The violent winter storms that rocked the country in 2014 had the power to physically shake cliffs to a degree in excess of anything recorded previously, say marine scientists.
A team at Plymouth University used seismometers, laser scanners and video cameras to evaluate the impact of the massive waves – up to eight metres high – that struck the cliffs in Porthleven, West Cornwall, during January and February.
In a paper accepted for publication in Geophysical Research Letters, the team from the Coastal Processes Research Group found that the level of shaking was of an order of magnitude greater than ever previously recorded.
They also recorded 1,350 cubic metres of cliff face being eroded along a 300-metre stretch of coastline in just two weeks – a cliff retreat rate more than 100 times greater than the long-term average.
PhD student Claire Earlie, in the School of Biological and Marine Sciences, said:
“Coastal cliff erosion from storm waves is observed worldwide but the processes are notoriously difficult to measure during extreme storm wave conditions when most erosion normally occurs, limiting our understanding of cliff processes. Over January-February 2014, during the most energetic Atlantic storm period since at least 1950, with deep water significant wave heights of 6–8 metres, cliff-top ground motions showed vertical ground displacements in excess of 50–100μm (microns), an order of magnitude larger than observations made previously anywhere in the world.”