Tsunamis boulders on the rocky shores of Minorca (Balearic Islands)

Abstract

Large boulders have been found on marine cliffs of 24 study areas on Minorca, in the Balearic archipelago. These large imbricated boulders of up to 229 t are located on platforms that comprise the rocky coastline of Minorca, several tens of meters from the edge of the cliff, up to 15 m above the sea level and kilometers away from any inland escarpment. They are mostly located on the south-eastern coast of the island, and numerical models have identified this coastline as a zone with a high probability of tsunami impact. The age of the boulders of the studied localities range between 1574 AD and recent times, although most of them are concentrated around the year 1790 AD. Although some storm waves might play a role in their dislodging, the distribution of the boulder sites along the Balearic Islands, the degree and direction of imbrication and the run-up necessary for their placement suggest transport from northern African tsunami waves that hit the coastline of Minorca.