Dr Susanne Sergeant of the British Geological Survey told ITV News earthquakes like today's 4.1 magnitude "tend to happen in the UK once every two-three years on average".
The largest earthquake recorded in the UK was a 6.1 magnitude, hitting Dogger Bank in the North Sea in June 1931.
"It released approximately 900 times more energy than today's earthquake," Dr Sergeant said.
Speaking of today's earthquake, she said: "I am not aware of any reports of damage - because the earthquake happened in the Bristol Channel (about 20 km north of Ilfracombe), the area of strongest shaking would have been under the sea.
"It would not be unusual for this earthquake to be followed by aftershocks".
More top news
Over 2,000 People's Climate March protests have taken place in 166 countries ahead of a major UN conference on climate change.
On English votes for English laws Ed Miliband is damned if he does and damned if he doesn't.
School fees, pricey private medical care and the fear of interest rate rises mean even those on £200,000 are feeling the pinch.