Tsunamis and megatsunamis have devastated 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 the Megatsunamis in Gran Canaria, Lanzarote and Tenerife linked to the eruptions of Tenerife 170,000 years ago. But you don’t have to go back that far in time to talk about tidal waves in the Canary Islands.
Up to 11 tsunamis have affected the Canary coasts in the last millenniumsome of them undocumented because until the fifteenth century there are no references associated with 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 Museum of Sciences. Natural from Tenerife.
What is the current interest in tsunamis?
Although the theory about possible megatsunami that would generate the collapse of Cumbre Viejaon La Palma, has gained popularity in recent years and has become topical again with the eruption of the volcano in the La Palma massif on September 19, 2021, the research carried out and published in Geosciences 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, today very populated. Part of the basis that tsunamis may affect the Canary Islands.
According to what was exposed 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 can be explained by 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Although there are historical references to tsunamis that could have affected the Canary coasts and even vestiges that accredit them in sedimentary deposits on some islands, only eight are currently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 measurement devices. Several of them were not even perceived as tsunamis by the population and just as waves larger than usual.
November 1, 1755
This tsunami was caused by the Lisbon earthquake of magnitude 8.5 mbLg. It devastated the southwestern coasts of the Iberian Peninsula and northern Morocco and was even recorded in America, both North and South. The investigation shows that “the damage and deaths that 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 a.m. on November 1, 1755, some inhabitants of Tenerife felt the earth tremble and, at the same time, the sea withdrew in Tenerife and Gran Canaria more than a kilometer. There are historical references that it affected all the islands, as well as that the level of flooding it caused was more than five meters high. In Gran Canaria, the hermitage of Light was flooded, which was filled with fish.
March 31, 1761
This other episode also had its origin in an earthquake of magnitude 8.5 mbLg in the southwest of the Iberian Peninsula. It was felt in Portugal, Spain and Morocco. There are records that it reached the south and west coasts of the Peninsula, United Kingdom, as well as the archipelagos of the Azores, Madeira, the Canary Islands and Barbados. Its effects on the coast of Tenerife “were similar to those reported by the 1755 tsunami,” according to the investigation.
July 7, 1941
This tidal wave was recorded in the newspaper La Tarde, which reported three huge waves that flooded the coast of Santa Cruz de Tenerife and San Andrés. They affected the Cabildo building and Avenida Marítima, where it flooded the Naval Command. These waves have been attributed to a local landslide near the Tenerife capital, as no earthquakes or other extreme wave events occurred that day.
November 25, 1941
Shortly after the previous tsunami, an 8.3 mbLg magnitude landslide submarine 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 due to the absence of damage.
February 28, 1969
On this date, a low-intensity tsunami was produced by an earthquake at 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 tide gauges in Santa Cruz de Tenerife and in various points in Portugal, as well as in Casablanca.
May 26, 1975
As a consequence of a 7.9 mbLg earthquake 200 kilometers south of the Gloria fault, in the Atlantic, a tsunami was produced that was seen in the Azores and was recorded on a Gran Canaria tide gauge.
November 14, 2020
The massive fall of rocks on the coast in Valle Gran Rey, in La Gomera, gave rise to a local tsunami. There are videos of falling stones and the wave it caused. It did not cause damage.
