continue.
Barren Island is sitting on the older oceanic crust, not on the new oceanic crust formed by the spreading centre.The local crust is some 100 million years old, and must have formed during the break-up of Gondwana. Where exactly this would have been located may be hard to determine!
Other volcanoes
There is one more island here with a volcanic origin. Narcondam Island lies 150 km north of Barren Island. Like Barren Island, it is small, at only a few kilometers across, but it is a more impressive 700 meter tall and has three separate peaks. The volcano is extinct or dormant, apart from one report of a mud eruption 20 years ago. There is a suggestion that it may have had an eruption 20,000 years ago. More secure is a large andesitic eruption 560,000 years ago. The mountain has suggested to be 700,000 years old. But the history of this island is quite understudied. The lava here was a bit more dacitic than at Barren Island. The underlying crust is also different: while Barren Island is build on oceanic crust, Narcondam is underlain by continental crust.
Baratang Island could also be mentioned: it is known for its mud volcanoes. Baratang is located at the main Andaman islands. In spite of the name, mud volcanoes are not volcanic. They are also not quite as large as Barren Island.
Baratang island mud volcano
Final word
Barren island is a remarkably interesting place with a name that does not fit the location. It is the only active volcano of the world’s most populous country, and is the only active volcano in southeast Asia. Since 1991, it has changed from a volcano that slept for a century, to one that erupts every other year. (Perhaps somewhere a prince is regretting that stolen kiss.) But Barren Island is remarkably little studied. There is even controversy over whether or not the eruption produce significant lava, a rather unique unknown for a volcano that erupts so frequently! Perhaps the ill-fitting name really refers to the lack of data. There is work to be done – before Barren Island starts another century of solitude.
Albert, October 2024
see also: https://volcanohotspot.wordpress.com/2015/05/05/barren-island-volcano-india-is-presently-erupting/
Brazil or Kazakhstan. Or Greenland if that counts 🙂
I think Brazil is the correct answer.
Well, that was quick. Ding! (1/3rd of the ding for Chad for taking three bites of the cherry.)
Triple dipping ..
Ok then Kazakhstan, Brazil is probably the right answer but its hard to find information on Fernando de Noronha and it might still be active.
With Brazil, there is some uncertainty called Martin Vaz. Martiz Vaz island belongs to Brazil and is the youngest volcano of the Trindade hotspot that has been active for tens of millions of years. The subaerial part of the volcano has yielded ages as young as 300,000 years old:
https://www.sciencedirect.com/science/article/abs/pii/S0895981120306337
But the volcano is almost entirely submarine, with only some tiny islets above the ocean. So it may have erupted recently and we wouldn’t know. There is some potential for it to erupt in the future.
Yes, Martin Vaz is Brazil’s Barren Island. The volcanic exception in a volcano free nation.
I would not call a volcano that hasn’t erupted for 300,000 years (or more?) as dormant. So Brazil it remains. But submarine volcanoes are the big uncertainty. There are many submarine cones: they last forever (very little erosion) and it is hard to tell when they erupt. Strong evidence is required to proof activity.
Has volcanism there shut down or is it able to recur again?
Martim Vaz is dicussed to be related to a hotspot: https://en.wikipedia.org/wiki/Trindade_hotspot
Well… it is likely to reoccur. As mentioned, Martin Vaz has 300,000-year-old nephelinite ages, although with a very large error. The youngest solid ages are 450,000 and 500,000-year-old ages on nephelinite and phonolite. Trindade is apparently even younger, the well-preserved Paredão nephelinite cone on the south coast has an age of 60,000 years:
https://www.sciencedirect.com/science/article/abs/pii/S1871101424000220
GVP doesn’t consider either of them to be active volcanoes since they haven’t erupted in the Holocene. But as a hotspot Trindade is likely to go on. A hotspot that has been erupting since, the Mesozoic? is unlikely to go out 60,000 years ago. Whether it’s Martin Vaz or Trindade or a new volcano growing offshore it’s likely to happen at some point.
If you want Greenland, you may add it to the “Danish Realm” which this way is the biggest non-volcanic Realm in the world. https://en.wikipedia.org/wiki/Danish_Realm
The Danish Realm lost all its volcanoes 1944 with Iceland: https://en.wikipedia.org/wiki/1944_Icelandic_constitutional_referendum
The Danes are good in hiding their Realm. When they lost with France the Napoleonic wars, no one thought about to take over the northatlantic Danish possessions. Danmark only lost Norway, but remained ruler of Iceland, Greenland and Faroe.
It still wouldn’t beat Kazakhstan, though.
Barren Island is an example that for some countries strombolian eruptions are “big events” while others in the world would notice them as “boring events”. Youtube has a volcano tourism clip of Barren Island: https://www.youtube.com/watch?v=Gxmxn-CM8-U
The cone of Barren Island volcano reminds me to the pre-2018 Anak Krakatau cone. Do they have a similar magma and average eruption type?
