28 Major U.S. Cities Are Sinking — But the Real Danger Isn't the Drop

Why are major U.S. cities sinking without an earthquake? Satellite radar reveals land subsidence beneath all 28 American cities examined in a major study — and the hidden danger isn't simply how far the ground drops. From Houston to New York City, sinking ground can be caused by groundwater pumping, sediment compaction, ancient ice-sheet adjustments, and local changes beneath the streets. But the biggest engineering concern can be differential settlement: neighboring areas moving at different rates, potentially stressing foundations, pipes, and infrastructure. In this Earth science documentary from WHAT MAPS HIDE, we follow the evidence underground and explain how Sentinel-1 satellite radar (InSAR), groundwater wells, GPS monitoring, and deep extensometers help scientists investigate sinking cities. The 2025 Nature Cities study analyzed observations from 2015–2021. Researchers found sinking areas in every one of the 28 sampled cities and estimated that about 33.8 million residents lived on land mapped as subsiding. More than 29,000 buildings fell into higher modeled-risk categories — this does NOT mean they were inspected or confirmed damaged. We also explore NASA-led research on New York City and USGS monitoring of groundwater-related subsidence in Houston. What makes the ground beneath a city move? Why can a tiny difference in settlement matter more than a citywide average? And can the sinking be slowed? *SOURCES & FURTHER READING* 1. *Nature Cities (2025)* — Land subsidence risk to infrastructure in US metropolises https://www.nature.com/articles/s4428... 2. *NASA / JPL (2023)* — NASA-Led Study Pinpoints Areas of New York City Sinking, Rising https://www.nasa.gov/science-research... 3. *USGS* — Hydrogeology, land-surface subsidence, and the Gulf Coast groundwater-flow model https://pubs.usgs.gov/publication/pp1877 4. *Harris–Galveston Subsidence District* — Annual Groundwater Reports and monitoring data https://hgsubsidence.org/science-rese... *SCIENTIFIC NOTE* The national satellite study covers 2015–2021. Other cited studies use different observation periods and locations. Modeled infrastructure risk is not confirmed damage. Scientific 3D cross-sections are explanatory reconstructions rather than direct underground photographs. *ABOUT WHAT MAPS HIDE* WHAT MAPS HIDE explores hidden geology, earthquake faults, deep-ocean discoveries, and Earth's changing surface through scientific evidence, real measurements, and 3D reconstructions. What Maps Can't Show You. Subscribe for more Earth science documentaries. #LandSubsidence #EarthScience #Geology ABOUT THE DEEP TERRAIN THE DEEP TERRAIN explores Earth's hidden geology, seafloor structures, tectonic forces, volcanoes, and extraordinary landscapes through scientific evidence and immersive 3D reconstructions. Explore What Lies Beneath. Maps, scientific figures, field imagery, and reconstructions are credited in each video's sources and visual credits. Illustrations and models are identified when they are not direct observations.