If you lived in La Guaira during the June 2026 earthquakes, you might have felt the ground roll beneath your feet. But what you couldn’t feel is that, in many places, the ground actually moved — permanently. Radar data from the newly operational NISAR satellite now shows that parts of Venezuela’s coastal state shifted by several centimeters during the tremors. That’s enough to crack foundations, misalign pipelines, and destabilize slopes. And for the half a million people in the Caracas metropolitan area who rely on roads and ports through this region, the implications are immediate.
The twin quakes — a magnitude 6.7 on June 3 and a magnitude 6.2 aftershock on June 7 — struck along the San Sebastián fault system, a major but previously understudied tectonic boundary that runs just north of Caracas. The epicenters were offshore, but the deformation spread inland. NISAR, a joint NASA-ISRO satellite launched in 2024, used its L-band synthetic aperture radar to compare before-and-after images of the ground. The result? A detailed map of displacement that is already reshaping how engineers assess the damage. And it’s not just Venezuela: the same technique is being used worldwide, from monitoring extreme weather events to volcanic inflation.
How NISAR Saw the Shift
NISAR doesn’t take photographs. It bounces microwave pulses off the Earth’s surface and measures the return signal with incredible precision. By comparing two passes over the same area — one before the earthquake, one after — scientists can detect changes in the ground’s position down to a few millimeters. This technique, called interferometric synthetic aperture radar (InSAR), has been around for decades, but NISAR brings a global, systematic coverage that previous missions lacked.
“The June 2026 sequence was a perfect test case for NISAR’s rapid-response capability,” says Dr. Mariana Rojas, a geophysicist at the University of Los Andes in Mérida, Venezuela. “Within 72 hours of the main shock, we had a displacement map covering La Guaira, Maiquetía, and the coastal mountains. The data showed a zone of uplift near the coast — about 4 centimeters — and a broader area of subsidence inland, up to 6 centimeters in some places.”
Why the difference? The San Sebastián fault is a thrust fault, meaning one side of the fault is shoved over the other. In this case, the offshore plate moved upward and landward, causing the coast to rise while the inland side dropped. But faults are never simple. The NISAR images also revealed smaller, secondary fractures — previously unmapped — that may have accommodated some of the strain. That’s critical information for rebuilding.
“We’re not just looking at where the ground broke. We’re seeing where it stretched and where it squeezed. That tells us which areas are still under stress.” — Dr. James Carter, NASA Jet Propulsion Laboratory, NISAR Science Team Lead
What Ground Displacement Means for Venezuelan Communities
For most people, the immediate danger after an earthquake is from collapsed buildings. But the slower, less visible hazard — ground displacement — can be just as destructive. A differential movement of just 2 to 3 centimeters across a building’s foundation can cause shear cracks in masonry, break water and gas lines, and tilt structures in ways that make them unsafe long after the shaking stops.
In La Guaira, the displacement map has already led to the closure of three schools and two health clinics pending structural inspections. The region’s main port, which handles nearly 60% of Venezuela’s container traffic, showed a 1.5-centimeter offset along one of its main cargo piers. Port authorities have restricted heavy loads until engineers can verify the pier’s integrity. And in the hillside communities above the city, where homes are built on steep slopes, the subsidence zones overlap with areas already prone to landslides. “We’re now cross-referencing the NISAR data with rainfall forecasts,” says Dr. Rojas. “If the ground is already weakened, a heavy rain could trigger catastrophic slides.”
That’s not just a local concern. The main highway connecting Caracas to its international airport in Maiquetía runs right through the displacement zone. Satellite imagery confirms that a 400-meter stretch of the highway settled by 2.5 centimeters. Repairs are underway, but the road may need to be entirely realigned in places — a project that could take years and cost hundreds of millions of dollars in a country already struggling with economic crisis.
