NASA Radar Just Captured Mexico City Sinking Into the Ground After a Century of Unstoppable Collapse

Parts of Mexico City are sinking by more than half an inch every month, and a newly launched radar satellite has now measured exactly where. Data released April 29 by NASA’s Jet Propulsion Laboratory shows the NISAR satellite tracking urban land subsidence across one of the world’s largest cities with a level of detail that earlier space-based systems could not consistently achieve in dense or cloudy environments.

The readings were taken between October 2025 and January 2026, during Mexico City’s dry season. Areas sinking fastest appear in dark blue on the published imagery, with some zones recording ground subsidence exceeding two centimeters per month. Benito Juarez International Airport sits at the center of the frame, with Lake Nabor Carrillo visible to the northeast.

A Century of Sinking, Still Accelerating

The problem predates the satellite by a hundred years. Mexico City is built on a drained ancient lakebed, and relentless groundwater pumping combined with the weight of development above has compacted the soft sediment beneath it for generations. An engineer first documented the sinking in 1925.

By the 1990s and 2000s, parts of the city were dropping roughly 14 inches, or 35 centimeters, per year, enough to fracture Metro tunnels, buckle roads, and split water mains across the metropolitan area. The damage is not cosmetic. It accumulates in infrastructure that serves millions of people daily, and the sediment driving it has no natural mechanism for recovery once compressed.

The Angel of Independence monument on the Paseo de la Reforma tells the story plainly. Built in 1910 for Mexico’s centennial, it once sat at street level. Fourteen steps have since been added to its base as the surrounding ground dropped away. The monument has not moved. The city has.

Why NISAR Sees What Other Satellites Miss

Previous radar satellites have tracked Mexico City’s subsidence, but with real limitations. Cloud cover, dense vegetation, and darkness all degrade optical sensors and higher-frequency radar systems. NISAR’s L-band radar, operating at a 24-centimeter wavelength, cuts through all three without losing signal quality.

The satellite also carries an S-band instrument at 9.4 centimeters, making it the first ever launched with a dual-frequency synthetic aperture radar configuration. Together, the two instruments give researchers more ways to separate genuine ground motion from atmospheric interference, improving confidence in the measurements, particularly in regions where a single instrument would struggle.

It passes over the same point on Earth’s surface twice every 12 days, building a consistent record that researchers can compare over time to detect motion measured in millimeters. Craig Ferguson, deputy project manager at NASA Headquarters in Washington, said the Mexico City imagery confirms the sensors are performing as designed. He pointed specifically to the L-band’s value for coastal regions where land subsidence and rising seas occur simultaneously, compounding flood risk in ways that are difficult to untangle without precise ground-movement data.

Built for Scale, Designed to Last

NISAR launched from Satish Dhawan Space Centre on India’s southeastern coast on July 30, 2025. The mission is a partnership between NASA and the Indian Space Research Organisation, with JPL leading the U.S. side and providing the L-band instrument and antenna. ISRO supplied the spacecraft and the S-band radar.

The satellite’s most striking physical feature is its antenna reflector: a drum-shaped structure 39 feet, or 12 meters, across. NASA calls it the largest radar antenna reflector ever sent to orbit. A wider antenna captures more of the returning radar signal, which translates directly into finer surface measurements across larger areas, a critical advantage when the goal is detecting motion of just a few millimeters across an entire city.

The satellite operates at an altitude of 464 miles and is currently in its active science phase. As of late February 2026, it had released more than 100,000 data products through the Alaska Satellite Facility, all publicly available. That open-access model is deliberate: the mission is designed to serve not just NASA researchers but government agencies, urban planners, and disaster-risk teams around the world who need reliable ground-deformation data.

What the Maps Show and What Comes Next

The Mexico City results are preliminary. JPL notes that the yellow and red areas visible in the imagery are likely noise artifacts that should diminish as the mission collects more passes and builds a stronger baseline. The dark-blue subsidence zones, by contrast, align with decades of prior measurements and the known behavior of compressed lakebed sediment.

David Bekaert, a project manager at the Flemish Institute for Technological Research and a member of the NISAR science team, called Mexico City a proof-of-concept for what the satellite will do worldwide. “Mexico City is a well-known hot spot when it comes to subsidence, and images like this are just the beginning for NISAR,” he said. “We’re going to see an influx of new discoveries from all over the world, given the unique sensing capabilities of NISAR and its consistent global coverage.”

NISAR data is archived and openly accessible through the Alaska Satellite Facility DAAC. Mexico City’s next dry season will produce another comparable set of measurements, giving scientists a cleaner year-over-year look at how the city’s sinking lakebed is responding — or not — to any changes in water use or urban load above it.

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