Early warning system fails again as M6.7 quake hits Tokyo, Ibaraki, Saitama and Chiba

Thursday 08th May, 02:49 PM JST

TOKYO —

An earthquake with a magnitude of 7.0 hit extensive areas centering on the Kanto region including Tokyo in the early hours of Thursday injuring six people, with an early warning failing to be issued in time again. The six people in Tokyo, Ibaraki, Saitama and Chiba prefectures sustained minor injuries due to the 1:45 a.m. quake, according to the government’s Fire and Disaster Management Agency.

The quake measured lower 5 on the Japanese seismic intensity scale of 7 in Mito, Ibaraki Prefecture, and Motegi, Tochigi Prefecture, the Japan Mete, the Japan Meteorological Agency said. No tsunamis were reported.

The meteorological agency’s early warning system for major quakes made an announcement 58 seconds after preliminary tremors were detected.

When an earthquake jolted Miyako Island, Okinawa Prefecture, and its vicinity on April 28, the agency announced a quake intensity warning for the first time since its introduction last October but the warning was not issued before the arrival of the quake’s principal motion.

Takashi Yokota, the head of the agency’s Earthquake and Tsunami Observation Division, said the agency will study the feasibility of improving the methods for calculating magnitude because its initial underestimation of the 1:45 a.m. quake was behind the delay in Thursday’s issuance of an early warning.

The early warning system is designed to predict how strong the intensity of a quake may grow—as soon as possible before the quake actually shakes a region—and it is supposed to be activated when intensity is expected to be at a level of lower 5 or above.

Weaker temblors were felt in extensive areas including Tokyo, where the quake registered 3 on the Japanese scale.

The focus of the quake was around 51 kilometers below the surface of the sea in the Pacific off the coast of Ibaraki Prefecture.

The meteorological agency initially estimated the quake’s magnitude at 6.7 and the depth of the focus at 40 kilometers but later revised those figures.

Latest 15 of 37 Total Comments Show All

ebisen at 04:41 PM JST - 8th May

In our room we have a very nice "wind bell" "風鈴" made from four hanging long metallic tubes with a heavy metallic disk hanged between them. It is the best "early warning system" as it started ringing at least 30 seconds before the really big tremors and shakes came AND before I noticed what was happening. Also in our area (Nerima) it was mostly horizontal movement as opposed to the (more dangeourous) vertical ones.
smithinjapan at 04:53 PM JST - 8th May

It's not a question of if, but when... if you'll allow the overuse of a factual statement. It doesn't mean people on the 22nd floor of a building should suddenly vacate and find 'safer' ground -- there is no safe ground at all in Japan. People seem to congregate, build, and congest in areas prone to, or expecting, natural disasters, but in Japan what can you do? I'll admit it's incredibly stupid to build the world's biggest nuclear reactors on major fault lines, but as for living, not much you can do in this country but pray it doesn't happen at the 'wrong time'.

As for me, I personally think there's an earthquake every time a medium size car drives by my house... which goes to show you how safe my place is. About the best anyone can do here is prepare for the earthquakes/volcanoes/tsunami/typhoons/landslides and hope their emergency packs are reachable when the time comes. As for being safe in 'the sticks', you're not safe there at all if a major fissure opens up beneath you.
Himajin at 05:15 PM JST - 8th May

> Next time you may be tumbling 22 floors to the ground. >

Yeah Sarge, but if he lives on the 1st floor those 22 will come down on top of his head ;-) Can't win!
Sarge at 05:30 PM JST - 8th May

Hima - Exactly, exactly! That's why I wouldn't live in a building with 22 floors.
Farmboy at 05:51 PM JST - 8th May

So does anyone know if it was a magnitude 7, as it says at the top of the article, or a magnitude 6.7, as it says in the title. Or was it initially estimated at 6.7, and then revised upward?
Farmboy at 05:54 PM JST - 8th May

PS: The USGS has it at 6.8... http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008rtbu.php
VOR at 08:08 PM JST - 8th May

I'm jealous. I slept like a baby last night.

The Kanto Plains is overdue. Maybe this is it?
capone at 08:14 PM JST - 8th May

so the early warning system is now 0-for-2 ...nice
northlondon at 10:18 PM JST - 8th May

PS: The USGS has it at 6.8... http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008rtbu.php

That guarantees it as a 7 for me then.
jipster at 11:03 PM JST - 8th May

I enjoyed it in Ibaraki..but i am one of the injury statistics..alarm clock fell on my foot. cant help that the media are giving these early warning guys a hard time..if you look at the complexity of the geology of the earth and all the science involved its not surprising they didn't get it right the first few times..not like you can ask tectonic plates for a quick test run. and the warning system is only ever going to be a few seconds 'bing bong bing bong'..oops too late
Alfie_in_Tokyo at 11:36 PM JST - 8th May

Part of the reason the long-wave tremors go on for so long here in Tokyo sometimes, longer than in other parts of Japan, is because of the nature of the Kanto Plain: large area of softer material sitting in a dip in the bedrock. The shock waves move easily through it and go on for longer than through solid rock. Makes the whole potential scenario for a big one here even more interesting when it comes.
northlondon at 11:47 PM JST - 8th May

Alfie,

I would have thought the reason why we feel these shockwaves late at night for longer here in Tokyo, is because the more modern buildings that we live in are built on the roller base system which makes our more modern Tokyo buildings 'ride' the tremor ? I don't think it's because of the soft bedrock.
presidentbaka at 03:52 PM JST - 9th May

ebisen:

In our room we have a very nice "wind bell" "風鈴" made from four hanging long metallic tubes with a heavy metallic disk hanged between them.

Yep, me too, only mine is charcoal sticks. Best early warning system there is!
Orangeporange at 09:05 PM JST - 9th May

That's it! I am getting a windbell and putting it in our bedroom! The earthquake on Thursday morning was scary here in Chiba, had the dishes clanging and windows rattling. My husband covered my daughter while I ran for the door. He grabbed one of my skirts to cover himself up, grabbed the girl and we were out the door (1st floor of a 5 story building on reclaimed land so we ARE NOT taking any chances!) We were out before the bigger tremors hit. I must say it was good practice should it have been "the big one".
romulus3 at 12:27 AM JST - 10th May

yeah well you are all screwed if you don't have a survival bag with water, dried or canned foods, torch, some kind of blankets and perhaps first aide kit with you once you get outside. In a mass disaster I assure you its gaijins last. prepare to look after yourselves.