Using GPR to Track Tsunami Deposits Inland at Whale Firth, the Shetland Islands

Abstract

Deposits from the Second Storegga Slide tsunami can be seen at outcrop at the beach in Whale Firth. Ground-penetrating radar has been used to track the sand layer inland until it truncates against the underlying glacial deposits. The elevation of the end of the tsunami deposits combined with the sea level rise since the tsunami can be used to estimate a minimum run-up height. Much thinner sand layers were resolved with the GPR than would be expected. This is due to a combination of factors that optimized the return signal allowing the sand layer to be traced almost 150 m inland from the outcrop at the coastline.