Askja Volcano (Iceland)

[WesL]

Spotted this story in my feed this morning. Looks like Askja is causing some concern in Iceland and across the European continent.

Hundreds of earthquakes have rocked the Icelandic Askja volcano which is situated in the eastern volcanic belt. There have been more than 550 earthquakes so far, the highest with magnitudes 3.2 and 3.4, felt by local residents. If it were to erupt, the ash cloud would be carried directly over western Europe before circulating back over into central Europe and up to Scandinavia, according to severe weather Europe.

Volcano warning: Intense earthquake swarm in Iceland disrupts Europe

EUROPE is under threat of a volcano in Iceland erupting causing a huge ash cloud to swamp the entire continent and enormous disruption to millions.

www.express.co.uk

 

[bjdeming]

That may just be tabloid journalism. Every story like this is usually the same, but the volcano might instead be named Katla or Hekla or Krafla -- and then nothing happens.

Iceland volcanoes are very active, very confusing for those of us who aren't from the country or volcanologists, and as we've seen in the last decade they can be both dangerous and a nuisance. They are extremely well monitored, and it's those sources that give reliable information.

Gonna lay what hopefully are some good information links down:

I've been following Askja's swarm here It's intense but could just be tectonic, per Jón Frímann, though he's not an official source. The Iceland Met Office does have all volcanoes at Aviation Code Green. (Like Japan, Iceland combines its meteorology and geological hazard offices.)

They had raised Askja to yellow back in 2014 -- it could indeed be the next Icelandic volcano to go off, since it's close to Bardarbunga, another volcano in this fissure zone, which erupted in 2014 -- but they lowered it again as the seismicity back then waned.

Also volcanologist Eric Klemetti would probably mention Askja at his current blog, if anything were likely. He hasn't, yet. However, London VAAC did an Askja exercise earlier this month.

Mr. Frímann is interesting. I don't who he is, but he isn't a volcanologist and instead appears to be the volcanophile equivalent of a very knowledgeable amateur who keeps a state-of-the-art weather station in the back yard. Frímann, instead, builds a seismic network in Iceland -- must be nice!

I follow him to help understand what's going on in Iceland because he held his own in online detailed discussions at Dr. Klemetti's old blogs when other volcanoes erupted (Eyjafjallajokull in 2010 and Bardarbunga in 2014). But I rely more on information from the Iceland Met office and Dr. Klemetti.

 

[bjdeming]

Spotted this story in my feed this morning. Looks like Askja is causing some concern in Iceland and across the European continent.

Volcano warning: Intense earthquake swarm in Iceland disrupts Europe

EUROPE is under threat of a volcano in Iceland erupting causing a huge ash cloud to swamp the entire continent and enormous disruption to millions.

www.express.co.uk

Those have continued and also there has been some ground uplift. It got exciting in recent months when the volcano's big crater lake (there's a small, hydrothermally heated one, too) deiced in winter conditions, but the water temperature increase wasn't substantial, per Iceland media and per Vedur.is and scientist tweets I followed; then it froze up again.

Haven't heard anything since March, but here is the live blogging on it, to be updated if and when....

 

[bjdeming]

At the end of November 2023, land rise at Askja reportedly stopped. We'll have to wait until snow melts off before they can check the deformation (if any) this year.

PS: Not sure if that Facebook link still works. Per RUV in January 2024 (autotranslated), it is only a slowdown.

 

[bjdeming]

IMO did an update (autotranslated) today after some increased seismicity. Basically, inflation has begun again but not at quite as fast a rate.

Of note, my reading on the Peninsula volcanism has brought some side highlights, including the fact that Askja most often erupts in lava flows, including some filmed in the early to mid twentieth century:



So, if anything does eventually develop out of this long deformation phase, it most likely will be effusive.

Explosive major events happen but are few and far between; presumably, too, the buildup to such a powerful eruption would have strong precursors, and Askja is monitored closely.

 

[bjdeming]

From the IMO update:

A
satellite image from March 19 shows that traditional winter conditions prevail in the area and the lake is covered in ice outside separated by two areas that are always open due to geothermal activity. In February about a year ago, Öskjuvatn became ice-free, which was unusual so early in the year. Towards the end of last year, the Norwegian Meteorological Agency installed a webcam inside Öskja that looks at its southern part. The camera sends pictures every 10 minutes that show the conditions inside Askja. A recent photo taken on a good weather day, where the environment is clearly visible, accompanies the news.

