Iceland volcano: New quakes raise concern over large eruption

[jakeXT]

Last edited Thu Aug 28, 2014, 06:03 AM - Edit history (2)

Source: BBC

A volcanic system close to Iceland's Bardarbunga's volcano was hit by a magnitude 4.5 earthquake in the early hours of Wednesday.

It adds to concerns that magma from Bardarbunga could feed into the nearby Askja volcano.

British and Icelandic scientists say that 50 million cubic metres of molten rock has moved in a 24 hour period.

If it continues to head north, it could link up with the Askja system and trigger a large eruption.

Read more: http://www.bbc.com/news/science-environment-28943708

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New features, including cracks and sinkholes, were spotted Wednesday night in the ice that encases Iceland's Bardarbunga volcano, ratcheting up concern that an eruption is near.

The volcano, which has been on orange alert for days, sits several miles under the Dyngjujökull glacier.

During a flight to monitor the glacier Wednesday, scientists spotted several 3.5-mile long rifts in the ice, according to the Icelandic National Broadcasting Service. The agency also reported scientists saw calderas, which Science Daily explains describes as "volcanic feature(s) formed by the collapse of the volcano itself."

http://www.weather.com/news/icelandic-bardarbunga-volcano-new-fractures-and-sinkholes-spotted-20140827

[Voice for Peace]

1. Have you got a short summary of what the big concerns are about this?

I keep reading bits and pieces, and know at one time it
impacted earthly climate.. but don't know much. Any insights
welcome, thanks!

[starroute]

9. The historical precedent is Laki - but Bardarbunga could be worse

http://www.dailykos.com/story/2014/08/17/1322378/-Just-To-Let-You-All-Know

The winter of 1783-1784. The Revolutionary War had just ended, and Benjamin Franklin was puzzling over the nation's bizarre weather. Congress had been delayed getting to Annapolis to vote for the Treaty of Paris because the Chesapeake Bay just wouldn't melt. The Mississippi River froze down to New Orleans, and ice was reported floating in the Gulf of Mexico. Reports from Europe were of a bizarrely hot summer with thick fog that was choking people to death in Scotland, massive hailstones, lightning, and crop failures. The sun was blood-red at noon. Mass starvation that would ultimately kill 1/6ths of Egypt's population took hold due to a historic drought of the Nile. As many as six million people would die from the bizarre weather.

Franklin was one of the few scientists of the era to (almost) correctly speculate as to its cause:

"The cause of this universal fog is not yet ascertained [...] or whether it was the vast quantity of smoke, long continuing, to issue during the summer from Hekla in Iceland, and that other volcano which arose out of the sea near that island, which smoke might be spread by various winds, over the northern part of the world, is yet uncertain."

He, however, had mixed up his Icelandic volcanoes, for it was not Hekla that erupted that year, causing the planet-altering weather, but Laki (Eldgjá). A rift 23 kilometers long opened up in places up to 100 meters wide with lava fountains at times reaching over a kilometers into the air - and it continued erupting for 8 months.

The total quantity of lava erupted - 14 cubic kilometers - was not that much more than Mount Pinatubo (largest eruption of the 20th century)'s 10 cubic kilometers. But the eruption kicked out a staggering 120 million tons of sulfur dioxide, compared to Pinatubo's 17 million - nearly supervolcano levels. Also unusually, Laki emitted 8 million tons of hydrogen fluoride - normally a trace volcanic gas. These gasses created the "Laki Haze" across Europe. In Iceland, the consequences were most severe - a quarter of the population starved or died of fluoride poisoning, and most of the livestock died. Denmark considered evacuating the entire island.

[Voice for Peace]

14. yikes! thank you. jeez.

[Hestia]

20. Isn't this also what killed all of Napoleon's men in Russia? Or was that another volcano?

[magical thyme]

19. it can change the weather for a couple years. it won't stop global warming.

With sufficient particulate in the atmosphere, enough sunlight can be blocked to make for a couple cooler years. Once the particulate falls out, though, that impact stops. It temporarily disrupts weather; not the long term trend of climate change.

[Cleita]

2. We need to keep an eye on this one.

Some think it could be as powerful as the Yellowstone volcano should it erupt. The good news is it could stop global warming, however, the price paid would be large.

[magical thyme]

4. do you have any links?

I haven't seen anything comparing it the the Yellowstone Caldera.

I have seen that it could disrupt air traffic, similar the the Iceland eruption a couple years back.

[Cleita]

5. Actually no. It was told to me by another DUer I know

in my town while we were having lunch. She's a teacher so not prone to pulling facts out of her behind. I'll try to find out from her and get back to you

[Maedhros]

18. Yellowstone and Iceland are two very different tectonic environments,

which lead to greatly different eruptive styles.

