At about 10:55 p.m., there was a earthquake magnitude 5.1 with epicenter 32 kilometers southeast of Petatlan, Guerrero. even though it was perceived by citizens the alerts were not activatedcausing annoyance and concern.
According to inhabitants of the Mexico City, the earthquake was perceived significantly; however, because the seismic alert did not sound could not evict property on time, a situation that worried.
Some pointed out that on other occasions that the alert has sounded they have not felt the earthquake, but on this occasion that it was not activated, the perception of the movement was high.
“When the alert sounds I don’t feel them and now that it didn’t sound, it felt too much movement”; “Fatal, when the tremor is perceptible ‘the alarm does not sound’ and when it is not perceptible, ‘the alarm sounds and scares half the world’…. Increasingly worse with their systems and warnings…”; “What are you talking about? Yes, right now it was felt and the time it rang, nothing was felt,” were the comments of the citizens.
The head of government of Mexico City Claudia Sheinbaum Pardo reported that the quake was only perceived “in some areas” from the capital and that the Command, Control, Computing, Communications and Citizen Contact Center (C5) indicated that the magnitude of 5.1 did not warrant the activation of the alert.
For its part, the Mexican Seismic Alert System (sasmex) explained that the tremor did not deserve that the alerts will sound because “the energy estimate in the first seconds, did not exceed the pre-established levels”.
The organism has sensors that cover the subduction seismic regions of the Cocos Plate and the southern Transverse Neovolcanic Axis in the states of Jalisco, Colima, Michoacán, Guerrero, Puebla and Oaxaca.
For the above, when an earthquake is detected, in a few seconds its size is estimated and the warning is sent by radio to cities with Sasmex alert: Mexico City, Chilpancingo, Acapulco, Oaxaca, Morelos and Puebla.
It indicates that earthquakes of magnitude equal to or less than 4.0 generally only affect the region near the epicenter and may even not be felt by humans. “However, the perception of intensity of an earthquake not only depends on the magnitude, but also on the distance or type of subsoil from where we are, among other factors.”
“That is why earthquakes of magnitude even less than 4.0 (for example, with an epicenter in metropolitan areas such as Mexico City or Jalisco), can be intensely perceived and reported by the inhabitants of that area and, in those cases, in the SSN, the pertinent calculations are made to report them in a timely manner”, added Sasmex.
The alert is activated when in the first seconds it is estimated to have a magnitude greater than 5 and the epicenter is no more than 170 kilometers away; of magnitude greater than 6 that does not occur more than 350 kilometers, and of magnitude greater than 5.5, whose epicenter is no more than 350 kilometers away.
Google indicates that Petatlán is approximately 400 kilometers from Mexico City. The earthquake was of magnitude 5.1 and did not cause damage to any entity, according to the report by the Ministry of National Defense (Sedena) received by President Andrés Manuel López Obrador (AMLO).