A satellite image showing conditions in Askja on March 19, 2024. You can see an ice-free area on the western shore of Lake Askja, where there is a known geothermal area.​

 

[bjdeming]

Askja is still at Green/normal alert level, but there is some low-level activity there showing on the earthquake graphic at least once a week.

That's just background to this tweet from Iceland's Volcano Centre:



At last word -- months ago -- ground deformation had slowed down but was still underway, with the cause suspected to be inflow of magma but at deep levels.

Some of the other Icelandic big guns are restless, too, though no trouble from them appears imminent, either. There's a blog post on that, though any alert increases will get a separate post there and here, too

 

[bjdeming]

Nothing imminent -- just an update.

They were able to do an InSAR recently --



-- and Benedikt at IMO told mbl.is (autotranslated) that the ground about 3 km from the calderas has risen almost a meter since July 2021: a sign of magma accumulation. However, he says there are no signs of an eruption coming any time soon.

 

[bjdeming]

Well, that was a brief opprtunity window!

...when you get to a kilometer high, the snow layer is thick.

"We were a little afraid that winter had arrived, but luckily I don't think it's quite like that. We'll get a little bit of autumn anyway... even though it's actually been autumn all summer," says Anna. Facebook/ Gígur guest room​

Turn away guests who are not in larger cars​

Anna says that the road is impassable unless the drivers are in modified cars. "And not even on modified cars, because we were getting into trouble." It's hard snow, it's wet snow," adds Anna, but one ranger fixed the car today in the snow, then on 35-inch tires.

On the Facebook page of the Gíg guest house in Mývatnsveit, it is recommended against drivers of smaller vehicles driving the road. He is not "Jeep capable". Snow has also stuck on other roads, including Gæsavatnaleið, Dyngjufjallaleið and the road around Dyngjufjalladal.

The rangers are now trying to prevent people from traveling to Askja, as four of them stand by the road and direct visitors away from the area. Fortunately, there has been little traffic on the road, says the national park ranger.

The weather outlook for the next two days is not good, with snowfall, wind and poor visibility in the area...

-- Source (autotranslated)

The InSAR did show that Askja's slowed inflation rate is continuing though the ~1-meter rise over two years is impressive.

Askja has been rumbling a bit, as have Grimsvotn and Bardarbunga, notably, but that's all.

IMO says that Bardarbunga, near Askja, has been waking up again after the 2014-15 Holuhraun eruption but that eruption doesn't appear imminent.

Grimsvotn has been on yellow alert for a while, but there is a new concern, per IMO and interviews with their spokespeople.

There is a jokulhlaup coming down the Skafta River right now; it's not volcanic but instead a more or less regular occurrence: the Skaftarhlaup, they call it. (Yes, WesL , if I have to deal with these words, so does everyone else! ;^) )

This ongoing glacial outburst flood comes from one of two hydrothermal centers under the big glacier Vatnajokull, third largest glacier in Eurasia; it conceals Bardarbunga's caldera, all of Grimsvotn, and also covers several other volcanoes.

Reportedly, this run is probably from the smaller hydrothermal area in there. It's small. But if the larger one starts a run, too, that might release enough subglacial water to lighten the weight on Grimsvotn's crater surface, which can lead to an eruption.

So there's that. I didn't want to get into a multiple review here. The point is that crustal stress from the intrusions under Svartsengi, on the peninsula, seems to be triggering more seismic activity everywhere, including at the volcanoes.

That could be the reason behind microquakes and some low-level quakes at Askja and perhaps also Bardarbunga.

With Grimsvotn and Katla, it's hard to know.

For the purposes of this thread, though, <layperson speculation> an Askja eruption now or in the coming few months is unlikely </layperson speculation>.

 

[bjdeming]

In-depth article on Askja (Icelandic).

Per browser translation:

...

No noticeable changes in geothermal systems and no indication of sudden events​

Benedikt says that seismic activity at Askja is higher than before, although it has not increased much with the land giant. Scientists have not seen any noticeable changes in geothermal systems there. "But having said that, these are natural signs that something more is going to happen there in the future." But we can't predict when, or exactly what, and can do nothing but just watch the trend. And of course if there are changes like a big increase in the seismic activity or changes in the deformation, likewise if we see any big changes in the geothermal system, then of course people need to review things. But if it continues like this, maybe we won't be too worried about something happening suddenly."

