A probabilistic seismic hazard analysis was performed for İstanbul considering the seismotectonic structure of the region. Earthquakes that occur in seismic regions has the possibility of triggering each other to a certain extent, and this causes earthquakes to cluster in time and space. In this study, the Poisson model was preferred for probabilistic seismic hazard analysis. Conventional integration approach was adopted to calculate the hazard curves to describe the likelihood of exceeding ground motion in a particular period. This paper presents results on the impact of seismic hazard on structural performance of an existing masonry tower, by evaluating the seismic response for different levels of ground motions.