Evaluation of site effects using numerical and experimental analyses in Città di Castello (Italy)

In the paper the results of the numerical and experimental analyses, at a site in the Umbria Region (Citta` di Castello--PG), are finalized and the evaluations of site effects are shown. The aim of the work was to compare the two types of analyses and give some methodologies that may be used at the level of urban planning. Therefore a series of geological, geomorphological (1:5.000 scale), geotechnical and seismic analyses have been carried out, to characterize the lithological units and to identify the areas affected by site effects. The expected seismic inputs were provided and two-dimensional numerical analyses have been done. An experimental analysis, using the registrations of small events, has been done. The results for the two approaches were performed in terms of elastic pseudoacceleration spectra and amplification factors. The results are given as a ratio between spectral intensity, calculated using the pseudovelocity spectra, in the periods of 0.1-0.5 s and 0.1-2.5 s of output and input. The results have been analyzed and compared, to provide a methodology that may be comprehensive and precise. r 2006 Elsevier Ltd. All rights reserved.