Tsunamis and megatsunamis they have plagued the coasts of the Canary Islands for thousands of years. Many of these tsunamis have been caused by explosive volcanic eruptions, followed by landslides that have ended up falling into the sea and displacing the water generating large waves. This is the case of megatsunamis in Gran Canaria, Lanzarote and Tenerife linked to the eruptions of Tenerife 170,000 years ago. But you don’t have to go so far back to talk about tidal waves in the Canary Islands.
Up to 11 tsunamis have affected the Canary Islands coasts in the last millennium, some of them undocumented because until the fifteenth century there are no references to the Canary Islands in the chronicles. All of them are detailed in a recent investigation, carried out between the Geological and Mining Institute of Spain (IGME) of the Higher Council for Scientific Research (CSIC), with the collaboration of researchers from the University of La Laguna (ULL) and the Science Museum Naturals of Tenerife.
What is the current interest in tsunamis?
Although the theory about the possible megatsunami that would generate the collapse of Cumbre Vieja, on La Palma, has gained popularity in recent years and has become current again with the eruption of the volcano in the Palmero massif on September 19, 2021, the research carried out and published in Geosciences it has nothing to do with this.
The purpose of the study is try to prevent the destructive effects of future tsunamis that could damage the Canary coasts, nowadays very populated. It is based on the fact that it is possible that tsunamis may occur that affect the Canary Islands.
According to what has been stated by the researchers, in the past there is no evidence that tsunamis caused human damage, among other reasons because the populations in the Canary Islands lived with their backs to the sea, both before and after the Conquest. The reasons for the terror of the sea of the ancient Canaries are not known for sure, but the reasons for the settlements in the interior have their explanation in the pirate attacks.
Dates of the eight documented tsunamis in the Canary Islands
Although there are historical references to tsunamis that could have affected the Canary coasts and even vestiges that prove them in sedimentary deposits on some islands, only eight are currently documented. The documentation of the eight tsunamis detailed below comes in some cases from chronicles and, in others, from measuring devices. Several of them were not even perceived as tsunamis by the population and only as waves greater than usual.
November 1, 1755
This tsunami was caused by the Lisbon earthquake, of magnitude 8.5 Mw. It devastated the southwestern coasts of the Iberian Peninsula and northern Morocco and was even registered in America, both North and South. The investigation shows that “the damage and deaths it caused on the coasts of the Peninsula were so important that the damage that occurred in the Canary Islands went almost unnoticed”. The study narrates that around 9.30 am on November 1, 1755, some inhabitants of Tenerife felt the earth shake and, at the same time, the sea withdrew in Tenerife and Gran Canaria for more than a kilometer. There are historical references that it affected all the islands, as well as that the flood level it caused was more than five meters high. In Gran Canaria, the hermitage of La Luz was flooded, which was filled with fish.
March 31, 1761
This other episode also had its origin in an earthquake of magnitude 8.5 Mw in the southwest of the Iberian Peninsula. It was felt in Portugal, Spain and Morocco. There are records that it reached the southern and western coasts of the Peninsula, United Kingdom, as well as the archipelagos of Azores, Madeira, the Canary Islands and Barbados. Its effects on the coast of Tenerife “were similar to those reported by the tsunami of 1755”, according to the investigation.
July 7, 1941
This tsunami was recorded in the newspaper La Tarde, which reported three huge waves that flooded the coastline of Santa Cruz de Tenerife and San Andrés. They affected the Cabildo building and Avenida Marítima, where the Naval Command was flooded. These waves have been attributed to a local landslide near the Tenerife capital, since no earthquakes or other extreme wave events occurred that day.
November 25, 1941
Shortly after the previous tsunami, an 8.3 Mw magnitude underwater landslide earthquake off the coast of Portugal caused a tsunami whose large waves reached the Canary Islands, but it is not mentioned in the local press in the absence of damage.
February 28, 1969
A low intensity tsunami occurred on this date, caused by an earthquake in the Gorringe bank, a seamount 130 miles west of Portugal, between the Azores and the Strait of Gibraltar. It was recorded by tide gauges in Santa Cruz de Tenerife, Santa Cruz de La Palma, Las Palmas de Gran Canaria and Arrecife.
July 17, 1969
On this day, a small tsunami of unknown origin was detected in mareograms of Santa Cruz de Tenerife and in various parts of Portugal, as well as in Casablanca.
May 26, 1975
As a consequence of a 7.9 Mw earthquake 200 kilometers south of the Gloria fault, in the Atlantic, a tsunami occurred that was seen in the Azores and was recorded in a tide gauge in Gran Canaria.
November 14, 2020
Massive rockfall on the coastline in Valle Gran Rey, La Gomera, resulted in a local tsunami. There are videos of the falling stones and the wave it caused. It caused no damage.