How Britain was struck by FIVE tsunamis in history including ‘catastrophic’ 70ft wall of water caused by rockslide
BRITAIN isn’t known as a tsunami hotspot – but it’s been struck by giant and terrifying waves.
The biggest that we know of saw a wall of water 70 feet high crashing into Britain’s shores.
Some tsunamis may have hit the UK but simply haven’t been discovered or confirmed yet.
But there’s good evidence to suggest our island has faced some truly enormous waves.
SCOTLAND – 6100 BC
The biggest and most iconic of Britain’s confirmed tsunamis made land roughly 8,000 years ago.
It took place in Scotland around 6100 BC, hitting the east coast and some of the Shetland Islands.
Scientists believe that the wave may have reached heights of around 70 feet.
It was caused by the Storegga slide, a massive underwater landslide at the edge of Norway‘s continental shelf.
There were three such slides, moving thousands of cubic miles of debris.
It affected around 370 miles of Scotland’s coastline, with water reaching as far as 18 miles inland.
Experts think that it would’ve damaged or destroyed several seafronts if it happened today, including places like Aberdeen and Inverness.
It’s also been described as causing “catastrophic flooding” by scientists.
This would’ve included on Doggerland, a low-lying area on England‘s east coast that once connected our island to Denmark and the Netherlands.
CORNWALL – 1755
A smaller tsunami struck the UK’s Cornish coast on November 1, 1755.
The 10-foot tsunami made land at around 2pm, after travelling four hours from its source.
It was caused by the 1755 Lisbon earthquake, which almost completely destroyed the Portuguese capital.
The earthquake itself has been linked to as many as 40,000 to 50,000 deaths.
In Britain, the tsunami’s effects were mostly concentrated on Cornwall, with fast-rising sea levels reported at St Michael’s Mount, Penzance, St Ives, Hayle, and Newlyn.
Reports suggest there were as many as three tsunami waves – with some effects also noted on the south coast, London‘s Thames, and in Pembrokeshire’s Cleddau estuary.
CORNWALL – 1761
In 1761, another earthquake struck Lisbon, powerful enough that it was felt across Western Europe and even Morocco.
Lisbon was still recovering from the 1755 event, meaning there was just a six-year gap between the two disasters.
It triggered a small tsunami in the north Atlantic Ocean, which measured around six feet tall at Mount’s Bay on the south coast of Cornwall.
The sea is also said to have risen up to six feet at Penzance and four feet in the Isles of Scilly.
It’s reported to have advanced as many as five times over the course of an hour, beginning at 5pm on March 31.
SOUTH COAST – 1929
In the summer of 1929, a large wave struck England‘s south coast.
It’s believed to have been a special type of wave called a meteotsunami, or meteorological tsunami.
This is caused by changes to barometric pressure, which is air pressure within the Earth‘s atmosphere.
It significantly affects weather, and is even behind airplane turbulence.
WHAT CAUSES TSUNAMIS?
Here's what you need to know...
Tsunami is a Japanese word used to describe huge waves – generally on oceans, but sometimes in lakes or large rivers.
Ocean tsunamis are caused by sudden motions, which displace a large amount of water.
This is typically an earthquake, but it could also be a volcanic eruption or underwater landslide.
A huge impact into water – like a large landslide or meteor – can also cause tsunamis.
When an earthquake happens, huge tectonic plates crunch together.
When the “snap” eventually happens, this gives a large shove to water.
This creates a tsunami that travels very quickly across the open oceans.
As the ocean becomes shallower, the tsunami wave is forced upwards.
This means tsunami waves typically grow very quickly in height (and slow down) as they approach the shallow shorelines near land.
Tsunamis are typically a series of waves, rather than one single wave
As they approach land, these waves get closer together.
One of the best ways to spot an incoming tsunami is a sudden retreat of coastal water.
If the tide goes out very quickly, it’s a telling sign that something is wrong.
What you’re actually seeing is the trough of the incoming tsunami wave – on a huge scale.
The initial tsunami impact can be deadly.
But tsunami flooding also drowns people, damages buildings, destroys infrastructure and spreads waste and disease.
Picture Credit: SADATSUGU TOMIZAWA/AFP/Getty Images
When barometric pressure rapidly changes, it can cause displacement in large bodies of water – leading to a meteotsunami.
A typical meteotsunami is caused when bad weather moves in the same direction as waves moving towards the coastline.
The July 20, 1929 wave is believed to have reached heights of between 11 and 20 feet.
it struck the south coast at popular tourist hotspots like Brighton, Folkestone, Hastings, and Worthing.
In this case, it’s thought the a line of thunderstorms travelling along the English Channel caused the event.
SOUTH COAST – 2011
A very small tsunami in the English Channel in 2011 is also believed tgo have been a meteotsunami.
It struck on June 29, affecting Cornwall, Devon, Dorset, and Hampshire on England’s south coast.
The event was considered mild as the peak wave height anomaly reached 16 inches – meaning it was 16 inches higher than what would be considered normal.
There were no earthquakes recorded at the time, which led the British Geological Survey to conclude that it was probably a meteotsunami.