Yes, the Spanish Mediterranean is at risk of tsunamis in the coming years. But not in the way we imagine

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Tsunamis pose a threat to some coastal communities and UNESCO has designed a plan to reduce it. For this, it has identified a series of areas that present a greater risk of suffering these events, areas that include the Mediterranean coast. This has aroused the attention of many, so it is convenient to attend to some questions, such as what is the real risk that tidal waves pose to our coastline, what does the UNESCO plan consist of and what should we know in case of an alert.

What has UNESCO said?
The news has emerged in the context of the Decade of Ocean Science and Sustainable Development 2021-2030, led by the United Nations Educational, Scientific and Cultural Organization (UNESCO). The UNESCO statement has been published in anticipation of the United Nations Ocean Conference, which will take place from June 27 to July 1 in Lisbon. In the statement, the organization warned that “statistics show that the probability of a tsunami exceeding one meter in the Mediterranean during the next 30 years is close to 100%”.

The statement is striking and should be analyzed. In the first place, the statement itself explains that tsunamis are more common phenomena than we think. He gives as an example the average of 7 annual tsunamis that have been detected by the Pacific Tsunami Warning Center operated by UNESCO itself in the United States.

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A meter of tsunami, what does it imply?
One meter of elevation is a mark that in different countries more accustomed to suffering from these phenomena indicates the point at which tsunamis begin to be dangerous. The New Zealand National Emergency Management Agency qualifies as “potentially lethal” these tsunamis. Of course, establish a scale based on the height they reach.

Between one meter and three meters, a tsunami would cause damage to some coastal infrastructure and buildings, as well as some damage to electrical and mechanical equipment. Between three and five meters would cause widespread flooding and possible damage to concrete buildings. The coastal infrastructures would again record damage. Between five and eight meters damage and flooding would be widespread, with some buildings swept away by the current and others suffering structural damage.

The tsunami that in 2004 caused more than 200,000 deaths around the Indian Ocean reached more than 50 meters when it reached the island of Sumatra, according to data of the US National Oceanic and Atmospheric Administration (NOAA). The danger of tsunamis comes from the enormous amount of water that they displace, first towards the interior and then, when receding, towards the sea.

How do tsunamis form?
Tsunamis can be caused by different reasons. It is usually a earthquake under the seabed in what causes them. Landslides and submarine volcanoes may also be behind some of these events, and less frequently, meteorological conditions and even the fall of a asteroid into the sea. The Mediterranean follows the course of the border between two tectonic plates, the Eurasian plate and the African plate. This makes the seismic activity of the region relatively high.

Not all of the Mediterranean is at the same level of risk.
But the border marked by the plates also means that the risk of tsunamis, like earthquakes, not spread evenly along the sea. Some areas like the southern Italy and some Greek archipelagos they are more prone to earth movements than the rest of the areas. The geographical distribution of the seabed and of the various islands in the sea also affect how tidal waves spread.

The risk of a tsunami affecting the Spanish coast is not new. a little less than a year ago a study in the magazine Scientific Reports alerted tsunami risk in the Alboran Sea environment. A tsunami in this area could bring waves of up to six meters, although the main risk would be its short distance from the coast, which would imply little time for reaction, between 21 and 35 minutes, insufficient time for early warning systems to comply. its function.

Tsunami ready.
UNESCO’s warning is accompanied by a prevention plan, the program Tsunami-ready. The organization seeks to equip coastal communities at risk with tools to minimize risk during this decade, and has already started a pilot test in 40 communities spread over 21 countries. The program seeks to create individualized plans for each community since each context differs, in the probability of an event occurring, but also in demographic, geographic and socioeconomic characteristics.

Each community must have “a tsunami risk reduction plan, in addition to identifying and mapping danger zones, developing public education and outreach materials, creating publicly accessible tsunami evacuation maps, and publicly displaying information on tidal waves”, according to UNESCO.

Image | Martin Vonk

Tsunamis pose a threat to some coastal communities and UNESCO has designed a plan to reduce it. For this, it…

Tsunamis pose a threat to some coastal communities and UNESCO has designed a plan to reduce it. For this, it…

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