A powerful earthquake jolted central Mexico on Tuesday, causing buildings to sway sickeningly in the capital on the anniversary of a 1985 quake that did major damage.

National Civil Protection chief Luis Felipe Puente tweeted that there were no reports of damage so far, but thousands of people fled office buildings along the central Reforma Avenue as alarms blared, and traffic stopped around the Angel of Independence monument.

The U.S. Geological Survey said the quake had a magnitude of 7.1 and was centered near the Puebla state town of Raboso, about 76 miles (123 kilometers) southeast of Mexico City.

In Mexico City pictures fell from walls, objects were shaken off of flat surfaces and computer monitors toppled over. Some people dove for cover under desks.

Earlier in the day buildings across the city held preparation drills on the anniversary of the 1985 quake.

Much of Mexico City is built on former lakebed, and the soil is known to amplify the effects of earthquakes even hundreds of miles away.