09-05-2025
Oklahoma City is sinking. Here's why, and what other US cities are sinking
A new study raised concerns for the 28 most populous cities in the United States, most of which are sinking a small amount each year.
Known scientifically as land "subsidence," the most common cause of the sinking is "massive ongoing groundwater extraction," say the study authors, though other forces are at work in some places. The cities include not just those on the coasts, where sea level rise is a concern, but many in the interior.
The study was published May 8 in the British journal Nature Cities. In every city studied, at least 20% of the urban area is sinking – and in 25 of 28 cities, at least 65% is sinking.
It's a unique study: "This is the first high-resolution, satellite-based measurement of land subsidence across the 28 most populous U.S. cities, and for several of these cities, it is the first time we have such detailed insights," study lead author Leonard Ohenhen of the Lamont-Doherty Earth Observatory told USA TODAY on May 7.
Oklahoma City, the nation's 20th most populated city, is among those observed in the study. Here's what we know.
Subsidence is often called an 'invisible threat' because it can go unnoticed for long periods, Ohenhen said. "Here, (in the study), we are making it less invisible."
When land shifts downward, even just a little bit, the structural integrity of buildings, roads, bridges, and dams can be profoundly impacted, said Ohenhen, a geosciences graduate student.
He told USA TODAY that "some early warning signs (of subsidence) that are often overlooked include: Cracks in walls, foundations, or around windows and doors, uneven or sloping floors; doors and windows that no longer close properly, warped roads or buckling pavement, tilting fences or utility poles, and fire hydrants sticking out more than they once did."
Generally, according to a statement from Lamont-Doherty, it happens as water is withdrawn from aquifers made up of fine-grained sediments; unless the aquifer is replenished, the pore spaces formerly occupied by water can eventually collapse, leading to compaction below, and sinkage at the surface.
However, the problem can also be exacerbated by pumping of oil and gas, the study says.
Oklahoma City is sinking between 1 and 2 millimeters per year, according to the study.
The most significant instances of subsidence is happening east of Interstate 35, spreading to both far southeast and far northeast OKC.
In these areas, the land is sinking anywhere from 1 millimeter per year to 4 millimeters per year. This number gets up to 6 millimeters per year along the North Canadian River.
The concentration of oil wells in northeast Oklahoma City — visible on the Oklahoma Corporation Commission's Well Data Finder — could be one explanation, but a similar density of oil wells in central and south Oklahoma City doesn't appear to have a sinking effect.
"A lot of small changes will build up over time, magnifying weak spots within urban systems and heighten flood risks," said Ohenhen. "This subsidence can produce stresses on infrastructure that will go past their safety limit," he added.
Right now, the risk to Oklahoma City's infrastructure from land subsidence is low, and in some areas medium, according to the study.
The researchers say that continued population growth and water usage combined with climate-induced droughts in some areas will likely worsen subsidence in the future.
'As opposed to just saying it's a problem, we can respond, address, mitigate, adapt,' said Ohenhen. 'We have to move to solutions.'
The study looked at the 28 most populous cities in the United States, with all but three cities (San Jose, Memphis, and Jacksonville) sinking on average overall.
Of the 28, 11 cities are coastal (or near major rivers and heavily influenced by tides and sea-level-rise): New York, Los Angeles, Houston, Philadelphia, San Diego, Jacksonville, San Francisco, Seattle, Washington, DC, Boston and Portland.
Nine cities are riparian (close to major rivers): San Antonio, Austin, Columbus, Ohio, Indianapolis, Nashville, El Paso, Detroit, and Memphis.
Nine cities are inland: Chicago, Phoenix, Dallas, San Jose, Fort Worth, Charlotte, Denver, Oklahoma City and Las Vegas.
The nation's fastest-sinking city is Houston, with more than 40% of its area dropping more than 5 millimeters (about 1/5 inch) per year, and 12% sinking at twice that rate.
Some localized spots are going down as much as 5 centimeters (2 inches) per year, according to the study.
Two other Texas cities, Fort Worth and Dallas, are not far behind.
This article originally appeared on Oklahoman: Map: Which US cities are sinking the most each year, and why?
