Site classification map of Italy based on surface geology

Abstract In this article a method developed for the creation of a site classification map at a territorial scale, starting from the geological mapping available at 1:100 000 scale, is described. This map has been used to embed amplification factors as provided by the Italian seismic code in seismic hazard studies, in order to consider the contribution of the surface geology on the expected ground motion values. The Italian territory has been divided into polygons classified on the basis of lithologies that the seismic code considers homogeneous in their average seismic response. The data processing has been conducted in a GIS environment, starting from the digital format of the lithological map of Italy at 1:100 000 scale. Our results can be used in seismic risk analyses that take into account the local seismic amplification due to the geological characteristics of an area, and in studies on ground motion prediction equations (GMPE).