The shallow 6.0 magnitude tremor hit late Tuesday in Yunnan province, close to China’s borders with Myanmar and Laos, China’s official Xinhua news agency said.
School buildings were widely damaged in the area, reports said, although the quake struck during the night and no pupil deaths were recorded.
Xinhua said 100 schools were damaged and cited a local official as saying an estimated 170,000 square metres (1.8 million square feet) of buildings needed repairs.
School construction is a touchy subject in China, where more than 5,000 children died as their schools collapsed on top of them in a huge 2008 earthquake in neighbouring Sichuan province. Shoddy buildings, with corruption playing a key role, were widely blamed, provoking public anger.
The latest quake had taken only one life so far, Xinhua said, citing local officials.
More than 124,000 people had been forced from their homes by the quake, Xinhua added, but there had been “little to no rain” in the region in recent days, reducing the risk of landslides.
The US Geological Survey (USGS) measured the earthquake as magnitude 6.0.
“Many houses collapsed and we are investigating the casualties,” a local official told Xinhua. “The aftershocks seem non-stopping.” China’s President Xi Jinping and Premier Li Keqiang were both quoted in state-media urging rescue efforts, with 3,200 troops dispatched in a “race to save more lives”, according to Xinhua.
More than 800 firefighters were taking part, with 35 sniffer dogs, it said.
The epicentre was in Jinggu county, 85 kilometres (around 50 miles) from Pu’er city, in a region famous for its tea plantations. The quake was also felt in Yunnan’s provincial capital Kunming.
China uses a different magnitude scale to the US and Xinhua said the China Earthquake Networks Center gave it a reading of 6.6.
The agency said buildings shook for several seconds, while some towns in the area had lost power supply and telecommunications.
“The whole building was shaking terribly with a loud cracking sound. Plates fell off in the kitchen. We all ran out and the streets are now packed with people,” Li Anqin, a woman living in Weiyuan town, the county seat of Jinggu, told Xinhua via telephone.
Thousands of homes were also damaged in neighbouring Lincang, it said.
Photos on social media showed damaged houses, cracked walls and fallen roof tiles, and crowds of people gathered outside into the night.
The epicentre of the quake was in a densely populated but underdeveloped area that is home to a number of ethnic minorities.
It is also a well-known tourism site, thanks to its local production of Pu’er tea, and population of wild elephants.
Yunnan is acutely vulnerable to earthquakes. The region sees frequent seismic activity from the collision of the Indian and Eurasian tectonic plates, which form the vast Himalayan mountain range.
In August, a 6.1-magnitude struck the province killing more than 600 people. More than 3,000 people were injured, while more than 80,000 homes were completely or partially destroyed.
Rescuers said the destruction did not initially appear to be on the scale of the August quake.
“It’s not like last time in Ludian — there are no massive collapse of buildings. It’s such a relief,” rescue chief Chen Xianhe told Xinhua.
Social media users said the effects were manageable.
“The beautiful town is as usual, aftershocks are constant, but people still live in order. My house is all right!” wrote one local resident on Sina Weibo, a Chinese equivalent of Twitter.
“It’s scary… but I’m fine,” wrote another.