The Soufrière eruption on St. Vincent has put more than 100,000 people in the Caribbean at risk. A much greater crowd lives in the shadow of two volcanoes, along with a history of earthquakes, in a city on the American continent. Including its suburbs and satellite towns, Mexico City is has an estimated population count approaching 22 million. That’s comparable to urban super-giants like São Paulo, Brazil and Shanghai, China. What’s lacking in São Paulo and Shanghai are volcanoes and frequent earthquakes. Mexico City has got them. Not one, but two active volcanoes loom over its densely populated satellite towns.
Consider two of them, for example: Atlautla and Amecameca. The crater of Popocatepetl is a mere 10 miles from Atlautla’s town center. From Amecameca to the top of Iztaccihuatl volcano it’s only 9 miles. When we look back at the Mt. Pinatubo eruption of 1991 in the Philippines, we see that its hot ash burned 154 square miles. That’s more than the area of the two towns plus many others combined. The more widespread total ash fall from the event in the Philippines was larger than the area of Rhode Island. An eruption of Popocatepetl or Iztaccihuatl, producing lava and ash of Pinatubo dimensions, would cover most of the 3,000 square miles that form Greater Mexico City.
But more important than volcanoes and towns with complex names are earthquake drills. They are held regularly in Mexico City, as a student of mine with family in that area pointed out. Much of the city is built on soft, unstable ground. That’s a characteristic it shares with some parts of San Francisco, California. Unlike hard bedrock, soft and swampy soil carries quake vibration and shaking over long distances. The Great Quake of 1985 originated 235 miles away in Michoacán State. But at magnitude 7.5, it made major buildings collapse in the City, including Benito Juarez Hospital.
More recently, a massive 7.1 quake struck in Atencingo, Puebla. In Mexico City, 75 miles away, it brought Enrique Rébsamen Elementary School down, killing 32 children and 5 adults. The most recent sizeable quake was magnitude 4.7 on April 8, centered in the state of Guerrero 130 miles away. Serious earthquakes occur just about every day somewhere in Mexico. But its capital city, with two volcanoes and a devastating earthquake history, exemplifies the phrase “living in harm’s way.”
Rudi Kiefer, Ph.D., is a professor at Brenau University, teaching physical and health sciences on Brenau’s Georgia campuses and in China. His column appears Sundays and at gainesvilletimes.com.