Maria Chiara Turrini

An objective method to rank the importance of the factors predisposing to landslides with the GIS methodology: application to an area of the Apennines (Valnerina; Perugia, Italy)

The present work aims at contributing to further our knowledge on the predisposing factors to landslides as well as proposing a method that allows us to weigh up, as objectively as possible, the influence that the various factors have on landslides in order to construct a realistic map of potential landslide hazards. In order to assess the differential incidence of very predisposing factor to landslides, maps of the various factors considered were drawn up with the aid of IDRISI software (1997). The factors were as follows: the distance from faults, parallelism between the fractures and the landslide scarps, land use, lithology, distance from the streams, orientation and steepness of slopes, orientation of layers compared to the slope. The global analysis of the different incidence of the factors analyzed on the landslides present in the study area was carried out by comparing the respective maps with that of the scarps; in this way the number of pixels forming the scarps which fell into the various classes of the maps was calculated. The result thus obtained can form the basis of an objective assignation of the different ratings to be attributed to the various factors under consideration. In fact, the analysis carried out in this study has shown that the factors act differently and, for every factor, only some of the classes considered have marked importance.

Proposal of a method to define areas of landslide hazard and application to an area of the Dolomites, Italy

Abstract A numerical–cartographical method has been developed to create landslide hazard maps. This method allows the assigning of a rating to the various parameters which contribute to landslides. The parameters considered are: (1) erodibility and degradability of the rocks and Quaternary deposits; (2) permeability of the ground to identify areas prone to hydraulic overpressure; (3) the geometric ratio between discontinuities and slope, and thickness of Quaternary deposits; (4) angle of the slopes; and (5) land use. A thematic map is constructed for each factor considered which defines different areas through ratings, after which all the thematic maps are overlaid and the ratings added up (or multiplied). The map which is thus obtained is reclassified in order to create the final map of landslide hazard. This method, which has already been tested in various areas, has produced excellent results in this case too, allowing a map to be constructed which corresponds to the actual instability problems.

La più antica occupazione tardoglaciale nelle Dolomiti Bellunesi: primi dati dal sito epigravettiano di Casera Staulanza (Val di Zoldo, BL)

The most ancient Late Glacial occupation of the Belluno Dolomites: first data from the open-air Epigravettian site of Casera Staulanza (Val di Zoldo, BL)

Utilizzo dei sistemi GIS per la revisione di dati stratigrafici da depositi plurifase: il caso-studio di Riparo Tagliente (Stallavena di Grezzana, VR)

Application of GIS systems for the revision of stratigraphical data from multi-phase deposits: the case-study of Riparo Tagliente (Stallavena di Grezzana, VR)