GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.3 GNGTS 2024 recovery of the instrumentaton. A dispersing nozzle was also designed to optmize the burying system. The whole data acquisiton system is composed of a broadband seismometer Nanometrics Trillium OBS 120 s and a Guralp DM24 digitzer inside the electronics vessel. A 150 m long marine cable, carrying data and power, connects the vessel to the surface unit. As it can be seen in Fig. 1 (a-c), a custom-made centering disc, made of polyethylene, guarantees the correct positoning of the bundle formed by the cables, rope and pipe above the sensor. It supports the electronic vessel and prevents the bundle from touching the walls of the c.p., as they may transmit mechanical noise to the sensor through the bundle. The core of the surface unit is a Guralp EAM-U digital acquisiton system, hostng a SEEDLink server. The server is accessible from the INGV seismic monitoring center, where a SEEDLink client will contnuously receive the seismic data, available in near real-tme. Fig. 1 – Schematc arrangement of the whole instrumentaton deposited at the botom of the c.p. D (a). In (b) and (c) a focus on the centering disc supportng the digitzer. Quality evaluaton of the recorded signals As a frst step, we collected the signals of the frst week of each month, day by day, between March 2020 and October 2023 through the dedicated FDSN Web Services (htps://www.fdsn.org) .