"Dynamic triggering", with seismic waves propagating from one quake affecting other faults, may operate at much longer distances, but usually happens within hours or a few days of the triggering quake; a 12-day gap is hard to explain.  19 September is designated as a day of remembrance for the 1985 Mexico City earthquake, which killed approximately 10,000 civilians. Every year at 11 a.m., a national earthquake drill is conducted by the government through the use of public loudspeakers located throughout Mexico City. The 2017 drill took place as scheduled, at 11 a.m., around two hours before the central Mexico earthquake. According to the National Seismological Service (SSN) of Mexico, the epicenter was located southeast of Axochiapan, Morelos, and from Mexico City. The earthquake was measured at a magnitude of 7.1, occurring at 13:14:40 Central Daylight Time, at a depth of . The United States Geological Survey (USGS) placed the epicenter ENE of San Juan Raboso and reported a measurement of VIII (Severe) on the Mercalli intensity scale; While there was a report of strong shaking for about one minute, which is a long time for an earthquake, acceleration/velocity/displacement seismograms at UNAM showed about 20 seconds of strong shaking with a period of ≈1 second. SSN reported a peak ground acceleration of at the Popocatépetl reporting station in Tlamacas, Estado de México. According to the USGS, the earthquake occurred on a moderately dipping normal fault. According to the bulletin of Mexico's SASMEX earthquake warning system, 20 seconds' advance warning was given in Mexico City; however the general experience in the capital was that the alarm and cellphone alerts started only a few seconds before, or during the quake. Some residents reportedly mistook the alert for a continuation of the earlier drill. 25 of the early-warning seismic sensors detected the earthquake, and alerts were also provided to Oaxaca, Acapulco, Chilpancingo, and Puebla, with lead times stated to range from 12 to 48 seconds. Nine days after the earthquake, at least 361 people had been reported killed. At least 74 people were killed in the state of Morelos, 220 in Mexico City, 45 in Puebla, 13 in the State of Mexico, 6 in the state of Guerrero and one in the state of Oaxaca. In Mexico City, the bodies of 26 students and four instructors were pulled from the rubble of the Enrique C. Rébsamen school; 30 students and 8 adults were still unaccounted for .