NASA's GUARDIAN System Uses GPS Signals to Detect Tsunamis Minutes Earlier

Eight minutes after a magnitude 8.8 earthquake struck off Russia's Kamchatka coast on July 29, 2025, GUARDIAN's artificial intelligence-powered detection algorithms had already spotted the disturbances in satellite navigation signals that would soon confirm a tsunami was tearing across the Pacific. By the time the wave approached Hawaii, GUARDIAN had flagged the incoming wave west of Hawaii some 32 minutes before it made landfall and was detected by tide gauges.

A new data visualization illustrates how the experimental NASA technology can provide extra lead time to communities in the path of a tsunami. Called GUARDIAN, which stands for GNSS Upper Atmospheric Real-time Disaster Information and Alert Network, the software detects slight distortions in satellite navigation signals to spot hazards on the move.

The animation breaks down a real-life case study: last summer's massive Kamchatka earthquake and the tsunami that it sent racing across the Pacific and towards Hawaii at over 500 mph (805 kph). The visualization, credited to NASA's Scientific Visualization Studio and published by JPL on March 23, 2026, color-codes the event in real time: the magnitude 8.8 earthquake appears in purple, while red, orange, yellow, and green ringlets represent real-time readings from ground stations tracking GPS and other navigational satellite signals. Tide gauges, which GUARDIAN outpaced by 32 minutes in the case study, are shown in blue.

The physics behind the detection are counterintuitive. Tsunamis and earthquakes, by displacing large amounts of air at Earth's surface, unleash pressure waves that can slightly perturb the radio signals coming down from satellites, and while systems are in place to correct for this "noise," GUARDIAN considers it a useful signal. JPL scientist Siddharth Krishnamoorthy noted that "those extra minutes of knowing something is coming could make a real difference when it comes to warning communities in the path."

Currently, GUARDIAN scours data from more than 350 GNSS ground stations around the Pacific Ring of Fire, a hotbed for the ocean's deadliest waves. The system is being developed at JPL by the GDGPS project, which is partially supported by NASA's Space Geodesy Project. A day before the Kamchatka quake, the team had deployed two new elements that were years in the making: an artificial intelligence to mine signals of interest and an accompanying prototype messaging system, meaning the July 29 event was effectively GUARDIAN's first live test of its fully assembled toolkit.

The system is not confined to tsunamis. Earthquakes, volcanic eruptions, missile tests, spacecraft reentries, meteoroid splashdowns: anything that produces a large rumble on Earth is potentially fair game. It could potentially provide as much as an hour of warning, depending on the distance of the tsunami origin from shore.

Near-real-time outputs from GUARDIAN must still be interpreted by experts trained to identify the signs of tsunamis, but it is already one of the fastest monitoring tools of its kind, capable of producing a snapshot of a tsunami's rumble reaching the upper atmosphere within about 10 minutes of receiving data. The goal of GUARDIAN is to augment existing early warning systems, not replace them. While the Kamchatka event didn't cause widespread damage to people or property, it showed how the next time disaster strikes, NASA science could give communities a few more minutes to act.