Iceland sits on top of the Mid Atlantic Ridge, and eruptions consist almost entirely of very hot, very fluid basalt. Basalt is relatively silica-poor compared to other kinds of lava (such as andesite, dacite or rhyolite) and therefore contains less dissolved water vapor. Because basalt is relatively "dry", basaltic eruptions tend to be quiescent.

Yellowstone, in contrast, sits on top of a "hot spot," or upwelling mantle plume, underneath the North American continental plate. Unlike in Iceland where the basaltic magma is almost instantaneously erupted onto the surface, magma generated under Yellowstone takes a long time to travel through nearly 50 km of continental crust before reaching the surface. As it does so, it accumulates in vast magma chambers and "fractionates" (i.e. certain minerals crystallize and fall out of the magma, leaving behind more silica-rich liquid) and it soaks up water. When it finally extrudes onto the surface, the liberation of all that dissolved water makes for great explosive eruptions (think: Mt. St. Helens, or Mt. Mazama (Crater Lake) in the past).

There is evidence for a large magma body beneath Yellowstone that has raised concerns. Think of that large magma body as a huge champagne bottle, with the dissolved water in the magma analogous to the dissolved carbon dioxide in champagne. When an eruption occurs that is big enough to blow off the "overburden" (i.e. the rock lying above the magma body that holds it down), it's like popping the cork on a champagne bottle - all the dissolved carbon dioxide fizzes out at once, and the entire contents of the bottle sprays out. This happened at Mount Mazama in 5700 BC and at Mount St. Helens in 1980. But the magma body beneath Yellowstone (and also Long Valley Caldera in California) is much, much, much bigger - thus, a "supervolcano."

[jakeXT]

6. The BBC only mentions the 1875 eruption

Askja was virtually unknown until the tremendous eruption which started on March 29, 1875. Especially in the eastern fjords of Iceland, the ashfall was heavy enough to poison the land and kill livestock. Ash, or tephra from this eruption was wind-blown to Norway and Sweden. The eruption triggered a substantial wave of emigration from Iceland. Another less well-known eruption occurred in the early Holocene, ca 11,000 years ago. Tephra from this eruption has been found in south-east Sweden, Northern Ireland and north Norway. The last eruption of Askja was in 1961.

The outer caldera of Askja, representing a prehistoric eruption, is about 50 km², and there is evidence of other later caldera-forming events within it. The main crater floor lies at about 1,100 m.

In June 2010, Volcano expert Hazel Rymer said seismic activity was increasing at Askja and that an eruption could be around the corner[3] The increased earthquake activity is located to the northeast of the central volcano, in the direction of Herðubreið. It was ruled out that any activity from Eyjafjallajökull was responsible for the increase in activity at Askja. The news came as scientists continue to watch Katla.

In early April 2012 it was noted that the lake in the caldera was totally clear of ice, which usually does not happen until in June or July in a normal year. It is believed that increased geothermal activity in the volcano is heating the lake. Travel in the area was restricted until further research could be carried out. [4]

http://en.wikipedia.org/wiki/Askja

[magical thyme]

7. actually it specifically references the 2010 eruption

"Prof White added that several scenarios were possible.

"One is that it erupts under the glacier," he said.

"That is bad news because this kind of eruption can drive the big ash clouds that can go up 35,000-40,000ft, and that is what happened in 2010 with Eyjafjallajokull.""

(The one with the unpronounceable, unspellable name! )

[jakeXT]

10. I meant getting into Yellowstone type levels

The Askja eruption in 1875 has been classified as VEI-5, that is a lot less than Yellowstone

http://www.almannavarnir.is/upload/files/Volcanic%20hazards%20in%20Iceland.pdf

Volcanic eruptions are classified using the Volcanic Explosivity Index, or VEI.

VEI – 8 eruptions are colossal events that throw out at least 1,000 km3 (240 cu mi) Dense Rock Equivalent (DRE) of ejecta.

VEI – 7 events eject at least 100 cubic kilometres (24 cu mi) DRE.

VEI – 7 or 8 eruptions are so powerful that they often form circular calderas rather than cones because the downward withdrawal of magma causes the overlying mass to collapse and fill the void magma chamber beneath.

...

By way of comparison, the 1980 Mount St. Helens eruption was a VEI-5 with 1.2 km3 of ejecta.

http://en.wikipedia.org/wiki/Supervolcano

[Voice for Peace]

17. you're right

I don't even begin to know how to try.

