A Bedfordshire town has been rocked by two earthquakes in one day, and four in a fortnight, with residents reporting houses “shaking and shaking”.
The 3.0 and 2.1 magnitude tremors were centered around Leighton Buzzard around 8:32 a.m. and shortly after 12:30 p.m. Tuesday, the British Geological Survey confirmed.
Thought to be aftershocks after an initial magnitude 3.3 quake, since it was upgraded to 3.5, on September 8, leaving locals speechless.
“It was an explosion and a jolt, a real jolt,” said Sheila O’Connell, an NHS worker who lives in Leighton Buzzard, while another said the tremors “almost knocked me out of bed”.
In fact, the UK sees more earthquakes than you can imagine.
Why do earthquakes happen in the UK?
Glenn Ford, a BGS seismologist, said Tuesday’s temblor would be classified as an aftershock of the quake from two weeks ago.
“They’re not happening more frequently in the area, they’re happening all the time in the UK,” he told the Standard.
“What’s unusual about them is that only 10 per cent feel them. We don’t really perceive the UK as a country associated with earthquakes, so when they do happen it can be quite disruptive.”
“But it’s very typical behavior you see in the UK and we’ve had historic activity in that area. Most of them are so small that people don’t notice them.”
Ford said Britain sees about three magnitude 3.0 earthquakes every year, but that’s a billion times smaller than Japan’s devastating magnitude 9.0 TÅ hoku earthquake in 2011.
The Bedfordshire quake started several hundred meters below the surface, on hidden fault lines, experts said.
Dr Matthew Blackett, natural hazards lecturer at Coventry University, called Leighton Buzzard’s tremors “very, very strange”.
“What seems to have happened is that it was an initial earthquake on a hidden fault, caused by some stress or other,” Dr. Blackett said.
“These two subsequent events are a readjustment of the fault lines to return to some kind of stability.
“The crust has to adjust to get back on track, that seems to have happened to the poor folks at Leighton Buzzard.”
How many earthquakes have there been in the UK and how often do they occur?
Most earthquakes in the UK are so small that they cannot be felt, because the UK does not sit on a fault line between tectonic plates.
Between 20 and 30 earthquakes are felt by people in the UK each year, according to data from the British Geological Survey, with hundreds of small ones recorded by sensitive instruments.
In the 50 days to September 22, for example, a total of 39 earthquakes were recorded in Great Britain.
These ranged from minus 0.1 on the Richter scale to Tuesday’s high of 3.0, including a 1.0 temblor near Bristol city center on September 4. Many tremors occur off the coast.
The Richter scale is the globally recognized numerical scale for measuring seismograph oscillation, and destructive earthquakes typically measure greater than 5.5.
The British Geological Survey said: “A magnitude 4 earthquake occurs in Britain approximately every two years. We experience a magnitude 5 about every 10 to 20 years. Research suggests that the largest possible earthquake in the UK is around 6.5”.
The agency’s scientists added: “The driving forces of seismic activity in the UK are unclear; however, they include regional compression caused by the movement of the Earth’s tectonic plates and uplift resulting from the melting of the ice sheets that covered many parts of Britain thousands of years ago.
What has been the largest earthquake so far?
The largest known British earthquake occurred near Dogger Bank in 1931, with a magnitude of 6.1.
Fortunately, it was 60 miles offshore, but still powerful enough to cause minor damage to buildings on the east coast of England.
The UK’s most damaging earthquake was in the Colchester area in 1884. Some 1,200 buildings needed repairs, chimneys collapsing and walls cracking.
The most recent severe earthquake, measuring magnitude 5.2, struck Market Rasen in Lincolnshire in 2008 and was felt as far away as Newcastle and London.
Where else in Europe is prone to earthquakes?
Several areas of the Mediterranean region have suffered severe earthquakes.
Italy is the most earthquake-prone European country, with the Eurasian and African tectonic plates shifting around 4 to 10 mm per year beneath its southern half.
These plates are not only responsible for some of the deadliest earthquakes in Europe, but also for Italy’s famous volcanoes: Vesuvius, Etna and Stromboli.
The most recent major earthquake to hit Italy was on August 24, 2016, when magnitude 6.2 tremors rattled towns and villages 65 miles northeast of Rome in the early hours.
It claimed 297 lives and particularly devastated the towns of Amatrice and Arquata del Tronto, with almost 4,000 people left homeless as a result of the destruction.
Dozens of people were feared dead in January 2017 after a series of four earthquakes, the strongest measuring 5.3, shook buildings in Florence and Rome and triggered an avalanche that inundated the Hotel Rigopiano in Abruzzo.
The deadliest documented earthquake in Europe was on December 28, 1908, when a magnitude 7.0 earthquake in the Strait of Messina between Sicily and the Italian mainland killed 72,000 people.
“The greatest seismicity is concentrated in the central-southern part of the peninsula, along the Apennine mountain range, in Calabria and Sicily and in some northern areas, such as Friuli, part of Veneto and western Liguria,” explains the Italian Civil Protection Department.
The US Geological Survey adds: “The region’s tectonic activity cannot be explained simply by the collision of the Eurasian and African plates. It has been suggested that deeper lithospheric processes are controlling some of the observed deformation at the surface.”
Spain, France, Greece and Portugal have also suffered deadly earthquakes in the last three centuries.
The most recent was in May 2011, when at least eight people were killed when a magnitude 5.1 earthquake struck southern Spain below Granada province.