A new investigation from the National Autonomous University of Mexico (UNAM) reveals that behind the increase in microseisms in Mexico City, there is not only the Plateros-Mixcoac fault but also another geological fault in the Barranca del Muerto area, located about 800 meters south of the former. The research, published in the scientific journal Tectonophysics, reports that a microseism on May 11, 2023, with a magnitude of 3.2, occurred on the Barranca del Muerto fault, refuting the previous belief that it was on the Plateros fault.
Another microseism of similar intensity took place on December 14 of the same year on the Plateros-Mixcoac fault. Although authorities indicate that these events are not expected to exceed a magnitude of 4, the proximity between both faults and the possibility of long-term interaction that could trigger more intense earthquakes is concerning. This risk is particularly sensitive in a densely populated city like Mexico City.
According to UNAM, the two faults could be working together to limit tectonic sliding to shallower levels, which reduces the risk of stronger earthquakes. It is being investigated whether the extraction of water from wells in the area could influence the increase of microseisms and the movement of the faults.
The study suggests that fluid diffusion could stabilize friction along the faults and trigger seismic radiation. It is considered that the extraction of water from wells near the faults, in a densely populated area where water demand is high, could be an influencing factor. The persistence of water extraction in Mexico City over time complicates the attribution of microseisms and the development of the faults to particular anthropogenic events.
