Wednesday, 18 July 2012

Iceland: a round up

Iceland. Photo: John Stevenson, 2012


I flew back from Iceland (24hr sun, clear blue skies, no rain) to the UK (dark, rain, floods) last Thursday. Apart from readjusting to a life that doesn't invole living in a campervan and searching for tephra layers in Iceland's soil, I've been thinking that a sign posting summary of the trip would be useful for finding bits and pieces and highlighting the blogs and websites I have found particularly useful whilst in Iceland.


 Where to start:



It's best to begin with my post on an introduction to Iceland and the research I was assisting John with: sampling ash that was erupted from Hekla from two eruptions - Hekla 3 and Hekla 4. This post also explains why we were sampling ash and how this could assist with estimating the impact from future volcanic eruptions. 


To understand exactly how we were identifying and measuring the ash, read this post on the sampling process. It's not just a case of digging a hole in a ground and sifting through soil though, as this post explains. The ash layers from the Hekla 3 and 4 eruptions can be found across Iceland, including the impressive eastern fjords area and the mountains north of the Vatnajökull ice cap, which are stacked full of interesting human and physical geography, as well as Iceland's highest mountain (climbed by the intrepid ash samplers, of course.)


Finally, there is a post on how the Hekla 3 and 4 eruptions compared to the more recent Eyjafjallajökull eruption of 2010particularly in terms of the amount of tephra that was erupted.


Useful information sites for Iceland:


For getting information and news from Iceland
  • A separate section of the above website shows you recent tectonic activity across Iceland. It's quite interesting to monitor the eruptions around Katla (Mýrdalsjökull  area)
  • The Iceland Review website is useful for catching up on a range of news stories
  • The Grapevine is another great website for catching up on news and comment from Iceland.


Geology blogs:


I've found the following blogs very useful for reading up on volcano and general geology information:

  • Volcan01010 - John's website provides lots of information on volcanoes generally as well as vulcanology specific to Iceland.
  • Highly  allochthonous  - Lots of useful information on all things geology as well as a very useful weekly twitter link to geology/environment related news and stories.
  • Metageologist. - Great website on the geology of mountains written in a very easy to understand way.

Hopefully those links will be of interest. Enjoy!


Enjoying the light. Photo: Alasdair Monteith, 2012




Wednesday, 11 July 2012

Eyjafjallajökull VS Hekla.

Ask someone to name an Icelandic volcano and most of the time they'll make a good attempt at tryingto pronounce Eyjafjallajökull. After all, this is the volcano which 2 years ago brought chaos to flights across Europe and is estimated to have cost airlines around $1.7 billion dollars in cancelled flights. On top of this, the photos and impressive film-footage of the eruption and ash cloud made headline news stories for several days. I always find it interesting when talking to pupils at school to hear how the eruption affected their lives; trips to Florida and Australia were disrupted through cancelled flights and delays. A truly global event!


How much ash did each eruption produce?


The Eyjafjallajökull eruption was fairly small by Icelandic standards chucking out around 500 tonnes of tephra per second. Although this sounds a significant amount, it is worth bearing in mind that the Grímsvötn eruption of 2011 threw out around 10,000 tonnes of tephra per second. Quite a bit more. John wrote a good comparison on the two eruptions on his blog last year.



What has become apparent to me over the last three weeks whilst digging sample pits and looking at ash samples from across Iceland, is really how little ash and tephra Eyjafjallajökull put out in comparison to other eruptions, most noticeably the Hekla 3 (1000 BC) and Hekla 4 (2300BC) eruptions that we have been focusing on during the trip.

For example, the photo below is taken on the main road just outside of the Þorvaldseyri farm, approximately 10km from Eyjafjallajökull. You can see the Eyjafjallajökull 2010 eruption ash around 1cm down in the soil profile. It's a black grey fine ash that is approximately 1.5 cm in thickness. The ash colour comes from the composition of the magma that was thrown out in the eruption which was an andesite-like composition. The Hekla ash is of a rhyolitic composition so is white in colour.


Cut away of the soil outside of Þorvaldseyri farm, 9 km south of Eyjafjallajökull. Photo: Alasdair Monteith, 2012



Now, compare the photo above with the photo below. This sample pit was dug close to a towncalled Egilsstadir in Iceland's eastern fjords. You can see the layer of white ash from a Hekla eruption that is, again, approximately 1.5 cm in height. As the Hekla 3 eruption took place around 3000 years ago there has been time for soil and organic matter to accumulate on top of it.

Suspected Hekla 3 ash (in white) from a sample pit near Egilsstadir. Similar thickness, but what about the distance? Photo: John Stevenson, 2012



This photograph was taken 300 km from Hekla!

