Historic monuments are cultural assets of each society. Their importance results from the variety of roles they play in urban landscape and hence, their preservation is significant for the development and sustainability of cities. This study aims at application of Structural Health Monitoring (SHM) on the Four Days Memorial in the city of Naples which lies above an isolated podium using four elastomeric isolators and four sliding bearings. To control the dynamic response of the monument under seismic events and ambient vibrations produced by the vehicular traffic and the nearby Metro Line 6, triaxial velocimeters have been installed on foundation slab and isolated basement. Then the recorded signals can be processed based on the Italian Standard UNI 9916 and the German DIN 4150-3 to find the maximum response of the monument under any vibration and compare them with the threshold given by the standards for both short-term and long-term monitoring. The results of data processing indicate that the response of the monument both at foundation level and isolated podium did not overcome the allowed limit for permanent traffic vibration and for the occasional vibration caused by numerous earthquakes occurring recently due to the Phlegrean Fields bradyseism activity. A comparison between day and night structural response to traffic induced vibrations for weekdays and weekends has been done and moreover, the dominant frequency of structure subjected to the vibrations due to earthquakes and vehicular traffic are measured as well.