GNGTS 2022 - Atti del 40° Convegno Nazionale

214 GNGTS 2022 Sessione 2.1 The results are comparable, indicating that the SSRh method allows estimating amplification factors that are in good agreement with well-established methods based on earthquake ground-motion data. Even though the standard deviation for the noise-based spectral ratio is significantly higher than for SSR because of the variable nature of the ambient noise wavefield, the mean values can be used to derive a reliable local amplification model. The SSRh method is at the same time relatively cheaper than techniques based only on the earthquake ground motion data and allows for higher spatial resolution. Hence, we decided to evaluate the site response for the points where only ambient vibration recordings are available. The final local amplification model (Fig. 3) is referenced to Swiss reference bedrock conditions (Poggi et al. , Fig. 2 - Comparison of the relative amplification function using the SSR and SSRh methods for all stations of the temporary seismic monitoring network.