Hekla: a much bigger eruption


Weather patterns, type of eruption and magma composition (amongst other things) will obviously effect how far tephra travels from the sourceof eruption. But the comparison of the two samples gives you an ideaof how big the Hekla eruptions must have been. Hekla 3, for example, resulted in cooler temperatures in the northern hemisphere for a few years afterwards and has even been held as a cause of famines during Ramasses III's reign in Egypt.

So, how much tephra is there from the Hekla 3 eruption 9km from Hekla? The photo below says it all really! Except this time it's a mix of white to pink pumice. The sample site is a similar distance to the one below Eyjafjallajökull, both sites were downwind of the original eruptions.

 

Anyone order two metres of Hekla 3 tephra? Photo: Alasdair Monteith, 2012

Pumice, 2-3cm in size, deposited 9km from Hekla. Photo: Alasdair Monteith, 2012
So, although Eyjafjallajökull 2010 caused a considerable amount of disruption, it's effects could be shadowed by future Icelandic eruptions, particularly those on a scale with Hekla 3 or the Laki fissure eruptions of 1783-84.

*Update*

Following the Eyjafjallajökull eruption in 2010, the UK government updated the country's risk register to include the dangers from explosive eruptions- such as Eyjafjallajökull 2010, and effusive eruptions - such as the Laki fissure eruptions of 1783-84. You can view the 2012 register here, the section on volcanoes starts on page 17.

 

Monday, 9 July 2012

R+R Iceland style


Pit digging, tephra collection and driving around Iceland have been on hold for the last few days as we enjoy the best Iceland has to offer in climbing and mountaineering. The van's crew increased by 2 on Thursday night when Gemma and Dave, expert field assistants and climbers, arrived from the UK to join the fun.


Time for some climbing


With mild weather and sunny skies forecast for the weekend we headed to Hnappavellir, Iceland's premier sport and trad climbing venue on the south coast of the island, 4-5 hours drive from Reykjavík. Despite an abundance of very impressive volcanic rock around the island the way in which much of the basalt lava cooled in contact with water or ice means a lot of the rock is very broken, loose and isn't that great for climbing. Hnappavellir is a basalt lava flow that has bucked the loose and chossy trend; the rock is pretty compact with great friction and an abundance of fantastic routes. A very keen and dedicated group of local climbers continue to put up both trad and sport climbs and have set up a little campsite at the foot of the crag which provides a great base to access the crag from. It's a very friendly and enjoyable location!

Bolt clipping in the sun. Photo: Gemma Stevenson, 2012

Iceland's highest mountain


Hnappavellir is also below Oraefajokull on the Vatnajokul Ice cap. It is Iceland's highest mountain (and volcano) with a nunatack peak called Hvannadalshnúkur. At 2,100 metres (1.5 Ben Nevis') it's a reasonable climb to the top, made more interesting by glaciers which guard it on all sides. The guide book times for completing the walk are between 9-16 hrs depending on the weather and state of the snow. We opted for a liesurely and not to alpine start of 8.00AM from the car park as catching the snow before it was too soft and tedious to walk through was more important than being benighted – not a problem you really suffer from in a country where it doesn't get truly dark at this time of year. We took the popular Sandfellsleið path up that wasn't too eroded considering it is the easiest route to the top and used by guided parties on an almost daily basis. It makes makes walking routes in the Lake District and Scotland look like motorways.

The crevasses (large cracks in the ice) close to the summit were particularly impressive and the natural snow bridges that enable you to cross them won't last long if the current hot weather continues. The surrounding ice cap is covered in a thin dark ash layer from the Grímsvötn eruption of 2011, which is located further north and west under the Vatnajokull Ice cap. In certain places on the ice the ash is several centimetres thick and has insulated the underlying snow from the heat of the sun, this leads to some interesting hummocky mounds that can be seen below. John has an interesting post about these ash cones and the Grímsvötn eruption on his blog 


Ash cones on the ice. Photo: Alasdair Monteith, 2012

From Oraefajokull you get an impressive site of the Skeiðarársandur area, from which we get the word sandur plain. This is the sediment that is washed out of a glacier and accumulates in the outwash plain below, slowly building land into the sea and helping increase the size of Iceland. A jökulhlaup, or glacier flood occured here in 1996 due to the sub glacial eruption of Grímsvötn that destroyed an ice dam and sent 3.2 km3 of water, ice and rock down onto the plain, destroying a bridge on the main road amongst other things.


Lunch stop, with the great expanse of the Skeiðarársandur plain below. Photo: John Stevenson, 2012

From start to finish took 10.5 hours; not bad considering the snow was pretty slushy although the high cloud did a superb job of shadowing us from the full strength of the sun. The summit rewarded us with some great 360 degree views.


