Tag Archives: Earth science

Ups! Another Icelandic Volcano Starts Shaking

Indications of magma movement is evident underneath Europe’s largest ice cap glacier, Vatnajokull. The glacier covers at least three volcano systems with, at least, seven active volcanoes. More than 30 earthquakes occurred rapidly on Sunday,  many within minutes of each other.

“Interestingly, the earthquake pattern generally forms into a broad line rather than a random circular pattern. This could be indicative of a magma channel undergoing bulging stress.”

Modern Survival Blog

Vatnajoekull. Eruption 1996.

Most all the earthquakes magnitudes have ranged from 1,5 to 3,7 on the Richter scale. Tremor measurements from nearby stations clearly recorded the activity and is viewable at the Icelandic Met office website.

The Mid-Atlantic Ridge plate boundary passes right underneath the west side of the glacier separating the North American plate and Eurasian plate, where recent very active earthquake activity has taken place near the Bardarbunga volcano and is apparently ongoing at this moment, albeit slightly subdued from yesterday’s cluster.

The very active region is located very near the western edge of Vatnajokull glacier, about 15 km southwest from the Bardarbunga volcano and 25 km northwest from the Grimsvotn volcano.

“Interestingly, the earthquake pattern generally forms into a broad line rather than a random circular pattern. This could be indicative of a magma channel undergoing bulging stress,” the Modern Survival Blog reports.

Vatnajokull: Earthquake Cluster Location, 27 Sept. 2010.

This means that Iceland remains the world’s hot spot for volcanic activity.

With the recent eruption of Eyjafjallajokull during April this yer, causing disruptions in European air travel and European economies, all eyes have been on the north side of Iceland, watching for signs of a dangerous eruption at Katla – which historically usually follows a Eyjafjallajokull eruption within months thereafter.

Now we have this new suspicious activity beneath the gigantic Vatnajokull glacier.

The Superstar of Glaciers

Vatnajokull is one of the worlds superstars when it comes to natural phenomena.

With an area of 8,100 km², it is the largest ice cap in Europe by volume (3,100 km³), and the second largest after Austfonna on Nordaustlandet, Svalbard(Norway) in area.

(Not counting the still larger Severny Island ice cap of Novaya Zemlya, Russia, which may be regarded as located in the extreme northeast of Europe).

It is located in the south-east of the island, covering more than 8% of the country.

The average thickness of the ice is thus 400 meters, with a maximum thickness of 1,000 meters.

According to Guinness World Records, Vatnajökull is the object of the world’s longest sight line, 550 km from Slættaratindur, the highest mountain in the Faroe Islands.

GWR state that “owing to the light bending effects of atmospheric refraction, Vatnajökull (2,109.6m), Iceland, can sometimes be seen from the Faroe Islands, 340 miles (550km) away”.

The glacier was used as the scene for the opening sequence (actually set in Siberia) of the 1985 James Bond film “A View to a Kill”.

A Source of Disaster

Under the ice cap, as under many of the glaciers of Iceland, there are several volcanoes.

The volcanic lakes, Grímsvötn for example, were the sources of a large “jökulhlaup” (glacial lake outburst flood) in 1996 that destroyed roads and bridges.

There was also a considerable but short-time eruption of the volcano under these lakes at the beginning of November 2004.

During the last ice age, numerous volcanic eruptions occurred under Vatnajökull, creating many sub-glacial eruptions.

These eruptions formed tuyas, such as Herðubreið which was beneath Vatnajökull during the last ice age.

(Source: Wikipedia).

Related by the Econotwist:

Volcano Ash Can Send The Earth Into “Deep Freeze”

Katla Now Rumbling – Ready To Blow?

Katla Could Be 100 – Not 10 – Times More Explosive Than Eyjafjallajokull

More Mysterious “Monster Fish” Comes To Surface

Low-Oxygen Zones In Oceans Worry Scientists

Earthquake Frequency Up 133% In 2010

Earthquake May Have Shortened Days on Earth

Is The Earth Moving?

The Earth: A Danger Zone

Mother Earth On Crack

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Planes Forced To Change Destination Due To Ash Treath

Two aircrafts on route from Cyprus to Gothenburg Airport in Sweden and had to make a last minute change of destination because they were not safe enough for high levels of volcano ash in the air.

