Extreme waves impact on Malta (Mediterranean Sea)

Abstract

The accumulation of large boulders related to waves generated by tsunami and extreme storm events have been observed in different areas of the Mediterranean. Along the NE and E low-lying rocky coasts of Malta tens of large boulder deposits have been recognised and mapped (Furlani et al., 2011; Mottershead et al., 2014). These boulders are detached and moved by the seafloor by the action of sea waves. Reconstructing the history of these blocks and distinguishing events, such as storm waves or tsunami, play a crucial role in assessing the coastal vulnerability and risk. The Maltese coasts are seasonally affected by extreme storm waves: heavy seas are in fact frequent and are originated by the NE and NW winds. Moreover in the past some important tsunami events which occurred in the Mediterranean Sea, such as the 1693 and the 1908, have been reported on the historical chronicles of Malta (Galea, 2007). The seismicity is related mainly to the Malta Escarpment, the Sicily Channel Rift Zone and the Hellenic Arc. In this study we present a multidisplinary approach, which aim to characterize the boulder accumulations in order to assess the natural hazard for the coasts of Malta Island, where extreme waves have been and are able to detach and move large rocky blocks on the coast.