Richard Luckett, from the British Geological Survey, has described today's earthquake as "fairly unusual", adding that a magnitude of 4.1 is large for the UK.
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The Valleys is home to some of Wales' most successful entertainers and personalities.
The South Wales Valleys once produced coal, but now they're producing wind energy - with the biggest onshore windfarm in England and Wales.
Sammy Samuels, 27, was jailed for four and a half years today after he admitted wounding with intent.