Detection of 2009 L’Aquila’s Earthquake Effects on Collemaggio Church through Experimental Surveys

Abstract

Ten years after the earthquake that affected central Italy in 2009, noninvasive investigations were carried out in L’Aquila on the Basilica of Santa Maria di Collemaggio. These were conducted to characterize the ground from a site-response point of view. The study consisted of 11 ambient noise recordings using the Nakamura technique and distributed along two profiles: one longitudinal to the central nave and one transverse. Analyzing the results, it was possible to determine the frequency of the vibration of the ground. After comparison with data from previous literature, it was possible to graph the contrasting sections of the impedance of the subsoil up to about 300 m depth (bedrock) drawing on a passive seismic survey from the single station. Furthermore, sonic tests were performed on the 14 octagonal columns of the central nave. The data were compared with those collected 10 years earlier (post earthquake) and with postearthquake structural restorations. The new tests show an increase of velocity in the resistant sections of the pillars subjected to the structural consolidation.