How to pronounce Eyjafjallajokull:

http://www.forvo.com/word/eyjafjallaj%C3%B6kull/#is:

[Spitfire of ATJ]

21. In this case it might actualy sound like "Bar-dar-bung-ga!!!" when it blows.

Not to be confused with the "Big Badaboom"

[Cleita]

11. While I'm waiting for my friend to get back to me, I did some quick research on my own.

It seems volcanoes get a VEI rating for the strength of the biggest eruptions they have had. Iceland's Bárðarbunga Volcano has a rating of VEI6 and Yellowstone VEI8. So the volcano acting up right now in Iceland is not as volatile as Yellowstone but it's still a super volcano and can bring a nuclear winter sort of event just like Yellowstone can.

Heres a few links that I found:

http://volcanoscience.blogspot.com/

Scroll down below the California earthquake entry.

http://en.wikipedia.org/wiki/Supervolcano

http://en.wikipedia.org/wiki/Bárðarbunga On edit. My browser won't paste the entire link but you can google it.

http://en.wikipedia.org/wiki/Yellowstone_Caldera

[magical thyme]

15. ok, I looked at the wiki link on Baroarbunga

"The Veiðivötn eruption in 1477 is the largest known Icelandic eruption, with a VEI of 6.[2]"
http://en.wikipedia.org/wiki/Bárðarbunga


I don't think that is really comparable with a VEI of 8. The absolute largest VEI 6 would be <1/10th the explosivity of VEI 8.
The ejecta volume for VEI 6 ranges from >10m3 - <100m3. The volume for VEI 8 is >1,000m3.
http://en.wikipedia.org/wiki/Volcanic_Explosivity_Index


VEI – 8 eruptions are colossal events that throw out at least 1,000 km3 (240 cu mi) Dense Rock Equivalent (DRE) of ejecta.

Both Mount Pinatubo in 1991 and Krakatoa in 1883 were VEI-6 with 10 and 25 km3 (2.4 and 6.0 cu mi) DRE, respectively.
http://en.wikipedia.org/wiki/Supervolcano

"The Island Park Caldera supereruption (2.1 million years ago), which produced the Huckleberry Ridge Tuff, was the largest and produced 2,500 times as much ash as the 1980 Mount St. Helens eruption.

One such caldera, the Bruneau-Jarbidge caldera in southern Idaho, was formed between 10 and 12 million years ago, and the event dropped ash to a depth of one foot (30 cm) 1,000 miles (1,600 km) away in northeastern Nebraska and killed large herds of rhinoceros, camel, and other animals at Ashfall Fossil Beds State Historical Park.
http://en.wikipedia.org/wiki/Yellowstone_Caldera

[dhol82]

3. the airlines are concerned with traffic

if ii's anything like the 2010 eruption it could interfere with air traffic for a long time.

that's in addition to spewing a whole bunch of stuff into the atmosphere.

http://www.newsday.com/business/airlines-on-alert-as-iceland-volcano-shows-signs-of-eruption-1.9137277

[Cleita]

12. They already have elevated it to a red alert, which is the highest alert in the system

so they are worried.

[Louisiana1976]

8. I read about the possibility of a big eruption on Daily Kos yesterday. The article said there had

been a big eruption of Askja in 1783 (I think?) and it had adversely affected the weather in the US and Europe. So a major eruption of that volcano would be scary.

[Cleita]

13. Here's a wiki page with a list of category VEI6 volcanos.

http://en.wikipedia.org/wiki/Category:VEI-6_volcanoes

Pinatubo that erupted in 1991 is one we are familiar with.

[bigworld]

16. "something called volcano monitoring"

what a waste of money, right?

[jakeXT]

22. 'Cauldrons' in Iceland glacier could point to volcano eruption: Met Office

(Reuters) - Ice over Iceland's rumbling Bardarbunga volcano has melted to reveal a row of 1-km wide "cauldrons", possibly due to a sub-glacial eruption, the country's meteorological office said late on Wednesday.

Rumblings at Iceland's largest volcano system for about a week have raised worries of an eruption that could spell trouble for air travel. In 2010, an ash cloud from the Eyjafjallajokull volcano closed much of Europe's airspace for six days.

The Met Office said on its website it had not observed an increase in the level of tremors in connection with the discovery of the 4 to 6-km long line of 10 to 15-metre deep "cauldrons".

Palmi Erlendsson, a geologist at the Met Office, said the warning code for possible volcanic disruption to the aviation industry remained orange, the second-highest level.

http://www.reuters.com/article/2014/08/28/us-iceland-volcano-idUSKBN0GS08C20140828