On the 32nd anniversary of the magnitude-8.1 earthquake that devastated Mexico City on Sept. 19, 1985, 41 U.S. seismic experts were in a workshop near Los Angeles, polishing a new tool to identify “killer” buildings: non-ductile concrete structures that often perform poorly in quakes. Suddenly, the attendees started getting pager alerts from the U.S. Geological Survey: A magnitude-7.1 quake had struck about 120 kilometers from Mexico City.
When the dust settled from the Sept. 19, 2017, Puebla-Morelos quake—the most damaging seismic event in Mexico since the 1985 quake—44 buildings had partially or fully collapsed in Mexico City (ENR 10/9 p. 14). As of Oct. 17, the known death toll was 369. Of those fatalities, 228 were in the capital, according to Mexican officials.