Dominant processes that amplify the swell towards the coast: the Nazaré Canyon and the giant waves

Abstract

The Iberian Atlantic coast is typically featured by incisions that deeply affect the continental shelf, commonly known as submarine canyons. Among the submarine canyons located off the Portuguese Atlantic coast are the canyons of Porto, Aveiro, Nazaré and Lisboa-Setúbal, being of note the canyons of Nazaré and Lisboa-Setúbal for their dimensions, characteristics and dynamics. Nazaré is a small city located about 100 km north of Lisboa, known worldwide for the occurrence of recently surfed giant waves. The Nazaré Canyon is one of the largest submarine canyons in Europe. It is about 225 km long and 5000 m maximum depth, with several steep slopes. The present work aims to contribute to the general understanding of the canyon systems dynamics throughout the Portuguese Atlantic coast. The Nazaré Canyon and its giant swell are discussed. A brief description of the most recent giant waves surfed and listed in the Guinness book is also provided.

Forearc crustal faulting and estimated worst-case tsunami scenario in the upper plate of subduction zones. Case study of the Morne Piton Fault system (Lesser Antilles, Guadeloupe Archipelago)

“…Submarine canyons (known to focus the waves: Nazarè Portugal: Martins et al, 2010;do Carmo et al, 2022;Delpey et al, 2021) and shallow water plateaus located around the islands slow down the waves which leads to particular propagation patterns like the wrapping around islands (Figure 8). In fact, it underlines the wrapping effect of the waves around Marie-Galante associated with two distinct tsunami sources, i.e a primary source at fault and a secondary one at the Colombie Bank.…”

Pull and Push Drivers of Giant-Wave Spectators in Nazaré, Portugal: A Cultural Ecosystem Services Assessment Based on Geo-Tagged Photos

“…The awareness of Nazaré as a surf tourism destination exponentially increased with the publication of photographs of surfers riding the waves and beating Guinness records 3 . Since then, the international media has been highlighting the shift in the strategic positioning of this small fisherman's town, from a (summer) beach destination to a (winter) giant-wave surfing/chasing destination 4 .…”

“…This causes a change in the direction through the canyon, which leads to an increase in speed. According to the steep vertical variation of the canyon, the depth reduction causes a shoaling effect, which means that the wave length is reduced while an increase in the wave height occurs [4,5].…”