Landslide hazard evaluation: a review of current techniques and their application in a multi-scale study, Central Italy

In recent years, growing population and expansion of settlements and life-l ines over hazardous areas have largely increased the impact of natural disa sters both in industrialized and developing countries. Third world countrie s have difficulty meeting the high costs of controlling natural hazards thr ough major engineering works and rational land-use planning. Industrialized societies are increasingly reluctant to invest money in structural measure s that can reduce natural risks. Hence, the new issue is to implement warni ng systems and land utilization regulations aimed at minimizing the loss of lives and property without investing in long-term, costly projects of grou nd stabilization. Government and research institutions worldwide have long attempted to assess landslide hazard and risks and to portray its spatial d istribution in maps. Several different methods for assessing landslide haza rd were proposed or implemented. The reliability of these maps and the crit eria behind these hazard evaluations are ill-formalized or poorly documente d. Geomorphological information remains largely descriptive and subjective. It is, hence, somewhat unsuitable to engineers, policy-makers or developer s when planning land resources and mitigating the effects of geological haz ards. In the Umbria and Marche Regions of Central Italy, attempts at testin g the proficiency and limitations of multivariate statistical techniques an d of different methodologies for dividing the territory into suitable areas for landslide hazard assessment have been completed, or are in progress, a t various scales. These experiments showed that, despite the operational an d conceptual limitations, landslide hazard assessment may indeed constitute a suitable, cost-effective aid to land-use planning. Within this framework , engineering geomorphology may play a renewed role in assessing areas at h igh landslide hazard, and helping mitigate the associated risk. (C) 1999 El sevier Science B.V. All rights reserved.