[Folda] Fwd:[Jhi]Friday Seminar Series 3rd November - Þorsteinn?==?utf-8?q? Sæmundsson - A new source of hazard in Iceland: thawing of mountain permafrost – a case study, the Móafellshyrna landslide in 2012

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Subject: [Jhi] Friday Seminar Series 3rd November - Þorsteinn Sæmundsson - A new source of hazard in Iceland: thawing of mountain permafrost – a case study, the Móafellshyrna landslide in 2012 
Date: Tuesday, October 31, 2017 09:47 GMT 
From: Maxwell Christopher Brown <maxwell at hi.is> 
To: jhi at hi.is 
 
 
Dear all,

This Friday we have:

Þorsteinn Sæmundsson (Department of Geography and Tourism, Faculty of Life and Environmental Sciences)

Title: A new source of hazard in Iceland – thawing of mountain permafrost – A case study, the Móafellshyrna landslide in 2012
Abstract: On the 20th of September 2012, a large debris slide occurred in the Móafellshyrna Mountain in the Tröllaskagi peninsula, central north Iceland. The slide initiated after an unusual warm and dry summer followed by a month of heavy precipitation. Furthermore, the slide originated after a seismic sequence, whose epicentres were located ~60 km NNE of Móafellshyrna Mountain. The main source of material was ice-rich talus deposits perched on a topographic bench. Blocks of ice-cemented deposits broke off the frontal part of the talus cone and fell onto the talus slope below. Further downslope, the landslide material became over-saturated, causing it to evolve into a debris slide. We estimate that the total volume of the debris slide is around 500,000 m3 and that its primary cause was intense precipitation. We cannot exclude the influence of the seismic sequence as a contributing factor. The presence of ice-cemented blocks in the slide deposits shows that thawing of ground ice could have played an important role as a triggering factor. Ice-cemented blocks of debris have been observed in the deposits of two other recent landslides in northern Iceland, in the Torfufell Mountain and the Árnesfjall Mountain. This suggests that discontinuous permafrost is degrading in Iceland, consistently with the decadal trend of increasing atmospheric temperature in Iceland due to climate change. This study highlights that ground ice thaw could represent a new source of hazard in Iceland. The knowledge of the detailed distribution of mountain permafrost on the island is poorly constrained and should be a priority for future research, as it is hard to predict where the next hazardous slide could occur in the future.

Date: Friday, 3rd November
Time: 12:30
Place: 3rd Floor meeting room, Askja

All are welcome.

Best wishes
Maxwell

-- 
Maxwell Brown
Research specialist
Institute of Earth Sciences
University of Iceland
Askja, Room 333
Sturlugata 7
101 Reykjavík
Iceland
  
email:maxwell at hi.is
tel (office): +354-525-4730
tel (lab): +354-525-4794
tel (mobile): +354-832-0015