There is a giant roaring underground in central Mexico. The Popocatépetl volcano has been active since 1994 and everyone knew it, but for a few days the alarms have gone off due to its increasing activity: there are hundreds of explosions in more than 40 uninterrupted hours. Around 7,000 soldiers have been mobilized to the States of Puebla, Morelos and the State of Mexico in case it is necessary to organize an evacuation of the populations near the volcano, classes have been suspended in 40 municipalities and a security perimeter of 12 has been established. kilometers around the Popo. Everything is ready, but the scientists call for calm: this episode is not unique, it has happened many times before and what recent history suggests is that the volcano will stabilize, without a dramatic eruption, at a high level of activity and ash emission. “It is likely that in the coming months there will be many episodes like the one that is happening now,” says volcanologist Robin Campion.
The researcher answers the phone to EL PAÍS in an interval between his trips to the active giant: “It is a continuous gas leak that generates a lot of noise and carries incandescent fragments and ash with it.” He has spent three days in the Paso de Cortés, the gap between the Iztaccíhuatl and Popocatépetl volcanoes, monitoring. He brings irritated eyes, somewhat red nose. The emission of ash is not innocuous. Tonight he leaves again, he is going to get closer four kilometers more, inside the restricted area. These are busy days for researchers who have dedicated their careers to studying Mexican volcanoes: “What stands out the most is the duration of the episode, 40 hours non-stop. It is an anomalous episode due to its duration, due to the constant production of ash for so long, ”he describes.
This ash is now falling on the State of Puebla and has forced the closure of the Hermanos Serdán airport, but the next winds are heading towards Mexico City, where chaos broke out on Saturday in the already saturated AICM due to the closure for only a few hours. of the tracks. “The probability that the ash will go to Mexico City is very high. We know that during the winter the ashes go to Puebla, but starting in May, in June and July it goes to Mexico City,” explains researcher Ana Lillian Martin at a conference organized by the National Autonomous University of Mexico (UNAM).
The volcanology expert points out that the ashes irritate the respiratory tract, the eyes and can also itch the skin. When they get wet they become muddy and create a paste that is difficult to undo. They darken the environment and can get into aircraft engines, damage car windshields. They also affect cell phone telecommunications, for example. Thus, the National Center for Disaster Prevention (CENAPRED) has recommended staying indoors, covering doors and windows, wearing a mask and glasses if you have to go outside and avoiding driving.
How long will it have to be like this? “We don’t have a crystal ball for that,” replies the volcanologist Robin Campion, who points out that it is difficult to make exact forecasts at the three speeds that are handled: it is not known how long this episode will last -it could be days-, nor when This most intense period that has just begun will end —it could be months— or when a volcano that has been awake for three decades will go back to sleep —it could be years. “You have to be humble: there are many things that we have no way of forecasting regarding the volcano,” explains Campion, “quantifying is important, because it allows you to compare current activity with previous ones, it’s like measuring a river and its floods.”
“What we are seeing in geological terms is something small”
Volcano times are not like humans. It helps to imagine them as big machines that store energy and then release it. For example, explains the researcher Servando de la Cruz, in Popocatépetl there was a great eruption 23,000 years ago and also 14,000 years ago. Another in the year 800. “These very violent episodes are very separated in time. The other type of activity is an activity of smaller cycles, easier for the volcano to manage, as happened from 1919 to 1927, or from 1994 until now”, describes the UNAM expert.
Within the Institute of Geophysics it is contemplated that every 70 years the volcano reactivates, lasts awake for a while and then goes back to sleep. For almost three decades he has been with one eye open. In this last period of activity, many episodes like the one now have been recorded: it occurred in December 1994 and in 2000, also in 2012, in 2019 and 2020.
The energy peaks of these days in May have not yet exceeded, for example, those of the beginning of the century. “In the 2000 activity, 42,000 people were evacuated, 14,000 went to shelters. We are not in that situation or in that condition,” says researcher Carlos Valdés. That same idea is underpinned by Carlos Gutiérrez Martínez, CENAPRED Research Director: “The volcano is at least half a million years old. Without wanting to downplay the problem, what we’re seeing in geological and volcanic terms is a small thing.”
The image of now began to take shape at the end of December, explains Robin Campion. The volcano began to recharge with juvenile magma, which is richer in gases —and the gases are the motor of the eruptions. The increase was first gradual. On May 10 at 00:05 a noise made the windows of the nearest towns vibrate, the sound woke up the neighbors. More explosions were recorded, until, finally, on May 19, the parameters that measure gases, tremor, ash production, and thermal energy production jumped up. “Everything increased in parallel,” says Campion.
Since that time it does not stop. This continuity has led to the lifting of phase 3 of the yellow alert. To reach a red alert, the situation would have to get out of control, which does not appear to be the case. “We are prepared to do so if necessary, but everything indicates that the best probability is that the activity will remain more similar to what we have seen in 27 years. The same thing has happened on previous occasions and in no case have we needed to go to higher states of the traffic light”, explains De la Cruz.
The current situation with Popocatépetl is what there would be in a hospital with a patient in intensive care: there are 24-hour specialist doctors from different areas observing, analyzing and making decisions so that everything goes well. The attention is focused on whether and how it decreases its energy output. An abrupt descent could mean that there is a clogging of the volcano’s conduit, which would trigger what scientists call an explosive release.
For now, it is positive that it continues with a “constant stream”. “It means that the duct system is still open and is still releasing energy in a regular way,” Campion explains. “In the coming months, everything will depend on the amount of new magma that is entering the system and the capacity of the conduit to evacuate the excess pressure that this magma generates. Hopefully it will continue to be quite constant and moderate and that everything will not be released in one hit, as the volcano has done in prehistory ”, he points out. The latest data reported by Campion pointed to a stabilization of values.
Mexico is a country of volcanoes. There are more than 2,000 and 48 are active, or potentially active. 60% of the country’s population lives on the soil that they modified. Nine million people live in a radius of 20 kilometers around Popocatépetl alone, if it is extended to 60 kilometers there are already 25 million. Being so close to a densely populated area has made Popo the second riskiest volcano in the world. Although the spectacular images of the erupting volcano, the rain of ash, and the closure for hours of the airports in Mexico City and Puebla have ended up creating the perfect apocalyptic setting, Campion insists: “You have to resist the temptation of catastrophizing ”.
Subscribe here to the EL PAÍS México newsletter and receive all the key information on current affairs in this country