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Activity in Reykjanes Peninsula, 20km from Reykjavík, strongly suggests an eruption could be about to happen. Because Icelandic magma comes fairly directly from the mantle, eruptions are not that violent, but the lava can flow out a long way after the initial fountain. And can keep erupting for months or years. explanation of magma activityIn places like South America or Mt St Helens put simply the heat rises as well as some magma, and melts crust, which is higher in silica and more viscous than the mantle, so it blows apart more violently when it erupts. But still, this one is being observed very closely to see what happens next. It isn't under the ice cap where the usual risk is catastrophic flooding. earthquake activityIt is currently on orange level - high alert but not erupting Ash, which is the aviation safety issue.  Latest maps from the Meteorological Office earthquake page, constantly updating: https://en.vedur.is/earthquakes-and-volcanism/earthquakes/And a snapshot of recent earthquake activity as I write this:   And for just that area:
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Eruption has started. Fagradalsfjall. Nice when your geophysical models prove to be valid. Now we just have to see what happens.  Alert status changed to red - eruption in progress.  Image from a Coastguard helicopter sent to assess the sutuation:  The airport is closed because its nearby, but as you can see this isn't producing ash on the scale of Eyjafjallajökull so there is no threat to more distant European air travel. The magma reached a hindrance or constriction under the Nátthagi area, south of Fagradalsfjall. It has erupted in Geldingardalur so its being called Geldingadalsgos. The volcanologist were right to say the decrease in earthquakes was probably a sign of imminent eruption.  A report from earlier: Quote:Ten earthquakes with a magnitude greater than 3 have been recorded since midnight last night, according to the latest data from the Icelandic Met Office. In a surprise twist, none of these were located near the Fagradalsfjall mountain—rather, they have all been located just off the southwestern tip of the Reykjanes peninsula.
In fact, the last recorded quake near Fagradalsfjall with a magnitude of 3 or greater, at the time of this writing, was at around 11:20 yesterday morning. The location of the new quakes is at a major fault line, Reykjaneshrygg, strongly indicating continued seismic activity. However, Elísabet Pálmadóttir of the Icelandic Met Office cautioned that it is not possible to connect this newest activity with the ongoing activity near Fagradalsfjall.
While the decreasing quakes has given people reason to relax, Kristín Jónsdóttir, a specialist at the Icelandic Met Office, told RÚV that decreased seismic activity can also be a precursor to a volcanic eruption.
She points out that increased earthquakes followed by a quieter period was in fact exactly what was observed when Krafla, near Mývatn in northern Iceland, last erupted. As such, it is still far too early to say that a volcanic eruption in Reykjanes is no longer in the cards.
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That’s interesting thar, a pretty good prediction by Kristín Jónsdóttir.
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No mention of people being in any danger. It seems odd to have so many eruptions and no people in danger of magma flows. Is that normal? Or do people have to be ready to move on a moment's notice?
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No towns in the route as it flows down. Volcanic rock weathers to fertile soil, which is why volcanic regions can be highly populated. But in the cold it happens so slowly there is no rich soil - these are lava fields covered in moss. This is unusual in being close to Reykjavik and the airport at Keflavík, but they are not in its path coming from this fissure. Neither is the pipeline. There are other towns Grindavik and Þorlákshöfn which are being affected but not by the lava flows. . The dangers are If a settlent is in the route downstream Hitting pipelines and infrastructure (the main road) Poisonous gases If it becomes explosive. The gas emissions are not too bad so far but people in town downwind told to keep positive air pressure in their homes. If it gets bigger and the wind blows it towards Reykjavik that could be an issue. Also if othe fissure systems in the area get involved. Also depends how long it lasts. Closing the airport for a couple of hundred years might require a plan B. https://youtu.be/mozO06h-CMI
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Different types of volcanoes have different styles of eruptions. There are volcanoes that have a ‘sticky” lava and don’t erupt easily, typically they are inland erupting through continental shelf. In these the pressure builds up and up until they blow suddenly. Think of a soda can that has got shaken up and left somewhere too warm. I’ve seen those tear themselves in half in the back of a car. These are often the most dangerous, although not through lava flows, it’s the pyroclastic flows like Mt. St Helens or that covered Pompeii and Herculaneum after Vesuvius erupted that kill people. Iceland is a special case, a bit like Hawaii it’s a hotspot volcano and it’s across the Mid Atlantic Ridge, the volcanoes there erupt a less “sticky’ lava a type of basalt, once it erupts it tends to flow more freely and follow the slope of the land. They don’t explode and produce flows in the same way.
