Quake warning system provided seconds of notice for Tokyo

An advanced network of more than a thousand seismographs can provide seconds of warning before a major quake

A one-of-its-kind early warning system provided seconds of advance notice to many residents of Tokyo shortly before a massive earthquake rocked the Japanese capital on Friday afternoon.

The system went into operation in 2007 and links more than a thousand seismographs across Japan. Each location is linked to a central computer that attempts to detect the weak but fast-moving primary waves that are generated by an earthquake and use them to triangulate the location of the quake and estimate its size.

The amount of warning provided depends on the distance from the earthquake's epicenter. Those closest to the source of the quake and susceptible to the strongest shaking get little or no warning. The warnings begin to make a difference around 50 to 100 kilometers from the epicenter of a strong quake, where up to 30 seconds warning can be provided.

That may not sound like much, but it's enough time to bring high-speed trains to an emergency halt, stop factory production lines and get schoolchildren under their desks.

On Friday afternoon, the system sprung into action and a warning flashed automatically on television screens. The first waves of shaking from the quake arrived in Tokyo about 10 seconds later, said people who had televisions on at the time.

A recording of the warning as it appeared during a live broadcast from Japan's parliament, has been posted to YouTube. The warning appears at the 8-second mark, and the shaking can be seen beginning about 40 seconds later and continues to build for about 2 minutes.

The same system also extends to the cell phone network, but on Friday many phones did not sound a warning until after the shaking had stopped.

Japan is one of the most seismically active nations on earth, with about 100,000 earthquakes occurring in and around the country each year. But few come even close to the power of Friday's earthquake.

The temblor was centered about 10 kilometers under the Pacific Ocean and triggered a 7-meter tidal wave that obliterated several coastal communities. Several hundred people are reported dead and public broadcaster NHK said the death toll could rise to over 1,300.

Japan's Meteorological Agency measured it at magnitude 8.8, making it the largest since the country started keeping records in the 1800s. The U.S. Geological Survey estimated its strength at magnitude 8.9.

In 1923, Tokyo was largely destroyed and up to 142,000 people were killed by a quake that was estimated at between magnitude 7.9 and 8.4. In 1995, a magnitude 7.3 quake caused widespread destruction in the western Japanese city of Kobe and killed 6,434 people.

Martyn Williams covers Japan and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is martyn_williams@idg.com

Tags NTT DoCoMotelecommunicationKDDIJapan earthquakeNTT EastSoftbank

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Martyn Williams

IDG News Service

Comments

Comments are now closed.

Most Popular Reviews

Follow Us

Best Deals on GoodGearGuide

Shopping.com

Latest News Articles

Resources

GGG Evaluation Team

Kathy Cassidy

STYLISTIC Q702

First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni

STYLISTIC Q572

For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell

LIFEBOOK UH574

The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi

STYLISTIC Q702

The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott

STYLISTIC Q702

My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.

Latest Jobs

Shopping.com

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?