Landslide Activity Maps for Landslide Hazard Evaluation: Three Case Studies from Southern Italy

This paper focuses on the application of landslideactivity maps for evaluating the mass movementhazard in selected areas of the Southern Apenninesof Italy: Bisaccia, Calitri, and Buoninventre. Theavailability of multi-year aerial photo coveragehelped to assess the morphological changes whichoccurred in the last 40 years. This information,integrated with historical data on slope instabilityand field checks, were used to produce landslideactivity maps. These maps represent a short-cut inthe assessment of mass movement hazard, because theyfocus on the effects of slope instability ratherthan on the causative conditions and processes;however, if kept simple and prepared at large scale,they may help the local administrators and land-useplanners to reduce the socio-economic costs oflandslides. Furthermore, the comparative study oflandslide activity represents a relativelyinexpensive and quick method for evaluating theperformance of the engineering control efforts.The quantification of landslide activity in terms ofareal frequency can represent an additional step,useful to determine the relative landslide hazard(zonation in more or less hazardous areas). Forexample, the estimates of areal frequency of activelandsliding for the last 40 years demonstrated thegreat influence of the 1980 Irpinia earthquake(M_s = 6.9) on the stability of slopes situatedclose to its epicenter (within a radius of about20 km).