Britain’s worst earthquakes REVEALED: Interactive maps chart the most powerful quakes that have rocked the UK over the past 640 years – as both Norfolk and Essex are hit by tremors
- The British Geological Survey has charted every tremor felt in the UK since 1382
- Two interactive maps show all the data from instruments and historical archives
- The largest ever earthquake was in 1931 and measured 6.1 on the Richter scale
This month, the UK has been rocked by two earthquakes in Norfolk and Essex, measuring 3.7 and 2.6 on the Richter scale respectively.
While Britain is not prone to extreme tremors, seismologists record up to 300 quakes every year, around 20 to 30 of which are actually noticeable.
The British Geological Survey (BGS) has put together two interactive maps that show exactly how many have been felt in Britain since the year 1382.
The biggest on record occurred in June 1931, with a massive 6.1-magnitude quake in Dogger Bank out in the North Sea.
As it was 60 miles offshore, there was only minor damage caused to a few buildings in the east of England, although a few vessels did report that they felt tremors.
The British Geological Survey has collated all the earthquakes felt in Britain since the year 1382. Pictured: Top ten largest UK earthquakes
The map with the red dots shows all earthquakes with epicentres in the vicinity of the UK that occurred from 1956 to the present day, that were recorded instrumentally.
Britain’s worst earthquakes
The largest known earthquake in the UK happened offshore in the North Sea on 7 June 1931, with a magnitude of 6.1.
Its epicentre was in the Dogger Bank area about 75 miles North East of of Great Yarmouth.
A woman in Hull died of a heart attack, apparently as a result of the earthquake.
The most damaging earthquake in the UK for several centuries was in Colchester in 1884, with a magnitude of 4.6 which caused considerable damage to churches
While the map with the yellow dots shows the earthquakes recorded in historic archives from 1382 to 1970.
Around 10,000 quakes have rippled through Britain in the past 50 years.
In 2017, to celebrate National Richter Scale Day, mapping experts at Esri UK uncovered the ten most seismically active areas in the country.
These areas in England are Manchester, Blackpool, Stoke-on-Trent, Mansfield, and Gweek in Cornwall – all largely towards the west.
The Llyn Peninsula was the most active area in Wales, while in Scotland, Edinburgh, Clackmannan, Knoydart Peninsula and Dumfries were found to have the most activity.
However, earthquakes are almost completely absent from eastern Scotland, north-east England and Ireland.
The North Sea is more seismically active than mainland Britain.
The UK will feel a magnitude-4.0 earthquake roughly every two years, and one magnitude-5.0 or higher every eight years.
It also experiences a tremor of between 1.0 and 1.9 on the Richter scale every two and a half days.
This map shows all earthquakes with epicentres in the vicinity of the UK that occurred from 1956 to the present day, that were recorded instrumentally
This map shows the earthquakes recorded in historic archives from 1382 to 1970
According to the BGS, the largest possible earthquake in the country would have a magnitude of about 6.5, but this remains to be seen.
Earthquake magnitude scale
Great: 8.0 or larger
Significant damage expected
Major: 7.0 to 7.9
Damage expected
Strong: 6.0 to 6.9
Damage may occur
Moderate: 5.0 to 5.9
Minor damage may occur
Light: 4.0 to 4.9
Likely felt
Minor: 3.0 to 3.9
May be felt
Earthquakes are caused when two tectonic plates that are sliding in opposite directions stick and then slip suddenly.
They are composed of Earth’s crust and the uppermost portion of the mantle, while below is the asthenosphere: the warm, viscous conveyor belt of rock on which tectonic plates ride.
They do not all move in the same direction and often clash, which builds up a huge amount of pressure between the two plates.
Eventually, this pressure causes one plate to jolt either under or over the other.
This releases a huge amount of energy, creating tremors and destruction to any property or infrastructure nearby.
Severe earthquakes normally occur over fault lines where tectonic plates meet, but minor tremors – which still register on the Richter sale – can happen in the middle of these plates.
This is because movement occurring on fault lines causes stresses in the Earth’s crist which are relieved within the tectonic plates.
This is why earthquakes still occur in the British Isles despite it being a fair distance from the nearest tectonic plate boundary – the Mid-Atlantic Ridge.
Earthquakes are detected by tracking the amount of energy released, or magnitude, and intensity of the shock waves they produce, known as seismic waves.
Around 75 per cent of the world’s seismic energy is released at the edge of the Pacific.
Severe earthquakes normally occur over fault lines where tectonic plates meet (pictured)
Earthquakes still occur in the British Isles despite it being a fair distance from the nearest tectonic plate boundary – the Mid-Atlantic Ridge (pictured)
An earthquake is understood to have hit an area 56 miles off the Norfolk coastline in the North Sea at around 7.14am on February 12 2023
The biggest UK earthquake in recent years happened on February 27 2008 with its epicentre on Market Rasen in Lincolnshire.
It measured 5.2 on the Richter scale and was felt across Newcastle, Yorkshire, London, the Midlands, Norfolk and parts of Wales.
The ten-second tremor which struck at a depth of 9.6 miles just before 1am, before a 1.9-magnitude aftershock followed at 4am.
It was the biggest earthquake recorded since a magnitude-5.4 which struck at Leyn in North Wales on July 19 1984 that was felt over 150,000 square miles.
The most destructive UK earthquake hit Colchester and surrounding Essex villages on April 22 1884, damaging about 1,200 buildings.
It was thought to be the result of movement along a fault of the Palaeozoic rocks underneath the county.
The quake lasted around 20 seconds and measured 4.6 on the Richter scale.
The biggest UK earthquake in recent years happened in February 2008 with its epicentre on Market Rasen in Lincolnshire. Pictured: Damage to a room in Barnsley as a result of the quake
The most destructive UK earthquake hit Colchester and surrounding Essex villages on April 22 1884. Pictured: Ruins of Virley church, that was destroyed in the earthquake
The Earth is moving under our feet: Tectonic plates move through the mantle and produce Earthquakes as they scrape against each other
Tectonic plates are composed of Earth’s crust and the uppermost portion of the mantle.
Below is the asthenosphere: the warm, viscous conveyor belt of rock on which tectonic plates ride.
The Earth has fifteen tectonic plates (pictured) that together have moulded the shape of the landscape we see around us today
Earthquakes typically occur at the boundaries of tectonic plates, where one plate dips below another, thrusts another upward, or where plate edges scrape alongside each other.
Earthquakes rarely occur in the middle of plates, but they can happen when ancient faults or rifts far below the surface reactivate.
These areas are relatively weak compared to the surrounding plate, and can easily slip and cause an earthquake.
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