NASA-ISRO satellite tracks months of eruption at a reawakened Russian volcano

A radar satellite built jointly by NASA and India's space agency has produced the most detailed time-lapse record yet of a volcano reawakening after thirteen months of dormancy, tracking lava as it filled a crater, spilled over its rim and fanned out across a remote stretch of Russia's Kamchatka Peninsula.

The satellite, known as NISAR, stitched together a time-lapse animation from 17 radar passes collected between December 2025 and this past August, showing molten rock spreading from the northern crater of Krasheninnikov, a pair of overlapping volcanoes inside a caldera on Kamchatka's Pacific coast. Scientists at NASA's Jet Propulsion Laboratory, who released the imagery this week, said the sequence is among the clearest demonstrations to date of the spacecraft's ability to monitor a hazard as it unfolds, rather than after the fact.

The numbers

The eruption itself traces back to one of the largest earthquakes ever recorded. On July 30, 2025, a magnitude 8.8 earthquake struck the seafloor off Kamchatka, and within days the Krasheninnikov volcano pair began erupting for the first time in nearly five centuries. NISAR was not yet watching when the eruption began; the satellite had launched that same month and did not begin returning high-resolution imagery of the site until Dec. 25, 2025, once it finished post-launch checkout and became fully operational.

Since then it has revisited the same patch of Kamchatka twice every 12 days, once heading north and once heading south, building a radar dataset with roughly 10-meter pixel resolution, each one covering an area about half the size of a tennis court. The spacecraft orbits 464 miles above Earth and carries a 39-foot, drum-shaped antenna reflector, NASA says is the largest radar antenna the agency has ever flown. Across the planet, the mission now provides frequent, cloud-penetrating coverage of roughly 1,300 active volcanoes located above sea level, most of which have never been observed with this combination of resolution and revisit frequency.

How a record earthquake reawakened a dormant giant

The July 2025 earthquake ranks among the ten most powerful ever measured by modern instruments and was the largest anywhere in the world since 2011. It sent tsunami waves across the Pacific basin, prompting warnings and evacuations in Japan, the United States and elsewhere; a global tsunami response effort coordinated through UNESCO's Intergovernmental Oceanographic Commission tracked the wave as it crossed ocean basins over the following hours. Krasheninnikov, which sits inside the Kronotsky Nature Reserve and had shown no confirmed activity since roughly the 16th century, began erupting only days after the quake, its dormant magma system apparently jolted loose by the shaking.

The NISAR mission, whose name stands for NASA-ISRO Synthetic Aperture Radar, was designed years before the earthquake to systematically map changes in the planet's land and ice surfaces, not to chase a single eruption. Managed for NASA by Caltech, the mission pairs an American L-band radar and antenna with a spacecraft bus and S-band radar built by the Indian Space Research Organisation, making it the first free-flying satellite to carry two synthetic-aperture radar instruments operating at different wavelengths. The longer L-band signal can penetrate tree canopies to image the ground beneath, while the S-band system captures complementary detail depending on vegetation cover. That the eruption happened to fall within a joint U.S.-Indian mission built for broad Earth monitoring, rather than a single-purpose volcano watcher, is part of what scientists say makes the resulting record notable.

Kamchatka sits on the Pacific "Ring of Fire," one of the most volcanically active stretches of the planet, but its remoteness and near-constant cloud cover have long made it difficult to monitor with conventional optical satellites, which cannot see through overcast skies. Radar instruments like NISAR's sidestep that problem by bouncing microwave signals off the ground regardless of cloud, darkness or, to a large degree, ash in the air, which is part of why the mission's steady drumbeat of Kamchatka images was possible even though the region rarely offers a clear view from space.

Who is watching, and what comes next

Krasheninnikov itself sits far from population centers, inside a protected nature reserve, so the immediate practical stakes of this particular eruption are limited. But scientists who study volcanic hazards said the episode illustrates a capability with far broader reach, since many of the roughly 1,300 volcanoes NISAR now revisits sit close to cities, farmland or shipping routes where advance warning of ground deformation or lava movement could matter far more directly.

Matthew Pritchard, a geophysicist at Cornell University and member of the NISAR science team who analyzed the Kamchatka data, said the value lies in the satellite's steady, repeated look at the same ground.

"The consistency is crucial. Twice every 12 days, acquiring in this high-resolution mode and in two observation directions, this shows the promise of NISAR to closely monitor natural hazards," said Pritchard.

Pritchard, who did his doctoral research on Kamchatka's volcanoes more than two decades ago, noted that back then, analysis-ready radar data of the region was hard to come by, both because satellites revisited less often and because the images available were far coarser. Data from NISAR's L-band instrument is now made freely available to researchers through the Alaska Satellite Facility's data archive in Fairbanks, which distributes NASA's synthetic aperture radar products to scientists worldwide.

NASA and JPL said the Kamchatka time-lapse will not be a one-off. The satellite is expected to keep returning to the same volcanic sites on its 12-day cycle for years to come, gradually building a global archive of ground movement that scientists can mine both for slow-building hazards, such as swelling magma chambers, and for fast-moving ones, such as active lava flows. For a mission built to survey the whole of the restless Earth, the Kamchatka eruption has become an early proof that the approach works as intended, even when the hazard in question arrived without warning, in one of the most remote volcanic landscapes on the planet.