An effective strategy for the seismic risk mitigation needs the use of advanced seismological
methodologies for a realistic estimate of the seismic hazard and, consequently, to reduce
earthquake damage through a preventive evaluation of vulnerability and actions for
structure safety. Prediction of earthquakes and their related effects (expressed in terms of
ground shaking) can be performed either by a probabilistic approach or by using modelling
tools based, on one hand, on the theoretical knowledge of the physics of the seismic source
and of wave propagation and, on the other hand, on the rich database of geological, tectonic,
historical information already available. Strong earthquakes are very rare phenomena and it
is therefore statistically very difficult to assemble a representative database of recorded
strong motion signals that could be analyzed to define ground motion parameters suitable
for seismic hazard estimations. That is, the probabilistic estimation of the seismic hazard is a
very gross approximation, and often a severe underestimation, of reality.
A realistic and reliable estimate of the expected ground motion can be performed by using
the Neo-Deterministic Seismic Hazard Analysis (NDSHA), an innovative modelling
technique that takes into account source, propagation and local site effects (for a recent
review see Panza et al., 2011). This is done using basic principles of physics about wave
generation and propagation in complex media, and does not require to resort to
convolutive approaches, that have been proven to be quite unreliable, mainly when
dealing with complex geological structures, the most interesting from the practical point
of view.
