The Probabilistic Seismic Hazard Analysis (PSHA) refers to the calculation of a ground- motion parameter (e.g. peak ground acceleration, seismic intensity and the estimation of its occurrence probability to cause ground-motion exceeding a given value within the given time intervals at the site. The method assumes that the earthquakes in the database used are independent of each other and the earthquake frequency is stationary, i.e., the frequency does not change during the considered time interval.