A massive earthquake off Russia’s Kamchatka Peninsula in late July triggered a tsunami that rippled across the Pacific — and NASA’s experimental detection system tracked the event in real-time by monitoring the atmosphere above.
NASA’s GUARDIAN (GNSS Upper Atmospheric Real-time Disaster Information and Alert Network) taps into signals from global navigation satellite systems (GNSS), like GPS. When a tsunami forms, the surge of water pushes on the air above it, sending invisible pressure waves up through the atmosphere. These waves continue rising until they reach the ionosphere — a region high above Earth where satellites send navigation signals down to the ground.
As the pressure waves ripple through the ionosphere, they bend and distort the signals, causing subtle changes that are detectable by GUARDIAN, allowing scientists to detect signs of a tsunami moving across the ocean, before the waves make landfall, according to a statement from NASA’s Jet Propulsion Laboratory (JPL).
“Those extra minutes of knowing something is coming could make a real difference when it comes to warning communities in the path,” JPL scientist Siddharth Krishnamoorthy said in the statement.
During the July 29 tsunami, GUARDIAN detected atmospheric disturbances within about 20 minutes of the magnitude 8.8 earthquake. As the tsunami waves traveled across the Pacific, the technology confirmed clear signs of their approach roughly 30 to 40 minutes before the waves reached Hawaii and other coastal sites.
While the waves themselves caused little damage, the event demonstrated that GUARDIAN could track a tsunami in real time and provide valuable lead time for coastal communities — just one day after a critical software upgrade was deployed to the ground-based network.
“NASA’s GUARDIAN can help fill the gaps,” Christopher Moore, director of the National Oceanic and Atmospheric Administration (NOAA) Center for Tsunami Research, said in the statement. “It provides one more piece of information, one more valuable data point, that can help us determine, yes, we need to make the call to evacuate.”
GUARDIAN’s readings require expert interpretation, but it is already one of the fastest tsunami-monitoring tools. Within about 10 minutes of receiving satellite data, it can detect ripples in the upper atmosphere formed by a budding tsunami. By adding a space-based layer of observation to traditional forecasting tools like buoys and seismometers, GUARDIAN could improve early warning for tsunamis worldwide.