Tokyo ward mistakenly e-mails citizens of earthquake

A routine test of an earthquake information system in Tokyo on Friday mistakenly notified citizens about an earthquake that hadn't occurred.

Subscribers to a cell phone e-mail service provided by Tokyo's Minato ward received messages just after 1pm that a "moderately strong earthquake" had been registered at the city hall. "Beware of aftershocks. Check that fire-prone areas are secure and remain calm," read the e-mail which said the quake had registered 4 on the Japanese scale.

A quake of that level is capable of frightening many people, considerably swaying hanging objects and noticeable to people walking on the street and driving cars. However the 1,800 subscribers to the ward's e-mail service were likely more puzzled than frightened when the message came.

"We were testing the system and we mistakenly sent out an e-mail," said an official at the ward's disaster prevention office. Officials sent out a second e-mail a few minutes later notifying subscribers of the error.

Japan is one of the world's most earthquake-prone countries and tremors happen someone in the country on a daily basis. Earthquake information systems are highly advanced and TV stations automatically flash news within minutes of a quake occurring. Yahoo Japan Corp. has also begun to carry information on its site, replacing all the banner ads with information when a strong quake occurs.

Last year testing began of a new system that is capable of giving people several seconds warning of an impending temblor. The system catches fast moving but low energy P-waves from a quake and quickly calculates the earthquake's source and strength. Then it can map where the more destructive S-waves will be felt at what time and at what strength.

The system could provide anything from a few seconds to a minute's warning of shaking from a major earthquake -- long enough to bring trains to a halt, cut gas supplies and stop factory production lines.