As representatives from around the world gathered in Kobe, Japan, to discuss earthquakes and tsunamis, a magnitude 6.8 earthquake hit the sea some 200 km southeast of Tokyo. Within minutes, Japan's warning system had kicked in, broadcasting a message on television screens across the country saying that the quake would not cause dangerous waves for those on land, but that there was limited danger for those in the water.

Most tsunami experts agree that nowhere is more prepared for tsunamis than Japan, which gets hit by damaging waves roughly once every seven years. “It's the best-prepared nation both in terms of hardware and general awareness,” says Laura Kong, director of the International Tsunami Information Center in Honolulu, Hawaii.

Earthquakes are detected within two minutes by seismic monitors all around the country. Seismic information is quickly fed into a computer simulation that contains 100,000 pre-calculated outcomes for earthquakes of various magnitudes and depths at 4,000 different locations. One minute later, one of six regional centres, staffed around the clock, can disseminate warnings by TV or radio.

For tsunamis triggered by earthquakes farther away, Japan is helped by the Pacific Tsunami Warning Center in Hawaii — a US system consisting of six seafloor pressure sensors — which triggers alarms for Pacific nations. This is the only oceanic tsunami warning system currently in place. It has won plaudits for detecting tsunamis and evaluating the danger — it was successfully used to cancel a tsunami warning and prevent an evacuation in Hawaii in November 2003, for example. But it isn't perfect: three of its six buoys have been out of commission since at least September 2004; one has been down for 18 months. The United States plans to upgrade the system to 38 buoys across the Pacific, Atlantic and Caribbean by mid-2007.

But despite all this investment, Pacific nations still face the problem of human error. Tohoku University tsunami specialist Fumihiko Imamura notes that even when tsunami warnings are issued in Japan, people go to the beach to watch.