SELF-AFFINE ROUGHENING IN A MODEL EXPERIMENT ON EROSION IN GEOMORPHOLOGY

The basic mechanisms producing rough surfaces during geomorphological evolution are studied by carrying out model experiments and analyzing the results in terms of fractal scaling. We have been able to find an experimental evidence for kinetic roughening in our micromodel of moun tain ranges. We have observed that during the watering of an initially smooth ridge made of a mixture of granular materials, the surface evo lves into a shape analogous to actual mountain profiles with self-affi ne geometry. For the exponents describing respectively the spatial and the temporal scaling of the surface width, alpha = 0.78 +/- 0.05 and beta almost-equal-to 0.9 have been obtained. Our value for the static exponent alpha is in very good agreement with several earlier results for various mountains and we have calculated the estimate alpha = 0.8 +/- 0.1 for a set of genuine transect profiles taken in the Dolomites, Italy. The results are interpreted in terms of ''landslides'' of wide ly scattered magnitudes.