What was the cause of the earthquake in north-west England?

Residents of a small village in Lancashire described feeling as if "the roof was collapsing" when an earthquake struck their area. The tremor, which occurred on Wednesday evening, was strong enough to alarm emergency services, who initially feared an explosion, and it was felt across much of the country.

The quake happened around 23:23 GMT and registered a magnitude of 3.3, with Silverdale identified as its epicentre.

What triggered the earthquake?

Experts from the British Geological Survey (BGS) stated that the exact cause of the quake remains uncertain. Since the earthquake originated about 3 km beneath the surface, it is challenging to connect it to the known fault lines mapped throughout the UK. Such tremors typically result from minor shifts along geological faults in the Earth's crust, which are unpredictable and not influenced by seasons. Generally, earthquakes occur due to movements and friction between tectonic plates. The UK lies within the Eurasian plate, farover 1,600 kmfrom the nearest plate boundary, which explains why it does not experience extremely large earthquakes like other regions.

Are earthquakes frequent in the UK?

The BGS noted that Wednesday's earthquake was "not unusual." The UK can experience several magnitude-3 quakes annually, including one in Scotland last October. Magnitude-4 quakes are less common, appearing roughly every three to four years. Smaller tremors are more frequent, with BGS recording 200300 each year, though only about 2030 are noticeable and typically do not cause damage.

Previous seismic activity in the region

According to the BGS, a similar-sized earthquake occurred in 2009 near Morecambe Bay, with a magnitude of 3.7. Another tremor of magnitude 2.9 was recorded in 1993 in the area. Most earthquakes in the UK are too weak to be felt.

The largest earthquake in UK history

The strongest recorded earthquake in the UK took place in 1931 near the Dogger Bank, off the coast of Yorkshire in the North Sea. It measured 6.1 in magnitude and caused minor damage to buildings along Englands east coast, despite its epicentre being about 60 miles offshore. Historical records suggest that damaging earthquakes remain rare in the UK.

Author: Sophia Brooks