To evaluate the vulnerability of a center it is important to implement security measurement for residents, but also for the preservation of the building and it’ historical identity.

Because of their particular shape, the historical centers, cannot be regarded as a set of buildings to be treated individually and independently but as part of an urban tissue composed by a series of networks such as communication and technologic.

It is therefore a clear need to define the procedures of investigation involving the territorial dimension of regional geology, the land-use, and the full characterization of the residential units (from material consisting of typological and constructive evolution), with particular reference to their vulnerability to the earthquake.

The data, summarized by defining the representation and the modes of damage, permit to prepare scenarios of damage and then plan security schemes and operations in case of situations of emergency.

To value the vulnerability of an historic building we can use models to analize the risks, more or less complex, considering that it has two equally important components: the probability and the consequence.

We offer a finalized methodology at the definition of seismic risk assessment process to value the effects of the event in terms of damage and to face the post-earthquake emergency in order to reduce potential hazards to the humans and the building.

Described the earthquake Si it can occur on land area T with different levels of intensity (intensity or energy) Sei. For every event we can define a joint probability density function q (SEi, T) of the probability of occurrence of the event to the vary of the intensity level SEi and of the territorial zone T in a fixed period.

The final objective is the definition of a curve that can define an acceptable level of risk. The curve identifies the possible combinations of consequence-frequentness of events in the space, considering the sectors of acceptable risk and non-acceptable risk.

The information gained allows to run the risk control and thus to improve the security of the historical centre and their inhabitants.