“The aircrafts are now undergoing an extended check before they will be ready for departure back to Cyprus later this afternoon and tonight.”

Lena S. Petersson


The ash levels are divided into three categories; the planes were only cleared for level one, while the airspace around  Gothenburg and at the airport, is located at level two, the Norwegian web site dagbladet.no reports.

The two planes had to make landings in another Swedish airport, Örebro, where they’re now are undergoing maintenance.

“It was not possible to fly to the airport at Gothenburg, so the planes landed in Örebro. This was a planned diversion, which was settled last night,” Lena S. Petersson, communications director of Star Tour, says to the Norwegian news paper Dagbladet.

The aircrafts are now on the ground for an extended technical checks that have become a  routine because of the high ash levels in the air, the news paper writes on its web site.

Reported Ash In Engines

It was initially reported by the tour operator Star Tour that it was found ash in all engines.

But now the tour operators communication director say that this has not been confirmed.

“It was only a matter of if there was ash in the engines,or not, but it has not been proved by our people in Örebro. The aircraft is undergoing an extended check before they are ready for departure back to Cyprus later this afternoon and tonight, “ Petersson says.

It is the first time Star Tour experience ash problems after air travel began to work more normally.

Still, the incident raises more questions about the safety of air travel under these conditions.

Related by the Econotwist:

Ash Clouds: Chaos At Norwegian Airports (Update)

Threat To Air Travel From Icelandic Volcanos Still Troubling

Volcano Ash Can Send The Earth Into “Deep Freeze”

Stunning Volcano Pictures

Iceland: New Eruption – More Ash

Volcano Ash Can Send The Earth Into “Deep Freeze”

“Mini Ice Age” Underway?

As Climate War Intensifies, So Does Extreme Weather

When Will God Destroy Our Money?


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Threat To Air Travel From Icelandic Volcanos Still Troubling

European airports have reopened for business. Eurocontrol, which co-ordinates national air-traffic controllers, expects around 75% of flights to operate in Europe on Wednesday April 21st. It will take far longer to sort out a backlog of canceled flights, to move planes and crew in the wrong places to where they should be, and to return supply chains to normal, The Economist writes.

“When explosive volcanic eruptions in Iceland and elsewhere in the Arctic are large enough to insert significant long-lasting hazes into the upper atmosphere they can change weather patterns around the world.”

The Economist


Iceland has a lot of volcanoes, and it’s a rare decade where one of them doesn’t erupt. So why has the eruption of Eyjafjallajokull caused such chaos, and what does that mean for the future? The answer to the first question is that the Eyjafjallajokull eruption is peculiarly well attuned to messing with air travel; most eruptions of a similar size would do a lot less long-distance harm. The answer to the second is that less well attuned but considerably larger eruptions are all but certain in decades to come, The Economist writes in a new article.

The earth’s volcanoes appear for the most part in three types of setting. The most familiar, and most of the most dangerous, are found where one tectonic plate overrides another, as happens in the ring of fire around the Pacific. Then there are those which sit over isolated “hot-spots” of upwelling magma from deep in the earth, like the volcanoes of Hawaii. Finally there are those—a great many, but normally deep under the ocean—formed at the spreading ridges where tectonic plates pull away from each other and new crust is formed. Iceland is peculiarly volcanic because it is formed by the intersection of a hot spot and a mid-ocean ridge. The hot spot has pushed the spreading ridge up to the surface and supplemented its activities with some extra volcanism on the side. There are 33 large volcanoes on the island, or just offshore, which have erupted since the end of the last ice age, around 12,000 years ago.

As these volcanoes go, Eyjafjallajokull is not a very big one. It is, however, particularly good at producing fine-grained ash — the sort of stuff that can hang in the air for days—and it has done so at a time when weather conditions have allowed that ash to be spread to the south east, in a slightly clumpy way, through a great deal of European sky.

The fineness of the ash is, says Thorvaldur Thordarson, an Icelandic vulcanologist, unusual. Ash particles are normally in the 50-100 micron (0.05 to 0.1 millimeter) range. But at a site 50km east of the eruption, 24% of the ash falling to the ground was in the form of particles 10 microns or less in size. Studies of ash captured from the air show that for every one of the largest particles (about 300 microns) there are a million or more in the 2 micron range. So though the total volume of the eruption, put at about 0.14 cubic kilometers, is low, the amount of ash capable of traveling long distances is high.

