Quantification of site effects in the Amatrice area (Central Italy): Insights from ground-motion recordings of the 2016–2017 seismic sequence

This work focuses on site response analyses in the Amatrice area (Central Italy), taking advantage of the 3A temporary seismic network, installed after the first shock (MW 6.0) of the 2016–2017 seismic sequence, and of a detailed site characterization. Classical empirical methods are applied on seismic signals to evaluate their capabilities to infer site response parameters. For about one-third of the stations, the H/V method fails in estimating the empirical SSR amplification function, as a consequence of the vertical amplification. Although the majority of sites belong to the EC8-B soil category, all the empirical methods show great variability in the site responses. For this reason, to find common features among the sites we perform a cluster analysis on SSR functions finding 5 clusters characterized by three site parameters: VS,30, f0 and Af0 (i.e microtremor H/V amplitude at f0). This result seems promising for site response estimation in Central Italy from velocity profiles and noise measurements.