Thursday, August 16, 2018

do you rock?

"We do not have earthquakes in San Miguel de Allende."

I have heard that refrain as long as I have been coming here. But I always filed it away in the same drawer of the second greatest myth of San Miguel de Allende -- that the city is built on a giant crystal that gives the place its magical aura.

"No earthquakes" sounded far too much like Camelot --  "a law was made a distant moon ago here/ that July and August cannot be too hot." After all, Mexico City is just down the road. And it is famous for its earthquakes.

So, i was skeptical. No, that is not quite true. I just didn't believe it.

Mexico sits atop the ring of fire that arcs Up from Saith America along the Pacific coast of the Americas, across the Aleutians, and down the Pacific coast of Asia through Indonesia to New Zealand. Why should San Miguel de Allende be spared earthquakes when it sits on the ring.

The reason is that it does not sit on the ring. I should have believed the people who live here. A quick bit of research proved I was wrong. The central highlands of Mexico, at least, north of Mexico City, are almost earthquake-free. South of Mexico City, it is a Seurat-inspired canvas of earthquake dots.

It is true that Mexico is part of the notorious ring of fire that hosts earthquakes and volcanic eruptions. But, it is the Pacific coast and the triangular portion of Mexico that are most at risk.

The science is simple.  Mexico sits on top of three of the Earth's largest tectonic plates. The North American. The Cocos. The Pacific. These plates are in constant motion rubbing against one another. When one gets stuck and suddenly releases itself, we feel that familiar jolt and shaking accompanied by the sound of a freight train.

San Miguel de Allende rides on top of one of the plates -- relatively far from the fault lines. On the other hand, Barra de Navidad, is located just about where the three plates meet. That explains why no one there ever says: "We do not have earthquakes in Barra de Navidad." Because we do. And all of us who live there have felt them.

The map at the top of this essay shows all of Mexico's earthquakes -- from 1990 to 2017. Only for the past 27 years. There are hundreds more.

I took a look at a chart that includes a more complete history. There are 61 recorded earthquakes over 7.0. Of those, 13 occurred within about 60 miles of my house. Only Oaxaca has more.

Do you see the red dot on the Pacific coast about a quarter of the way up on the map? That is just about where I live. All of the additional colors are tremor marks.

That may explain why rock and roll is so popular in Barra de Navidad and why the serenity of the chamber music festival is held in San Miguel de Allende.

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