On September 19, 2025, Mexico held its national earthquake drill, the Simulacro Nacional. In Mexico City alone, according to the head of government, Clara Brugada, 8.1 million people took part. The city sounded the alert through 13,992 loudspeakers, and 99 percent of them worked. (Video in Spanish.)
The alert comes from the Sistema de Alerta Sísmica Mexicano, the seismic alert system, which began operating in August 1991. A study published in 2022 said that about 25 million people receive its alerts.
For earthquakes, the response is prepared in advance and rehearsed.