More than 300 earthquakes have been detected across the United Kingdom in the past twelve months, according to new data released by the British Geological Survey (BGS). The findings highlight a year of notable seismic activity, with the most powerful tremors centred near Loch Lyon in Perthshire and significant events felt in Lancashire and southern Wales.
Mapping the UK's Seismic Hotspots
The BGS, which operates a network of 80 monitoring stations nationwide, reported a total of 309 recorded earthquakes in 2023. The data pinpoints several regions as particularly active. Perthshire and the western Highlands of Scotland led the list, followed by southern parts of Wales and the English counties of Yorkshire and Lancashire.
The two most substantial onshore quakes occurred just hours apart on 20 October near Loch Lyon in Perth and Kinross. The first registered a magnitude of 3.7, with a second tremor of magnitude 3.6 following shortly after. Residents described the experience vividly, with one reporting it felt "like an underground subway under my house," and another noting "the house shook and all the windows rattled." The BGS received 198 'felt reports' from the public, some from over 37 miles away from the epicentre.
Significant Tremors and Public Impact
In the months following the Loch Lyon events, a cluster of 34 tremors was recorded in the area between October and December. The third-strongest onshore earthquake of the year was a magnitude-3.2 event at Silverdale, Lancashire, on 3 December. This tremor prompted an impressive 700 people to submit felt reports to the BGS, demonstrating its widespread perception.
Dr Brian Baptie, a seismologist at the BGS, commented on the annual data. "The data shows that earthquakes occurred in many parts of Great Britain over the past 12 months, with numerous events in Scotland, England and Wales that were each significant enough to be widely felt by many nearby," he said. Dr Baptie emphasised that while major quakes are uncommon, the UK experienced a detectable tremor virtually every day this year.
Understanding Britain's Geological Faults
Dr Baptie explained that the prevalence of activity in western Scotland is no surprise. "The west of Scotland is one of the more active parts of the UK. Some of this activity can be attributed to well-known geological faults like the Great Glen fault and the Highland Boundary fault," he stated.
He further clarified that seismic events can happen across the UK due to its complex geological history. "The earth under our feet has got lots of what we call geological faults in it... Sometimes those faults are activated by present day stresses, and when they are, you get these small earthquakes," Baptie added. This ongoing deformation means tremors are a constant, if usually minor, feature of British geology.
Throughout the year, the BGS collected a total of 1,320 reports from members of the public who felt earthquakes. While most UK quakes are too faint to be noticed, history shows the potential for stronger events. The most powerful earthquake ever recorded in the UK was the 1931 Dogger Bank quake, which measured magnitude 6.1.
The BGS provided a frequency estimate for larger events: a magnitude-4 quake in the UK or nearby areas is typically recorded every three to four years, a magnitude-5 every few decades, and a magnitude-6 every few hundred years. This underscores the importance of continuous monitoring. "It remains of critical importance that they are studied to help us understand the possible impact of the rare large earthquakes on major energy and infrastructure projects around the country," Dr Baptie concluded.
