The epicenter was located in the boundaries of the states of Puebla and Morelos, 12 kilometers southeast of Axochiapan, Morelos, and 120 kilometers from Mexico City.
Because in the territory on which Mexico sits, five tectonic plates converge. These are the plates of Cocos, North America, Pacific, Rivera and Caribbean. Plates are segments of the Earth’s crust, which they divide as a puzzle, whose interaction as they move over a slimy, viscous mantle is one of the major causes of earthquakes in the world.
“Mexico is in a complicated, very complex tectonic context,” Xyoli Pérez Campos, director of the National Seismological Service (SSN) of the National Autonomous University of Mexico (UNAM) explained at a press conference.
But what produced the earthquake on Tuesday in particular?
An SSN technical report on Tuesday’s earthquake noted that in the earthquake’s epicenter region, “the Cocos plate subduces (sinks) below the North American plate.” That is, Mexico is on the edge of this second plate under which sinks the first. Cocos, getting under the North American, gets stuck and produces great tension. When it manages to break free and unleash, earthquakes occur. That is why almost all the earthquakes in the country occur in the southwest and central strips, under the states of Oaxaca, Guerrero and Michoacán.
The epicenter was located in the boundaries of the states of Puebla and Morelos, 12 kilometers southeast of Axochiapan, Morelos, and 120 kilometers from Mexico City, at a depth of 57 kilometers.
Does this make the area between Morelos and Puebla especially sensitive to seismic movements?
So is. Perez explained that the area between Morelos and Puebla, where the most recent earthquake originated, has “a history of major earthquakes,” the most recent, recorded on June 15, 1999 and October 24, 1980, with respective magnitudes of 7 and 7.1. The one from 1999 occurred 218 kilometers from Mexico City and “was very similar to the one we had this afternoon (Tuesday) at 120 kilometers; that makes the difference in intensity, “summarizes Perez.
Does the impact on human lives and collapsed buildings in Mexico City have to do with the location of the city?
Partly yes. Mexico City is one of the areas with the largest concentration of population in the world, which was also built on a lagoon that in times past surrounded the great Aztec city of Tenochtitlan. This means that it is built on very porous grounds, which amplify the energy of the seismic waves. Much of the land of the city is located on volcanic ash, which has little resistance to seismic movements.