Tsunami alert: how it works in Italy

Tsunami alert

On February 6, the region between Turkey and Syria was hit by an earthquake of magnitude 7.9 - such violence as to trigger the tsunami alert for the Italian coasts. Based on the data processed by the Tsunami Alert Center (Cat) of the Italian Institute of Geophysics and Volcanology (Ingv) and by Ispra, the Civil Protection Department has issued an alert for possible tsunami waves. This is how the national alert system for seismic tsunamis (SiAM) works.

(At 7:15 am on February 6, the tsunami alert for the Italian coasts was revoked)

What is a tsunami

Especially since 2004, the year of the Indian Ocean earthquake and tsunami, we have been using the Japanese word  tsunami more, which means tsunami, that is, as explained on the Civil Protection Department website, "a series of sea waves produced by the rapid displacement of a large mass of water", with heights that are almost imperceptible in the open sea but which, approaching the coasts, decrease in speed to quickly increase in height (even tens of metres). The main causes are strong earthquakes with an epicenter at sea or near the coast, or submarine and coastal landslides and volcanic activity. Rare, however, are those produced by meteorites falling into the sea.

Warning systems in Italy

In Italy, since 2017, there has been a National Warning System for tsunamis of seismic origin ( SiAM). Coordinated by the Civil Protection Department, it also includes the Tsunami Alert Center (Cat) of the Italian Institute of Geophysics and Volcanology (Ingv) and the Higher Institute for Environmental Protection and Research (Ispra).

The Cat-Ingv analyzes the data of the monitoring networks in real time so as to detect earthquakes in the sea or near the coast and receives from Ispra the sea level data detected by the tidal network. If the experts believe that there is a possibility of a tsunami occurring, an "assessment in progress" communication is sent to the National Civil Protection Department, which can be followed in the shortest possible time by the actual alert message. According to the directive of the President of the Council of Ministers of 17 February 2017, it is the Civil Protection that has the task of issuing the alert throughout the territory, quickly reaching the local authorities directly involved and activating the communication chain (mail, sms) which reaches as far as the municipal administrations to possibly mobilize the operational bodies.

In 2018, the indications for updating the civil protection planning for the tsunami risk were published. The aim is to provide the various components and operational structures of the National Service with useful elements for planning the civil protection interventions to be implemented to safeguard the population of the coastal areas affected by a possible tsunami.

time, the protocol provides for the continuous monitoring of seismic data and sea levels by Cat-Ingv and Ispra, which send the Civil Protection an update message (in the case of changes), an alert revocation message (in the case in which "the sea level measurement networks, for an adequately assessed time, [...], do not register significant anomalies associated with the tsunami, or in the event that no other evidence of significant anomalies becomes available along the various stretches of coast. This message indicates that the seismic event, recorded by the monitoring networks and evaluated as potentially generating a tsunami, did not really give caused a tsunami event or gave rise to a very modest tsunami. The emission of this message cancels the previous warning message”) , or a confirmation message (in the case of instrumental confirmation of tsunami waves) followed by an end of event message .