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NASA Tests GPS Tsunami Prediction System

Researchers used data from a GPS network to successfully predict the size of the tsunami that followed February's 8.8 earthquake in Chile.
NASA has successfully tested a GPS-based prediction system for assessing the risk and size of tsunamis that may result from significantly sized earthquakes.

A NASA team from the Jet Propulsion Laboratory (JPL) used realtime data from its Global Differential GPS (GDGPS) network to successfully predict the size of the tsunami that resulted from a magnitude 8.8 quake on Feb. 27 in Chile, the agency said this week.

The JPL manages the network, which combines global and regional data from hundreds of GPS sites, estimating their positions every second. The NASA team used those measurements to estimate the energy an undersea quake would transfer to the ocean to generate a tsunami, the agency said.

The prediction method was developed by NASA researcher Y. Tony Song in 2007, but first proven after the Chile quake. Song led the JPL team that made the prediction.

Specifically, NASA's GDGPS network station in Santiago, Chile, captured the ground motion of the quake when it struck. The data was then made available to Song within minutes of the event, and he used it to calculate the source energy for a tsunami.

Basing his conclusion on ground motion that transferred minimal kinetic energy to the ocean -- and despite the fact that the earthquake was the largest ever recorded by instruments -- Song rated the tsunami as moderate, or a 4.8 on a 10-point scale, with 10 being most destructive.

His prediction was confirmed by measurements from two joint NASA/French Space Agency satellites, called Jason-1 and Jason-2, according to NASA.

More accurate technology for tsunami prediction has become a more pressing need since the 2004 tsunami in the Indian Ocean that killed more than 200,000 people in Thailand, India, Sri Lanka, the Maldives, and Indonesia

The technology typically used in tsunami warning systems estimates an earthquake's location, depth and magnitude but does not take into consideration other factors that historically have shown to affect whether a tsunami will result from a quake, according to NASA.

Computer modeling of tsunamis has shown that both the shape of the seafloor and horizontal motions of a continental slope during a quake also contribute to whether a powerful wave will be generated, the agency said. The latter is a major component of Song's theory.