Juliane Heiland (Institute of Rock Structure and Mechanics, Czech Academy of Sciences, V Holesovick ch 41, CZ-18209 Prague 8, Czech Republic)

In this paper will be described the results of detailed geological, geotechnical and geomorphological mapping in two areas showing translational block-type slope movements. Both areas are located in the Austrian Alps in similar geological settings, one in the vicinity of Salzburg, the second near Bad Ischl. In both cases finegrained limestones of the liassic "Oberalm beds" are creeping on underlying weaker beds or on clayey intercalations due to gravitational forces existing in a dip slope. It is very interesting that in one area the shear zone is situated in the higher parts of the "Ruhpolding beds" which consist of thinbedded, flinty marls. These rocks are considered to have a very high strength, but due to their intense fracturing and content of clay-minerals their shear strength is very low. In both areas the developped gaping fissures are strongly determined by tectonical prediposed planes and in one case the morphology is superimposed by karst phenomena. The start of the movements is probably connected with the glacier retreat in the postglacial period and the total amount of movements until now is more than 10 m. The depth of the creep zone is up to 15 m. .