The epicenter was located about 20km - 12 miles - north-north-east of Swansea, said the British Geological Survey.
Many people took to Twitter to ask "what was that?"
The club said on Twitter: "43' - temporary stop in play".
One person on Twitter wrote: "Was there an quake in Bristol?"
Closer to the epicentre, James Leonard tweeted: "Wow was that an natural disaster in Swansea my house just shook". "It didn't last more than about 10 seconds but it was the strangest sensation I've ever experienced".