Might not have been the cone’s growth:
Sea level had a low period around 70Ka (marked “MIS4” on the graph). This may have brought the top of the cone shallow enough for Surtseyan explosions to take over from pillow lavas, if the water pressure at the vent was below the critical point for water. The lack of explosions between 60Ka and 24Ka then is likely due to the higher sea levels. in between MIS4 and the LGM. Then at the LGM the sea level was even lower than around 70Ka, and there were more kaboomeys. Since then, the volcano has grown enough to become subaerial, even with the high sea levels of the present time. Likely during the LGM it became subaerial and was able to grow rapidly at the top, unhindered by wave erosion, outpacing subsequent sea level rise.
Also, the article has quite a few typos:
Maybe “VO” should be “VA”?
… but the accompanying map has a label saying “Rahkine mountains”. One of them is presumably wrong.
“thses” -> “these”
Perhaps not technically incorrect, but definitely unusual.
Erm, “Eurasian plate”.
“The fact that” …
Presumably only one of these spellings is correct.
One typo can be excused, though:
Hardly the worst of the British Empire’s sins in the region, though, to be sure.
Happy to fix typos but these posts take considerable effort to write and I am afraid spelling does not always take priority over content! Hope that the meaning is clear even where the spelling is not perfect
Maybe have a shot at Grammarly. Pretty good for me and does it better than I can when I’m typing.
A matter of personal pride, personal writing style, and having to correct the auto-correct as often as it corrects me..
Understandable, simply a suggestion. Some things on there would be “autocorrected”, basically.
And even autocorrect doesn’t know when “build” should actually be “built”, a mistake I have often seen in this blog, by several authors.
But…, regardless, this is still one of the best sites on the net!
I missed one before: “The failure started at the southern extreme of the Burma plate and traveled north as fas as Port Blair.” I note that most of the others have now been fixed, aside from the erroneous label “Rahkine” in one of the images (which I expect might be a bigger PITA to edit than the text is).
B.Bound
This reminds me of an exchange on a (random) YouTube video where a pedant was correcting another’s spelling and got replied with
” ah. .fixing the internet one spelling at a time” good luck with that!
I am always grateful that people with knowledge, and the ability to convey it, take the time and effort to write these extraordinarily good posts on VC. The standard really is top notch. Any minor typos can easily be interpreted and for my part rarely (if ever) get in the way. Indeed, it is usually my own ability to comprehend that is called into question rather than the failure to explain!
I’ve always been interested in Barren Is, and North Sentinel Is too, but I was going to post this one. After which I’ll do justice to Albert’s post and actually read it… 😀
Increased chance of eruption at end of November? (RÚV, 29 Oct)
A new assessment of magma accumulation in Svartsengi on the Reykjanes Peninsula indicates that the probability of a new magma flow and even an eruption at the end of November will increase.
This is stated in the latest data published by the Icelandic Meteorological Agency’s natural disaster experts on the agency’s website.
That’s a little earlier than I was saying (around Christmas) but I defer to IMO volcano peoples, they know their island a lot better than I do. (And no Australia, where I live, isn’t the largest country without a volcano. But Heard Is is not precisely easy to get to!)
Oops, the blockquote didn’t work, the two paras after the headline are from the RÚV story.
Not just Heard Island, there are either two or as many as 4 active volcanoes on the mainland too. Newer Volcanics in Victoria, and the Nulla, Undara and Atherton fields in north Queensland. Undara is potentially an embryonic central shield volcano but thats only on morphology it is very poorly known apart from a few spots. Anyway Newer Volcanics and Undara have confirmed Holocene eruptions and Atherton is very probable. Nulla has an eruption 21000 years ago but very wide intervals are typical.
It also does have to be added that Papua New Guinea was a part of Australia when Mt Lamington erupted in 1952, it isnt now but I wonder if it counts still 🙂
Yes, that is correct. Australia didn’t qualify as, apart from Heard, it has volcanic fields on the main land with live magma which could erupt. There have been holocene eruptions
It’s still looking like a Christmas or New Year eruption.
Or end of November?
https://www.ruv.is/english/2024-10-29-increased-chance-of-eruption-at-end-of-november-426032
They are talking about the lower limit of magma they believe is required before an eruption can happen and when that level will be reached. Before the last eruption, that level was reached on July 16 and at that point IMO stated that there was a high probability of an eruption within the next three weeks. In the end it took five weeks, so they weren’t that far off.
The only thing they are saying now, is that by the end of November, the probability of an eruption will increase. They are not actually predicting an eruption to start at the end of November.
An increasing probility of a new intrusion/eruption doesn’t mean that it will happen. Now we’re in a very safe situation for Grindavik that eruptions can be excluded for today or tomorrow and a visit is without risks.
If the next eruption actually happens in January, the subjective risk/probability in the volcanic field will begin to increase much earlier. I’d advice to keep out of life-threatening parts during at least the four weeks before the eruption. That’s around December 1st and confirms the statement of IMO about increasing probability with end of November / beginning of December .
I have to support Chad with regards to Brazil, but a possible second is Kiribati (3,441,810 km2 via wiki).
