A small earthquake rumbled through the city centre of Manchester this morning, the sixth to hit the area this month.

Residents were woken by the tremor, which struck at 5.45am and measured 2.2 on the Richter scale.

The British Geological Survey (BGS) received a dozen calls from concerned locals who reported windows rattling and furniture shaking.

"People usually panic because they don't think the UK is on fautlines, so they think it's a bomb or something,'' BGS spokesman Bennett Simpson told Times Online.

"But it was a pretty small earthquake in terms of a world scale, and quite small for the UK.''

The area has already experienced five earthquakes since August 10, with the highest measuring 2.5 in magnitude. Mr Simpson said this one was noticed more than the others because it occurred right in the city centre.

According to the BGS, the UK is criss-crossed by many small faultlines and areas such as the Midlands, Wales and northwest Scotland have a lot of earthquakes, but because they are not as densely populated they are frequently unreported.

In 2002 Manchester received a cluster of 150 tremors over a four-month period, with the largest measuring 3.9 on the Richter scale.

Mr Bennett said there is no particular reason Manchester was receiving so many tremors at the moment.

The last major tremor to hit the UK occurred in April, when an earthquake measuring 4.2 hit Folkestone, damaging several houses.

Historically the largest onshore earthquake in the UK occurred on the Llyn Peninsula in North Wales in 1984. Measuring 5.4, it caused structural damage to buildings, such as chimneys cracking and falling down, but there were no injuries.

According to the BGS, a magnitude of about 4.5, or verging on 5, is needed to cause any damage. Quakes of 2.5 magnitude hit Britain between eight and nine times a year.