University researchers are using GPS to almost instantly determine whether an earthquake is big enough to generate an oceanwide tsunami.

A team at the University of Nevada's Bureau of Mines and Geology and Seismological Laboratory and Northwestern University in Evanston, Ill., recently demonstrated that a large quake's true size can be determined within 15 minutes using GPS data.

“We need to know immediately whether the earthquake is giant enough to produce a huge tsunami,” said Northwestern geologist Seth Stein.

Warning centers have only a few minutes to decide whether to issue alerts so emergency response authorities in affected areas have time to react. It can take two hours to make this determination with conventional technology, unacceptable when you consider tsunamis travel at the speed of a jetliner. The 2004 Sumatra tsunami reached Sri Lanka in two hours.

“At the same time, we don't want to issue false alarms that incite panic, because then people might ignore legitimate alarms,” Stein said.

The new scheme, called GPS displacement, combines GPS with seismometer and ocean buoy data. GPS displacement works by measuring the time radio signals from GPS satellites arrive at ground stations located even thousand of kilometers from a quake epicenter. From this data, scientists can calculate how far the stations moved due to the quake. They can then derive an earthquake model and the quake's true size, called its “moment magnitude,” which is directly related to a quake's potential for generating tsunamis.

The math part is complete. What remains is finding finances for an operational organization.