Ricerc@Sapienza

Predicting the seismic site effects in complex real case histories is a non-trivial scientific and technical task. In fact, it requires the overall geometry of the problem (i.e. surface and underground) to be properly described and combined to adequate soil models, accounting for the peculiar aspects of the dynamic soil behaviour. These latter should include the dependency of the initial stiffness on the stress state and its non-linear evolution with strain amplitude, together with the corresponding one of the damping ratio.

This paper critically examines the numerical predictions of the seismic site response of both ideal and real cases as obtained by means of mono- and multi-dimensional Finite Element (FE) approaches. Ideal case-studies are first considered, aiming at validating the adopted numerical approach against existing analytical or simple numerical solutions. Then a three dimensional model of the Bovino urban area, located in southern Italy, was generated taking into account the real site conditions.

The use of Rayleigh wave ellipticity has gained increasing popularity in recent years for investigating earth structures, especially for near-surface soil characterization. In spite of its widespread application, the sensitivity of the ellipticity function to the soil structure has been rarely explored in a comprehensive and systematic manner. To this end, a new analytical method is presented for computing the sensitivity of Rayleigh wave ellipticity with respect to the structural parameters of a layered elastic half-space.

After the 2016–2017 seismic sequence in Central Apennines, seismic microzonation studies were planned in the framework of the Ordinance 24 of the 12 th of May 2017 (OPCM 24/2017) issued by the Italian Presidency of the Council of Ministers. Numerical simulations aiming at estimating seismic amplification factors of uniform microzones located in several municipalities of the Latium Region were carried out in order to provide quantitative elements for reconstruction. The investigated areas include alluvial valleys of variable