Analysis of Seismic Site Effects in Plio-Quaternary Intermontane Basin (L’Aquila, Central Italy)

This study presents a comprehensive analysis of site effects in the highly seismic area of L’Aquila in central Italy, which has been conducted within the framework of a seismic microzonation project funded by the Abruzzo Region’s Department of Government of the Territory and Environmental Policies. The project was aimed at best practices on the management of urban and land territory for seismic risk mitigation. Through the integration of detailed geophysical and geotechnical data with numerical modeling, we provide an accurate assessment of local seismic amplification. Two-dimensional numerical simulations using the LSR 2D code were performed on many representative geological sections to compute amplification factors for various period ranges. This case study allowed us to outline some key considerations for best practices in local seismic response analysis and seismic microzonation studies in Italy. Given the prevalence of 2D basin edge, buried morphology, and topographic effects in Plio-Quaternary geologically complex intermontane basins in central Italy, as demonstrated in the L’Aquila case study, use of two-dimensional models is suggested. In order to validate the numerical models and their associated spectra and amplification factors, it is also suggested to compare transfer functions with HVSR microtremor measurements at control points along the studied sections.