Yao'an county in Yunnan province was hit by a 5.9-magnitude quake that sent people scurrying out of their homes. About 1 1/2 hours later, the county was hit by an even stronger aftershock with a magnitude of 6.5, said a county seismologist who gave just his surname, Su.
Four people were killed, 29 were seriously injured, and 371 were slightly hurt, government seismologists and state-run television said. The State Seismology Bureau in Beijing said 4,000 buildings collapsed, but state-run television said up to 10,000 buildings collapsed or were seriously damaged.
The television broadcast footage of crumbled mud-built walls and a house with a caved-in wooden beam roof. Medical staff in white coats treated some of the injured on beds in the street. An old woman and three children huddled under quilts on a layer of straw.
The main compound of Yao'an's government headquarters was seriously damaged, the state-run Xinhua News Agency said. Power in the area also was cut, it added.
But there was no damage to a valuable historical site 30 miles from the epicenter where remains of China's oldest fossil man were found in 1965, Xinhua said. The site of Yuanmou Homo Erectus, who dated back 1.7 million years, is now a tourist destination.
The authorities and media did not specify which tremor caused which damages and injuries. Quakes in China often produce high figures for building damage, because officials may count smaller structures other than homes and because of fragile building materials. Outside of cities, one-story homes, sometimes made of mud bricks, are common.
In the town of Guantun, 18 miles from Yao'an, the early morning quakes woke tens of thousands of people and sent residents flocking into the streets, Xinhua said. Guantun started up 10 generators to produce electricity, it added.
Authorities moved in 10 tons of building material, 5,000 rolls of woolen felt and food into affected areas, Xinhua said.
A strong tremor also was felt in the provincial capital Kunming, some 125 miles to the east of Yao'an, it said.
Yao'an was also hit by a 6.5-magnitude quake in 1962 and a 5.6-magnitude quake on August 14, 1993, Xinhua said.