The Spanish company Mediterranea Senales Maritimos (Msm) is making for the Tsunami Alert Center (Cat) ofIngv (National Institute of Geophysics and Volcanology) high seas which in the coming months will be installed in the Ionian Sea For monitor tsunami. Boe are able to detect and measure the passage of the tsunami wave caused by an underwater earthquake before arrival on the coast and thus improve the forecast tsunami in the Mediterranean. Even in our sea, in fact, these destructive events can occur, as has happened in the past. Based on the data obtained from monitoring with the boes and with other tools, an ‘is issuedalert In the event that an underwater earthquake is potentially able to generate a tsunami, thus allowing promptly evacuate the population.
How the Tsunami alert works in the Mediterranean
An earthquake, when it takes place under the seabed, can trigger the movement of huge water masses in the form of marine waves that reach the coasts by devastating them. This phenomenon, which takes the name of tsunami, can be foreseen thanks to early alert systems avoiding the most serious consequences for the population. The Early alert system for tsunami In Italy it is called Siam (National alerting system for seismic seamotes), is active since 2017 and is managed by Tsunami Alert Center (Cat) of the Ingv and the Department of Civil Protection. Its function is the Continuous monitoring of strong earthquakes which take place along the coasts and in the Mediterranean Sea. The system uses one sensors network who record the seismic waves and of Mareografi which detect the variations of the sea level.
In the coming months the Boe high seaswhich allow you to detect and measure the passage of the wave before arrival on the coast. The buoys will be connected with an acoustic modem to a pressure sensor on the seabed, positioned at an inclusive depth Between 2600 and 3200 m. The data collected with these tools are transmitted via satellitein real time, in the alert center, where they are analyzed. If the data reveal a concrete threat of tsunami, an ‘is transmittedAlert to the Department of National Civil Protectionwith an estimate of the theoretical arrival times of the possible wave of tsunami. The Department of Civil Protection, in turn, has the task of spreading the alert of the Cat in the shortest possible time.
The Alert levels of the Cat
The cat alert is activated for earthquakes of magnitude equal to or greater than 5.5. There are several alert levels depending on the magnitude and distance of the coast from the epicenter of the earthquake.
- Green alert (Information) Indicates that an earthquake has occurred but that it will probably not generate a tsunami. However, near the epicenter, small variations in currents and wave motorcycles may occur, in particular in the inlets.
- Orange alert (Advisory) Indicates that a strong earthquake occurred potentially capable of generating a tsunami, whose effects on the coast can be mild. Those who are near the coast must move towards higher and internal areas.
- Red alert (Watch) Indicates that a strong earthquake occurred and that the coasts of one or more regions can be affected by tsunami in which the water height exceeds 1 m compared to the sea level. Anyone who is both on the coast and inland in unrelated areas must move immediately to high places, following the indications of the evacuation plans.
Tsunami alerts in the Mediterranean
Since the Cat became operational, in 2017, in the Mediterranean there have been numerous submarine earthquakes, of which Seven of magnitude between 6.4 and 7.0who activated the alert. Among these, some actually produced tsunami, even if of modest entity: the 20 July 2017 An earthquake of magnitude 6.8 off Turkey has generated a tsunami along the coasts of Greece and Turkey; The 25 October 2018 A 6.8 magnitude earthquake in the Ionian Sea caused small tsunami waves that have reached Italy; The 02 May 2020 An earthquake of magnitude 6.7 south of Crete was the cause of a small tsunami; The 30 October 2020 An earthquake of magnitude 7 in the Aegean Sea produced a tsunami on the coasts of the island of Samos and the Smirne region in Türkiye.
Even if the extent of these tsunami has been modest, the Mediterranean can be the scene of much more serious events: in 1908a Earthquake with epicenter in the Strait of Messina of magnitude 7.1 caused one tsunami which destroyed most of the buildings of Messina and Reggio Calabria.
