ON THE STUDY OF THE RELATIONSHIPS BETWEEN HYDROLOGICAL SYSTEMS AND DIFFERENT TYPES OF SLOPE MOVEMENTS

M.C.Turrini (University of Ferrara, Dept. of Geological and Paleontological Sciences, Corso Ercole I d'Este 32, 44100 Ferrara, Italy) V. Villi (CNR IRPI Padova, Corso Stati Uniti 4, 35020 Padova, Italy)

The relationship between rainfall and slope movements of different types in the Alps are studied. Two distintive aspects are taken into account: the effects on natural slopes of high intensity-short duration rainfall; and the role as a triggering mechanism of landslides of groundwater level fluctuations which depend mainly on the cumulated raiffall.
Regarding the first aspect exaples are given from the Eastern Italian Alps where the more frequent landslide type is that of soil slips. In this area austroalpine terrains crop out, mostly phillite and micaschist. These rocks weather into an impervious regolite layer less than 2 m thick, in which no groundwater flow occurs. Lastly, the evolution of large, deep-seated, landslides with respect to rainfall is studied. Slope activity is found to be strictly coupled with the local hydrological, geological, structural and morphological setting. The cumulated rainfall that triggered mass movements that caused damages to villages and human activities is analysed.