On behalf of the IPA Working Groups on Mountain Permafrost and on Periglacial Environments, and with the Glacier Commission and the Geomorphological Society of the Swiss Academy of Sciencesas co-sponsoring agencies, the Swiss Coordinating Group on Permafrost organized the International Workshop "Permafrost and Periglacial Environments in Mountain Areas" at Interlaken, Switzerland, 16-20 September 1991. Most of the ongoing research projects in the Swiss Alps were presented at this conference.
Efforts continued to develop a system for long-term monitoring of alpine permafrost by photogrammetrically analyzing repeated aerial photography of several rock glaciers and by measuring borehole temperature and vertical/horizontal deformation. Monitoring of borehole temperatures at the Murtèl drill site reveals a pronounced warming trend as aconsequence of the late 1980s. At 10-m depth where the amplitude of annual temperature variations is reduced to about 0.3°C, the warming rate during the past four years was about 0.5 to 1 °C per decade. Following detailed geophysical mapping and surface sounding (BTS, seismic refraction, DC resistivity, radar), two new permafrost boreholes into bedrock were installed, logged and equipped at the site Ursina above Pontresina/Engadin in connection with problems of avalanche protection and debris flow hazards. First results from borehole temperature and deformation measurements are now available from this site: mean annual permafrost temperatures are close to -0.6° and -1.7°C, permafrost thicknesses are about 35 and 40 m, and surface creep rates of the frozen sediments with up to about 80% ice by volume are 6 and 10 cm/year.
On the large rock glacier Suvretta at Piz Albana near St. Moritz/Engadin, new investigations started with geophysical soundings (seismic refraction, DC resistivity) and tracer experiments in a small river passing underneath the rock glacier front. First attempts were also made to apply gravimetric and VLF-resistivity measurements to Alpine permafrost. With respect to the permafrost cores from the Murtèl drilling, methods of gas extraction are currently being tested (Paul Schemer Institute, ETH Zurich), rock particles are being analyzed (Engineering Geology, ETH Zurich) and the special characteristics of the main shear horizon (fabric, isotopes) are being investigated (Laboratoire de Géomorphologie, Université Libre de Bruxelles).
In accordance with her Academy of Sciences, Switzerland has offered the IPA Council to host one of the forthcoming International Permafrost Conferences.
Prepared by Wilfred Haeberli