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Apart from the local effects of lava flows, the ash clouds and the flodding from melting glaciers, it is the poisonous gases you really have to worry about. Quote:Around the late 18th century, there were plenty of priests present on Iceland, including, most notably, one Jón Steingrímsson. Along with plenty of other people back on June 8th 1783, he witnessed a fissure eruption begin and not stop effusing lava for around eight months.
“The ground swelled up with tremendous howling, then suddenly a cry shattered it into pieces and exposing {the earth's] guts, like an animal tearing apart its prey,” Steingrímsson noted at the time, as recalled marvelously over at Scientific American.
Pouring out of 135 separate crevasses covering 2,500 square kilometers (965 square miles) – around three times the area of New York City – it ended up killing around 9,000 people directly through the release of toxic gases and, well, a seemingly endless flood of lava. The ash that polluted the agricultural land around the fissures ended up killing off so much cattle and destroying the crop-growing land ultimately led to a famine in which one-third of the country’s population, about 20,000 people, died.
Steingrímsson’s diary – which you can grab a copy of for yourself – proved to be a valuable assest for volcanologists down the line looking for a blow-by-blow account of the Laki eruption, named after the chain of fissures that emerged back then. Apart from also handing out food and comforting those that were dealing with the terrifying emergence of the hellish, liquid conflagration, he also, on one particular Sunday, held a now-legendary mass. The difference with Iceland is that it is being pulled apart. So the fissure eruptions can keep going. Places like the area around the Pacific are oceanic crust being forced and dragged under the continents, so the eruptions are more violent but unsustainable. Quote:Laki was one of the defining events of Iceland’s history. Its impact went well beyond the nation, covering much of the northern hemisphere. It seems amazing that something that caused so much suffering was seen by so few people. This it shares with Eldgja, which was even larger and must have devastated Iceland, but of which no eye witness report remains. There are reasons. The largest disasters leave the local population decimated and local areas uninhabitable, and the historical record is lost. The region in which the eruptions occurred, and which Lurking has named the Dead Zone (because of lack of earthquake activity), was unsuitable for habitation due to previous lava floods. So no one saw the rift opening, and the lava was only seen when it came spilling out from the river canyon, some days later.
The best record we have is from the local priest, mentioned by Carl: Jon Steingrimsson. He was quite a remarkable person, well educated and caring, and his observations have stood the test of time. His diary is much more than a scientific record: it is a personal story of happiness, worry, despair, suffering and survival, in a developing disaster that would claim the life of his wife and leave him destitute and starving and decimated his human flock. It is about being human in a time of the inhumane. But it doesn’t answer the major questions that we would like to answer about the Laki eruption. What made it happen? Where did the magma come from? Could it happen again?
Looking back
Let’s first get the lie of the land. The map shows the main locations in the story of Laki. Klaustur is the place where Jon lived during the events. It is along the river Skafta, which in those days came from a 200-meter deep canyon further west. The canyon has been filled by Laki lava and no longer exists. Nowadays the Skafta is fed by multiple small tributaries. The first lava flows came down the Skafta gorge, after the rift southwest of Mount Laki fissured. Later, the eruption shifted towards the northeast and now the lava flowed through the canyon of the Hverfisfljot river.