Sometimes I look at Google maps. The topography of the ocean floor is interesting. Here’s the area around Barren Island (which is in the centre of the map).
I was surprised Albert to see your comment about a north south spreading centre. I’d never known that. The link though shows three trenches just east of the Andaman-Nicobar island chain. Those trenches and/or back arc basins look to be an extension of the Sunda Trench system. Although subducting to the west rather than the east.
Which may say that Barren Island is actually a volcanic arc volcano…on the eastern side of some old trenches. I have no idea. But the linear features in the map are interesting.
That whole area is a complicated place!
Just reread what I wrote. If Barren Is is a volcanic arc island then the plate would be subducting under it – like the Kermandecs. So it would be subducting to the east not the west. I get the whole left-right thing mixed up too…
Nice article Albert: it does sounds like a very nice cute little pirate island still its not Io .. 😉
No volcano is too big for me…
Its not Loki Patera but its still a very good read 🙂
Did any volcano in the region react anyhow to the megathrust earthquake 2004? I imagine that a physically moving earthquake like this also changes the situation on subduction zone volcanoes a bit. The oceanic plate moves by some meters during a megathrust quake. It may interrupt the plumbing system below volcanoes.
Barren Island erupted 2005-06.
Kerinci 2007 (had already erupted 2004), Dempo in 2006, Sinabung 2010 onwards.
Nothing really concrete
It’s probably an overestimation that changes by the megathrust quake are visible by volcanic action. A movement in the plumbing system doesn’t have to lead to a significant change in eruption behaviour.
Maybe an ongoing sonic monitoring (comparable to medical ultra sonic examinations) of the geological structure of the volcanoes nearby the epicentere would have discovered possible movements in the volcanic plumbing systems.
There have been claims that the 2004 earthquake triggered eruptions at Barren island, but the data is far from convincing. The link between earthquakes and mud volcanoes may be stronger! In general, earthquakes can destabilise slopes and slope failures can trigger eruptions, but slope failures can also be confused with eruptions.
I’d distinguish between ordinary earthquakes and megathrust earthquakes. Megathrust earthquakes are linked to a “macro” movement of a plate and shift the position of the volcano above a bit. 2004 was a major movement along the plate boundary, where some islands rose significantly. Hotspot islands like Hawaii can also do its own type of a megathrust quake like 1868, when a big part of the island was sliding and created a tsunami, followed by unusual eruptions of Mauna Loa (low SWRZ) and Kilauea (Iki).
https://www.nps.gov/havo/learn/nature/mauna-loa-1868.htm#:~:text=The%20eruption%20of%20Mauna%20Loa,the%20associated%20tsunami%20and%20landslides.&text=As%20with%20most%20eruptions%20of,summit%20caldera%2C%20Moku%27%C4%81weoweo.
Kilauea has become quiet, which js something I have seen it do immediately before a flare up that typically results in an intrusion. Dikes have an over 90% success rate erupting in the middle ERZ since 1950 though so chances are Pele will say hi before 2025.
SDH and Iki are inflating, so magma comes up below the summit … before it either is going to go down to ERZ or does something in the summit area. We’ve had numerous intrusions this year without eruptions. This remains an important outcome up there.
The Mauna Ulu era showed that ERZ activity can be accompanied with random activity around the summit and even SWRZ. Again 2008-2018 was a time of parallel summit and ERZ eruptions.
The summit and SWRZ erupted while Mauna Ulu was active because Mauna Ulu grew taller than the rim of Halemaumau. For that to happen with a middle ERZ vent it would need to build a 300+ meter tall vent, which is twice as high as the vent of Pu’u O’o ever got above its original base. The only time a vent was ever able to form at the summit while there was a vent erupting in the middle ERZ was the lava lake from 2008 to 2018 but being realistic it only actually properly erupted right at the very end when Pu’u O’o was at its tallest and that was enough to break everything.
Its possible the next eruption could be in Halemaumau, or on the SWRZ, or near Pauahi. But the fact the summit has been dead for over a year coinciding with rift activity, and that out of 4 intrusions from the upper SWRZ and ERZ connectors only one slightly erupted while the first time a dike gets east of Mauna Ulu it erupts quite successfully… I think there is an obvious preferrence where it is easier.
Does magma first go up below the summit and then down towards ERZ or is the whole path from the summit’s root towards ERZ an upward path?
The summit and SWRZ eruptions 1971 happened, when Mauna Ulu did a break. Maybe there was a temporary hesitation or blockage towards the middle ERZ. In fact Mauna Ulu’s 1969-1974 was divided into two seperated blocks: 1969 – June 1971 and February 1972 to July 1974
“When a 29-month-long eruption at Mauna Ulu on the east rift zone began to wane in 1971, the summit region of the volcano began to inflate rapidly; apparently, blockage of the feeder conduit to Mauna Ulu diverted a continuing supply of mantle-derived magma to prolonged storage in the summit reservoir. Rapid inflation of the summit area persisted at a nearly constant rate from June 1971 to February 1972”
https://pubs.usgs.gov/publication/70011736
Again since July 1974 the summit and SWRZ were able to erupt: July 19th and September 29th summit, December 31st SWRZ.
