Francesco Dramis

Abstract

The occurrence of permafrost in the Italian Alps is an important predisposing factorfor landslides. Debris flows are frequent on slopes overlying permafrost and are likely the resultof active-layer supersaturation. The role of permafrost degradation in triggering landslides fromhard rock slopes as a response to climatic warming has been pointed out only recently. Geotechnicalinvestigations demonstrate that ice-filled fractured rock slopes at temperatures between–2° and 0° C are less stable than when in an unfrozen state. The Val Pola rockslide, whose accumulationmass included ice-cemented blocks, could be explained therefore as the result of strengthreduction along pre-existing potential sliding surfaces, filled with warming ground-ice.

Keywords: permafrost degradation, landslides, global warming, Italian Alps.

Mauro Guglielmin, Department of Structural and Functional Biology, Insubria University via J H. Dunant, 3-21100 Varese, Italy