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Eruption expected soon Options
thar
Posted: Friday, August 6, 2021 4:32:35 PM

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Had a few naps but keeps coming back

https://youtu.be/z5P-owDJouE

https://youtu.be/mBJOq2weUGg
thar
Posted: Saturday, August 7, 2021 12:42:44 PM

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Some extra lava lake meditation.

https://youtu.be/QIuljmzmb-c
Hope123
Posted: Saturday, August 7, 2021 1:21:18 PM

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thar wrote:
Some extra lava lake meditation.

https://youtu.be/QIuljmzmb-c


Wow! Some footage.

The next video came up and I also watched a volcano dome collapse.
Jyrkkä Jätkä
Posted: Saturday, August 7, 2021 2:15:26 PM

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OMG, thar! I look these videos in awe.
thar
Posted: Sunday, August 8, 2021 11:29:49 PM

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People seem drawn to putting epic-sounding soundtracks to it.

https://youtu.be/jyIDDcGC11A

Its going to the north a bit, which is problematic. There is a valley but if it fills that and overtops the lip it is heading for Reykjavík.
Although since this seems to be a proto-shield that was always going to be a problem if the eruption lasts for years or decades.

I am amazed you can fly drones there with such control. . Even at zoom distances and with any image stabilisation, the air currents everywhere must be chaotic and intense.
Lotje1000
Posted: Monday, August 9, 2021 1:51:51 AM

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I am definitely here for the epic music addition - that was well-chosen and well-timed. I was half expecting to see dawn break over the edge of the crater at any moment.
Oscar D. Grouch
Posted: Monday, August 9, 2021 4:20:18 AM

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thar wrote:
People seem drawn to putting epic-sounding soundtracks to it.

https://youtu.be/jyIDDcGC11A

Its going to the north a bit, which is problematic. There is a valley but if it fills that and overtops the lip it is heading for Reykjavík.
Although since this seems to be a proto-shield that was always going to be a problem if the eruption lasts for years or decades.



It looks like things have died down at least for the time being.

https://www.youtube.com/watch?v=v_SrRgyX8OM

https://www.youtube.com/watch?v=dWYnv1tBGjs
thar
Posted: Wednesday, August 11, 2021 3:22:27 AM

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Yes, it has been up and down. Literally. Really interesting to see the funnel. Drone technology is showing so much more than was possible previously. Overtopping/breaching the cone again recently, to the north (the high side) as well.

A few new fissures but this still seems to be the main one. Main point is whether/when it starts with other systems.

Seismic monitoring trace shows activity (from gas bubbles coming out of the liquid as it rises and erupts) rising and falling every night.

http://hraun.vedur.is/ja/oroi/faf.gif

for some reason I can't post the image, just a link. But it is safe. In Iceland volcanoes and earthquakes come under the met office. hraun = lava. veður = weather. is= Ísland domain name. faf = Fagradalsfjall (fair dale fell)
thar
Posted: Thursday, August 12, 2021 4:57:37 AM

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This is a trace of plate movement at the geothermal power station site near Grindavík and the Geldingadalir volcano. There was a pulse of movement but it is otherwise stable horizontally. There does appear to have been some active up and down movement at the onset of eruption and since.






thar
Posted: Thursday, August 12, 2021 2:35:45 PM

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Seismic trace shows the continued pulsing of eruptions at the moment. Was >24 hrs apart but possibly getting closer together. The funnel has constricted slightly making the eruptions more vigorous so that could alter the pattern.

thar
Posted: Saturday, August 14, 2021 7:24:04 AM

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Not quite as scientific as usual, but some footage of it over-topping. It has breached the walls a few times to burst out, but the cone repairs as it cools to keep the cone shape.

https://youtu.be/n1rli9YcV1Q


I don't know how far away they are but I am guessing it is some distance. And it's not dark, so they can see to move. So not as dangerous as some might be thinking unless it suddenly and radically changes character which is unlikely.
thar
Posted: Tuesday, August 17, 2021 7:39:42 PM

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So many bad things happening in the natural world at the moment, fires and floods and earthquake and hurricanes, it seems odd to be monitoring our volcano and finding the beauty in it. But it does remind us there is no intent in natural disaster, only consequence.


https://youtu.be/FF12kxc59SE

Epiphileon
Posted: Friday, August 20, 2021 5:12:03 AM

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Now here, to me, is an interesting thing. I can appreciate how one could perceive beauty in these videos but although I can cognitively grasp that possibility, the normal emotional content of perceiving something beautiful is absent. What is there instead is fear. It took me a few days of coming back to this to be reasonably certain of what I was experiencing while viewing but that seems to be on the mark. Perhaps it is because I have absolutely no personal experience with active volcanic activity whereas someone in Iceland is inured to it?
thar
Posted: Friday, August 20, 2021 7:18:36 AM

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It is learned behaviour, I guess. Like I am not scared of snakes or spiders where a person living somewhere else would learn to be more wary. Live in a place with subductive volcanoes and you are taught they explode with devastating effect. Mt St Helens. Pinatubo, Mt Pelee, Krakatao!



