The 4.2 magnitude quake occurred near Swansea, south Wales, around 2.30pm at a depth of six miles.
Residents across the UK - from Bristol to Cornwall - have reported tremors in its aftermath.
Five buildings have reportedly been damaged but there are no indications of injuries.
Dyfed-Powys Police said they had received an "extremely high call volume".
Tyrone Williams, from Port Talbot, said:
"Our house shook and ornaments fell. Our birds flapped and squawked and our dog went nuts. My wife's family in Newport also felt it."Port Talbot Town FC temporarily stopped play during the quake.
Dramatic footage also shows students being evaucated from Swansea University.
One Bristol resident wrote: "Was there an earthquake in Bristol? The whole building just shook!"
A Twitter user from Gloucester wrote: "The entire house just started shaking - things fell off my wardrobe and ceiling and my mum said that things on the table started shaking."
South Wales Police issued this statement: "There has been a minor earthquake throughout South Wales.
"No need for you to contact the emergency services unless you have something to report, i.e. injuries or damage."
It comes just hours after Mexico was rocked by a 7.5 magnitude quake.
Comment: See:
- 7.2 magnitude quake strikes Mexico near Pacific coast
- Earthquake swarm hits Canary Islands' La Palma
- 'Like an explosion': Western France shaken by 4.8 magnitude earthquake
- Quakes shake Pacific plate as Ring of Fire activity returns
- Scientists predict upsurge in major earthquakes for 2018 due to slowdown in Earth's rotation
Mr James, from York Road, shared pictures of cracks running up the side of his walls and said: "We thought someone had crashed into the building because it shook from left to right.
"Then the cats started going crazy.
"Then we noticed the front of our flat was damaged.
"Events of this magnitude only happen in the UK every 2-3 years"
An earthquake which shook parts of the UK on Saturday is the sort of event which happens only once "every two or three years", experts have said.
The British Geographical Survey (BGS) said the epicentre was 20km (12 miles) north of Swansea, with a 4.4 magnitude at a depth of 7.4km (4.6m).
A BGS tweet added:"Events of this magnitude only happen in the UK every 2-3 years."
Comment: A Sott.net reader wrote in to tell us that she felt it too: The British Geographical Survey says an event of this magnitude only happens in the UK every 2-3 years. Actually, there have been about 7 similar-strength quakes in the UK in the last 3 years alone...
22 May 2015 - A 4.2 magnitude earthquake 'causes homes to shake' in Kent, UK
25 May 2015 - Magnitude 3.0 earthquake recorded in North Wales
29 Jan 2015 - Britain's second earthquake in 48 hours strikes in East Midlands
7 Mar 2016 - Earthquake 'shook houses' in south-east England
3 Jan 2017 - 3.9 magnitude tremor strikes off UK coast - biggest quake for nearly a decade
4 July 2017 - Earthquake recorded off Shetland was largest in UK for nine years
5 Aug 2017 - Scottish Highlands are rocked by their biggest earthquake for 30 years