23. September 2008

Collecting the first year of temperature data from the Nordnes rock slide mountain, Troms

Contact person for additional information: Hanne H. Christiansen

Text and photos by Hanne H. Christiansen, UNIS

Last week two TSP Norway members, Hanne H. Christiansen, UNIS and Lars H. Blikra, ICG/NGU went back to the mountain Nordnes to collect the first full year of rock and ground surface temperatures from the different installations done last year  (August 2007) and to continue the collaboration with the inter municipality, local (Fjellskred i Troms) rock slide monitoring project www.fjellskreditroms.no.

The processing of last years geophysical data collected by the Geological Survey of Norway, UNIS and local community rock slide project (Fjellskred i Troms ) indicate permafrost to be present above 750 m above sea level (asl). This seems to be verified by the stable bottom of the snow temperature to be around -4ºC at 765 m asl for long parts of the winter below a snow cover of at least one meter.

During summer three shallow 2.5 m boreholes were drilled at 625 m, 800 m and 900 m asl on Nordnes in close collaboration with the inter municipality, local (Fjellskred i Troms) rock slide monitoring project. The lower two are located relatively close to the open cracks in the rock slide area. During last week we instrumented these boreholes with thermistor strings and associated dataloggers to start continuous temperature monitoring.

Henning Hansen ‘Fjellskred i Troms ’ manager on Nordnes is showing where the lower borehole temperature installation is located at 625 m asl. next to one of the largest open cracks.

In collaboration with the local community rock slide project (Fjellskred i Troms) we hope to be able to drill a 30 m deep permafrost borehole in the permafrost just above the unstable rock slope in the summer of 2009. During last weeks fieldwork we had a local drilling company to estimate if it would be possible for a drill machine to drive up to the drill site on the mountain, and they are positive ! If we manage to get a 30 m borehole drilled, we will of course instrument the borehole for permanent permafrost temperature monitoring.

Again this year we had excellent collaboration with the local ‘Fjell i Troms’ project also with respect to logistics, allowing us to use their ATV vehicles to get up to our working sites on Nordnes and letting us stay in their mountain station.

Fieldwork on Nordnes is very effective when using an ATV.