Scientists have found evidence of a powerful earthquake 3,000 years ago in central China, apparently the earliest known tremor in the country's history, state media reported.

The earthquake, which hit an area now part of Henan province, was of magnitude 6.8 to 7.1, archaeologists told the state-run Xinhua news agency on Thursday.

Signs of the quake were first found in 2005 in seriously damaged ash pits, residences and graves that lay buried under a village in the province, Xinhua said.

Carbon dating indicated the earthquake struck the area sometime between 1500 BC and 1260 BC, it added. China did not start keeping seismological records until 843 BC.

Many parts of China are prone to earthquakes.

Scientists also found a human skeleton whose pelvis and leg bones were found in a pit 1.5 metres (five feet) away from his upper body, Xinhua said.

"The skeleton couldn't have been damaged by human force," Xinhua cited Chu Xiaolong, associate researcher with the Henan Provincial Institute of Cultural Relics and Archaeology, as saying.

"It had been apparently torn apart under the impact of the quake."

The discoveries were made on the central route of the south-to-north water diversion project, a huge scheme to transport water from central provinces to Beijing that is due to open this month.

Researchers also found intact skeletons of cattle, pigs and other domestic animals at the site that were believed to be sacrifices made to ward off future quakes, Xinhua said.