A new study of 28 most populous U.S. cities found that all sink to one degree or another. These cities include not only cities on the coast that are opposite to sea level, but also many cities inside. Additionally, using new particle data, the study found that some cities sink at different speeds in different attractions, or sinking in some places and falling in others, could introduce pressures that could affect buildings and other infrastructure. The authors say that large-scale ongoing groundwater extraction is the most common cause of these land movements, although other forces are working in some places.
The study was published this week in the journal Nature City.
“As cities continue to grow, we will see more cities expand into lurking areas,” said Leonard Ohhenhen, a postdoctoral researcher at the Lamont-Doherty Earth Observatory at the Columbia Climate Institute. “Over time, this settlement creates pressure on the infrastructure, which will exceed its security limits.”
The rapid settlement of coastal metropolis such as Jakarta, Venice and New Orleans has attracted attention, and several recent studies have shown that many parts of the U.S. East Coast and elsewhere are occupied. However, most studies rely on relatively sparse data distributed across a wide range of areas to map a wide range of scenes.
From all cities in the United States, the new study uses the latest satellite data to map vertical land movements into grids of only 28 meters (about 90 feet) squares and vertical land movements to millimeters. The authors found that in 25 of the 28 cities, two-thirds or more of the areas were sinking. Overall, about 34 million people live in affected areas.
The fastest city is Houston, where over 40% of its area lands more than 5 mm (about 1/5 inch) while the 12% drops twice as fast. Some local attractions drop by up to 5 cm (2 inches) each year. Fort Worth, Texas and two other cities are not far from Dallas. Some local quick link areas elsewhere include areas near LaGuardia Airport in New York and parts of Las Vegas, Washington, D.C. and San Francisco.
In addition to measuring changes in surface height, the researchers also analyzed county-level groundwater extraction in affected areas. Related to land movement, they determined that removing artificial groundwater is the cause of 80% of the overall sinking. Typically, this is due to the aquifer composed of fine-grained sediments being taken from the water; unless the aquifer is supplemented, the pores previously occupied by water eventually collapse, resulting in compaction below and sinking on the ground. In Texas, the problem has exacerbated the problem through oil and gas pumping, the document says.
In some areas, population growth and continued growth in water use, as well as climate-induced droughts may worsen in the future, researchers say.
In some areas, natural forces are at work. In particular, until about 20,000 years ago, the weight of the towering ice sheet that occupied much of the interior of North America raised upwards along its edges, like a person squeezing from part of the balloon to another. Even today, the ice disappears, and some of the bumps still drop at a rate of 1 to 3 mm per year. Affected cities include New York, Indianapolis, Nashville, Philadelphia, Denver, Chicago and Portland.
Even the huge weight of a building can cause losses. A 2023 study found that more than one million buildings in New York are so imminent on Earth that they may contribute to the city’s ongoing settlement. A recent independent study found that some buildings in the Miami area have partially declined from the damage caused by the construction of new buildings nearby.
The new study found that eight cities (New York, Chicago, Los Angeles, Phoenix, Houston, Philadelphia, San Antonio and Dallas) account for more than 60% of the land that resides on sunken land. It is worth noting that more than 90 major floods have occurred in these eight cities since 2000, possibly driven in part by lowering terrain.
Houston, Texas is the fastest city in the United States, with an area of more than 20 mm per year. Warm colors indicate larger sinking; click to view data and features. The data has been summarized as a 500-meter grid. (Map by Jeremy Hinsdale, based on Ohenhen et al., Natural Cities 2025.)
Another key discovery: some cities are seeing differential movements, adjacent places sinking at different rates, and even as other regions rise. Upward movement may be caused by rapid charging of aquifers near rivers or other water sources. (The uplift in some areas is actually to make up for the overall sinking range of three cities: Jacksonville, Florida; Memphis, Tennessee, and San Jose, California).
Differential motion is a problem because, as the authors point out, if the entire urban area moves upward or evenly upward at the same speed, the danger of stress on building foundations and other infrastructure can be minimized. However, if the structures are subject to a series of uneven vertical movements, they may experience dangerous tilts.
“The risk is manifested only when the high settlement rate drops to the height of land below the critical threshold, even in the case of small changes in land movement, and infrastructure damage induced by sinking occurs,” the author wrote.
The study found that in 28 cities, only about 1% of the land area is located within areas where differential movements may affect buildings, roads, railway lines and other structures. However, these areas tend to be located in the densest urban core and currently contain about 29,000 buildings. In this regard, the most dangerous city is San Antonio, and researchers say 1 in a quarter of buildings is at high risk; Austin (one in 71); Fort Worth (one in 143) and Memphis (one in 167).
The results of the various structures of these fields are not yet clear. That may require more sophisticated research, Ohenhen said. Early studies of 225 U.S. buildings between 1989 and 2000 found that only 2% were directly attributed to settlement. However, the new study says the factors behind 30% are designated as unknown, suggesting that settlement may have played a bigger role.
This article concludes that cities should use this new information to focus on solutions. In many places, flooding can absorb flooding by raising land, enhanced drainage systems and green infrastructure such as artificial wetlands, they say. Cities that are vulnerable to tilt hazards can focus on renovating existing structures, integrating land actions into building regulations, and limiting new buildings in the areas with the greatest threat.
“With just saying that this is a question we can answer, solve, mitigate, adapt,” Ohhenhen said. “We have to turn to solutions.”
The study was co-authored by researchers from Virginia Tech, the Netherlands Organization for Applied Science Research, the University of California, Berkeley, Texas A&M, the University of Colorado Boulder, Brown University and the United Nations University.
