After a magnitude 8.8 earthquake struck off Russia’s Far Eastern Kamchatka Peninsula on Wednesday, damaging buildings and generating a tsunami of up to 4 metres (13 feet) that prompted warnings and evacuations stretching across the Pacific Ocean - what is the chance of a tsunami in Spain? Although it may seem impossible, the study “Probabilistic tsunami in the Mediterranean Sea” published in the scientific journal “Pure and Applied Geophysics” has warned of the high probability that the Mediterranean region, including Ceuta and Melilla, will be affected by a large tsunami in the near future.
The Intergovernmental Oceanographic Commission states that the chances of this phenomenon occurring are 100% in the next 30 years. Tsunami events have been documented in the western part of the Mediterranean. The last of these was in 2003, when the earth before the Algerian coast shook so strongly that waves up to two metres high caused a huge amount of property damage in the port of Palma. Due to the waves, several yachts were damaged, in some cases severely.
According to research, climate change is the main cause of the increased likelihood that the Spanish Atlantic coast is at risk. The Averroes marine fault in the Alboran Sea has the potential to generate waves six metres high that could hit the Spanish coast in less than 25 minutes. But in the Canary Islands, they could reach eight metres. Other cities such as Huelva and Cádiz could also fall victim to this threat. Researchers have determined that they are likely to experience a tsunami of between one and three metres in the future, with a 10% probability in Huelva and 3% in Cádiz.
On the other hand, there are areas with a lower risk of tsunamis, such as the Cantabrian coast in northern Spain, where water levels are not expected to exceed half a metre. Therefore, in regions such as Asturias, Cantabria and the Basque Country, the impact of a possible tsunami would be less severe.
Given this scenario, it is vital to have a good warning system in place, even if the arrival of tsunamis still seems a long way off.
Ceuta, for example, is already part of the State Civil Protection Plan for Tsunami Risk, which is part of the State General Civil Protection Emergency Plan (PLEGEM). This plan establishes an early warning and alert system that allows civil protection authorities, emergency services and citizens to be informed of the imminent arrival of a tsunami.
What are common in the Balearics are rissagas or meteotsunami which is a coastal meteorological phenomenon that causes a very strong variation in high tide caused by changes in atmospheric pressure. Rissagas are the oscillations of sea level in ports, coves or bays, caused by meteorological factors such as strong winds in the troposphere , warm air at low levels of the atmosphere and weak or moderate at the surface, and which in resonance conditions, that is, sudden rise and fall of sea level in a very short time (minutes or even seconds) which, when very intense, usually cause damage to moored ships and flooding of port infrastructure.
The last major rissaga in Menorca, the largest in 20 years, occurred on June 15, 2006, with oscillations of up to 4 metres that caused damage to numerous boats. For a rissaga of this nature to occur, as also happened in Menorcaq on June 21, 1984, it is necessary that the conditions under which they normally occur are accompanied by a storm with strong winds and sudden changes in atmospheric pressure . In the most common rissagas, sea level oscillations are 60 to 120 cm. On August 8, 2015, a meteotsunami also occurred in central Chile off Valparaíso. About 50 weather warnings are typically issued each year.