Mexico is preparing to carry out the first national drill of the year in the next few hours. That means the more than 13,000 speakers installed on poles in the country, like the sirens of schools, public buildings, offices and supermarkets, will give a fictitious seismic alert so that the population prepares for a hypothetical earthquake of magnitude 7.5 located between the limits of Puebla and Veracruz.
Although it may seem too extreme, drills are practiced regularly in Mexico to improve earthquake preparedness, since the country is located in one of the most seismically active regions on the entire planet. In fact, every year, the country carries out a large national drill like the one that will take place today and that also serves to commemorate the devastating earthquake of 1985, which killed 9,500 people and had a traumatic effect on the country.
Since that incident, Mexico has taken drastic measures to reduce deaths and property damage from earthquakes. And one of them is drills. In addition to the activation of the seismic monitors and the alerts through loudspeakers, the helicopters the skies fly above and firefighters are deployed through streets and buildings during the simulation. The goal is to offer residents a realistic simulation in which to practice and help identify common errors in the process.
Everyone can participate in the drill. To do so, it is best to register your property on the web preparados.gob.mx and fill out a form so that the National Coordination of Civil Protection has proof of participation. And it is not the only one that takes place every year. Since the 1985 earthquake, simulation exercises have been carried out monthly in hotels, schools and offices.
#VIDEO Thus the rescue actions during the #DrillCDMXthis allows us to react in a timely manner to real earthquakes #PoliceCDMX pic.twitter.com/0IFdpEsKtG
— SSC CDMX (@SSC_CDMX) September 19, 2017
Although one of the problems is that his effectiveness it can only be assessed once the magnitude of the disaster is known, which in this case does not exist. And another bigger one is that the drills can coincide with real earthquakes. In 2017, a mega drill in various regions of the country. What the Mexicans did not expect was that, two hours later, an earthquake would hit the state of Puebla and the south of the country.
Its seismic situation and the measurements
As we mentioned before, Mexico City was built on the bed of an ancient lake, which makes it extremely vulnerable to earthquakes hundreds of kilometers away, since the soft clay amplifies tremors up to 500%. In fact, more than 80% occur in Michoacán, Guerrero and Oaxaca, where five tectonic plates converge, the collision of which endangers more than 33 million people, according to the National Center for Disaster Prevention.
To be prepared, Mexico uses what is known as “opportunity time.” According to the data that was analyzed after the 1985 earthquake, the seismic waves it took more than two minutes to travel from the epicenter, which was more than 350 kilometers away on the Pacific coast. That translates into a window of time to act: the period between the occurrence of an earthquake and the arrival of the catastrophe. The opportunity time for Mexico City is typically 60 seconds.
In order to take advantage of that time and give the alert, Mexico designed an early warning system (SAT) called SASMEX: the Seismic Alert System of Mexico. Sensors identify the location and intensity of an earthquake, and whether the magnitude is considered a threat, and alerts are sent to state and local governments and emergency organizations.
At the end of the 1980s, the Government financed twelve seismic sensors on the Guerrero gap with the aim of alerting Mexico City, the most exposed to shocks and with the highest population density. Since then, Sasmex already has at least 97 sensors distributed along the Pacific coast and in Michoacán, Guerrero, Oaxaca, Morelos, Mexico City, the State of Mexico and Puebla.
Also, the country has improved building codes and spent part of the economy to strengthen the infrastructure making it more resistant to earthquakes, especially hospitals, government sites and first aid buildings. But the truth is that enforcing these standards remains very difficult in many areas of the country, where buildings are built without permits or professional guidance.
In fact, according to this article from The Conversation, it is estimated that these types of “unengineered” construction represent 40% of all property in Mexico City, and it is higher in areas far from the center, where there is more poverty and inequality.
Image: Flickr / Government of Mexico
In Magnet | “Seven million buildings are not safe from earthquakes”: the catastrophe in Turkey had been announced for years