Why is the recent 7.1 earthquake in southern Mexico a concern?

Why is the recent 7.1 earthquake in southern Mexico a concern?

The 7.1 magnitude earthquake that shook central and southern Mexico last Tuesday originated near the Guerrero Brecha, a disturbing proximity because, according to experts, this seismic zone would have accumulated great tension in the last century.

The movement left one person dead and damaged homes, hospitals, shops and hotels, mainly in the tourist port of Acapulco.

Mexico registers intense seismic activity because it is located in the Pacific Ring of Fire, which joins America with Asia and where most of the earthquakes in the world occur.

The memory of the 7.1 earthquake of September 19, 2017, which shook the central region and left 369 dead, is still present in the country, mainly in the capital. On that same date, but in 1985, Mexico City was devastated by earthquakes that left more than 10,000 dead.

– Where did Tuesday’s earthquake occur? –

The epicenter was located 11 km southeast of Acapulco, in the southern state of Guerrero. This region usually registers tremors due to the interaction of the Cocos and North American tectonic plates.

“The Cocos plate, which is under the sea, is all the time trying to enter below North America, which is the continental plate where most of the territory of Mexico is,” explains Arturo Iglesias, head of the National Seismological Service. .

In the subduction (sinking) zone of these plates is the Guerrero Brecha, a 230-kilometer strip between Acapulco and Papanoa, a town in the municipality of Tecpan de Galeana.

– Why is it causing concern?

Although earthquakes cannot be predicted, the Guerrero Gap raises concern because it has not had a major earthquake since 1911.

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“It is an area that is off the coast of Guerrero that has not had a major earthquake for a long time. There is no certainty, these are all statistical issues,” says Dr. Ana María Soler, director of the Geophysical Museum of the National Autonomous University of Mexico (UNAM).

“It has been 110 years since an earthquake has occurred and they typically occur with rates of return of between 30 and 50 years. That rate is already exceeded,” adds Iglesias.

– What could happen in the Guerrero Gap?

Although it is impossible to predict when an earthquake will occur, specialists estimate that a large earthquake or several of lesser intensity could occur there.

“The northwestern edge of the gap already broke in an earthquake in 2014, so what remains of the gap can generate an earthquake of up to 7.8, but it may be more earthquakes and smaller ones,” says Iglesias.

The expert details that the rate of return from tremors in that area could be much longer than originally thought.

“It is well known that this area has significant seismogenic potential, so much so that we have an early warning system for Mexico City,” he observes.

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