Photo: Canva

By KELIN DILLON

A series of 15 “microseisms” – or small earthquakes – rocked Mexico City on Thursday, Sep. 27, a phenomenon geologists say may be tied to the emergence of a new geological fault directly underneath the Mexican capital.

A few weeks before the so-called “seismic swarm,” five small earthquakes were felt throughout Mexico City over the course of five days. 

Thursday’s chain of 15 microseisms, while not unprecedented, marked a significant uptick in seismic activity in the area.

The epicenter of the tremors was concentrated in the heart of Mexico City, and due to its location, it failed to trigger the metropolis’ earthquake alarms. 

“It is a ‘swarm of earthquakes’, just like the Mixcoac sequence; they can last several days, while the fault adjusts; the one that started the activity was the first quake in the early morning,” geological engineer Alejandro S. Méndez told daily Mexican newspaper Reforma.

Seismic experts have identified a new fault, separate from but running parallel to the Plateros-Mixcoac fault. This new fault, which remains unnamed, could potentially have a significant impact on the Seismic landscape of Mexico City.

Méndez went on to note that while the cause of the fault’s activation remains to be determined, activities such as extracting drinking water from the area’s wells could have contributed to its arousal.

Meanwhile, a 5.2-magnitude earthquake with an epicenter in Ciudad Altamirano, Guerrero, also struck Mexico on Thursday, though the capital authorities determined it was not strong enough to trigger a city-wide alert.