Submerged notches on the coast of Skyros Island (Greece) as evidence for Holocene subsidence

Detailed mapping along the coasts of Skyros Island (Aegean Sea) provided new evidence concerning the rates and the modality of subsidence in the area. The results are provided through the study of the shape and the dimensions of the two submerged notches detected around the carbonate coasts of the island.It is apparent that the island has been submerged not only due to the global sea-level rise during the last two centuries (1.8 ± 0.3 mm/year between 1950 and 2000), but also because of tectonic events testified by the type of the submerged notches. Some of these tectonic events seem to be of gradual and some of co-seismic origin. The transition of MSL from the retreat point of the lower notch to the retreat point of the upper notch seems to have been produced by co-seismic subsidence of about 55 cm at slightly less than 850 years BP.

► Two submerged notches are observed along the Skyros island coast. ► Upper notch submergence happened during the last 2 centuries. ► Cause of upper notch submergence is global sea-level rise. ► Co-seismic subsidence of about 55 cm occurred slightly less than 850 years BP. ► Submergence was not always gradual, but occurred also by abrupt changes.