Within the scope of the International Decade ofNatural Disaster Reduction (IDNDR), cause-effectmodels of large landslides are being developed toestimate hazard. This work is based on a structuralexploration of the landslide areas mainly by seismicmethods. Information about the status of deformationis obtained by comparison of the actual topographywith a reconstruction of the original topography, byGPS, and by SAR interferometry. Geologic andgeomorphological evidence, as well as relevantinformation from other geo-scientific disciplines, isconsidered. The Finite Element Method is used to modelthe initial phase of a mass movement. Later on thismodeling will be extended to the quasi-stationarycreep phase and the transition from creeping to rapidsliding.Four large landslides within the crystalline rocks ofthe Eastern Alps have been investigated since 1997.Two of them are evaluated so far, and are presented inthis paper. The largest one is the Köfelslandslide with a total volume of 3.9 km<Superscript>3</Superscript> and apotential energy release of 5 × 10<Superscript>16</Superscript> Joule.Refraction and reflection multi-component seismictechniques were used to resolve structure and elasticparameters of the landslide masses. For the modelingof the initial phase of the landslides by the FiniteElement Method a strain softening behavior of the rockmass has been assumed. The development of softened orfractured zones was successfully simulated, inagreement with the structures obtained by the seismicmeasurements. Copyright Kluwer Academic Publishers 2001
