Mexico City will test its seismic warning system every 15 days beginning on Monday, July 30, according to head of the Mexico City government José Ramón Amieve. The loudspeakers will not play the typical siren and will also state that a test is being performed. These system tests are in response to a 5.9-magnitude earthquake in Oaxaca state, approximately 400 km (250 mi) from Mexico City, on Thursday, July 19, when 12 percent of the approximately 11,000 loudspeakers did not function properly. In the event of an earthquake, the city's loudspeakers will emit a loud throbbing alarm along with the words "alerta sísmica."
In the event of an earthquake or aftershocks, individuals present in the area are advised to protect themselves from falling debris if indoors (e.g. move under a table, drop to your hands and knees and cover your head and neck), to move away from windows, and to not attempt to leave the building unless there is immediate danger. If outdoors, move away from tall buildings, utility wires, and streetlights.