Tsunami landfalls in the Maltese archipelago: reconciling the historical record with geomorphological evidence

Abstract

AbstractThe Maltese Islands lie in the middle of the tsunamigenic Mediterranean domain, around whose margins and islands evidence of historical tsunami landfall has been increasingly recognized in recent years. Critical review of historical evidence of events in 1693 and 1908 indicates extremely modest tsunami impacts. In marked contrast, though, recently discovered geomorphological evidence summarized herein suggests that Malta's coastlines have been overwashed up to elevations of >20 m above sea level by an exceptional event. A new perspective is provided by a review of the central Mediterranean context within which the Maltese evidence is located. Recent advances in understanding the Holocene sequence forming the floor of the Mediterranean Sea present a new stratigraphic and temporal framework within which to elucidate tsunami history. Within 100 km of Malta, terrestrial stratigraphy on Sicily also provides supporting evidence of tsunami impact. Review of these advances suggests that the exceptional event required to emplace the most extreme sedimentary and geomorphological signatures on and around Malta is likely to have had a far-field origin. The currently available circumstantial evidence points strongly towards a probability that the AD 365 earthquake and tsunami were responsible. This, in turn, enables critical reassessment of the exposure of Malta to tsunami hazard.