BEIJING—The owner of a 71-floor office tower in the southern Chinese city of Shenzhen closed the building on Friday pending an investigation into what caused the skyscraper to begin shaking on Tuesday. Shenzhen Electronics Group Co Ltd will close the 1,167-foot SEG Plaza to tenants and shoppers to carry out inspections into the cause of the swaying, it said in a notice posted on the Weibo social media account of the state-owned Xinhua News agency. Reuters could not immediately contact Shenzhen Electronics for a comment on the closure. The swaying caused objects on desks in the building to move, and sfubsequently workers were evacuated from the tower. Videos shared on social media showed panicked pedestrians fleeing the area after the rocking began. Several nearby buildings were also evacuated, with police and fire crews sealing off the surrounding area. The main structure of the building is safe and no cracks were …