Influence of large scale topography on gravitational rock mass movements: New insights from physical modeling

Gravitational slope failures and associated rock mass movements can be observed at various scales in the same area. It seems obvious that the different movement scales should be interrelated, but their relationships are poorly understood. We address this problem using 3- D physical modeling. Experiments were conducted with mechanically homogeneous models with two- scale topographic features. A large scale corresponds to the whole mountain ( several kilometers), and a smaller one to a part of a mountain slope ( similar to one kilometer). Results show that large scale relief induces large- scale ( large volume) gravitational movements. Introduction of small- scale topographic features results not only in the generation of smaller- scale landslides, but also in considerable changes in the deformation pattern. The various- scale processes occur simultaneously and affect each other. To predict the evolution of a landslide, it is therefore necessary to take into account the topography and deformation pattern at various scales.