Look, Venezuela is no stranger to earthquakes. The 1997 Cariaco quake (magnitude 6.9) killed 73 people and destroyed thousands of homes. But the 2026 sequence is different: for the first time, satellite data gives authorities a precise, spatially continuous picture of where the ground actually moved. And that changes the calculus for recovery.
Why This Earthquake Was Different
The San Sebastián fault system is part of the complex boundary between the Caribbean Plate and the South American Plate. It’s not as famous as the San Andreas in California, but it’s just as active — and arguably more dangerous because many of its faults are hidden beneath the Caribbean Sea or buried under urban development. The June 2026 quakes were shallow, about 12 kilometers deep, which amplified the ground motion in coastal areas.
NISAR’s rapid data release also allowed scientists to model the aftershock sequence more accurately. Within two weeks, the U.S. Geological Survey (USGS) had updated its hazard forecasts for the region, incorporating the new displacement data. The forecast showed a 12% probability of a magnitude 6 or larger aftershock within the next month — a number that prompted Venezuelan authorities to extend evacuation orders for vulnerable neighborhoods.
“The NISAR data essentially gave us a high-resolution X-ray of the fault’s behavior,” says Dr. Carter. “We could see which segments slipped and which didn’t. The locked segments are now under higher stress. That’s where we worry about the next event.”
And worry they should. The same fault system produced a magnitude 7.7 earthquake in 1900 that devastated Caracas. The city’s current building codes are supposed to account for seismic risk, but enforcement is inconsistent. Many structures — especially in informal settlements — were built without any engineering oversight. The displacement map shows that some of these areas experienced the largest ground shifts.
Meanwhile, the world is watching. The same NISAR technology is being used to monitor other hazard zones: the Pacific typhoon belt, the Himalayas, and even the slow creep of landslides in California. Each new dataset improves our ability to forecast and respond.
Looking Ahead: Satellite Monitoring and Preparedness
The NISAR mission is designed to last at least three years, with a goal of mapping the entire Earth every 12 days. For Venezuela, that means continuous monitoring of the San Sebastián fault and other active structures. Scientists are already planning a dedicated observing campaign to track post-seismic deformation — the slow, ongoing adjustment of the crust after a major quake. That data could reveal whether certain fault segments are creeping aseismically (a good sign) or locking up again (a bad one).
But satellite data alone isn’t enough. “We need ground-truth measurements — GPS stations, tiltmeters, and field surveys — to calibrate the satellite observations,” says Dr. Rojas. “And we need the political will to act on the information. A displacement map is useless if it sits in a drawer.”
Venezuela’s National Institute for Seismic Research (INPRES) has begun using the NISAR data to update its seismic hazard maps for the first time since 2005. The new maps will influence building codes, land-use planning, and insurance rates — if they are adopted. For now, the most immediate benefit is for the engineers and emergency managers who can see, with unprecedented clarity, exactly where the earth moved. And that, for the people of La Guaira, might be the difference between a building that stays up and one that doesn’t.
Frequently Asked Questions
How accurate is NISAR’s ground displacement measurement?
NISAR’s L-band radar can detect changes in ground position with an accuracy of 5–10 millimeters under ideal conditions. The actual precision depends on factors like vegetation cover, atmospheric interference, and the number of satellite passes. In the Venezuela case, scientists estimate the displacement maps are accurate to within ±1.5 centimeters.
Can ground displacement from an earthquake predict future quakes?
Indirectly, yes. By mapping which parts of a fault slipped during an earthquake, scientists can identify adjacent segments that remain locked and are therefore building up stress. This stress accumulation increases the probability of a future earthquake on those segments. NISAR data is now routinely used to update short-term earthquake forecasts.
Should residents of La Guaira be concerned about aftershocks?
The USGS and Venezuelan authorities have indicated that the probability of a magnitude 5 or larger aftershock within the next six months is about 30%. Residents should follow local emergency guidelines, ensure their homes are structurally sound (especially if they are in the areas of highest displacement), and have an emergency kit ready. The NISAR data is being used to refine these risk estimates.
