Ancient Scottish tsunami could destroy entire towns if it happened today, new study finds

A new study led by researchers at the Universities of Sheffield, St Andrews and York has revealed that the Storegga tsunami that hit Scotland’s coastline 8,200 years ago, could devastate entire towns if it happened today.

A new study by Universities of Sheffield, St Andrews and York researchers suggest the ancient Storegga tsunami would have devastated entire coast-lines
The study models for the first time how far the tsunami would have travelled inland when it originally occurred 8,200 years ago
Study suggests a modern-day tsunami of the same magnitude would have worse consequences today due to denser populations and higher sea levels
The Storegga tsunami is considered to be the largest natural catastrophe to happen the UK in the last 11,000 years

A new study led by researchers at the Universities of Sheffield, St Andrews and York has revealed that the Storegga tsunami that hit Scotland’s coastline 8,200 years ago, could devastate entire towns if it happened today.

The findings suggest that should an event of the same magnitude happen on the coastline again today, many of our coastal towns and cities could be completely devastated.

Although the tsunami is considered to be the largest natural catastrophe to happen in the UK in the last 11,000 years, this is the first time that researchers have been able to model the inland impact of the ancient wave.

Using sedimentology and dating tsunami sediment deposits at Maryton, Aberdeenshire using luminescence, the study was able to determine the age, number and relative power of the tsunami waves. The researchers were then able to create models that show the wave would have travelled up to 30 kilometres inland along the Scottish coast. Areas such as Montrose, a town encompassing a coastal lagoon, nature reserve and a population of 12,000, would have been completely devastated.

While 600 km of the Scottish coastline was affected by the tsunami thousands of years ago, the modern-day impact would have graver consequences as a result of denser populations along the coastline and higher sea levels.

The tsunami was caused by the shifting of glacial and interglacial sediments on the coastal slopes at Storegga, along Norway’s continental shelf in the Norweigan sea. This slide displaced sea water levels and triggered a 95,000 sq km submarine slide that led to the resulting tsunami height reaching up to 30 metres.

Although the Storegga Tsunami has been known about for years, this is the first time we have been able to model how far inland from Scotland’s coastline the tsunami wave travelled by analysing the soil deposits left by the wave over 8000 years ago.

Professor Mark Bateman

Lead Author from the University of Sheffield's Department of Geography

“Though there is no similar threat from Norway today, the UK could still be at risk from flooding events from potential volcanic eruptions around the world, such as those predicted in the Canary Islands.

“These would cause a similar resulting tsunami wave due to the amount of material that would be displaced by the volcano. These models give us a unique window into the past to see how the country was, and could be affected again”

Professor Dave Tappin, of the British Geological Survey, commented on the study. He said: “30 years ago, identifying the Storegga tsunami flooding, that struck the coast of eastern Scotland over 8,000 years ago, was seminal in recognising that submarine landslides are a major hazard in triggering significant flood events.

“From the Montrose area, the new detailed analysis of the sediments deposited by the tsunami wave and their age dating using novel methods, together with the new numerical tsunami modelling of the wave impact on-land, provides important new insights into the understanding of the Storegga tsunami flood.

“The research highlights the importance of applying new scientific techniques to older-studied events, thereby improving our knowledge of their impact.”