Mexico City Metro threatened by subsidence

The signs of impending disaster are everywhere in the Mexico City Metro— tilted concrete road barriers, sinuous train tracks that rise and dip like a serpent. The cause, differential subsidence, may sound dry and technical, but according to Wired it's a recipe for disaster — and it could be coming to a city near you. According to a recent satellite survey, portions of Mexico City are sinking at an alarming rate, over 20 inches in the last year, while others have barely budged. That's because some areas were built on a drained lake bed, that now, after years of drought, are being compressed, while other sections, built on stone, are more stable. This imbalance is throwing the entire rail system dangerously out of whack.

"When you're here in the city, you get used to buildings being tilted a little," says Darío Solano‐Rojas, a remote-sensing scientist at the National Autonomous University of Mexico. "You can feel how the rails are wobbly. Riding the Metro in Mexico City feels weird. You don't know if it's dangerous or not—you feel like it's dangerous, but you don't have that certainty."

These imbalances can lead to train derailments and overpass collapse, and the problem isn't limited to Mexico City. New York City and the Bay Area are both at risk as the weight of cities presses down and sea levels rise. There are solutions, like bolstering the tracks, but the key to battling subsidence is to NOT hide our heads in the sinking sand.

Previously: Aztec Skull Tower discovered beneath Mexico City