We thought it was an accident outside, but it was like a really large tremor

Kevin Morris, Bargoed

Seismologists at the British Geological Survey said the shake at 1913 GMT registered 3.0 on the Richter Scale for earthquake severity.

South Wales Police say they received lots of calls from concerned people.

The tremor was first reported at 1915 GMT in Abercynon, drawing shaken residents out in to the street in search of an explanation.

Witness shaken

Kevin Morris from Bargoed, eight miles away, said the tremor lasted only a few seconds but was violent enough to shake his home in the Lower Wood Street area.

According to reports, there has been no structural damage and no-one has been injured.

Mr Morris added: "We thought it was an accident outside, but it was like a really large tremor - all the lights were shaking in the living room; it was a thud."

"There was one before Christmas and one after Christmas but, because of the bad weather, it wasn't really felt.

"With all the mine workings in the area, I suppose there is some concern.

Resident terrified

Ms Morwen Llewellyn from Llancaich View in Nelson, almost five miles from Bargoed, said she became "terrified" when she felt the shake at 1915 GMT.

More people reported the earth moved in Quaker's Yard, Treharris, further west still.

Experts have said deep coal mining in the valleys may have weakened geological fault lines in the area.

It is the third quake of 2002 in the Bargoed area, the others measuring around 2.0 on the Richter Scale.

One on 28 January measured 2.5 on the scale and struck 6.3km down into the earth - it followed a 1.7 event.

An earthquake on 9 October, 2001, registered three, waking residents at 0325 GMT and lasting just 25 seconds.

People felt the effects of the tremor as far away as Merthyr Tydfil and Pontypool.

Nuisance quake

Seismologists said residents have nothing to worry about - quakes in the UK are extremely rare and just a "nuisance."

At the time, Glenn Ford of the British Geological Survey said there were just 200 quakes in Britain annually, and only 10% of those were ever felt.

"There is unlikely to be any devastation," he said.

"The Bargoed tremor was 24m times smaller than the earthquake in India."

But he warned the area was to expect a force five quake at any time, toppling chimney pots and roof slates.

That would match the UK's biggest recorded earth tremor, which shook Lleyn in Gwynedd on 19 July, 1984.

Mr Ford said Tuesday night's quake was a natural tectonic shake unrelated to the area's mining history.

It coincided with a similar quake in the US as Washington was hit by a 2.9 quake earlier Tuesday.