The Cryosphere Discussions www.the-cryosphere-discuss.net 1994-0432 1994-0440 3 3 2009 10.5194/tcd-3-895-2009 http://www.the-cryosphere-discuss.net/3/895/2009/ http://www.the-cryosphere-discuss.net/3/895/2009/tcd-3-895-2009.html http://www.the-cryosphere-discuss.net/3/895/2009/tcd-3-895-2009.pdf 895 918 2009-10-30 Quasi-3-D resistivity imaging – mapping of heterogeneous frozen ground conditions using electrical resistivity tomography C. Kneisel kneisel@uni-wuerzburg.de A. Bast D. Schwindt Department of Physical Geography, University of Würzburg, Germany Up to now an efficient 3-D geophysical mapping of the subsurface in mountainous environments with rough terrain has not been possible. A merging approach of several closely spaced 2-D electrical resistivity tomography (ERT) surveys to build up a quasi-3-D model of the electrical resistivity is presented herein as a practical compromise for inferring subsurface characteristics and lithology. The ERT measurements were realised in a small glacier forefield in the Swiss Alps with complex terrain exhibiting a small scale spatial variability of surface substrate. <br><br> To build up the grid for the quasi-3-D measurements the ERT surveys were arranged as parallel profiles and perpendicular tie lines. The measured 2-D datasets were collated into one quasi-3-D file. A forward modelling approach – based on studies at a permafrost site below timberline – was used to optimize the geophysical survey design for the mapping of the mountain permafrost distribution in the investigated glacier forefield. <br><br> Quasi-3-D geoelectrical imaging is a useful method for mapping of heterogeneous frozen ground conditions and can be considered as a further milestone in the application of near surface geophysics in mountain permafrost environments. 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