A 70 plus-story skyscraper in China’s tech hub of Shenzhen city swayed again on Wednesday, after it inexplicably wobbled and caused 15,000 people to evacuate the day before.
No earthquake had been reported in the region, which was only experiencing light winds.
The swaying of the 21-year-old building started at approximately 12:31 p.m. local time on Tuesday.
Videos circulating on social media showed people running away from the building, with some screaming, holding umbrellas, and looking back over their shoulders.
Chinese media reported that all 15,000 evacuees escaped from the building within 90 minutes. Nobody was injured.
On Wednesday, some local media reports said the building had started swaying again, although not as dramatically as it had on Tuesday. The building remained closed off for investigators, although the landlord—Shenzhen SEG Co. Ltd.—had allowed shop owners from the major electronics market in first 10 levels of the building to collect their goods.
Three floors of crypto-mining computers in the electronics market—one of the main crypto-mining markets in China—were not accessible due to the incident.
Late Wednesday, the local government announced that investigating engineers had been unable to determine the cause of swaying, while noting that none of the building’s movements since they started monitoring late Tuesday had exceeded building code limits for skyscrapers.
Experts found “no safety abnormalities in the main structure and surrounding environment of the building,” the local government said, according to a statement.
Local media reports on Thursday following preliminary assessments noted that the skyscraper did not have a tuned mass damper—a large pendulum-like device installed in high rises to reduce excessive swaying.
The department of emergency management of Guangdong province also confirmed that the preliminary findings pointed to vertical rather than horizontal movement, which were said to be caused by factors like winds, underground rail lines, and the expansion of steel with increasing rising temperatures.
On May 19, SEG’s stock price had dropped more than seven percent on the Shenzhen Stock Exchange, and closed 4.88 percent lower than the opening price.
SEG Plaza is a landmark in Shenzhen. The building is 1,167 feet (355.8 meters) high, and the architectural height is 957 feet (291.6 meters).
The building has 75 floors above the ground, and four floors underground. The underground floors are parking and equipment levels. The first ten floors above ground are the electronic market, and the upper floors are offices and s hotel, according to Shenzhen city government run Shenzhen News.
According to the online database Council on Tall Buildings and Urban Habitat, SEG Plaza is the 18th-tallest building in Shenzhen and the 104th-tallest in China.
Buildings collapses have been reported in China. On March 7 last year, 29 people were killed as the five-story Xinjia Hotel, which was being used for COVID-19 quarantine, collapsed in Quanzhou in southern China’s Fujian Province.