The realistic definition of seismic input: an application to the Catania area

The realistic definition of seismic input can be performed by means of advanced modelling codes based on the modal summation technique. These codes and their extension to laterally heterogeneous structures allow us to accurately calculate synthetic signals, including body waves and of surface waves, corresponding to different source and anelastic structural models, taking into account the effect of local geological conditions. For the estimation of the destructive potential of the calculated signals, parameters obtained from their (a) direct analysis, (b) integration in the time or in the frequency domain, and (c) the structural (elastic and anelastic) response are investigated. As an example of application of our analysis we consider the Catania (Sicily) area where a pilot project of GNDT (Gruppo Nazionale per la Difesa dai Terremoti) is in progress for the reduction of the seismic hazard at a sub-regional and urban scale. In such an urban area more than 500,000 people are living and the application of advanced seismological methods for the definition of earthquakes.