A GIS for Data Mining in Seismic Microzonation Studies

The increasing spread of geographical information system (GIS), which represents a recognized technology that is mainly composed of data handling tools for storage, recovery, management and analysis of spatial data, made research and the application of automatic and semi-automatic cartographic techniques extremely interesting. The creation of a GIS for the city of Catania (Italy), using available data banks, allowed to make a first realistic microzonation of seismic geotechnical hazard of the urban area of the city, including geotechnical site characterization and mapping of geological and geotechnical features, based on about 1200 boreholes. The city of Catania (Italy) in the south-eastern Sicily has been affected in past times by several destroying earthquakes with high values of estimated magnitude. The area to the south of Volcano Etna, on the east of the Ibleo-Maltese escarpment, it is therefore a seismogenic area. According to the frequency and the importance of the seismic effects suffered in past times, Eastern Sicily must be considered one of the most high seismic risk areas in Italy. Today, on such a densely populated territory, a huge patrimony of historical and industrial buildings is placed. The realized GIS model presents ground-shaking scenarios associated with the repetition of historical earthquakes and contains several maps related to seismic geotechnical hazard linked with ground movements, landslides and potential soil liquefaction.