No country needs an effective earthquake-warning system more than Japan, with its dizzyingly dense population and constant barrage of earthquakes (more than a thousand of them strong enough to feel every year). By this spring they may finally have one—the first national system in the world.
If all goes according to plan, a network of nearly 1,000 seismometers deployed around the archipelago will pick up "P-waves," the fast-moving seismic grumbles that herald major quakes. A Japan Meteorological Agency computer will then determine the quake's epicenter and strength, providing a warning of up to 30 seconds. And not just any warning: In addition to general broadcast alerts, a server system will beam the timing and expected strength of the coming quake directly into households as well as to railway operators, fire departments, and other key institutions. Closer to the epicenter the warning time may be much shorter, but in a major ...