In Iceland tgese eruptions last longer and you just live with them.


Flood - if it melts a glacier that is instant destruction. In risk arras you have evacuation plans to the nearest headland zone and not long to get there.
Ash - Poisonous gases- if it is unexpected you are out of luck. If there is an eruption going on nearby always be aware of the wind direction.
Lava - fissures erupt a lot of lava very quickly, but nowadays you get instant alerts (or even forecasting!) and it takes time to flow anywhere.
They don't normally explode and blow the top off a mountain like Mt St Helens!. And when tbey do - well, that happens.


It is a tradeoff. There was not much to burn here - no peat, no coal, not much wood and a bit of sheep dung. Life would have been even harder without volcanic heat. Now that ground supplies heating and electricity.

Monitoring and modelling. Information is the key.

Quote:
There is a word in Icelandic for such floods from beneath the ice: jökulhlaup. Translated directly into English, it means glacier leap. This seems appropriate, as the water bursting under, over and through the ice tears off huge chunks and carries them suddenly forward down the valley. When the water subsided after the flood of 1918, the plain was strewn with giant icebergs, up to 60-80 m high.

Haukur Tómasson combined velocity and the depth of the flood with the shape of the channel and came up with an estimate for the peak discharge of 300,000 cubic metres per second. The total volume of water was estimated to be around 8 cubic kilometres. The flooded area was as much as 700 square kilometres. There was sufficient sediment in the flow to extend the coastline by 5 kilometres.

To put these figures in context, the average discharge of the Mississippi is a relative trickle at 17,000 cubic metres per second! The flood is equivalent to pouring out Loch Ness onto an area half the size of Greater London in less than 8 hours.


So you bet people are scared of volcanoes. Towns are perched along the coast. The road and bridges will get swept away. . You just want to be on a headland area at that time.





The eruption on Heimaey was the most dangerous recent eruption. Luckily there had been a gale and the fishing boats were in port. Luckily it had gone down, and people could evacuate the town on the boats as the lava advanced. If either of those things had been different it would have been very bad. You can plan but then you can just pray.




With this eruption, it was clearly a new fissure eruption. It has to fill the valleys before it can reach the road or a town. Longer term - yes, having a new shield volcano in the most densely part of the island will require a lot of hard and expensive decision-making.

But you have to admit it is beautiful. And awe-inspiring. This lava is primitive, as from the mantle. It is not partially molten existing crust. It is new crust.



Oscar D. Grouch
Posted: Friday, August 20, 2021 11:42:57 AM

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The explosiveness of a volcano depends on the lava type. Basaltic lava has a high temperature and a low silica content. This lets it flow for long distances like we see in Iceland or in Hawaii. In contrast, more explosive eruptions like Mount St Helens have lava with a higher silica content which increases its viscosity. Explosiveness also has a positive correlation with dissolved gas content.

https://www.elist10.com/different-types-of-magma/
thar
Posted: Friday, August 20, 2021 12:20:49 PM

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Really, does anybody think lava comes "from the centre of the earth" ? I know it is my field, but that sweeping dismissal of people's education sounds unlikely.

And it is way more fun than they make out.


Carbonatite lava can be so cool it freezes as it falls. Shatters and blows away in the wind. You can fall in it and survive, appdarently. .






Oscar D. Grouch
Posted: Friday, August 20, 2021 4:17:51 PM

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thar wrote:
Carbonatite lava can be so cool it freezes as it falls. Shatters and blows away in the wind. You can fall in it and survive, apparently...


Cool photo. Thanks.

thar wrote:
Really, does anybody think lava comes "from the centre of the earth" ? I know it is my field, but that sweeping dismissal of people's education sounds unlikely.


I have family members that think the Earth is only 10,000 years old. They've home schooled their children and they believe this as well. They have done a disservice to society by propagating such nonsense. I tried to explain geologic noncomformities (or, more specifically, angular unconformity) to them. I received blank stares indicating either a lack of understanding and/or a refusal to consider the concept. I tried to explain the iridium layer forming the KT boundary and that no dinosaur fossils are found above it. I tried to explain that crater from the asteroid impact that took out the dinosaurs and formed the iridium layer had been found off of the coast of the Yucatan. I received more nonsensical replies, e.g. "How do you know? Where you there?" I explained that everything is made out of really old star dust, i.e., stars burn hydrogen in fusion reactions to form helium which is burned to form heavier elements until we get to iron and the stars either die out or go super nova and form heavier elements. I received "Well, that may happen, but it doesn't explain how the Earth was created. I explained that if the 4.6 billion years representing the age of the Earth were compressed into a 24 hour day that the 200,000 years that Homo sapiens have been on this planet would only occupy the last 4 seconds of that day. I received blank stares.

