A team from NASA’s Jet Propulsion Laboratory in California has successfully demonstrated a new tsunami prediction system. The system, which uses real-time data from the agency’s Global Differential GPS network, successfully predicted the size of a tsunami following an 8.8 magnitude Chilean earthquake in February.

The prediction system combines global and regional real-time data from hundreds of GPS sites and estimates their positions every second. Based on NASA’s network, the scientists say it also can detect ground motions as small as a few centimetres.

Conventional tsunami warning systems rely on estimates of the location, depth and magnitude of an earthquake to help determine whether a large tsunami may develop, but this system has not been reliable.

“This successful test demonstrates that coastal GPS system can effectively be used to predict the size of tsunamis,” said Tony Song, team leader of the project. The team’s GPS-based prediction was confirmed using sea surface height measurements from the joint NASA/French Space Agency Jason-1 and Jason-2 satellites.

The motion of the 27 February earthquake was captured by the network’s station in Santiago, which is about 235 km from the quake’s epicentre. Song had access to the data within minutes of the earthquake, which allowed him to derive seafloor motions.

“We were fortunate to have a station sufficiently close to the epicentre,” said Yoaz Bar-Sever, of JPL. “Broad international collaboration is required to densify the GPS tracking network so that it adequately covers all the fault zones that can give rise to large earthquakes around the world.”