Deployment of a Multi-Parameter Volcanic Tsunami Monitoring System Offshore Sciara del Fuoco, Stromboli

A fully integrated tsunami monitoring unit, funded by the Italian National Civil Protection Department, was installed in July 2025 by INGV, offshore the Sciara del Fuoco, Stromboli, under the coordination of two INGV centres, the CME (Centro Monitoraggio Eolie) and CAT (Centro Allerta Tsunami), and has been operating reliably since.

The seafloor module, anchored to a reinforced-concrete deadweight, hosts multiple sensors, including a pressure sensor to detect rapid sea-level changes, a hydrophone to capture volcanic and underwater activity and an accelerometer to observe seafloor dynamics.

Information is exchanged bidirectionally between the buoy and the seafloor module through an elastic electromechanical cable, also supplying energy to the seafloor module, and simultaneously providing elastic mooring. 

The elastic cable can extend up to 2.5 times its unstretched length while maintaining its mechanical and electrical integrity. To reach the installation depth, two cable segments were connected using an intermediate connection buoy. A mechanical release system can be triggered acoustically to release the seafloor module from the deadweight.

The depth of the seafloor module, approximately 88 meters, was chosen so that pressure data can be converted into tsunami height values to limit as much as possible the deep-water high-wavenumber attenuation effects, as tsunamis induced by mass flows over the Sciara del Fuoco feature shorter periods signals than earthquake-generated tsunamis. 

Data streams are transmitted via radio and Wi-Fi to the shore station on Stromboli Island, then forwarded to the INGV-Osservatorio Etneo data center at the COA (Centro Operazioni Avanzate) in Stromboli. From there, the data are transmitted to the INGV-CAT. An STA/LTA algorithm, first introduced by Ripepe & Lacanna (2024) for the tsunami warning at Stromboli from the elastic beacons at a similar location, is applied experimentally to the data stream. The data will become in the future an important source of information for the tsunami warning system in Stromboli.