Mauna Ulu was taller than Halemaumau or actually anywhere that summit eruptions could occur. The 1971 and 1974 eruptions were at the caldera or nearby but were basically flank vents of Mauna Ulu according to gravity. Same reason Kilauea erupted in Halemaumau in 2020, ‘summit eruption’ but actually at a lower elevation above sea level than most of the ERZ.
Now the crater floor of Halemaumau is 900 meters, which is a lot higher than the middle ERZ. Its a very different scenario
1971 and 1974 the eruptions happened, when Mauna Ulu had problems resp. had stopped erupting. Now we are also in a moment, when the ERZ is relatively active, but doesn’t get an eruption done. As long as no eruption occurs there, it’s still possible that a “random” eruption like 1971 and 1974 in the summit region or upper riftzone happens.
‘Relatively active’ is a bit of an underestimate, in only a few months there have been 3 intrusions each being more than 1 dike from the looks of it. The fact there was a significant eruption among them after only 3 months of build up is a telling sign, the SWRZ had 2 intrusions in 9 months of rapid inflation and only one erupted slightly. The summit before that was dominant for about 3 years but was relatively weak, around half the average output of Pu’u O’o so clearly magma was going elsewhere even then.
The chances are that the currently rapidly filling ERZ under Makaopuhi and Napau will be where the next intrusion is again. The tiltmeter at Pu’u O’o looks like it shows deflation there but I think it actually reflects the ERZ west of it being uplifted.
Yes, Makaopuhi-Napau continues to rapidly uplift:
http://geodesy.unr.edu/NGLStationPages/stations/MMAU.sta
Right now, fracturing earthquakes along the rifts are mostly focused in two areas. Around Kokoolau and Hiiaka craters, and between Napau crater and Pu’u’o’o. I’d go for either of those two earthquake swarms sourcing the next dike intrusion:
https://www.usgs.gov/media/images/earthquake-hypocenters-map-and-cross-section-past-week-kilauea
Some not-so-good news concerning H5N1,
https://www.aphis.usda.gov/news/agency-announcements/federal-state-veterinary-agencies-share-update-hpai-detections-oregon
Significantly more people are getting infected than before now as well.
‘Go there, and do not expect any efforts to be made to recover your body. Effectively, they are independent – even their language is not known or understood.’
In 2024, it’s absolutely mad that there are still civilisations entirely disconnected from the rest of the modern world. It’s also kind of cool though.
The Sentinalese arent actually uncontacted, they do know the rest of the world exists but dont want contact. Their hostility is possibly a very extreme measure but it isnt just because they are really racist or xenophobic for no reason.
The british had first recorded contact, went as expected for late 19th century Empire… Probably where it started, but its likely there has been unrecorded conflict with people since and up to present. An Indian woman did manage to contact peacefully, maybe she was the first foreign woman they met given ships were usually men only and still often are. But it didnt change them.
Same might be true of the uncontacted people of South America, they probably deliberately avoid contact and do know about the wider world in concept. Perhaps contact with colonialism, or just because they dont like anyone. But chances are there isnt any truely uncontacted culture anymore, that has no awareness of the existence of our civilisation. It makes for a catchy title though.
The interesting thing is they seemed somehow to sense the 2004 tsunami before it arrived.
I have a personal theory that in urban environments some of our senses are dusrupted and we dont really learn how to use them. Also that wearing shoes probably kills most of our ability to sense vibration through our feet. Which other animals dont have to consider.
The indigenous population off the coast of Sumatra did the same. They turned out to have a tradition that if the sea suddenly withdraws, they go inland. Tsunamis must be common enough that such knowledge is passed on and survives. No need to involve 6th senses.
Also worth mentioning the Popa stratovolcano in Myanmar, which had a St.Helens -style significant eruption in 6050 BC – likely a VEI4. It also possibly erupted around 442 BC.
Given it’s location i’d say it was created by a combination of subduction and crustal extension.
I wasn’t aware of that! I considered it extinct.
Professor Thorvaldur Thordarson: The “area between Keilir and Trölladyngja is heating up” https://www.youtube.com/watch?v=DakFU5UNL_s
It looks as if we should still take care of Fagradalsfjall. Prehistorical eruption series expanded towards the north and lava flows crossed the northern road. The series 2021-2023 may resume, when Sundhnukur’s series is over.
A couple of comments about the content.
The hot ground that he found at Oddafell is well known if you look in geological maps. The light coloration of the ground is typical of geothermal areas in Iceland and gives a hint that it has probably been going on for a long time. https://maps.app.goo.gl/KZ9KUaKjMk4QXarZ6
He says “the earthquakes that surely were indicating magma on the move”. This assumption is most likely incorrect. He, and many with him, fails to realize that earthquakes happen in rock, not in magma. That particular area is in the perpendicular direction from the tip of the dyke that erupted near Litli-Hrútur, which is where the stress from the influence of the dyke is at its maximum. This is exactly the place you would expect trigger quakes to happen. Yes, it’s a sure sign of magma on the move, but the location where magma was moving is located 3km to the west.
