1. Department of Physical Geography and Geoecology, University of Ostrava , Chittussiho 10 , Ostrava , 710 00 , Czech Republic
2. Centre of Biology, Geoscience and Environmental Education, University of West Bohemia , Klatovská 51 , Pilsen , 30619 , Czech Republic
3. Institute of Hydrogeology, Engineering Geology and Applied Geophysics, Charles University , Albertov 6 , Prague , 128 43 , Czech Republic
4. Institute of Rock Structure and Mechanics, Czech Academy of Sciences , V Holešovičkách 94/41 , Prague , 182 09 , Czech Republic