Evaluating the impact of the Storegga tsunami on Mesolithic communities in Northumberland

The Holocene Storegga tsunami, 8120–8175 cal a bp, resulted in run-up heights of up to 3–6 m around mainland UK and coincided with a suggested large population decline in the coastally focused Mesolithic population in Northern Britain. At Howick, Northumberland, the site of a Mesolithic settlement, a nearby sediment deposit may be of tsunamigenic origin, but this is uncertain. Here, a numerical model was used to simulate the Storegga tsunami in Northumberland. Two scenarios of relative sea-level change, and a third incorporating high tide, were simulated with mortality estimated within the intertidal zone for the Mesolithic sites in the region. The results showed that only with the addition of high tide could the sediment deposit site have been inundated by the tsunami. At Howick, mortality estimates varied but were up to 100% within the resource-rich intertidal zone. The tsunami inundated a large area and would have led to the loss of key resources such as hazelnuts prior to the winter months. These combined effects would have probably been replicated throughout coastal settlements in Northern Britain, possibly leading to the contemporary population decline estimated to have occurred at this time.