This is a high temperature area, just like Svartsengi. It belongs to Krýsuvík. If magma enters this area from Fagradalsfjall, it will probably not go through the shallow crust like that. It will move silently at depth and maybe form a sill, just like at Svartsengi.
We might get eruptions in that area eventually, just like at Svartsengi. I just don’t buy the idea that magma moved there from Fagradalsfjall during the Litli-Hrútur eruption, and I don’t think observation of ground heat in a known geothermal spot is very sensational, unless it’s a real series of controlled measurements showing a clear trend deviating from historical measurements.
Indeed, this map from https://arcgisserver.isor.is shows what is translated as a “steam/clay bath” (red triangle at the mouse pointer position) at Oddafell. Colors indicate the temperature at -1km, so we are at the edge of a geothermal area.
There is, however, the video maker’s statement that his cam didn’t show these higher temperatures a while ago. But I guess this could also depend on the weather conditions.
And furthermore this is from Hogenson, “Geothermal Surface Mapping and Chemical Sampling in Krýsuvík at: Seltún, Trölladyngja, and Austurengjar” (thesis).
Another wondrous article !!
The macro-, mini- and micro-plate activity is migraine-inducing.
What of the ‘skid mark’ at 90_E ? Will Indo/Australian plate split N/S as resistance builds ? Will the ‘Crumple Zone’ around New Guinea become just the Westward extension of off-shore development, or will it become the ‘Himal-Eastern’ (sic) extension of the mega-range India has generated ??
Extending that great range Eastwards across Southern China etc to the Pacific, just as Africa / Euro collision has raised ‘alpine’ Westwards to Atlantic…
Just as a possible subduction zone developing near Gibraltar *may* arise a-new, or by roll-back of the Western Med arc, akin to the one looping East form ‘Drake Passage’…
Whatever, these will develop in ‘geological’ time, beyond our horizon…
==
Apologies for clunky wording / spelling as awaiting eye-surgery…
Now must turn on the ‘Halloween’ stuff I’ve spent afternoon setting in front garden: Half-term, dry, mild, I’m expecting many callers…
Various options for what will happen in the future! India at some point must be coming to a halt. It is probably being propelled by the subduction around Indonesia. That is far away: something is going to give. Australia is heading towards New Guinea which should be interesting. Behind that, Sundaland is moving east and may try to intercept the behemoth. If that fails, Australia ends up in the Pacific ocean at a time that ocean is trying to close. If subduction begins in the Atlantic, then other things may happen. Asia could split in two, for instance. Australia could do that too – it has happened before.
In my opinion, the answer is always in the oceans. Look for old cold oceanic crust which may begin to subduct, and see how the pull from that will change the world.
New Guinea is a part of Australia as a continent. The north part might be an island arc that collided with it but there is a new trench area forming north of there that is too young to have volcanoes yet. The volcanoes of New Guinea itself seem to be remnants of before the collision or might be intraplate volcanism like in northeast Australia.
Its a bit of an open question of how a subduction zone actually starts completely from scratch at a continental margin. The trenches in the Atlantic are microplates not major ones like the Pacific rim. One way they might form is from fracture zones at continental margins, so maybe the first major subduction of the Pangea breakup seafloor under a continent will be at the Diamantiba fracture zone south of Western Australia.
Im sceptical of an Atlantic subduction zone being able to reverse the trend of the Pacific closing though, or being able to rift apart Asia which is still undergoing accretion from most directions. Carls article on the Baikal and Gakkel ridges joining eventually didnt look convincing to me.
Most likely scenario for the nearish future, the next 100 million years, Africa fully merges with Eurasia and creates the next supercontinent, because apparently it doesnt count yet… Although this isnt a total supercontinent yet,
South America and Antarctica arent directly involved, although its likely the Panama isthmus will still exist. Australia might be an offshore landmass in the smaller Pacific but it also might be only a bit further north than it is now with a major mountain chain stretching from there to the Atlantic through the modern Himalayas, I guess the final completion of the Tethys saga. Zealandia might well be raised from the depths as it overrides one or more of the many powerful plumes in the Pacific, although doing so will likely result in a LIP than a new island paradise…
I think East Antarctica will remain at the south pole until subduction properly initiates south of Australia or Africa. But West Antarctica might rift away and float off into the Pacific, accelerating its closure. This might actually keep the planet in an ice age or induce another if it is further out.
I think the model of Novopangea from the show The Future is Wild is probably the most likely of the 3 popular models. Pangea Ultima is the least, but most popular. Amasia is the same as Novopangea but Antarctica stays put, which seems very unlikely for so long.
If the Baikal rift progresses (and that is an ‘if’) it could go east or north. There are old fractures in either direction which could reactivate. Subduction begins when ocean crust gets too old (cold) and exceeds the density of the mantle below. The oldest ages are normally found against continental margins (though not always). The Pacific ocean is a lot older than the Atlantic, so its subduction is well established. The arctic ocean seems a bit of an unknown: it is also old but left out from these projections.
