Researchers find traces of the Lisbon tsunami in Lanzarote, a key discovery.

A team of researchers has made a significant discovery on the western coast of Lanzarote, specifically in Timanfaya National Park, by identifying traces of the impact of the devastating tsunami that originated after the great Lisbon earthquake in 1755. This event, which resulted in tens of thousands of deaths and altered the history of many regions, has found a new narrative in the Canary Islands context thanks to the work of scientists who have meticulously documented its imprint on the islands. The study, conducted by a multidisciplinary group of researchers from the Geological and Mining Institute (IGME), the University of La Laguna, and other institutions, focused its analysis on deposits of large basalt blocks. Some of these blocks reach up to three meters in length and have been transported inland by what is suspected to have been the impact of an extreme wave, likely the result of the tsunami. This discovery adds a valuable piece to the geological puzzle of the region and underscores the power of natural phenomena in the history of the Canary Islands. The scientists explain that the identification of these deposits cannot be attributed to a storm, as calculations regarding the heights of the waves and flow velocities required to mobilize such blocks concluded that the extreme conditions recorded in the area were insufficient to form these rock accumulations. Thus, the tsunami of 1755 emerges as the sole probable culprit for these geological formations. The dating of the cobblestones was carried out based on an exhaustive geological and geomorphological mapping corresponding to the volcanic lava flows in the region. The researchers determined that these deposits formed between the end of the Timanfaya eruption in 1736 and September 3, 1824, when the lava flows from the Nuevo del Fuego Volcano reached the sea. It is important to note that the Lisbon earthquake occurred in 1755, a clear indicator that the effects of the tsunami were felt on the island. The magnitude of the tsunami was such that its influence extended not only across the Gulf of Cádiz but also throughout the North Atlantic, affecting various coastlines from Northeast Africa to North America and other locations in the Atlantic. In the specific case of the Macaronesian islands, there are records that clearly document the effect of the tsunami, including evidence on Lanzarote itself. The research concludes that the presence of cobblestones on the northern coast of Timanfaya can be interpreted as a direct consequence of the waves generated by the 1755 tsunami. It is estimated that the waves reached heights between 2.1 and 2.7 meters, with flow velocities exceeding 2.8 meters per second. This combination of factors was more than sufficient to move the rocks currently found on the coast. Furthermore, the study highlights that the inundation distance caused by the waves extended at least 188 meters from the shoreline, indicating the magnitude of the phenomenon. This finding not only offers a new perspective on the geological history of Lanzarote but also underscores the islands' vulnerability to extreme natural phenomena. Although the historical record of the 1755 tsunami had already been documented in the Canary Islands, this research represents the first concrete geological evidence of the event in the region. This advancement highlights the importance of continuing to investigate and understand the geological processes that have shaped our islands, as well as the need to be prepared for future similar events. In conclusion, the discovery in Lanzarote adds a layer of complexity to the understanding of the natural history of the Canary Islands. As scientists continue to unravel the effects of natural phenomena on the region's geography, it becomes evident that the Lisbon tsunami is not just a distant event in time, but a reminder of the powerful interaction between seismic activity and coastal ecosystems. The history of Lanzarote, marked by lava and water, continues to reveal its secrets and lessons over time.