Officials in Shenzhen say they haven't detected anything particularly unusual about the 71-story SEG Plaza skyscraper—apart from the fact that it started shaking Tuesday afternoon, causing panic in the south China city. Local authorities say the shaking was apparently caused by a combination of winds, two underground rail lines in the area, and changing temperatures, the Guardian reports. There were no earthquakes recorded in the area and safety inspectors said there were no issues detected in the building's structure or the surrounding area. Thousands of people were evacuated from the building after it started wobbling.
Local authorities said the 980-foot building's vibration frequency, tilt rate, and settlement degree were monitored and they all fell within official limits, the South China Morning Post reports. Officials also denied reports that the building was seen shaking again Wednesday. The building, which was completed in 2000, remains closed to the public, although vendors at the electronics market that takes up the first 10 floors of the building have been allowed to retrieve items. The US Consulate in Guangzhou has urged American citizens to stay away from the building. (Read more skyscraper stories.)