Residents of the Granjas México neighborhood in Mexico City were woken up by a loud bang in the twilight hours of Thursday morning.

But it was just another building sinking in the old lakebed on which the city sits.

Authorities determined that a nine-story building in the Iztacalco borough sank 70 centimeters on its southern side, damaging windows and the sidewalks surrounding the building.

Public safety personnel and firefighters evacuated 40 workers from the building and sealed off the area while Civil Protection personnel inspected the structure for damage. Another inspection was expected to be carried out later in the day.

Five neighboring houses and a factory were also evacuated as a safety measure. The building was undergoing a renovation at the time of its sinking and was being advertised for rent as office space.

The borough’s mayor told reporters that he planned to verify all documents and permits pertaining to the structure to determine the legality of the work being done at the time of the incident.

Armando Quintero added that he was in touch with the building’s owners and that they were cooperating to determine the costs incurred by neighbors in having to evacuate their homes.

Sinking buildings are not uncommon in the capital as some areas are slowly but steadily dropping.

Source: Reporteros Hoy (sp), La Silla Rota (sp), Milenio (sp)