With simplicity, skill and scientific proof, Pierre-Yves Frei and Sandra Marongiu, in an investigation that spans the ages, explain the reasons for and effects of the terrible tsunami that took place in 563. In its rage, it swept away mills and people.
Lake Geneva, the beautiful freshwater lake, calm and warm in summer, criss-crossed by thousands of bathers, experienced a tsunami of insane proportions and speed in 563: Le Tauredunum. The Christian chroniclers of the time, Marius, bishop of Avanches, and Gregory of Tours, bishop of the Kingdom of the Franks, describe Le Tauredunum, or Mount Taure, as the source of a tsunami with torrential waves, a veritable plague that swept away buildings, animals, mills and people in its path, as recounted by the bishop of Avanches:
«Post-consulate of Basilius, 22th year, 11th indictionThis year, the great mountain of Tauredunum in the diocese of Valais collapsed so suddenly that it crushed a nearby village and all its inhabitants. Its fall also set in motion the entire lake, 60 miles long and 20 miles wide, which emerged from its two shores, destroying ancient villages with their men and livestock. The lake even demolished many churches and the people who served them. Finally, in its violence it swept away the Geneva bridge, mills and men, and, entering the city of Geneva, killed many men.»
Turning hypothesis into certainty
These incredible chronicles have come down to us through the centuries, escaping fire, war, mould, water and oblivion, and arousing the curiosity of scientists from all walks of life and all eras. However, it wasn't until 2010, with the intervention of Katrina Kremer and Stéphanie Girardclos, two geologists from the University of Geneva, that the scientific tour de force of transforming a hypothesis into a certainty was achieved. Using an echo-sounder to probe the sediments that had lain dormant at the bottom of the lake for millennia, they discovered a thick, imposing and ancient layer, an irrefutable trace of Tauredunum, which they checked using a corer, taking four twelve-metre cores from different points in the sedimentary layer, which were then analysed.
The written legend of the past became a fascinating, established and documented reality. It took fifteen centuries to achieve this. Although there were scientific controversies between Vaud and Valais scientists as to the origin of the catastrophe, one day in 563, Lake Geneva's vague à l'âme began with a landslide from the summit of La Suche. The fallen rocks rolled from the Rhône plain to the lake at great speed, carrying everything with them until they sank into the lake. This created a series of deadly waves, travelling at 70km/h, the highest of which was 13 metres high, at Lausanne level, according to the numerical modelling scenario devised by physicist Guy Simpson.
Pierre-Yves Frei and Sandra Marongiu, the book's authors, not only inform the reader about Tauredunum with simplicity and skill, but also offer a historical review of the shores of Lake Geneva, colored by the changes of peoples and cultures, forged by the formation of the Alps, hollowed out by the slow extension of glaciers and kneaded by the struggle of earth and ice, under the debonair eye of the sun. Richly illustrated with paintings by David Alois Schmid and Hodler, a number of photographs, meticulous graphics, a chronological index and a bibliography, this research will satisfy the thirst of the most curious. They will also learn that there have been other tsunamis on Lake Geneva, such as the one that occurred between 1780 and 1620 BC during the period of the palafittic villages, and tsunamis on other lakes around the world.
The book thus makes its contribution to universal history. The big question is: could another tsunami take place today, in 2020, on Lake Geneva? It is with this nagging question in the back of his throat that the reader, sitting on the shores of Lake Geneva in summer, nervously fidgeting with his bath towel, will drop this book, then with a dumbfounded expression turn his worried gaze towards the lake, while his lips whisper: Papa, Maman...[1].
[1] A shameless paraphrase of Aragon's famous quote: «A book is excellent if the reader, tearing off his useless handkerchief, suddenly drops the copy he has looked through, then with a celestial expression turns to heaven a look of gratitude while his lips murmur : Papa, Maman.» A treatise on style, Aragon.
Photo credit: © Emiliano Arano/Pexels
Write to the author: arthur.billerey@leregardlibre.com
Pierre-Yves Frei and Sandra Marongiu
A tsunami on Lake Geneva, Tauredaunum 563
PPUR
2020
200 pages
French 
German 
English