Sinking land in U.S. cities

Land is sinking, or subsiding, at a slow rate of millimeters per year. For the Washington Post, Kasha Patel and Naema Ahmed report on the new research by Ohenhen, L.O., Zhai, G., Lucy, J. et al.

Researchers mapped out how land is moving vertically across the 28 most populous U.S. cities and found all the cities were compressing like a deflated air mattress to some extent. Twenty-five of them are dropping across two-thirds of their land. About 34 million people — about 10 percent of the U.S. population — live in the subsiding areas, according to the study published Thursday in Nature Cities.

It might not seem like an issue now, but when the foundation of a big building is sinking in the middle of the city, the structural integrity is probably not great.