The contribution of historical information in the assessment of landslide hazard

Results are presented of an historical and archival research on landslides in a sample area of the Sila Massif (Calabria, Italy). Information was collected from various types of sources, such as scientific publications, newspapers, Public Administrations, local Management Agencies, unpublished documents, direct and indirect witnesses. Seventy-one documented landslides or flooding events have been found, covering a time span from the 16(th) century to the present. In some cases a relationship between the documented events and the triggering factors (earthquakes and antecedent rainfall) has been ascertained. Further information on slope instabilities in recent historical time (1955-1996) has been derived from landslide activity maps, obtained through interpretation of multi-year air photos and field survey. Comparison between the information obtained from the different sources, and validity of collected data are discussed in detail.