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Earthquakes '18

Everybody knows that Oaxaca is a land of movers and shakers.

 

Movers? The largest moving company, Castores (Beavers) has a big terminal right on the highway leading north from the city. Shakers? Well, this morning’s Noticias had an article laying out the numbers, with ADNsureste adding more detail.

 

The problem seems to be that the North American Tectonic Plate and the Cocos Tectonic Plate, like any other pair of siblings who live in adjoining bedrooms, tend to grate on each other. The NATP is subucting, literally getting under the skin of the CTP, and the occasional noisy outbursts that reduce the tension between the two tend to be heard all through the neighborhood. And these two have a notable talent for constant niggling. That’s what we get for having chosen to reside on a living planet with a molten core and a bunch of plates that ride it like surfboards.

 

Eventos sísimicos (little earthquakes) happen all the time. That’s ALL the time. From January to this week Oaxaca had 943 (!) eventos sísimicos, 25 of them last Tuesday. Scientists with seismographs are the only folks who notice the little ones. I am not one of those, but every couple of days, sitting and reading, watching the Red Sox on TV, or playing the guitar on the front porch, I feel a little jiggle. There’s always a temptation to attribute it to indigestion, but it’s more likely a geologic hiccup. I felt Thursday’s wiggle in Ixtepec down in the Isthmus, a 5.9-er with its epicenter up north: the jiggle lasted maybe a second and a half. Ditto the 4.1 on Tuesday centered in Salina Cruz; at the time I was about 80 km distant and I attributed the brief queasiness to the very tasty salsa on the huevos aporrados I had for breakfast..

 

This current week seems to be typical. The paper reports 12,869 eventos sísimicos in the State of Oaxaca so far in 2018. In fact, 70% of the eventos annually in Mexico occur in the State of Oaxaca, and the next most geologically active is Chiapas, our neighbor to the south, with 11%.

 

What’s to worry about is the terremotos the big earthquakes, like the 8.2 on February 16 centered in Pinotepa Nacional, about 300 km north of the Isthmus of Tehuantepec, the narrowest part of Mexico before it widens into Chiapas and the Yucatán.  As a result of the peculiarities of the underlying strata of rock along the Pacific Coast and the depth of this particular quake—70 km down—, it was most strongly felt in the Isthmus, especially the big city of Juchitán, a good part of which was destroyed. There were 37 fatalities.

By June reconstruction efforts had begun on 30-50% of the ruined building, with the rest remain in rubble. The flow of aid promised by the newly elected governor Murat has been barely more than a trickle.

 

I spent the Wednesday night in the nearby Isthmus of Ixtepec, in the city’s second-best hotel, since the city’s best hotel collapsed in February. As did somewhere between a fifth and a quarter of the rest of the buildings in this medium-sized city which has received even less aid than Juchitán. I drove around Ixtepec for most of an hour trying to get a sense of it, and did not find a single street without piles of rubble that turned two lanes into one and sometimes blocked the street entirely.

Now, five months after the event, a few of the homes are being rebuilt – when folks have some money, and can find construction crews. The hotel restaurant was full of the latter, buff young men with muscle shirts and arms covered with tattoos, wolfing down the restaurant’s plentiful if mediocre food. After dinner the construction teams hang out at the local disco, four doors north of the hotel, whose pounding, highly-amplified bass-lines probably also set off the seismographs. The heavy-metal whomp-whomp quit about 2:45 AM.

 

By the way, the most dangerous place to be in an earthquake in Mexico is Mexico City, whose sky-scraper center is located over the slippery clay of former lakebed. Any big jolt in the geologic neighborhood sets the city center to slipping and pitching.

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