26. July 2008

Solifluction snapshot from Kapp Linne, western Spitsbergen

Contact person for additional information: Hanne H. Christiansen

Text and photos by Hanne H. Christiansen

One year ago the TSP Norway project established a solifluction station on a large solifluction lobe. This lobe flows from the west side of the mountain range  Griegaksla onto the strandflat.

We have now recovered the first full year of data from the station, which have worked successfully. The winter 2007-2008 was, however, very windy so the automatic camera, which records snow depth around the station flew away in early November 2007, just as the polar night began. We have now repaired and enforced the camera and it is back in operation at the site, ready for the coming winter. Also the top of the battery box ensuring the power for the station disappeared during winter, but no data was lost.

The solifluction station photographed on 27 July (left) and 6 November 2007 (right) by the automatic camera.

The first full year of data gives us a first snapshot of the solifluction activity here in the Kapp Linne area on the west coast of the Spitsbergen island of Svalbard . Solifluction is active from early June to the end of October, when melting of the active layer occurs and until the ca. 1.5 m thick layer again is completely frozen in the beginning of winter. During winter there is no movement of the ground surface, when it is completely frozen. The solifluction station has recorded 9 cm ground heave during freeze-up of the ground in the autumn, and already 11 cm of settlement again as the active layer thawed this summer. This annual movement is due to the formation of ice layers in the active layer. The resulting downslope movement this summer was 4.4 cm.

If in some years the active layer becomes deeper due e.g. to a very warm summer, the resettlement can be larger than heaving, which lead to ground lowering and increased downhill movement.