Written in SCIENCE he
On May 10, there was a earthquake of 3 degrees of magnitude that took the inhabitants of Mexico City (CDMX) by surprise because the seismic alert was not activated in any of the demarcations of the capital. Although no damage was recorded, as reported by the Secretariat for Comprehensive Risk Management and Civil Protection, the tremor had its epicenter in the Magdalena Contreras mayor’s office. Here we detail why the alert did not sound on the loudspeakers of the capital.
According to what was reported by the Mexico City Command, Control, Computing, Communications and Citizen Contact Center (C5), the earthquake on May 10 that occurred after 10:00 p.m. epicenter in the capital of the country, so when this type of earthquake occurs, the seismic alert is not activated in any of the demarcations of the capital. Below, we detail why this happens.
Seismo Alert Mexicana, which is an account on social networks with the disclosure of the tremors that occur in the country, when the earthquakes have their epicenter in the CDMX no HE activate thes seismic alerts because there is not enough time for this to happen given the warning time limitations compared to the speed at which seismic waves propagate, as it would happen in an earthquake whose epicenter is in another state of the country, where there is time for it to occur. the waves are perceived and the devices sound.
“A seismic alert NO It can be issued when the epicenter of the earthquake is within Mexico City (CDMX) due to limitations in alert time and the speed of propagation of seismic waves. The seismic alert system is based on the early detection of seismic waves generated by an earthquake, to then send an alert signal to the affected areas before the most destructive waves arrive,” explained Seismo Alerta Mexicana.
Therefore, when the epicenter is located within CDMX, the time it takes for seismic waves to travel from the epicenter to nearby areas is so short that it DOES NOT allow the seismic alert system to detect and transmit the preparation signal on time. , since the seismic waves arrive in the capital at the same time as the alert.
What are microseisms in CDMX and why don’t seismic alerts sound when they occur?
According to the Mexican Earthquake Alert, the CDMX is located in an area of high seismic activitywhere the Cocos Plate and the North American Plate interact, which causes the area to experience constant movement and deformations in the earth’s crust, it is there when what is known as a microseism. This type of natural phenomena occurs due to local faults in the capital, when a sudden displacement occurs on a geological fault.
The microseisms in the CDMX They occur when geological faults move due to the cumulative release of stresses in the subterranean rocks. Among the best-known types of local faults in the country’s capital are the Santa Fe Fault and the Chiquihuite Fault, which can generate micro-seisms by accumulating and releasing energy in small amounts. These movements are usually of low magnitude and frequency, and in general, they do not usually cause significant damage.
The micro-seisms that are generated in CDMX by local faults are of tectonic and not anthropogenic origin, in addition to the fact that, since they occur in the same territory where the seismic alerts are located, they are not given time to activate and prepare the population. tremor as they do when earthquakes occur and have their epicenters in other states of the country.
Why was the micro-earthquake felt more strongly in some CDMX municipalities than in others?
As detailed by the official Twitter account of Seismo Alert Mexicana, the perception of a microseism It varies due to several factors, such as the distance you are from the epicenter, the local geology, the magnitude, the depth of the seismic focus and the frequency of the waves. For this reason, the inhabitants of the CDMX who met at the mayor’s office Magdalena Contreras or close to this zone, they perceived it much more strongly than other demarcations where they only experienced a gentle rocking.
Follow Binary Herald on Google News, hit CLICK HERE.