Author(s)

M. Papini, L. Longoni & M. Alba

Abstract

Rock falls are really frequent on all Alpine and Pre-Alpine areas and these landslides have recently been front-page news. Among those, a rock fall involved the surroundings of the tourist resort of Varenna (area of Fiumelatte). The episode resulted in two human victims and seriously damaged some buildings and the railroad Milano-Lecco-Sondrio-Tirano. Because of rock fall diffusion, frequency and randomness, accurate scientific procedures for hazard prediction have recently been developed. Such procedures are focused on the definition of the areas of highest rock-fall hazard, to set up fast safety measures for preventing injuries. Rock-fall hazard evaluation procedures are actually based on mathematical models, which usually try to reproduce the geological phenomena. Such models usually require either the slope topographic characteristics or the rocks geo-mechanical properties. As slight differences in model parameters usually bring notable changes in events prediction, data collection procedure has to be clearly defined. In this paper we will bring focus on the important role that the topographic data collection plays in the accuracy of the previously mentioned models. Thus, we will compare results of risk evaluation procedure carried out using a modern laser scanning technique with results obtained by means of a traditional and widely used cartography technique. Keywords: rock fall, hazard, laser scanning. 1 Introduction This study is based on observations on a rock fall that involved the Varenna built-up area on November 13th, 2004. The present work is focused on hazard evaluation for similar rock-fall types using data collected in this event. For assessing limitations and advantages of actual prediction methods, different topographic approaches have been considered. Rock-fall hazard papers are based

Keywords

rock fall, hazard, laser scanning.