NISAR Radar Satellite Tracks Mexico City Ground Sinking at Over Half an Inch Per Month

by Clarence Oxford
Los Angeles, CA (SPX) Apr 29, 2026
The NISAR satellite has produced detailed radar maps of ground subsidence beneath Mexico City, showing parts of the metropolitan area sinking by more than half an inch - more than 2 centimeters - per month, driven largely by decades of groundwater extraction from the aquifer underlying the city.

The measurements, based on preliminary data collected between October 2025 and January 2026 during Mexico City's dry season, represent one of the first substantive operational datasets from the joint NASA-ISRO mission since its launch in July 2025. The findings demonstrate the satellite's ability to rapidly survey fast-changing terrain that has historically been difficult to monitor from space.

Mexico City sits atop an ancient lakebed. Extensive groundwater pumping combined with the compressive weight of urban development has caused the subsurface to compact continuously for more than a century. An engineer first formally documented the problem in 1925. By the 1990s and 2000s, portions of the metropolitan area were subsiding at rates approaching 14 inches (35 centimeters) per year, damaging metro rail infrastructure, roads, buildings, and water lines across the region. The city is home to approximately 20 million people.

NISAR - the NASA-ISRO Synthetic Aperture Radar - carries two SAR instruments operating at different radar wavelengths, making it the first satellite of its kind. Its L-band synthetic aperture radar is designed to operate day and night in all weather conditions, unimpeded by cloud cover or dense vegetation that limits optical sensors and higher-frequency radar systems. The spacecraft monitors Earth's land and ice surfaces twice every 12 days using a drum-shaped reflector measuring 39 feet (12 meters) in diameter, the largest radar antenna reflector NASA has placed in orbit.

In the newly released subsidence map, areas sinking faster than 2 centimeters per month appear in dark blue. The image centers on the urban core and surrounding metropolitan zone. Benito Juarez International Airport is visible as a structural feature near the center, with Lake Nabor Carrillo appearing as a dark green oblong shape to the northeast. Yellow and red areas in the data represent residual noise signals that are expected to diminish as NISAR accumulates additional passes.

One long-standing physical marker of subsidence in the city is the Angel of Independence monument on the Paseo de la Reforma. Completed in 1910 to mark the centenary of Mexican independence, the 114-foot (36-meter) structure has required 14 steps to be added at its base over the years as the surrounding ground level has progressively dropped.

"Images like this confirm that NISAR's measurements align with expectations," said Craig Ferguson, deputy project manager at NASA Headquarters in Washington. "NISAR's long wavelength L-band radar will make it possible to detect and track land subsidence in more challenging and densely vegetated regions such as coastal communities where they may have the compounding effects of both land subsidence and sea level rise."

David Bekaert, a project manager at the Flemish Institute for Technological Research and a member of the NISAR science team, said the Mexico City results are a precursor to a broader wave of findings. "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 is a joint mission developed by NASA and the Indian Space Research Organisation (ISRO). The satellite launched from Satish Dhawan Space Centre on India's southeastern coast. JPL, managed by Caltech and based in Southern California, leads the US component of the project and provided the L-band SAR instrument and antenna reflector. ISRO contributed the spacecraft bus and the S-band SAR instrument.