These are the Spanish cities experts say are at risk of a tsunami in the next 30 years

A recent study by Unesco's Intergovernmental Oceanographic Commission (IOC/Unesco) has highlighted the hypothetical risk of a tsunami in Spain, which it says should not be ruled out. The last one happened in Cadiz in 1755. Now experts say that a huge wave will hit the Spanish coast again in the next 30 years. In the 'Probabilistic Tsunami Hazard in the Mediterranean Sea', report the IOC analyses the probability of a tsunami occurring in the Mediterranean and affecting Spain.

The research warns that the possibility of a tsunami exceeding one metre in height in the Mediterranean in the next 30 years is almost 100 per cent. However, the possibility of the big wave affecting Spain is not as high, although it cannot be ruled out.

Among other causes, a tsunami could be the consequence of an earthquake. And southern Spain (Andalucía and Murcia) are areas with high seismic activity as two tectonic plates converge: the African plate and the Eurasian plate.

The Canary Islands are also not exempt from risk because they are of volcanic origin. The volcano on La Palma erupted three years ago (2021) devastating part of the island with lava flow, while local residents watched on as their houses collapsed or were burnt to the ground.

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In the event of an earthquake, the waves generated could reach a height of up to six metres and would reach the coast in 21 to 35 minutes. The same time the population would have to evacuate.

The IGN (national geographic institute) in Spain is in charge, along with other international bodies, of monitoring seismic activity that could generate tsunamis. They do this through networks of sensors and buoys capable of detecting changes in sea level in real time, providing early warnings to authorities and the public. Although these phenomena are quite difficult to predict in the short term, these tools would at least help the population to evacuate the area and avoid a humanitarian catastrophe.

In Spain, the risk of a tsunami is much lower than in other areas since the recorded earthquakes tend to be of a lower intensity. However, regions such as Andalucía have their own tsunami protocol.

The document includes a risk study to help town halls draw up their own Local Action Plan and the Junta de Andalucía has approved its Emergency Plan for the Risk of Tsunamis in Andalucía, the first to be drawn up in Spain.

The areas of highest tsunami risk in Spain include the coasts of the Gulf of Cadiz and the Alborán Sea. Although strong earthquakes do not occur frequently in Spain, there are several earthquake zones due to the European and African tectonic plates. Also the eastern coastal area - from Torrevieja to the Strait of Gibraltar - could be an area with a higher risk of tsunamis as there is more seismic activity.

The most critical danger zone is the Averroes fault in the Alborán Sea in southern Spain. An earthquake in this zone could cause six-metre waves, which would reach the coast in between 21 minutes and 35 minutes.

According to the report, "The greatest danger is in the eastern Mediterranean due to earthquakes along the Hellenic Arc, but most of the Mediterranean coast is prone to tsunami impact (...) We have found that the probability of a tsunami wave of more than one metre in height occurring somewhere in the Mediterranean in the next 30 years is close to 100 per cent. This underlines the urgent need for a tsunami warning system in the region."