Two factors are contributing to the fineness of the ash. One is the composition of the lava. The more viscous lava is, the harder it is for gases within it to bubble out, so such lava has an explosive tendency. Eyjafjallajokull’s lava is, by Icelandic standards, quite viscous. The other factor is the presence of water. Putting molten lava into direct contact with water or ice also leads to explosions, which again lead to fine dust. A small ice cap on top of Eyjafjallajokull has promoted such shenanigans.

Last time Eyjafjallajokull erupted, from late 1821 to early 1823, it also had quite viscous lava. But that does not mean it produced fine ash continuously all the time. The activity settled into a pattern of flaring up every now and then before dying back down to a grumble. If this eruption continues for a similar length of time, it would seem fair to expect something similar.

The effects of water and ice, too, are likely to be intermittent, and to trail off at least a bit as the reserves on top of the mountain are used up. There was some indication on April 19th that water has found new ways to drain away from the crater area, which is encouraging in this respect. Moreover, the wind is not always from the north-west. All this means that a repeat of 1821-1823 would not lead to a permanent pall over Europe, though it would undoubtedly cause further disruptions.

But what of the other volcanoes on the island? Much attention is currently being focused on Katla, a considerably larger volcano 25km from Eyjafjallajokull. Previous eruptions of Eyjafjallajokull seem to have acted as harbingers of a subsequent Katla eruptions.

There is no geophysical evidence for a causal relationship between such eruptions — no indication that the two volcanoes share the same plumbing — and since Katla erupts more often than Eyjafjallajokull the effect could just be coincidence. Only two or three (depending on who’s counting) of the 23 eruptions of Katla over historical times (which in Iceland means the past 1,200 years or so) have been preceded by eruptions of Eyjafjallajokull, says Dr Thordarson.

Katla is monitored with seismometers, which pick up little earthquakes, and with Global Positioning System stations, which pick up deformations in the crust (an early indicator of the Eyjafjallajokull eruption was that GPS monitors on opposite sides of the volcano moved six centimeters closer together).

Neither system is currently showing anything untoward.

That said, Katla does seem to erupt on a semi-regular basis, with typical periods between eruptions of between 30 and 80 years. The last eruption was in 1918, which makes the next overdue.

There is some evidence that the longer Katla waits before relieving itself, the more spectacular the results are. When it comes to lava output, its eruptions can be 100 times larger than what is going on at Eyjafjallajokull. This would be far more disruptive for the people living in southern Iceland and could also do harm much further afield. A very large eruption, thought to be one of Katla’s, left ash all across northern Europe about 10,300 years ago.

When explosive volcanic eruptions in Iceland and elsewhere in the Arctic are large enough to insert significant long-lasting hazes into the upper atmosphere they can change weather patterns around the world; there is some evidence for them weakening the flow of the Nile and disrupting monsoons.

And Katla is not the only game in town. Iceland has others capable of even greater nastiness. The eruption of Oraefajokull in 1362 may have been almost as large as that of the Philippines’ Mount Pinatubo in 1991, which was the largest eruption of the 20th century.

The Laki eruption of 1783 sent poisonous gases far and wide across Europe. And there is evidence that some of the island’s volcanoes, especially those under the central ice cap, (which, other things being equal, will produce more dusty and explosive plumes if they break through) may be in cahoots, their average activity rising and falling in a cycle of about 130 years. On this analysis, the past few decades have been one of the quiet patches.

It seems likely that the first 50 years of jet travel across the North Atlantic enjoyed, in historical terms, particularly clear skies, The Economist Online writes.

Source: The Economist Online.

Related by the Econotwist:

Stunning Volcano Pictures

Iceland: New Eruption – More Ash

Volcano Ash Can Send The Earth Into “Deep Freeze”

“Mini Ice Age” Underway?

As Climate War Intensifies, So Does Extreme Weather

When Will God Destroy Our Money?

Earthquake May Have Shortened Days on Earth

Low-Oxygen Zones In Oceans Worry Scientists

Mother Earth On Crack

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