The Directive of the President of the Council of Ministers of 17 February was published in the Official Journal which establishes, under the coordination of the Department of Civil Protection, the National Alert System for Tsunamis (SiAM) generated by earthquakes in the Mediterranean Sea.
Earthquakes are the main cause of tsunamis (about 80%), although not the only one. However, it is the only one for which it is possible, with the current monitoring networks, to define an alert system. Other causes can be underwater or coastal landslides or volcanic eruptions. The SiAM, created to analyze data from monitoring networks in real time, evaluate the possibility that a tsunami may occur as a result of earthquakes at sea or along the coast and of what magnitude and to disseminate warning messages, is made up of three institutions: INGV-National Institute of Geophysics and Volcanology which operates through the Tsunami Alert Center (CAT), ISPRA-Higher Institute for Environmental Protection and Research and the Civil Protection Department itself.
Specifically, the INGV Tsunami Alert Center - which operates 7 days a week, 7 hours a day - assesses the possibility that a given earthquake, with its epicenter at sea or in the immediate vicinity, could generate a tsunami and estimates the expected arrival times along the coasts exposed. On the other hand, it is the task of the Civil Protection Department, on the basis of CAT assessments, to disseminate the warning messages to the structures and components of the national civil protection service to reach the potentially affected population as quickly as possible. Finally, the data provided by the national tide gauge network managed by ISPRA and the tide gauges present along the coasts of other Mediterranean countries allow us to confirm or not a possible tsunami.
The Prime Minister's directive - reaffirming how the operation of the warning system is based exclusively on the recording and processing of seismic events potentially capable of generating tsunamis, thus excluding all other potential sources of a tsunami - also lists peculiarities and limits of the SiAM, recalling among other things that, given the characteristics of the Mediterranean, a relatively small and closed basin, and the incompressible times of recording and evaluating seismic data, does not guarantee that the impact of a tsunami on the coast is always preceded by the issuing of a warning message as well as that a warning message is always followed by a tsunami.
The directive, which also includes four technical annexes, provides that within three months of publication in the Official Gazette, the Head of the Civil Protection Department shall provide the various components and operational structures of the National Civil Protection Service with indications for updating their respective planning emergency, also with reference to the expeditious identification of coastal areas potentially exposed to tsunamis generated by earthquakes and the related warning zones, based on the elements provided by INGV and ISPRA.
However, within one year of publication of the directive in the Official Gazette, each person involved must draw up, update and adjust their plan.