The Temporary Seismometric Network near Bevagna (Perugia, Italy)

SCIENTIFIC STAFF: Enrico Priolo, Giovanna Laurenzano, Carla Barnaba, Paolo Di Bartolomeo
Centro Ricerche Sismologiche, Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Cussignacco (UD) e Sgonico (TS)

In 2009, OGS was charged by the Bevagna Municipality (Comune di Bevagna) with the task of performing a geophysical study aimed at estimating the seismic response of the site that hosts the Sanctuary of Madonna della Valle. Although the present building was made in the early '900 (Fig. 1), this church dates back to the 12th century and has been a traditional place of pilgrimage. The area of the Sanctuary is affected by hydrogeological upheaval that must be well understood in view of the restoration works of the whole building. The study performed by OGS encompassed the registration of earthquakes through a temporary seismic network, the acquisition of environmental seismic noise, and some numerical simulations of the seismic wavefield, and, eventually, the estimation of the local amplification and the definition of site specific design spectra.

Figure 1. The Sanctuary of Madonna della Valle.

The temporary network deployed for the Sanctuary of Madonna della Valle consists of five stations in synchronous acquisition located 2 inside the church, 2 outside the building, and 1 used as a reference at distance of about 2 km, respectively (Fig. 2). The recording equipment consisted of Reftek 130 stations with three-component 1 Hz sensors (Lennartz 3-DLite/1 s). The power was supplied by photovoltaic panels. The temporary network was deployed in June 2009 and remained effective till March 2010. The instruments were set for contiuous recording, however several segments of data are missing due to the lack of power during the winter season.

Figure 2. Map of the temporary seismometric network for the study at the Sanctuary of Madonna della Valle, near Bevagna (Perugia, Italy). Left: general overview; right: detail of the area.