London, April 22 : A team of seismologists has developed an early-warning system that can gauge how long an earthquake rumbles, thus helping tsunami warnings to reach vulnerable coastlines within minutes.

Most tsunami-warning systems work by measuring an undersea earthquake''s magnitude, because those above magnitude 7.5 are considered highly likely to generate a tsunami.

However, it takes at least 30 minutes to measure this accurately.

Previous studies have shown that quakes that shake for a long time are more likely to produce a tsunami.

Now, according to a report in New Scientist, Anthony Lomax, a consultant seismologist based in Mouans-Sartoux, France, and Alberto Michelini of the National Institute of Geophysics and Volcanology in Rome, Italy, have developed a way to spot this signature quickly.

The pair studied the seismic waves from 76 underwater earthquakes.

Sure enough, rumbles that produced high-frequency waves for more than 50 seconds had a high probability of generating a damaging tsunami wave.

Using this information, they developed an algorithm to filter out quake duration from seismic data.

If adopted in an early-warning system, “it could provide a warning within 10 to 15 minutes”, said Lomax.

“Used alongside other methods it could be promising,” said Emile Okal, a seismologist at Northwestern University in Evanston, Illinois.

The work will appear in Geophysical Research Letters. (ANI)