JPL Team Uses GPS for Tsunami Early Warning

Led by Dr. Attila Komjathy, who received his Ph.D. from the University of New Brunswick in 1997, a team from NASA’s Jet Propulsion Laboratory has demonstrated a technique that has the potential to significantly improve tsunami monitoring and warning.

The technique uses data from multiple Global Positioning System receivers on the ground to measure small perturbations in the ionosphere’s electron density caused by a tsunami.

The changing sea level of a tsunami, even far from a coast, generates waves in the atmosphere that make it all the way up to the ionosphere, some 350 kilometres or so above the sea surface. Here, they disturb the electrons that affect the propagation of GPS signals. The disturbance is so small that ordinary GPS receivers do not notice the passage of the waves. However, with advanced software processing of the data collected by specialized receivers used, for example, by surveyors and geodesists, the waves can be visualized and used to track the progress of the tsunami.

The JPL team has dramatically demonstrated their technique for the devastating tsunami associated with last year’s massive offshore Japanese earthquake. They used data from the more than 1,000 receivers of Japan’s permanent GPS monitoring network. The propagating ionospheric waves can be clearly seen in a video the team has posted to YouTube.

The video can also be downloaded from the GGE website.

An earlier report on NASA’s tsunami-detection work can be found here.

NASA is investing in research to obtain real-time GPS measurements from around the world so that researchers can integrate this technology into a global tsunami warning system. Additional potential applications might include the remote sensing of ionospheric perturbations generated by other natural hazards such as earthquakes and volcanic eruptions and human-made events such as nuclear tests.

Dr. Komjathy was one of the first to investigate the use of GPS signals to study the ionosphere. His pioneering Ph.D. research under Prof. Richard Langley was awarded a Gold Medal from the Governor General of Canada.