High-Resolution seismic measurements on an alpine rock glacier

Abstract

Rock glaciers are an important form of Alpine permafrost. Due to their potential instabilities, possibly caused by global warming, they pose a serious natural hazard for mountainous regions (Haeberli, 1992). To quantify the mechanical behavior of rock glaciers, a multidisciplinary research program consisting of geophysical, geotechnical and glaciological aspects has been initiated. The Muragl rock glacier, located in the eastern Swiss Alps, was chosen as a test site where a number of surface and borehole experiments are to be conducted in order to establish efficient monitoring procedures. Some of the problems that make this investigation difficult are: (i) strong heterogeneities of the rock glacier material, (ii) pronounced topographic variations and (iii) logistic constraints, in an Alpine region at an elevation of 2600 m above sea. Here, we present results from a reconnasaince seismic survey aimed at resolving the subsurface structure, with particular emphasis on delineating the bedrock depth. This information will form the basis for identifying suitable locations for boreholes where various cross-hole tomographic experiments will be conducted.