Baikal rift looks more like a passive tear in the crust because of all the tectonic activity around the continental margin. Its not an upwelling plume like under Africa. That isnt to say the rift is failed but I cant see it actually splitting the continent without force from below. I know there is volcanism in the rift but it isnt of a scale or intensity to suggest unusual melting rates.
Continental collisions rarely do volcanism. Baikal is tearing because of rotation caused the push from India. The rift is quite a bit longer than Lake Baikal itself but Baikal is by far the deepest part. The lake is still widening. If it gets deep enough that the mantle below starts to bulge up, then it can develop into a spreading centre. You don’t need a plume for that (although that can help): there is enough heat in the mantle. But Baikal is sitting on ancient crust (as shown by the fact it is a narrow tear, not like the wide valleys in the western US) and those can have stabilising keels. On the other hand, the continental keels can erode or dislodge: ancient cratons can and do split. It is a long shot but so was baikal itself.
I didnt make the claim continental collisions cause strong volcanism.
What I was saying is that The Baikal rift isnt caused by an upwelling but is just where the force of subduction at the continent margin is axting in different durections and the crust is tearing. I dont really buy the idea of rifts starting passively then flaring up, the mantle wouldnt bulge the crust up otherwise. The EARV shows several such areas where the mantle is upwelling even in places that arent very volcanic or werent until recently. Baikal as far as I know isnt like this.
There are areas that are pushed up without being on a plate boundary, Hawaii being probably the biggest.
I also do still argue we cant be certain subduction starts so easily. The crust can be denser than the mantle but if it isnt dense enough to break itself from its own weight that is irrelevant.
For all we know subduction might only be able to actually initiate from a passive margin if the continent suddenly stops (probably after a collision) and the plate is flexed down and snaps. If that is the case then major subduction of the Atlantic coasts of the Americas might only begin when the Pacific is all but gone, and the assembly of the next supercontinent is in the final stages, maybe over 200 million years from now. That is only speculation still, but its a very real possibility.
There is a lot here I would not agree with! But just on subduction: the mechanism is straightforward and works all around the passive margins of the Pacific ocean, so I am not sure what your point is. And there are places where continents move into oceanic crust which is too young to subduct: that gives flat-plate subduction (not actually subducting but being overridden). It happens along the US west coast. The flat plate stays close to the overlying continental plate until it is finally cold enough to sink. Say Montana.
One thing I’m curious about on a sort of related note, how does all the mostly pleistocene (?) volcanism in Burma fit into this tectonic setting? There’s a ton of volcanic fields there, can’t find that much surface level information about them unfortunately.
Yes, there is very little published about Myanmar. It is pretty inaccessible for research. There used to be oceanic subduction on the west side but that ocean is now gone. The volcanism comes from that. It is the continuation of the volcanic arc around Indonesia, but I had considered it extinct. Perhaps that needs to be reconsidered.
GFUM looks a bit lively?
Link:
The 536/540 double eruption and the vikings. The paper itself is hidden behind a paywall so not worth reading, sadly.
https://www.iflscience.com/has-ragnarok-already-happened-1500-year-old-evidence-of-possible-viking-apocalypse-found-76622
I’ve noticed that a lot of studies about obscure but fascinating events are the ones that are paywalled the most.
A bit more activity north of Reykjavik in the last 24 hours.
The most interesting thing is several of these tremors are quite shallow.
Snæfellsnes – earthquakes during the last 48 hours
I like to think the exact opposite. The most interesting thing is that so many quakes here are so deep…
The fact that this exact spot has been so persistent and even going back before the upgraded seismometers too, its very interesting. Might still be a while before an eruption but it seems a likely case that will occur soon enough.
The last eruption in the area was towards the start of the previous Reykjanes cycle so there could be a bit of a link between the two. Although, there was also the big eruption of Hallmundahraun that may have been closer to influencing Ljosufjoll, and is physically closer too. There have been a few places around Langjokull that persistently quake too, maybe we do eventually get the 10 year eruption we all wanted in 2021 just relocated… 🙂
Is it more related to Hreppar plate movement do you think? The area is closer to Prestahnukur than Ljosufjoll and there doesn’t seem to be evidence of movement at depth along the rift zone towards the concentrated area. The last eruptions here were at Grabrok and Raudhalsshraun but there are 2 pleistocene calderas to the north.
I mean, from the interferograms I have seen the Hreppar plate is kind of indistinct up at Langjokull, im not sure there is really any boundary proper there at all today. Its also on the other side of Langjokull from Snaefellsness.
Im not really sure how a tectonic link between the two is possible really, but it is at least an interesting consideration that Ljosufjoll is a rift zone but completely at right angle to both Þingvellir and to the old rift zone that passes through the same spot… Snaefellsjokull seems to be a mostly radial stratovolcano, and so does Oraefajokull on the opposite plate. Katla and Eyjafjallajokull are also a bit radial, and not exactly on thr plate boundary. But Ljosufjoll is a rift, even back as a central volcano in the Pleistocene. It being a rift might mean there is a bit more going on.
