Earthquake scenarios and seismic input for cultural heritage: applications to the cities of Rome and Florence

For historical buildings and monuments, i.e. when considering time intervals of about a million year (we do not want to loose cultural her- itage), the applicability of standard estimates of seismic hazard is really questionable. A viable alternative is represented by the use of the scenario earthquakes, characterized at least in terms of magnitude, distance and faulting style, also taking into account the complexity of the source rup- turing process. Scenario-based seismic hazard maps are purely based on geophysical and seismotectonic features of a region and take into account the occurrence frequency of earthquakes only for their classi cation into exceptional (catastrophic), rare (disastrous), sporadic (very strong), occa- sional (strong) and frequent. Therefore they may provide an upper bound for the ground motion levels to be expected for most regions of the world. The neo-deterministic approach naturally supplies realistic time series of ground motion, which represent also reliable estimates of ground displace- ment readily applicable to seismic isolation techniques, useful to preserve historical monuments and relevant man made structures. This methodology has been successfully applied to many urban areas worldwide for the pur- pose of seismic microzoning, to strategic buildings, lifelines and cultural heritage sites. We will discuss its application to the cities of Florence and, more extensively, Rome.