In October 2007, Japan launches its publicly available earthquake early warning system adding to the growing list of nations using early warning technology to mitigate seismic hazard. This website introduces the operation and management of the Japanese earthquake early warning system and public reaction to the system. It is my personal website and I am not responsible for the translation. Please refer to the original link for the precise information.

Index 1 What will happen in October 2007? 2 How can public people get the alert? 3 How much information can public people get? 4 What happened if public people are not watching NHK channel? 5 Can public people get the earthquake early warning except TV and radio? 6 What is the criterion to provide the warning on TV and radio? 7 Is there any system to provide more detailed information? 8 What is the algorithm? 9 How much do people understand the system? 10 Are there any examples of the warning so far?

What will happen in October 2007?

The Japan Meteorological Agency (JMA) starts providing the earthquake early warning (EEW) to the public in October 2007. They have run testing operation for limited users from 2004, and decided to open to general public. The warning is issued to all the public via TV and radio from October 2007.

• JMA website on EEW
• Movie explaining EEW (JMA)

How can public people get the alert?

NHK (national news channel) will broadcast the alerts via TV and radio. The message is inserted on the TV screen when the warning is issued. Radio immediately stops the regular program and broadcast the warning with alarm and voice.

• About broadcasting EEW (NHK) (in Japanese)

How much information can public people get?

The information includes the area subjected strong shaking (greater than JMA seismic intensity 5-) and location of the epicenter. The warning will not be updated to avoid confusion. ref. http://www.nhk.or.jp/nagano/eve/hatena/index.html

What happened if public people are not watching NHK channel?

Other private channels are preparing the broadcast of the early warning right now. People may not receive the warning if they are not watching TV or radio.

• Article about an action of other TV channels (Asahi.com) (in Japanese)

Can public people get the earthquake early warning except TV and radio?

Mobile phone companies are developing the service to provide the early warning via text message right now. At least NTT docomo and KDDI are working on the system. Softbank mobile also announced they will provide it by the end of 2007.
Some weather forecast companies are providing the online based warning. Uses need to install the software the company provide and subscribe the service to receive the warning with monthly fee.
Some local governments provide the earthquake early warning via community wireless system.

• Article about mobile service (Impress Watch Corporation) (in Japanese)
• Example of the community wireless system (JMA) (in Japanese)

What is the criterion to provide the warning on TV and radio?

JMA issues the warning if the ground motion is observed by more than 2 stations and the maximum JMA seismic intensity is estimated greater than 5-.

• Criterion to issue the warning (JMA) (in Japanese)

Is there any system to provide more detailed information?

JMA has two different type of information. One is provided for general users via TV and radio. The other targets special uses, who are more sensitive to the accuracy of the warning. The second type warning provides more information such as earthquake magnitude, hypocenter location, estimated seismic intensity at a given site, etc. The information is updated every second. JMA proides these information to the early warning probiders. In order to receive this type of warning, people need to buy an instrument and subscribe the service from probiders.

• How to obtain the alert? (JMA) (in Japanese)

What is the algorithm?

Please refer to the publications below.

• Algorithm (JMA) (in Japanese)
• Horiuchi. S., H. Negishi, K. Abe, A. Kamimura, and Y. Fujinawa. An Automatic Processing System for Broadcasting Earthquake Alarms, Bulletin of the Seismological Society of America, 2005; 95, pp.708-718.
• Odaka, T., K. Ashiya, S. Tsukada, S, Sato, K. Ohtake and D. Nozaka. A new method of quickly estimating epicentral distance and magnitude form a single seismic record, Bulletin of the Seismological Society of America, 2003; 93, pp.526-532.

How much do people understand the system?

According to the survey done by JMA in May 2007, 84% of the public people know the name of the system. 33% of the public people understand the system correctly. My impression is the understanding has been improved since TV and newspaper are advertising the system very frequently.

• Public survey (JMA) (in Japanese)
• 1. Do you know the name of the earthquake early warning?
  Yes --- 35%
  I have heard of --- 49%
  No --- 16%
  
• 2. If you know, what is that?
  The information about the strong shaking estimated from the first motion. --- 39%
  The information about the earthquake predicted before the rupture initiation. --- 20%
  The real-time information about the observed seismic intensity. --- 25%
  The real-time information about the seismic damage. --- 5%
  Not sure. --- 11%
  
• 3. Do you know when it will start?
  This fall. --- 8%
  Next spring. --- 1%
  Already started. --- 23%
  Not sure. --- 68%
  

Are there any examples of the warning so far?

Please refer to the following links.

• Warnings issued by JMA after August 2006 (JMA) (in Japanese)
• In 2004 Niigata-ken Chuetsu earthquake, Meisei electric co. recorded a video showing the warning issued before the S-wave arrival in the factory. Movie (Meisei electric co.) (in Japanese, Flash Player needed)
  
• In 2007 Niigata-ken Chuetsu-oki earthquake, one family living in Tokyo recorded a video showing the early warning system was working. Movie (youtube)