Eyjafjallajökull tephra fieldwork, July 2011

What a great trip. We got lots of samples that we wanted and were blessed with the weather. The Landrover didn´t break down, we saw old friends and old haunts and explored some beautiful places that I had never seen before.

Sampling Layer H tephra from Eyjafjallajökull, deposited around 1500 years ago

We should now have enough data points of thickness and samples for grain size analyses and deposit density to make significant progress with plans.

Eyjafjallajökull 2010 and Grímsvötn 2011 tephra being blown around

Some things that really struck me while we were away are a) that exponential thinning of tephra layers is certainly very close to being how things are (wow, it is hard to find where the layer goes from a trace to zero!), b) Þórsmörk is stunning especially if you cross a few dodgy looking paths and head away from the tourists, c) tephra blows around a lot after it is deposited so how can we assume geological records are good representations of the actual tephra at time of deposition? and d) Fieldwork is great and even better with good company (thanks Iveta).

Camping near Gígjökull: note the heather has coped least well with the recent ash falls

Katla in the distance under the ice cap Mýrdalsjökull. This is the Markarfljót, route of many prehistoric jökulhlaups.

Hekla 2000

From Iceland to Geneva to finish off grain size analyses of Hekla 2000 tephra...

This Hekla 2000 project has been a really fun learning experience for me, going from using tephras primarily to correlate and date other deposits to specifically looking at the tephra itself. It is amazing what you can find out about a past eruption from some bags of tephra.

Samples of Hekla 2000 tephra were collected shortly after the eruption by Guðrún Larsen at the University of Iceland and other scientisits and members of the public in Iceland. It is quite unusual to have such fresh material to look at and this means that we can look at the tephra itself, hopefully reducing complications of years of reworking, compaction and contamination.

During this project I have worked with Costanza Bonadonna at the University of Geneva who has given me a lot of training and encouragment, as well as Sebastian Biass at the University of Geneva, Guðrún Larsen, Ármann Höskuldsson and Freysteinn Sigmundsson at the University of Iceland. Initial funding came from Landsvirkjun (Icelandic energy company) and the University of Iceland postdoctoral fund.

We have:

• carried out grain size analyses on 31 new samples of Hekla 2000 tephra and estimated the total grain size distribution,
• carried out grain size analyses on 2 samples collected near Hekla in October 2008,
• analysed the componentry of the deposit and the density of tephra clasts,
• re-considered the isomass mapping of the deposit and estimated volume and mass, 
• investigated mass eruption rate,
• produced hazard curves for selected sites in southern Iceland for a VEI3 eruption of Hekla (Seb Biass)

Looking forward to bringing this all together soon.

1500 year old Eyjafjallajökull tephra

I´m off in to the field to track down the Layer H tephra (sometimes called E500) from Eyjafjallajökull. This is preliminary fieldwork for a new project trying to find out more about this prehistoric eruption of Eyjafjallajökull, in collaboration with Andrew Dugmore, Anthony Newton, Thorvaldur Thordarsson at the University of Edinburgh and Guðrún Larsen at University of Iceland.

So, after this fieldwork and a bit of lab work and analyses we should be able to:

• make an isopach map
• calculate deposit density and produce an isomass map
• estimate deposit volume and mass
• carry out grain size analyses of tephra samples
• estimate total grain size distribution from the deposit
• assess the size and explosivity of the eruption

We already have quite a lot of thickness data from my PhD research and Andy Dugmore´s decades of research in this area and good geochemical data so this new fieldwork and sample collection campaign will help us fill out some of the gaps in geographical coverage that we have just now and all us to make some interesting comparisons between this prehistoric eruption and the more recent eruptions of Eyjafjallajökull. Exciting stuff!!

Here´s hoping for good weather and some soils where I want to find them.

Tephra in Quaternary Science: Eyjafjallajökull 2010

5th to 6th May, 2011

Exciting: I am co-organising a workshop for the new Quaternary Research Association research group Tephra in Quaternary Science, with Prof. Andy Dugmore and Dr. Anthony Newton at the University of Edinburgh. With keynote talks from Thor Thordarson (University of Edinburgh) and Susan Leadbetter (UK Met Office) and a workshop summary from Sue Loughlin (British Geological Survey) and several discussion sessions these should be a really interesting couple of days. Many aspects of tephra to be covered: characterisation of deposits, proximal and distal deposition patterns, dispersal and modelling of tephra transport,.. and of course the Eyjafjallajökull eruptions themselves. Funding comes from INQUA and QRA and this is great because it means there doesn't have to be any registration fee and early career researchers and postgrads can be supported in their attendance. :) Looking forward to some lively discussions, a friendly few days and learning a lot.

Edinburgh Visiting Fellow

I am now based in Edinburgh and am a visiting fellow in Geography at the University of Edinburgh while still maintaining my affiliation with the University of Iceland. I can still be contacted at kate@raunvis.hi.is.