Sensors - An Earthquake Early Warning System

Researchers in Japan, one of the world’s most earthquake-prone countries, have developed a network that can provide several seconds’ warning that violent seismic shaking is about to commence.

The network, coordinated by the Japan Meteorological Agency (JMA), is expected to go into full operation later this year. It could provide anything from a few seconds’ to a minute’s warning of a major earthquake—long enough to bring trains to a halt, cut off gas supplies or stop factory production lines. How much warning people have will depend on how far they are from the earthquake; locations nearer the epicenter, which are likely to be shaken the most, will get the least warning. But researchers agree that any warning is better than none.

Earthquakes generate two main types of waves, called primary waves (P-waves) and secondary waves (S-waves). The P-waves travel at about twice the speed of the S-waves and are typically weaker. But by quickly detecting, measuring and analyzing the P-waves using a network of sensors, researchers can estimate the earthquake’s source and strength. This data can help researchers predict when the potentially destructive S-waves will be felt and how strong they will be. The data can then be used to deliver electronic warnings to offices, factories or people’s homes.

The JMA maintains a network of about 200 earthquake monitoring stations across Japan that collect the sensor data. Several companies have developed systems for homes and offices that use the JMA’s data to generate warnings and distribute them via the Internet.

One of the simplest comes from Tecs, which developed software that can be installed inside some Canon photocopiers. The software uses the copier’s network connection to maintain an Internet link with a server containing data from the JMA. When an earthquake is about to occur, the software can sound an alarm and also flash warnings on PCs connected to the office network, so long as they have a companion software application installed, says Shouji Nihei, a Tecs employee.

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Copyright © 2006 IDG Communications, Inc.

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