Catastrophic flooding that followed the eruption of Santorini in the late Bronze Age may have been generated by the pyroclastic flow of volcanic material into the sea, suggests a study in Nature Communications this week. The research challenges previous explanations for the creation of tsunamis associated with this eruption.

Tsunamis from the late Bronze Age eruption of Santorini have been proposed as a factor leading to the demise of Minoan culture. Evidence for waves at least nine metres high has been found at Minoan archaeological sites on the Greek Island of Crete. Previous studies had proposed that the collapse of the caldera (the volcanic crater) into the sea was the cause of post-eruption tsunamis, but Paraskevi Nomikou and colleagues put forward a different theory. By analysing the sea floor beneath the caldera and the surrounding features, the authors find evidence that suggests that the caldera did not collapse during the main eruption. Their observations indicate that a strait of water connected the caldera to the sea after the eruption, filling the caldera in less than two days, but this flooding event was unlikely to create tsunamis.

Instead, the authors suggest that large volumes of pyroclastic material flowing rapidly into the sea could have displaced enough water to create tsunamis. Pyroclastic deposits up to 60 metres thick found offshore from Santorini seem to support this theory.