Carl has explained the timeline of the Laki eruption. The first explosion happened in the morning of Sunday, 8 June 1783 (Pentecost Sunday), as Jon was getting ready for the church service. The ash turned day to night, but by afternoon the sky had cleared. The ash returned the next day. The Skafta river began to dry up, and by the afternoon had stopped flowing completely. The lava appeared in the lowlands on June 12, having come down the canyon. The following Sunday, some of the local farmers trekked into the highlands, climbing a peak (Kaldbakur, 8km due north of Klaustur – not the mountain of that name in northwest Iceland – still over 10 km from the Laki rift) to get a view of the events. They were the first (and only?) to see the rift in action, reporting twenty fountains of fire. (Following their example, these types of eruptions are now called ‘fires’). The number may well have been exaggerated – how would we know? By mid July, the lava was encroaching on Klaustur, but it stopped on Sunday 20 July, during Jon’s famous fire sermon. The flow ceased because of a combination of reducing lava flow and quenching by heavy rain (and of course the famous sermon of which sadly no transcript survives).
Four day later, the fissures northeast of Mount Laki opened up, with a major explosion on July 29. The new flows came down the Hverfisfljot river. By August 3 this river no longer flowed, and on August 7 lava appeared in the lowland. This was more sedate than the June eruption, but in the end just as devastating. Various eruption episodes continued, each one accompanied by a new lava flow down the river valley. The last of these was late October. After this, there was still fountaining but at rates too low to reach the lowlands. It was stopped by cooling. Lava can flow as long as it is hot enough. When eruption rates get less, the lava flows become thinner and therefore cool faster. Lava tubes can extend the reach by a lot, but for surface flows, the lava reaching less far is a first sign of a tapering off of the eruption. So it was at Laki. The last fire was seen on February 7, 1784. Quote:Fires of the Earth The Laki Eruption 1783-84 By the Rev. Jón Steingrimsson (trans. by Keneva Kunz)
As I read Fires of the Earth, the translation of Jón´s account of the Laki eruption and its aftermath, I thought Keneva Kunze´s translation easy to read, although I know that given Jon´s religious position and the times, that the original must have presented serious problems to a translator. This book is only ninety-five pages. It attempts nothing beyond sharing the observations of Jón Steingrimsson in English..
Many North American Icelandic readers are unlikely to recognize Jón by his name but they would know who he was the moment his Fire Sermon was mentioned. We all have images of him defiantly preaching in his church as lava from Laki flowed toward it. Before this climactic moment, at least two other churches had been destroyed so everyone knew that the house of God alone was not enough to bring the calamity of the lava to a halt. “on the fifth Sunday after Trinity…I proceeded to the church, along with all of those people then in the Siða area who could manage to do so. I was filled with sorrow at the thought that this might well be the last service to be held in the church, as the terror which now threatened and approached ever nearer appeared likely to destroy it as it had the other two.
“As we approached, the clouds of hot vapours and fog coming from the fire farther down the river channel were so thick that the church could hardly be seen, or its outline could only be hazily seen…Claps of thunder were followed by such great flashes of lightning, in series after series, that they lit up the inside of the church and the bells echoed the sound, while the earth tremors continued unabated.“
He makes his sermon longer than usual, keeping everyone in the church. When he, at last, finishes his sermon, he and others went to see how close the lava was to them. They discovered that it had not advanced at all. “The rivers Holsá and Fjaðará poured over the dams which the new lava had made them, and with great torrents and splashing smothered the fire”.
Jón´s chronicle of this time doesn´t stop with the eruption but goes on to describe the aftermath. Not many were killed by the eruption. The dying came because the feed for the sheep and cattle had been destroyed. To add to the misery, the animals suffer from some terrible disease, from rain that poisons everything and burns the leaves of plants and the skin of people and animals. Jón´s observations are detailed, his analysis intelligent. His bravery unquestioned.
Iceland had a population of around fifty thousand people at the time of the eruption. Ten thousand died. That is one in every five. Jón reports on the desperation of people dying of hunger, dying from eating the flesh of the animals poisoned by the water and grass. The effects on the animals are grotesque.
Jón names the farms that are destroyed, names how much each was worth before the eruption. These were prosperous farms. The owners were wealthy. After the eruption they became paupers. For people who don´t know Icelandic history, the term pauper isn´t terrifying. For those who do know, the word encapsulates forced removal, being sold to the person who will take the least amount from the sysla to keep them, to the loss of all rights until the debt is paid.
