Local seismic response change following an excavation in an area located in the territory of L' Aquila City (Italy)

This article presents the results of 2D numerical simulations to estimate the change of local seismic response due to an excavation that occurred during the L'Aquila city's earthquake (Italy) in April 2009. The modeling is an attempt to understand the very complex phenomenon produced by multiple reflections due to particular topographic and stratigraphic geometries, verifying whether the anthropic actions are able to modify or not the surface amplifications. In particular, the numerical simulations were performed considering national and international earthquakes databases, compatible to the spectral form expected at the site. The investigations were conducted with the VisualQ4M software that is a Pre & Post Processor capable to use up in the background the Quad4M calculation code for the study of 2D seismic amplifications. In the numerical context, the model was reconstructed according to the natural slopes and topographical conformations of the site and of the stratigraphic discontinuities, using a structured mesh with dimension suitable for the minimum speed of propagation of seismic waves (Vs) in order to avoid filtering or attenuations of wave propagation.