Use of microseismic data to monitor significant sea wave heights in support of marine weather forecasting and coastal protection

The focus of the Ph.D. project was the implementation of a network for monitoring significant sea wave heights (Hs) along the Ligurian coasts (north-western Mediterranean Sea), in order to provide near-real time data to weather forecasters and sea users (vessel captains, pilots, Coast Guard, Port Authorities and yachtsmen). The project was divided into a part dedicated to the use of microseismic data, interfaced with data derived from modelling hindcasts and from the wave buoy of Capo Mele, for the determination of Hs, and a part dedicated to the Interreg Italy-France Maritime 2014-2020 SINAPSI "Assistance to navigation for safe access to ports” Project, which involves the installation of instruments for measuring weather and sea parameters along the coasts of the Ligurian Sea. The first phase of the Ph.D. project involved the study and updating of a mathematical procedure for the estimation of Hs from the microseismic data recorded by the network of seismic stations along the Ligurian arch. The procedure exploited the existing relationship between sea wave heights and microseismic signal and included the use of hindcast data to calibration steps and data from the Capo Mele wave buoy to verify the reliability of the estimated Hs data. In October 2018, an extreme sea storm hit the Ligurian coast with waves characterised by Hs greater than 6 m; these wave heights were not matched by an equivalent energy in the microseismic signal, which therefore led to an underestimation of the Hs estimated by the procedure. It was therefore necessary to investigate the extreme event of 2018, which led to the evidence of a lack in the energy of the microseismic signal and the need for a data compensation, which was possible thanks to the use of weather data (wind speed and atmospheric pressure) that were included in an additional element to the estimation procedure. The second phase of the Ph.D. project therefore involved verifying the reliability of the data estimated by the procedure, which led to the evidence of a generic underestimation of Hs. This led to the study of a first modification of the procedure and to the consequent monitoring of its validity on a large time scale. The monitoring of the reliability of the estimated data will be continued after the end of the Ph.D., as well as the updating/refinement of the procedure. The Ph.D. project involved the participation in the SINAPSI Project, which started in April 2019, in all its components, from the management to the implementation of the monitoring network, also including the communication and dissemination of the project activities to the stakeholders. The Ph.D. has achieved the improvement of the Hs estimation procedure. The research activities will continue beyond the Ph.D. natural end to implement the results with data from a radar antenna system that will be installed in the Genoa area in the framework of the SINAPSI Project.