Jón begins by describing the years of plenty before the eruption. Times were good. They were so good that people became greedy, uncaring, vain, proud. The abuse of alcohol became wide spread. By the end of 1784, they had all been chastised. Being reduced to eating your leather clothes does that to people.
It is a shame that Fires of the Earth is out of print. It is a book that everyone of Icelandic background should read in order to understand their Icelandic ancestors and their current Icelandic relatives.
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thar wrote: It is a shame that Fires of the Earth is out of print. It is a book that everyone of Icelandic background should read in order to understand their Icelandic ancestors and their current Icelandic relatives.
Thanks for this post Thar, just the short bits of the account were gripping. It is a shame the book is out of print it sounds like one that should be read by everyone regardless of nationality. We become far too complacent in our acceptance of periods of the stability of the natural world and forget how fragile our prosperity actually is.
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Volcano Erupts In Southwestern Iceland After Thousands Of EarthquakesMarch 19, 2021 10:34 PM ET https://www.npr.org/2021/03/19/979438422/volcano-erupts-in-southwestern-iceland-after-thousands-of-earthquakes This is the first eruption in the Reykjanes Peninsula in nearly 800 years, the Associated Press reported. Thousands of earthquakes took place in the weeks leading up to the eruption, the meteorological office reported. Earlier this week, swarms of earthquakes rattled the peninsula, with over 3,000 quakes on Sunday alone. The strongest tremors took place around Fagradalsfjall Mountain. Scientists attributed the earthquakes to magma intrusions, molten rock movement about a kilometer below the earth's crust. Meteorological officials first mentioned the possibility of an eruption on March 3, as these intrusions continued and earthquake activity intensified.
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"everybody seems to be enjoying themselves" As long as there is wind, the gases don't end up in the valley creating a death pit. FD - this video explains why the danger is minimal at present. Except when tourism restarts and some idiot dies and their family sues " you should leave something dangerous like a lava flow without fences and guards. I'm serious, someone would try and sue! update
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"everybody seems to be enjoying themselves" "As long as there is wind, the gases don't end up in the valley creating a death pit." So that's OK. Just don't get blasé. FD - this video explains why the danger is minimal at present. Except when tourism restarts and some idiot dies and their family sues " you should leave something dangerous like a lava flow without fences and guards". I'm serious, someone would try and sue! update with some great video
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One issue, apart from the poison gas, is the road. On the video you can see the area labelled and at the bottom is Suðurstrandarvegur (southern coast road) ie the only road between those towns. If that gets cut it makes life difficult.
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Some more cool (or hot) video Geldingadalur Volcanic Eruption - IcelandMan, the fluid dynamics of a lava flow are so intriguing! Not many peoples get to see the process that built their home and their country. Kind of strange when you think of it that way.
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When you see the eruption and lava flowing in a video, it looks beautiful and a bit dangerous. I'm still glad we have no volcanoes here.
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Still cool Flow rate suggests it could last a few years. update
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Great thread, Thar, and thanks guys for the interesting info. My husband asked me if my friend from Iceland or even Finland on the forum had mentioned the volcano on the forum. I told him you had given us a lot of excellent detail.
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Ah, Finland is our Scandinavian cousin but isn't into volcanoes. Funny that Finland has some of the oldest and most stable rocks - a craton 3100 million years old, and Iceland youngest - just have to wait while it cools. Apart from some wearing down and some ice scraping, Finland is pretty much as it was at the the latest 1900 million years ago. Very thick, ancient crust. Not really into changing a good thing. Crustal thickness  Heat flow  Which is why Finland has hot saunas and cold lakes, and Iceland has hot pools and the occasional lava flow.
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Well put, thar ;-)
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He just meant interest because of proximity. Are the gases staying pretty much in the country?
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Just think if there were volcanoes in Finland. No sauna needed.
