Schema illustrato per la classificazione ed il rilievo dei danni da frana in aree urbane.

An illustrated scheme for classifying and surveying landslide damage to buildings in urban areas. In many geological domains, slope movements are one of the most important causes of damage to buildings and life-lines (FLEMING & TAYLOR, 1980; SCHUSTER, 1996; GODT et alii, 2000). Losses from landslides vary from area to area, depending on many factors - such as dimension and type of landslide, lithologies involved, slope gradient, typology of constructions. In mountainous and geologically complex areas (such as the Italian Southern Apennine), urban development has been greatly influenced by the presence and activity of landslides for many centuries (GUZZETTI, 2000). Consequently, living together with geological hazards was quite common, due to the physiographic setting of the Apennine (MERENDA et alii, 1990). In time, the situation has considerably worsened because of residential development. This has mostly occurred over recent decades: in fact, the millenary knowledge of the territory had induced people to settle on the least unstable sites. Yet over the centuries, several factors (i.e. overpopulation; loss of the memory of past damaging events; disregard of the law, together with the chance of compensation in the event of damage) encouraged people to choose more and more unstable areas. Moreover, repeated amnesties for infringement of local building regulations have further stimulated construction in landslide-prone areas. On the other hand, the construction of buildings and infrastructures, altering the original hillslope configuration, has often produced new instability phenomena and re-mobilised old, dormant landslides. Surveying landslide damage to buildings, and comparing their zonation to distribution, type and activity of mass movements can provide useful insights for planning mitigation actions in order to reduce landslide vulnerability and risk. Starting from ALEXANDER's (1986) scheme of classification of landslide damage to buildings in urban areas, a new proposal was performed through an interdisciplinary approach, which involved geologists, geomorphologists and civil engineers (CHIOCCHIO et alii, 1997). The latest scheme has 7 different grades of damage; it also provides suggestions regarding immediate and rehabilitation measures suitable to the different damage levels. Our scheme can be applied only to urban areas (CRESCENZI et alii, 1994; IOVINE & PARISE, 1995); it has been realised in order to facilitate the survey of landslide damage, and can be employed by a team of local technicians-provided that they have been suitably trained. In particular, levels 1-2 of the classification scheme are characterised by small damage not requiring intervention of the Authorities. Starting from level 3, when more serious damage is to be found, it is necessary to evacuate the building, even if temporarily, in order to renovate it. From level 4 on, there is a risk to the area surrounding the building and security measures such as cribs and cordoning should be adopted. From level 5 on, damage is so severe that it should be accurately evaluated whether to renovate or pull down the building and rebuild it in a safer area. In the present paper, each of the damage grades is briefly described and illustrated through pictures of real case studies, selected from recent investigations in Southern Italy.