Un’applicazione della metodologia sismica tomografica per lo studio di un problema di geologia urbana

Geophysical methodologies have been used more recurrently within urban geology in the past years. These
techniques, when correctly applied, offer a more or less complete frame on the physical and mechanical properties, on
discontinuities and on subsurface geometries of investigated mediums. Geophysical prospecting is also used because of its
low cost/advantages ratio. It’s also capable of overcoming the limits of more classical geognostical investigations (ie.
borehole drilling) that, being localised, can often give results which are not univocally interpretable, especially for
reconstruction of subsurface geometries in complex scenarios. This work presents an example of the use of high resolution,
P wave seismic tomography that has been applied within a study intended to securing an anthropic cavity so as to not
represent a threat for human lives and possessions. Instability conditions are due to the poor mechanical conditions of
existing lithotypes and the high degree of alteration of the lithologies. Proof of poor structural conditions have been the
numerous falls of debris during seismic events (ie. after the seismic event of 1997). Firstly, applicability and intrinsic
limitations of the methodology are discussed referring to the medium complexity. Eventually, the acquisition techniques and
the data processing are discussed, coadiuvated by the use of direct investigations like geological and structural survey,
exploration dig and rotary drilling.