New signs of eruption at Iceland volcano

[Buster's Uncle]

New signs of eruption at Iceland volcano
AFP
4 hours ago



Computer screens show seismic activity from the Bardarbunga volcanic eruption at the Icelandic met office in Reykjavik on August 23, 2014 (AFP Photo/Halldor Kolbeins)



Reykjavik (AFP) - Teams monitoring Iceland's Bardarbunga volcano have found evidence of a possible underground eruption as powerful earthquakes continue to shake the area, Icelandic authorities said Thursday.

Scientists flying over the area on Wednesday discovered a four to six kilometre (2.5-4 mile) line of giant craters or cauldrons -- 10 to 15 metres deep and one kilometre wide -- on the Vatnajoekull glacier which covers the giant volcano.

"The cauldrons have been formed as a result of melting, possibly a sub-glacial eruption," the Icelandic Met Office said in a statement.

The alert level for Bardarbunga was downgraded from red to orange on Sunday when the Met Office retracted its claim that an eruption had taken place under the ice.

Tremors continued on Thursday with an 5.0 magnitude earthquake just after 0800 GMT, far weaker than the strongest eruption of 5.7 magnitude recorded on Tuesday.

Bardarbunga volcano is part of Iceland's largest volcanic system and a major eruption could signal a replay of the global travel chaos triggered when another Icelandic peak Eyjafjoell blew four years ago, creating a massive ash cloud across Europe.

Last week Iceland evacuated areas close to the volcano following an uptick in seismic activity with the strongest earthquakes recorded in the region since 1996.

Iceland's most active sub-glacial volcano Grimsvotn erupted in 2011, forcing the country to temporarily shut its airspace and sparking fears of a repeat of the Eyjafjoell flight chaos.


http://news.yahoo.com/signs-eruption-iceland-volcano-190609158.html

[Buster's Uncle]

'Cauldrons' in Iceland glacier could point to volcano eruption: Met Office
Reuters
21 hours ago



Warning signs block the road to Bardarbunga volcano, some 20 kilometres (12.5 miles) away, in the north-west region of the Vatnajokull glacier August 19, 2014. REUTERS/Sigtryggur Johannsson



REYKJAVIK (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.

Red, the highest alert, indicates an eruption is imminent or underway, with a risk of emission of ash.

The Met Office said earlier on Wednesday that seismic activity in the area remained high after two earthquakes measuring more than 5.0 in magnitude hit the volcano overnight and another quake shook a nearby volcano. The night before saw a magnitude 5.7 quake - the biggest earthquake yet at Bardarbunga.

On Sunday, Iceland lowered its warning code to orange from red. [ID:L5N0QU0KB]

(Reporting by Robert Robertsson, additional reporting by Anna Ringstrom in Stockholm; Editing by Jeremy Laurence)


http://news.yahoo.com/cauldrons-iceland-glacier-could-point-volcano-eruption-met-035033416.html

[Buster's Uncle]

Quakes Keep Shaking Iceland's Bardarbunga Volcano
LiveScience.com
by Megan Gannon, News Editor  August 27, 2014 8:51 PM



This color-coded map shows the earthquakes that have occurred around Iceland's Bardarbunga volcano since Aug. 16, with the most recent tremors in red. The progression of seismic activity shows where the underground lava-filled dike is growing.



Earthquakes are still rocking Iceland as lava pushes through a long underground fissure near the ice-covered Bardarbunga volcano.

By 6:42 p.m. local time (2:42 p.m. EDT) today (Aug. 27), the Icelandic Meteorological Office (IMO) had detected about 1,300 tremors in the region, most of the them originating from the subsurface channel being carved out by magma, or molten rock. The long channel is called a dike.

Late in the day, the discovery of a long depression above the southeast edge of Bardarbunga's caldera sparked new speculation about an eruption. A team of scientists flew over the area this afternoon and spotted the new feature in the ice. A 2.5- to 4-mile-long (4 to 6 kilometers) row of cracks and sinkholes described as "cauldrons" appeared above where the dike emerges underground and drills to the northeast. The sinkholes are 32 to 50 feet deep (10 to 15 meters), the IMO said. As much as 10.5 billion gallons of water (40 million liters) could have melted and gone missing under the ice, the University of Iceland said.

Officials have not yet determined if an eruption under the ice caused the surface of the glacier to sink. Right now, the distored surface is the only indication of an eruption. Officials would also like to see two other signs, which have yet to appear: the characteristic seismic signals created when hot lava melts ice; and meltwater escaping from the glacier. Another inspection flight is planned for tomorrow morning, the IMO said.

An earthquake swarm started on Aug. 16 around Iceland's Bardarbunga volcano, which is buried under the northwestern edge of the huge Vatnajökull ice cap. So far, no eruption has occurred, but scientists are closely monitoring seismic activity and the movement of the lava-filled fissure, called an intrusive dike, which could potentially spark an eruption or unleash a flood of melted glacial water if it breaks through the surface.

The dike, now thought to be about 25 miles (40 kilometers) long, was first detected underneath Iceland's Dyngjujökull glacier. In the past day alone, this channel has gained 706 million cubic feet (20 million cubic meters) of magma, and it now extends some 7.5 miles (12 km) north of the glacier's edge, according to the IMO.



A radar image of a sinkhole that appeared Aug. 27 above Iceland's Bardarbunga volcano.


Overnight, a 4.5-magnitude earthquake shook the eastern side of the nearby Askja volcano. IMO scientists said this could be a sign that the dike is causing stress changes over a large area around the Bardarbunga volcano.

If the dike keeps creeping northwards, it could reach the Askja volcanic system, according to scientists at Cambridge University. The ash fall from a massive eruption at Askja in 1875 made subsistence farming in northeast Iceland impossible, but Cambridge scientists said there is still no guarantee that an eruption will take place this time, and the dike stretching from Bardarbunga may not even reach as far as Askja.

Even so, the event in progress could already be considered "a significant magmatic and tectonic event," Páll Einarsson, a geophysicist at the University of Iceland, said in a statement. 

"In terms of [the] seismicity, volumes and displacements involved, only two events in recent decades are comparable to this one," Einarsson said. "These are the Gjálp eruption in the Bardarbunga area in 1996 and the Krafla rifting episode of 1975-1989."

The Cambridge scientists said the volume of magma moving under and beyond Bardarbunga is already twice the size of the magma volume from the Eyjafjallajökull eruption of 2010, which forced thousands of flights to be canceled after it spewed ash over a large swath of Europe.

Live Science senior writer Becky Oskin contributed to this story.


http://news.yahoo.com/quakes-keep-shaking-icelands-bardarbunga-volcano-005129234.html