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.
The 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.
