The four minor earthquakes that struck Mexico City on Tuesday prompted the evacuation of eight buildings in the Benito Juárez borough.
The evacuations were ordered after a review of 24 residential properties, schools and other buildings in the area. Officials speaking on behalf of the borough mayor’s office said evacuees wouldn’t be allowed to return until specialists from the local Construction Safety Institute determine the habitability of each structure in question.
One quake added to tally
Initial reports yesterday put the tally at three small earthquakes over the course of three minutes, but two hours later there was another one.
The first three “micro-quakes” — with magnitudes between 2.4 and 3.0 — occurred between 11:06 and 11:08 a.m. at intervals of roughly one minute. The epicenters were in the city’s southwest borough of Álvaro Obregón, according to the National Seismological Service (SSN).
Though no seismic alarm sounded, shaken residents, office workers and others were quick to evacuate their buildings, particularly in the Mixcoac and Insurgentes Mixcoac neighborhoods of the Benito Juárez borough.
Just as nerves had calmed, another “micro-quake” struck at 2:23 p.m., registering 2.1 on the Richter scale.
How did people react?
Residents of the Lomas de Plateros condo complex in Benito Juárez said that although they are accustomed to feeling tremors, three in a row was a novelty.
“The strongest was the first, a sudden jerk, but it was very fast,” condo resident José Luis Montoya said in an interview with the newspaper Reforma. “We thought that would be the only one, and that’s why many neighbors did not come outside. But a few seconds later, another one was felt, and by the third, everyone was outside.”
Montoya, who lives on the ground floor, evacuated immediately with his pet, but residents on upper floors usually wait to hear the seismic alarm before heading for the doors.
Joaquín Jaubert, who lives 1.5 km from the epicenter, was in his kitchen when the first quake struck. “It was very strong,” he said, adding, “more ‘micro-quakes’ have been felt here since [the one on] May 10. Now cracks have opened up inside the house.”
The eight evacuated properties are along Los Echave, Campana and Donatello streets and Revolución Avenue and Adolfo López Mateos Blvd.
Why didn’t the seismic alarm sound?
Generally, it is expected that an earthquake alarm will ring out from nearly 14,000 loudspeakers in the capital. According to civil protection officials, the earthquake alarm didn’t sound yesterday for two reasons.
One, because the quakes originated within city limits, and warning sensors are located outside of Mexico City; and two, the quakes were only 1 to 2 km deep (10 km deep is the average), making them “surface” earthquakes, which don’t always trip the sensors.
With reports from Reforma and La Jornada