View from the summit. Photo: Alasdair Monteith, 2012


Happy team at the end. Photo: John Stevenson, 2012
We're now back on the road and from tomorrow will be heading towards Hekla with the intention of sampling much closer to the volcano. It will be interesting to see how much tephra has acuumulated so close to the volcano. In the mean time don't forget to watch the BBC'sVolcano Live programme these next few days and follow the links on Twitter through #volcanolive 

Thursday, 5 July 2012

We've been rained on.....

....but only for a couple of hours on the 2nd July whilst we were in the mountains north east of the Vatnajökull ice cap above the Lagerfljot lake. 


The Kárahnjúkar Dam


Having toured through a few fjords on Sunday and camped in the beautiful countryside outside of a small village called Eider, we headed up to the mountains with the intention of getting a few samples near the base of a mountain called Laugerfell. The map had the route to the mountain down as a mountain track, similar to the tracks we took whilst in the Kjölur area. However, the construction of a dam at the top of the Kárahnjúkar valley that was completed in 2006 meant that a tarmac road now exists all the way to Kárahnjúkar, making travel - and sampling - far easier.  
Rockwall of the 200m Kárahnjúkar dam.Photo: Alasdair Monteith, 2012
One big gorge, but then the reservoir has a capacity of 2.1 cubic kilometers. Photo: Alasdair Monteith, 2012

Kárahnjúkar generates around 4,600 GWh a year in electricity for an aluminium plant. The building of the dam raises a few interesting questions around sustainability and energy production as the dam sits in a large wilderness area and it's construction and will have had a significant impact on the environment both upstream and downstream. But when your economy is in recovery, you have access to cheap and relatively green energy, and aluminium makes up 37% of your exports, you can see the benefits from a  politicians point of view. Particularly if the alternative was aluminium plants powered by coal fired power stations.

Back in the fjords


Leaving the mountains (and rain) behind we headed across to the fjords area again and down into a small fishing and ferry town called Seydisfjordur. At this distance from Hekla the ash layers we're hunting become significantly thinner, harder to find and difficult to identify. Sampling conditions were hellish at times, as can be seen in the photo below of our lunch stop location. 

Just about acceptable as a lunch time stop ;-) Photo: Alasdair Monteith, 2012

The long and winding road back to Reykjavik


Today (Wednesday 4th June) we set off on the long road back to Reykjavik to pick up a couple of friends/field assistants for the next sampling sessions and catch up on some well earned rest and climbing. The incredible geography of Iceland kept coming though as we passed the Jökulsárlón floating icebergs calved from glaciers descending from the Vatnajökull ice cap as can be seen in the video below.

video


We also drove through the Laki lava fields, vast areas of land covered by a prolonged eruption of the Laki fissure in 1783. The scale of the eruption is hard to picture, but the fact that it formed the second largest basaltic lava flow in historic times and produced tephra that covered 8000km², puts the likes of the Eyjafjallajökull eruption of 2010 into perspective.

Looking across the eastern Laki lava field.  Photo: Alasdair Monteith, 2012

Monday, 2 July 2012

Moving East

Since leaving the Highlands and returning to Akureyri on Friday we've been travelling eastwards with the intention of sampling in the Eastern Fjords. The weather has remained settled and mild, quite the opposite to what seems to have hit the UK over the last few days. We've now been on the road since the 20th June and covered a fair distance along the North coast and down into the interior before heading East. The van and all her crew are doing very well!
Ash sampling through Iceland, the journey so far.... Red line marks our route, blue marks the van camp stops
After being amongst fairly young lavas and volcanoes whilst in the Highlands and north coast we've now entered an older area of Iceland with geology that is more similar to  the Alps or Scotland. 

The effects of frost action on a basalt rock.  Photo: Alasdair Monteith, 2012

Ridge above Bakkagerdi.  Photo: Alasdair Monteith, 2012
The route to Bakkagerdi, a small hamlet accessible by only one coastal road, was quite an experience. Faced with what would appear to be an insurmountable scree slope the Icelanders had simply ploughed a gravel track straight through the middle and are prepared to clear up whenever an avalanche or landslip takes it out. Tarmac is for whimps!

The Borgarfjördur scree/track towards Bakkagerdi.  Photo: Alasdair Monteith, 2012

The ash layers, they are a'changing

The ash layers we've been finding in the sampling pits have also changed the further east we have come. Where as previously the Hekla 3 and 4 layers stood out quite prominently (not least because they are predominately rhyolite and so white), quite a few black and white layers have appeared which we think represent eruptions from  Hekla 1158 near the middle of the pits and Askja 1875 near the top of the pits. The 1875 layer included some quite impressive pumice lapilli when we sampled in the Mödrudalur area. As we are now east of many of Iceland's volcanoes this change in pit profile was to be expected, it certainly means that every sample pit is different and surprising!

Continuing down the fjords and east coast tomorrow before winding our way back to Reykjavik on