ABSTRACT
We examine two case studies of monumental buildings analysed by theAcoustic Emission (AE) monitoring technique and located in two areas of Italy characterised by different levels of seismicity: a medieval tower rising in Alba, a characteristic town in Piedmont, and the Cathedral of Syracuse Sicily. The motivation of this research work is twofold. On one hand, a quantitative
non-destructivemethod for evaluating damagephenomena is of great importance given the number of ancient buildings at risk in the Italian territory, due to the intensity of the stresses to which they are subjected. In order to preserve this inestimable cultural heritage, AE technique can be highly effective for an early detection of the damage since it identifies a damaging process at the verymoment it occurs. On the other hand, when we try to consider the system-environment interaction, we cannot exclude that a share of the AEs measured on a structure really comes from external sources, such as environmental vibrations or, more interestingly for our purposes, from some high-frequency geodynamical activity. In this prospective, the relation between theAE activity on these buildings and
the regional earthquakes occurred during the monitoring period is investigated in order to explore the possibility that theAEs emerging from a structure can be considered also as seismic precursors besides as signs of developing structural damage.
