Thousands of people were evacuated from several high-rise apartment buildings in the northern Chinese city of Tianjin in recent days after land collapses created large cracks on nearby streets, according to state media and the local government.
Large fissures appeared on roads near a residential complex in Tianjin's Jinnan district and geological experts said they were likely caused by underground cavities below a depth of 1,300 m (4,270 feet), the Tianjin government said on Thursday on social media.
As of June 3, a total of 3,899 residents from at least three 25-storey high-rise buildings were evacuated to nearby hotels, state-backed Global Times quoted the district government as saying.
The Tianjin government called the incident a "sudden geological disaster" following preliminary information from geological experts and several government departments after they did surveying, mapping and monitoring at the site.
"The situation is very rare," according to an expert questioned about the incident at the Tianjin government municipal headquarters.
It cannot be ruled out that the drilling of geothermal wells had resulted in soil loss and land subsidence in the area, the Tianjin government said.
Experts said the high-rise buildings facing the street were affected to varying degrees.
Roads could be seen buckled and warped in photos on social media, while others showed a section of wall tile from a building collapsed on the floor.
The incident adds to concerns for building safety in China, where the government has enforced stricter rules and policies and handed out hefty punishment for lax management of properties.
In addition, the Chinese government has recently had several high-level meetings on geological and hidden disaster preparation.