In this work some of the most used techniques for estimating site effects are presented. This thesis has been developed and written inside the projects of the E.S.S. Earth System Sciences, doctorate school of the University of Modena and Reggio Emilia. Local seismic response are widely responsible nowadaways of a differentiation of the damages during and after an earthquake. Moreover seismic events occurre in alluvial basins could increase either in intensity and length in time of the shakes. This thesis after having studied some cases of site effects, focused on Rayleigh induced surface waves inside a singular italian case, namely the Norcia basin.