It is possible that we get surprise eruptions outside RVZ at neighbouring systems, but it is impossible what, when and how.
On Reykjanes Peninsula the Krysuvik area has had more earthquakes recently. It is next to Fagradalsfjall on the other (east) side. If a sill goes there as it did to Grindavik area, there could be the next eruption series.
Kama‘ehuakanaloa (Loihi) has had (or is still doing?) an earthquake swarm:
https://www.usgs.gov/volcanoes/kama%E2%80%98ehuakanaloa
The location is in the SE flank of the seamount. It has a “31-km-long (19-mi-long) rift zone that extends northwest and southeast of the caldera.” This means that the swarm occurs / has occured along the southeast rift zone.
Last significant earthquake swarm of Kama. was 10-13 September 2001
There was a big swarm in 2019 or 2020 I think, a deep intrusion. The eruption in 1996 was part of a major event that caused summit collapse so the time since is probably not a fair view of activity, its likely there were more 20th and 19th century eruptions but obviously not observable.
This swarm is no joke, there are five earthquakes magnitude 3 of larger. It could very well be a small dike. Maybe Loihi is erupting as we speak. It’s a submarine volcano so it’s hard to know when it erupts. There have been many swarms like this one, some even larger, in 2001, 2002, 2003, 2004, 2005, 2017, 2018, twice in 2020, twice in 2021, twice in 2022, and 2024. They are short-lived bursts of activity, with changing locations within the volcano, and no mainshock-aftershock distribution. All may have been dike intrusions, and many could have erupted.
Yes, there were swarms after 2001; the GVP bulletins confused me.
Can / did they observe volcanic tremor of Loihi? When around 1989 on Reykjanes Ridge (far from Iceland) a submarine pillow lava eruption happened, they observed tremor. I haven’t read about volcanic tremor 1996, although they discoverd pit craters on Loihi.
I don’t know. I’m not sure if submarine eruptions produce tremor anyway. In subaerial fissure eruptions, the tremor usually comes from fountains when fragments of spatter hit the ground. But submarine eruptions tend to be more of quiet effusions, I think.
The tremor comes from gas bubbles in the conduit. That could happen in submarine eruptions as well.
1989/1990 they didn’t observe tremor on Reykjanes Ridge, only earthquake swarms: “The large distance to the nearest seismograph (roughly 150 km) means that intrusion and extrusion tremor could have occurred without being observed.”
Large distances avoid the monitoring of tremor. Next stations to Kama (Loihi) are HPO and PPLD, but I can’t access the seismometer graphs now.
4.3 at 22:05 3.6 miles Near Loihi
. All the Seismometers are off line at this point.
An M 3.8 was upgraded to M 4 upon revision too. It would be interesting if someone did a bathymetric survey of the volcano after these swarms to see if any new cones have popped up.
According to Google earth, the bottom is 14 thousand feet. Quake is only 1 mile below the sea floor. Estimated!!!!
1 mile below sea level would be basically at the surface of the volcano, so this might well be an eruption. I wasnt aware of so many swarms there since 2000, only the big one of 1996 that was a confirmed eruption. Maybe Kama’ehuakanaloa does erupt as often as Kilauea and Mauna Loa just without as much volume.
This also might be useful in predicting when it reaches sea level. Only caveat there is that Kilauea might grow southwards a lot too, and possibly start burying its sibling to some extent and speeding up its growth. Same as happened to Kilauea itself with Mauna Loa 100+ thousand years ago.
They don’t need to be shallow to be an eruption though. In the 1996 caldera collapse, practically all earthquakes were 8-13 km deep, probably because that’s the depth of the magma storage and base of the dike intrusions (most earthquakes will always concentrate in the rock just under the dike), and also because the depth is not well resolved from the island seismometers.
I think this is likely to be a dike intrusion, whether it erupts or not that is another matter.
https://youtu.be/OI-2vsxqZuo?si=2__EaLqYOLHMoB-i
Looks like Geologyhub has his own thoughts on the future Reykjanes volcano eruption…
I don’t usually say this about this type of content, but he does have some valid points there. I think we have to consider the possibility that the next eruption goes south. I don’t really understand why IMO has lowered the danger level for Grindavík on the hazard map.
I agree with what he has to say but there’s times when he falls into the old youtube channel hyperbole trap either with the names of his videos or stuff like this. I think 80-96 million cubic metres is a very high estimate personally and every likelihood that it stays in the same northward area – it just seems to prefer erupting there and has difficulty erupting southward with any sort of substantial flow rate.
