The occurrence of permafrost in the Italian Alps is an important predisposing factor for landslides. Debris flows are frequent on slopes overlying permafrost and are likely the result of active-layer supersaturation. The role of permafrost degradation in triggering landslides from hard rock slopes as a response to climatic warming has been pointed out only recently. Geotechnical investigations 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 accumulation mass included ice-cemented blocks, could be explained therefore as the result of strength reduction along pre-existing potential sliding surfaces, filled with warming ground-ice.
Permafrost degradation and slope Instability in the Italian Alps
GUGLIELMIN, MAURO
2008-01-01
Abstract
The occurrence of permafrost in the Italian Alps is an important predisposing factor for landslides. Debris flows are frequent on slopes overlying permafrost and are likely the result of active-layer supersaturation. The role of permafrost degradation in triggering landslides from hard rock slopes as a response to climatic warming has been pointed out only recently. Geotechnical investigations 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 accumulation mass included ice-cemented blocks, could be explained therefore as the result of strength reduction along pre-existing potential sliding surfaces, filled with warming ground-ice.
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