Yes, the lack of basic science education really can be that bad, and worse...
thar
Posted: Saturday, August 21, 2021 10:20:30 AM

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Yeah, I guess I was forgetting that factor in education.

Funny how it includes beliefs where there is no contradiction with religion.
I mean, I dont think any god ever forbade unconformities.
It must be such a struggle to continue knowing you are right in your religion-given beliefs when there are such a lot of agravating realities and inconsistencies that have to be explained away all the time. Exhausting!
thar
Posted: Friday, August 27, 2021 2:56:47 AM

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Still going strong to the south, slowly working to fill the valley.
(the title reaching the sea is premature. It's a big valley.)
But the cooling and fluid dynamics of that flow.
Angel
https://youtu.be/_kEpZfqfp5o


Jyrkkä Jätkä
Posted: Friday, August 27, 2021 3:35:41 AM

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Cool!
(If that suits here ;-)
thar
Posted: Saturday, August 28, 2021 10:10:26 AM

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Still think it's beautiful
Now it gets properly dark again it is more impressive at night.
The way it goes from simmering and fountaining as gas escapes, to flowing like water, to treacle, to jostling like ice, to tumbling like clinker, and shoving like a rapid glacier....and seeing the layers get laid down just as you see in the rocks.
Definitely cool.

https://youtu.be/ApCawo10dtE



Hope123
Posted: Saturday, August 28, 2021 12:33:18 PM

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Neat photo, Thar.

The six weeks we spent on the Big Island, Hawaii, were a real eye opener to me. The land was all black, jagged, and much of it was sterile. You didn't want to fall on it. It was prone to just falling apart inwards or breaking off. The condo we rented was right on the ocean so we could walk along and even over some of the jagged outpourings but you had to be careful.

The volcano was active then. We were on the opposite side of the island but still had Vog at least in the distance most of the time we were there.

What really was interesting was the number of earthquakes they get. I mentioned to a Hawaiian that I'd felt one that morning and she said that they get those little ones all the time. We also had to be on alert for tsunamis.

https://www.usgs.gov/observatories/hawaiian-volcano-observatory/about-earthquakes-hawaii
thar
Posted: Sunday, August 29, 2021 5:00:29 PM

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Walking on broken glass.

Anyone interested in the geochemistry this is a short report.

http://earthice.hi.is/sites/earthice.hi.is/files/Pdf_skjol/Geldingadalir/trace_isotope_report_v1r3.pdf

Quote:
New trace element and isotope analyses of the Geldingadalir lava provide further evidence that the magma feeding the Geldingadalir eruption has a different composition to the historical Reykjanes lavas. This shift in geochemistry potentially reflects a new and distinct batch of magma arriving from the mantle beneath Reykjanes.



The Geldingadalir lava is marked by lower concentrations of incompatible trace elements, lower LREE/HREE ratios, and less radiogenic Pb-isotope ratios. These data suggest a greater contribution from higher degree partial mantle melts, sampling more depleted/refractory mantle components.


And a video from when it is not erupting, showing the shield growth and valley fill.
https://youtu.be/pHXQLMRDYyI
thar
Posted: Monday, August 30, 2021 4:29:43 AM

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Volcanic rock is usually pretty featureless in thin section through the light microscope but an electron microscope can show the crystals clearly.


Quote:
Description of rock samples collected during the first two days of the eruption in Geldingadalur.



Figure 1. Reflection electron image of sample 20210320-001. Rapidly cooled basalt magma with small crystals of plagioclase, clinopyroxene and olivine in basalt glass mass.


The Geldingadal lava field is dilated and contains the following minerals (sorted by quantity): plagioclase> olivine> clinopyroxene> spinel (Figure 1).

The lava has a combination of olivine tholite with Mg # = 60.1. The chemical composition of the rock approaches the composition of the most primitive magma that has erupted on the peninsula in Modern times.

Preliminary results from calculations with geometrical thermometers indicate that the temperature of the magma is 1180-1190 ° C when it comes to the surface. Plagioclase, agitate and olivine small particles crystallize in equilibrium with prey in the basic magma chamber, which is in accordance with geophysical observations. However, the magma itself originates from a much greater depth (probably from the boundary of the crust and mantle), which indicates that the corridor draws magma from a much deeper magma reservoir.



