EMU Limited detects the English Channel 'tsunami'

Survey & GPS - July 4, 2011

A network of coastal tidal and wave monitoring stations maintained by Southampton, UK-based EMU Limited recorded the progress of the waves caused by this week’s minor tsunami along the south coast.

A massive underwater landslide in the Atlantic 200 miles off the Cornish coast is believed to be the cause of a small tsunami along the south coast, which created waves of between 0.5 and 0.8 metres and resulted in abnormal tidal records at the Channel Coastal Observatory and Plymouth Coastal Observatory shore stations.

EMU Limited’s Principal MetOcean Scientist, Mr Robin Newman, initially thought there was a malfunction with the oceanographic instruments, installed by EMU for the Southeast and Southwest Regional Coastal Monitoring Programmes, due to the unusual data patterns recorded by the Etrometa Step Gauges and Rosemount WaveRex Radars.

“There was a significant amount of variation in the observed data against what would be expected so I checked at multiple sites and they were all consistent with some sort of movement from east to west,” Mr Newman said. “We subsequently realised we had recorded what appears to be a minor tsunami.”

“While 0.8 metres waves may not sound like much, it could have caused flooding events if combined with high tides,” he said. “Tsunamis are not expected to affect the UK so this is a very rare event. But from this week’s experience, clearly they can, but also clearly we can now say we have an operational system which can detect these unusual events.”

EMU Limited will monitor the continuing wave movements as these may be a form of standing-wave oscillation, or seiching, in the Channel.