The 85-96 million m3 number is based on the statement the next eruption might be 30% bigger than last time, although maybe a little on the high side of that.
https://www.mbl.is/frettir/innlent/2024/10/25/gaeti_ordid_thridjungi_staerra/
Im not really sure what is wrong about saying an eruption like the last one but going south would destroy Grindavik, because that is literally exactly what would happen… Before the last eruption none of the other ones had gone particularly far north either so its far from an unlikely case to go south, even if not certain.
https://youtu.be/nMmOrkFfj7w?si=EYCWDF34nx8qFv4R
Shawn Willsey also put in his thoughts, with it being likely in the area of most eruptions.
A balanced view. Good! I didn’t have time to watch it all, so might have missed something. I just like to point out that in his sketch of the dyke, before the last eruption the northern part that erupted would have looked like how it looks now under Grindavík. I also think he misses the impact of the tectonic setting. This is not only driven by magma pressure from below, it’s also the plates spreading. There is a limit how much they can spread in one location, so I think he’s underestimating the probability of a couple of scenarios.
In my opinion, I think the volumes might be exaggerated, like it was about 15 million m³ more with each eruption, so it might be about 75 to 80 million m³. Also, I think Shawn might be more cautious and called Geologyhub’s opinion ‘irresponsible’, and he is right in a way, maybe he’s worried about tourism going away because of this. Putting this lower than going the further north thing, of which that caught us off guard, is also equally as speculative. Of the 6 eruptions, two went north than usual, two went further south than usual, so there is each a 33.3% chance either could happen or none at all, then again, volcanoes are unpredictable. We’ll have to wait and see…
It is difficult to impossible to create a model for the eruptions. If we assume that it continues reliably the growth both of “lazy” time and of eruption volume, we get the 75-80 milion cubic meters.
The present RVZ cycle of eruptions is the first time that we observe during modern time an eruption series on Iceland that doesn’t happen linked to a big central volcano, but to the MAR activity on Iceland. That’s also a difference to Krafla, which was used by IMO as an example how the “Fires” also on RVZ would look like. Krafla has a central volcano and is – compared to RVZ – closer to the hotspot.
I have also the impression that the current RVZ eruption cycle behaves different to the Medieval cycle. The Medieval cycle doesn’t allow modelizing for our cycle.
Herdubreid (Askja) had next earthquake swarm this night. DYNG station on east side of Askja caldera shows an upward tendency since April 2023, but there is no GPS station on/close to Herdubreid
brunnur.vedur.is/gps/eldfjoll/askja/DYNG-plate_since-20210719.png
Herðubreið is a volcanic system in its own right. Interestingly, there were swarms here in the run up to Holuhraun.
Lewotobi just erupted, 12km eruption column, judging from videos I saw its pretty serious.
The current eruption is probably its biggest in the last 100 years. Thanks for the update
Facebook translate:
”Kupang (ANTARA) – Six people were reported dead due to Mountain Lewotobi Laki-Laki in East Flores County, East Southeast Nusa (NTT) eruption on Monday early morning.
Village head of Klatanlo Petrus Muda who was contacted by ANTARA from Kupang, on Monday said that the victim died due to the collapse of the house that collapsed due to the explosion.
“The mountain erupted around 00:30 WITA. There is a family of about 6 people who were hit by the building,” said Petrus Muda.
He said there was no evacuation process yet as all the citizens fleeing their villages.
“The new officers arrived at the scene for the evacuation process,” he said while hanging up the phone because he had to serve the officers who had just arrived at the scene.
East Flores County Government has not yet been confirmed.”
Looks like a bonafide VEI4.
10 killed and some buildings on fire as a result of lewtoni laki laki i gather. Hope to see an article about the volcano and its geological setting, is that the end of what we can expect, or was that just throat clearing?
It’s a small volcano with no large caldera nearby. I doubt it go any farther than a VEI 4
I doubt it’s the end. I think it must have been a vulcanian explosion, and may or may not have had a short subplinian phase. It can repeat more times, maybe even stronger/longer. Though I doubt it will reach Ruang levels. You don’t need super-big eruptions to be deadly though.
Maybe it was a vulcanian-pelean eruption with a horizontal movement of tephra (pyroclastic flow). In this case an eruption hasn’t to be very big, but only the wrong (lethal) direction.
Added to this the volcano is on a tiny island, where distances to population is small. The above-average eruptions of Stromboli show, how dangerous relatively small or moderate eruptions can be on volcano islands.
We will try to write something. Not much known yet though
GeologyHub just posted his video.
ps: thanks again for another high quality and fun article.
Shawn updates on the small earthquake swarm near Svartsengi https://www.youtube.com/watch?v=6NfAK-WTlxk
New post is up. Lewotobi on the island of flowers
https://www.volcanocafe.org/flores-and-the-lewotobi-eruption/
I’ll put this up here rather than distract from Albert’s new one on Laki-Laki.
Civil Defence partially activated after quake swarm (RÚV, 4 Nov)
I gather this means that IMO and RÚV are pretty jumpy. But it is Iceland, and they don’t have all that much news to fill the demand for it.
Think they are worried that there might not be a lot of time to get an alert out if/when magma does head for the surface again.
A nice summary of a complex area, and a semi-unknown volcano to boot! Thanks, Albert