ABSTRACT
Neapolitan Yellow Tuff outcropped (see Fig. 3), while in the surroundings alluvium and marine deposits characterise the subsoil. Greeks preferred to build up the city on the rock.
The aim of this report is to show the role that the subsoil has had on the birth and growth of the city of Napoli where, owing to the large diffusion pyroclastic rocks, a significant number of building has been constructed using these materials. Old quarries, tunnels and other underground works frequently involve these formations; cliffs and slopes of these rocks are often present into urban areas. Pyroclastic soils also influences the behaviour of buildings and other structures present in the city, especially when these soils, originally unsaturated, experience significant increase of water content.
