The Comprehensive Nuclear-Test-Ban Treaty Organization monitoring center in Vienna, Austria, a worldwide network of seismographs and other sensors designed to detect nuclear blasts, can be used to provide fast, reliable warnings of earthquakes, says Milton Garces of the University of Hawaii at Manoa.

The center spotted the most recent Japanese quakes, and alerted Indonesia and other governments to the quake off Sumatra that caused the 2004 tsunami.

The current monitoring system includes arrays of sensors at 60 sites across the world that listen for the low boom of atmospheric blasts. They are tuned to infrasound-frequencies under 20 Hertz (cycles per second), the lowest humans can hear.

The infrasound signals generated by tsunami-making quakes travel at up to 330 meters per second, while the tsunamis themselves propagate at about 260 meters per second, so the sound signal will arrive at monitoring stations before the wave hits.

Garces thinks this might be used to make a tsunami warning system — if the monitoring network is maintained by international treaty.