A physical stratigraphy model for seismic microzonation of the Central Archaeological Area of Rome (Italy)

A reliable litho-technical model for seismicmicrozonation requires a robust understanding
of the subsoil architecture, that is essential to extrapolate in the space geognostic data
that are often sparse. This paper presents the application to the level 1 seismic microzonation
of the Central Archaeological Area of Rome of a complete methodological approach implementing
physical stratigraphy concepts into an integrated analysis of a subsurface dataset.
Particular emphasis has been placed on the reconstruction of buried geometries, distribution
of lithofacies, and stacking pattern of geological bodies, which can control local seismic
response. The spatial distribution of paleovalley infill and interfluves domains in the subsoil
was reconstructed, which in virtue of their peculiar stratigraphy and morphology may determine
1D and 2D resonance effects. The summation of amplification effects due to the thick
anthropogenic layer allowed to outline five stable zones prone to ground motion amplification,
of which the most critical coincide with the narrow and deep infill of recent valleys.
Potentially less prone to valley effects is the Middle Pleistocene paleovalley infill in the subsurface
of the northern and eastern Palatine hill. Finally, the less hazardous zones correspond
to the ancient, multilayered volcano-sedimentary interfluves separating the paleovalleys.