Bees and locusts swarm and yesterday the people of Manchester discovered that earthquakes do too.

Seismologists declared that Manchester and its environs were officially at the centre of an “earthquake swarm” after the city was shaken by its sixth tremor in a month.

The latest quake struck at 5.45am and measured 2.4 on the Richter scale –a minor tremor but one that caused houses to shake and residents to think that they were being burgled.

The swarm - a succession of quakes that do not have a clear distinction between main shocks and after-shocks - is likely to be caused by the same movements of the Earth’s crust that led to 70 tremors in 2002.

Seismologists at the British Geological Survey in Edinburgh said that they had received reports of rumbling and shaking. “Some people said their beds rattled,” a spokesman said. “One person said a building creaked.”

Manchester lies on top of four large faults – the Pendleton fault, the east and west Manchester faults and the Ardwick fault – the legacy of Britain’s turbulent geological history.

Brian Baptie, of the Survey, said that the current quakes were likely to be a knock-on effect of friction between the Eurasian plate and either the African plate or the North American plate. Movements between the plates result in stress being placed on existing fault lines that were formed 50 million years ago, he said.

“The crust is full of faults because of our turbulent geological past. At the moment we are quite fortunate in that we are far away from any major plate boundaries, but [430 million years ago] Scotland and England were on two separate continents. You’ve got these old faults within the crust that are points of weakness. We are still subject to tectonic stress, and these stresses build up on those points of weakness. The fault slips and we get an earthquake. The origin of the stresses is likely to be a long way away.”

Britain is on the Eurasian plate, which borders the North American plate in the Atlantic Ocean and the African plate in the Mediterranean.

Dr Baptie said that Manchester could be hit by further shocks before the swarm subsided. “With the experience of 2002 it seems that perhaps Manchester has a propensity for these kind of quakes. It is possible that we haven’t felt the last of these.”

Seismologists are uncertain whether the tremors were caused by a single fault or a cluster. Householders to the east of the city centre and in Tameside reported the most dramatic effects of the latest quake. Gwen Graham, 51, of Droylsden, Manchester, said: “The earthquake physically shook our house. My husband Mike jumped out of bed and ran downstairs thinking we were being burgled. It felt like a patio door was being closed.”

The faults beneath the city have caused swarms of tremors for centuries, including one in 1753 which caused church bells to ring. The previous sequence of quakes caused minor damage between October 2002 and January 2003, when shocks reached a magnitude of 3.9 on the Richter scale. Yesterday’s tremor was recorded at the Holmfirth seismic station, West Yorkshire, one of a network of 145 seismograph stations covering Britain.

Other earthquake zones include the Lleyn Peninsula in North Wales, which experienced Britain’s largest onshore tremor in 1984, and Comrie, Glanalmond, Duone and Blackford, all in central Scotland.

Dr Baptie said that when plates meet, one pushes another down into the interior of the earth, causing friction. “The best way to grasp the idea is to picture them as large pieces of a jigsaw which are constantly moving against each other. As this happens, huge stresses build up which have to find a release and a tremor occurs when shock waves radiate outwards, usually along old fault lines.”

Mancunians have little to fear from the current swarm, however. “It will rumble on for a period of months or weeks, but a volcano rising in the centre of Manchester is completely out of the question,” said Dr Baptie.

Insurers said the earthquakes would not affect premiums. The Association of British Insurers said: “These events are relatively rare. Your standard policy will cover you.”

Shock and awe

— British earthquakes have killed 11 people since 1580. Six were killed by falling stones, two fell from upper floors, two died of shock and one committed suicide

— The largest earthquake recorded in Britain had a magnitude of 6.1 and struck offshore in the North Sea on June 7, 1931, about 75 miles northeast of Great Yarmouth

— Britain’s largest onshore tremor struck in Lleyn, North Wales, on July 19, 1984, with a magnitude of 5.4. It was felt over an area of about 240,000 sq km

— The last big British earthquake was in 1990, when a 5.1 tremor hit Bishop’s Castle, Shropshire

— The most damaging quake to date was the magnitude 4.6 Colchester earthquake of 1884. It shattered walls and brought down a church spire

— Homes in Folkestone, Kent, were damaged on April 28 this year when a magnitude 4.3 earthquake struck a few miles away in the English Channel. One woman was taken to hospital with a neck injury

— A magnitude 5 earthquake occurs on average every ten years. A magnitude 4 earthquake occurs on average every two to three years

— There are 200 minor tremors in Britain every year, but 90 per cent go undetected by the public

— Faults in the Earth’s crust were not identified as the source of quakes until 1855

— Moonquakes (“earthquakes” on the moon) do occur, but they happen less frequently and have smaller magnitudes than earthquakes on the Earth

Source: Times archive, United States Geological Survey

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