Structural control on mass-movement evolution: a case study from the Vizze Valley, Italian eastern Alps

A large post-glacial deep-seated mass movement is described from the area east of Vipiteno-Sterzing (Alto Adige-South Tyrol, Eastern Alps), mainly developing in caleschists of the ophiolitic Glockner nappe (southern antiform of SW Tauern window). A close relationship exists between differential slope evolution, structural setting, and slope attitude. Lateral spread develops in an area where the dominant schistosity is subvertical and parallel to the slope, and is facilitated by dissolution of evaporite-bearing bodies. Sackung develops in an area with low-angle schistosity and NNE-SSW high-angle faults, parallel to the ridge segment. A huge rock-fall was set off the intersection of the steep N-dipping schistosity with E-W and N-S to NNE-SSW faults and joints. As a whole, this deep-seated gravitational slope deformation (DSGSD) is an outstanding example of how the mechanics of large mass movements and their potential evolution are controlled by the structural framework, which is the ultimate result of a complex tectonic history.