...

 

[bjdeming]

An incredibly detailed IMO update (Icelandic) today expands on what Benedikt said. Here's the complete thing via GT for anyone interested in Askja AND its recent history/possible short-term future:

Annual measurements were made in Askja in August​

Landris in Askja continues, but there are no signs that the magma is moving closer to the surface​

2.9.2024

• The land continues to measure up to Askja.
• It is considered probable that magma accumulates at a depth of about 3 km
• No evidence of magma moving closer to the surface

An annual field trip was made to Askja last August, the trip is a joint project of the Icelandic Meteorological Office, the Institute of Geosciences of the University of Iceland and the University of Gothenburg. The field trip included geodetic measurements (level and GNSS measurements), pH and temperature measurements in Vítis crater, as well as multiple gas measurements (CO 2 , H 2 S and SO 2 ) in the steam hot spring area in Vítisgíg.

The results support what is seen from continuous GPS measurements and from recent InSAR images, that landrising continues in Askja, but at a slower rate since September 2023. However, there are no signs that magma is moving deeper into the Earth's crust.

About 12 cm of land has been measured at the GNSS station OLAC (west of Öskjuvatn) in the last 12 months. InSAR satellite data and tilt measurements confirm ongoing landrising. The results of modeling calculations indicate that the location and depth of magma accumulation in the area is similar to what has been previously estimated. It is believed that the flow is about 3 kilometers deep. There are no signs of magma movements moving closer to the surface. Model calculations indicate that 4.4 million cubic meters have been added in the last 12 months. Therefore, it is estimated that the total change in volume since the beginning of the land in July 2021 is now about 44 million cubic meters.

Measurements made in Víti show no significant changes (pH, water temperature and chemistry).





Doctoral students Catherine O'Hara and Sonja Greiner (from the University of Iceland) together with Dr. Ástu Rut Hjartardóttir (Meteorological Office of Iceland) performs GNSS measurements at station MASK on the northern edge of Öskjuvatn (photo: Michelle M. Parks/Meteorological Office of Iceland).



The development in Askja will continue to be closely monitored. After landrising began and expansion was noticed at Öskja in the summer of 2021, monitoring has been increased significantly.

The first deformation measurements in Öskja were slope measurements that started in 1966, and between 1970 and 1972 landris were measured. But after a break in measurements for a few years due to the Kraflu fire, slope measurements began again and then the land began to subside, and this trend continued until 2021 when the land surface began to be measured again. Land has been measured before without an eruption. At this stage, it is therefore difficult to assess how things will develop in Askja.

The omens were clear when there was an eruption in Askja in 1961​

The last eruption in Öskja was in 1961 when Vikrahraun was formed in an alkaline lava eruption, but such eruptions are the most common eruptions of the volcano. Similar eruptions occurred at the beginning of the 20th century. The lead-up to the eruption in 1961 was clear, but 20 days before it began, increased seismic activity was measured and a significant increase in geothermal activity. During the period 6.-12. October 1961, six earthquakes of magnitude 3 were measured, one of which was magnitude 4, and powerful geothermal springs formed in areas where there had been no activity before.

About four acid explosive eruptions are known in modern times (the last 11 thousand years), the youngest occurred on January 3, 1875. The eve of that eruption began at least in February 1874 with increased geothermal activity, and strong and frequent earthquakes (recorded in the North) started weeks before the eruption. In 1875, alkaline lava flows also erupted on Askja's fissure zone, Sveinagjárgosin, where, among other things, Nýjahraun was formed. In light of history, where a long time passes between acidic explosive eruptions in Askja, it is not considered likely that a sequence of events similar to the one that took place at the end of the 19th century will begin in the coming seasons. It is most likely that the consequences of continued activity will be volcanic eruptions comparable to those that have occurred in the 20th century, i.e. relatively small lava eruptions with minor pyroclastic fall. If there is an eruption at the bottom of Öskjuvatn, however, an explosive eruption can be expected while the magma is isolating itself from the water.

"Acidic explosive eruptions" are the big plinian blasts that occasionally happen here. Glad that doesn't seem too likely!

What they're referring to at Oskuvatn is the phreatomagmatic explosiveness you would expect if lava came up into a lake -- bad enough, but not 1875 style.

"Vikrahraun" might be the Icelandic term for what's shown in that "Askja on Fire" video.