A more detailed report with the main composition of rock and minerals:
http://jardvis.hi.is/sites/jardvis.hi.is/files/Pdf_skjol/Geldingadalur/characterization_of_the_1st_and_2nd_day_of_volcanic_products_from_geldingadalahraun_2021.pdf



Source. http://jardvis.hi.is/lysing_bergsynum_sem_safnad_var_fyrstu_tveimur_dogum_eldgossins_i_geldingadolum

Yes, it loses something in automatic translation but I have left the quote as it is. Whistle

thar
Posted: Saturday, September 11, 2021 4:01:49 PM

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That volcano has been quiet for a few days, and now it looks like new fissures are opening. Perhaps the collapses blocked the vent.
https://youtu.be/5p4F6kw0lf0
But the thought still is that regardless of whether the eruption is there or elsewhere, eruptions may continue in that system or other systems in Reykjanes for a couple of hundred years now.



Elswhere in the present, Grímsvötn, which is always a fairly active zone and is under the ice cap, has caused floods.



There was warning and sheep were herded out of the way as a precaution.
Quote:
A glacial outburst flood, a.k.a. jökulhlaup, from the Eastern Skaftárketill cauldron in Vatnajökull glacier started yesterday, mbl.is reports. As a result, an alert phase of the Department of Civil Protection and Emergency Management was declared in the area at noon yesterday.

The glacial outburst flood from the Eastern Skaftárketill cauldron comes in the wake of another flood from the western one, which began September 2 (see our report here).

A flood from the eastern cauldron has not occurred since 2018, and this one is expected to be about as large that year’s flood. The flood in 2015 was considerably larger and caused more damage.

Jökulhlaup in Skaftá river originate in a geothermal area under depressions in the ice cap of Vatnajökull glacier called Skaftárkatlar. These depressions are formed when geothermal heat melts the ice. Once the amount of ice that has melted and collected there reaches a certain level, an outburst flood occurs.

According to the Icelandic Met Office, when such floods occur, the meltwater first flows a distance of 40 km (25 mi) under the ice cap and then a 28-km (17-mi) distance along the river bed of Skaftá river, before reaching Sveinstindur mountain. From there, it takes the floodwater about 10 hours to reach the Ring Road near Ásar by Eldvatn.

Björn Oddsson, geophysicist for the Department of Civil Protection and Emergency Management, tells mbl.is the floodwater can be expected to reach the Ring Road tonight.

He states that residents have time to react. “The people who live here and travel in this are know precisely where the Skaftá glacial outburst floods have an effect.” The South Iceland Police Department monitors the area and directs operations there.

Roads in the area could close, and a great deal of silt and mud could spread around the area and be carried with the wind once the area dries.


Quote:
The glacial outburst flood, a.k.a. jökulhlaup, in Skaftá river, South Iceland, continues, and the situation is being closely monitored. The ice cap over the Eastern Skaftárketill cauldron in Vatnajökull glacier, where the flood originates, has sunk more than 60 meters (about 200 ft), and the discharge in Skaftá river has exceeded 500 m3 per second, mbl.is reports.

The discharge by Sveinstindur mountain was stable overnight, but had begun increasing again this morning. The flood is expected to peak tomorrow.

According to the Icelandic Met Office, the latest data indicate that the maximum discharge of this flood will be less than that of the 2015 and 2018 floods. In 2018, the discharge exceeded 2,000 m3 per second.

Despite that, measurements indicate that the amount of water from the Eastern cauldron will exceed that of 2018. In other words, the flood’s impact on inhabited areas could be similar to what occurred in 2018, even though the maximum discharge will be less than what it was then.

In addition, the area is saturated with water, following a recent flood from the Western Skaftárketill cauldron and heavy rain in recent days. This will likely increase the spread of the flood.

Several mountain roads near Skaftá river were closed last night, and the police sent travelers in the area text messages, asking them to leave. Travelers need to be aware that hydrogen sulphide pollution, which can be harmful to the mucous membranes of the respiratory system and eyes, can accompany the flood.


Also interest in Askja from geophysical measurements that it is growing and bulging more rapidly, along with increased seismic activity, both implying an influx of magma. But it doesn't mean it will eruot soon, necessarily. It does erupt fairly regularly, though. Last in 1961.

But it is under increased monitoring and has gone to yellow alert on its aviation status, because the elevation growth rate is significantly above background levels.
thar
Posted: Sunday, September 12, 2021 4:16:12 PM

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Now the main vent is blocked and the second vent is the source and it is coming out sideways under the lava crust instead of degassing in the cone, it is interesting in a different way.
Never seen an active lava field behaving like a lava lake. . Whistle
https://youtu.be/-tBlPhjqts4
thar
Posted: Wednesday, September 15, 2021 2:23:58 PM

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I find this fottage interesting because I imagining seeing the rock as a geologist, where yiu only ever see a tiny section of a structure. From the flow patterns in the rock, would I reconstruct this situation?

https://youtu.be/8uuf1LyMM3k
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