Where would I take my regular beer or two? In a local pub? Fearing the lava could flow in just when we started to have a good conversation about T.S.Eliot's Old Possum's Book of Practical Cats.
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Finland are our rather odd cousins (you know I mean that well, JJ!) so there is a certain cultural proximity. But geographically, Finland is almost the same distance away as Spain. They are just chiller about these things.  You can see the effect of being surrounded by sea, and of the Gulf Stream and North Atlantic Drift. Greenland is further south but frozen. Northern Scandinavia is further north and frozen. Iceland is in the middle of the sea and just right.
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INteresting new development, a new fissure. THat often happens but it depends what it indicates about the subsurface plumbing. new fissure
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A close up look at the new cone and its lavafall. https://youtu.be/ppnN94WK960
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Thank you, thar, for the video links. Fascinating.
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A pleasure, Wilmar. Third fissure time-lapse overnight. https://youtu.be/Xf0fsAzctK0And a bit more explanation of what is going on https://youtu.be/NitHqHAofdw
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La Soufrière in the Caribbean (on St Vincent, not the ones on Guadeloupe, Dominica or St Lucia)) - that is different. Everyone is being evacuated. It tends to gow a dome then erupt explosively. It has been in effusive phase with seismic activity increasing and of a style typical of magma movement. . Hard to predict when it will erupt explosively but orders have been given for evacuation as it is predicted to be imminent. Pandemic is not helping! But at least there is advance warning. All hoping for a safe outcome. On a less personal scientific note - the reason La Soufriere is explosive is it is a subduction zone - heat and water rise, the crust partially melts, producing a sticky, cooler, viscous silica-rich magma. Because that holds together better, it can contain the pressure and gases better until it fails and erupts explosively with lots of gas, ash and shattered rock.  In contrast, Iceland is being pulled apart, a hot spot on a spreading zone. . Semi-molten rock moves up from the mantle. It is low in silica, hotter, runny and pours out where it can find a crack. That is what is happening on Reykjanes at present. Much less short-term danger to life. At the most over-simplified level, the difference in eruption is the source of the magma. For anyone who has forgotten their high school geography lessons. , St Vincent  . Iceland  Plates are pulled apart by subducting slabs as well as forced apart by convective forces. But the Pacific plate is subducting under the Eurasian, and doing very complicated things under /against the North American, so the subductive slab pulls are a long way from Iceland. And of course these things are still only barely understood.
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Explosive eruption at Soufriere but so far appears to be plinian ash plume not side collapse or pyroclastic flows. That and mudslides/lahars down the flanks are the main danger. https://twitter.com/i/status/1380512071159320583
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Back to Iceland. What is amazing is the snow isn't melted even an inch away. Shows what a good insulator the rock crust is, even when it's still hot. How much the heat rises. And how cold the ground is. https://youtu.be/fo8G5sRcpm0
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Stil posting because still great images coming out. That roiling lava lake. Well, pond, puddle. It's a gash, it's got some clotting but a scab can't form and the earth won't stop bleeding. https://youtu.be/hsK0tMlYgLs
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thar wrote:Stil posting because still great images coming out. That roiling lava lake. Well, pond, puddle. It's a gash, it's got some clotting but a scab can't form and the earth won't stop bleeding. https://youtu.be/hsK0tMlYgLs Interesting video. How likely is it for that lobe of lava to collapse and surge forward? That could lead to unwanted results.
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So long as the lava front is low, any collapse back at the cone has to either push from the back or run over the top of the cooling lobe - so it won't be instant. But it could be pretty fast. But videos from the end of the lobe foreshorten it a bit.
La Soufriere seems to be going OK, ash fall but not pyroclastic flows.
Mont Pelée on Martinique is also rumbling, and that has a bad history from the eruption in 1902. Pyroclastic flow hit the town and killed 28000 people. But that is not dependent on the volcano, just the particular evolution of the eruption.
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Thanks for your clips, thar. Here we don't see such phenomena very often. Oh, last week there was an earthquake in Bothnia (western Finland). It was 1,6 in magnitude. People felt it, but no one's coffee cup broke.
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