In every city studied, at least 20% of the urban area is sinking – and in 25 of 28 cities, at least 65% is sinking. The nation's biggest cities are sinking, according to data from a new study.

Ohenhen has been analyzing subsidence rates in the US for the past year, and in a new study he and his team show that urban areas with 98 percent or more sinking land include Chicago, Dallas, Columbus, Detroit, Fort Worth, Denver, New York, Indianapolis, Houston, and Charlotte.