The 2nd International Workshop on Earthquake Early Warning- 2009 in Kyoto, Japan -Earthquake Early Warning and Realtime Earthquake Disaster Prevention
Yutaka Nakamura1,2
1. System and Data Research, Kunitachi, Tokyo, Japan
2. Tokyo Institute of Technology, Tokyo, Japan

Obviously, the basic of the earthquake disaster prevention is the strengthening against the earthquake
load.

The devastations caused by the Sichuan Earthquake in May 2008 were mainly based on thelack of the strength of the many facilities and structures.

However, in case of the facilities

functional with moving themselves as transportation system, because it will be unstable during theearthquake motion, it is necessary to escape from the situation as meeting with the large earthquake
motion during the system working.

The earthquake early warning is one of the triggers of the realtime earthquake disaster prevention.
UrEDAS is the first single station system for early warning in the world which is used actually atlater 1980’s.

UrEDAS processes almost same procedure whether an earthquake occurs or not, sothe system should not fail caused by the process enlargement and conflict because of the earthquake
detections. The processing time become to less than one second now, our products can issue thealarm minimum 0.1 seconds after the P-wave detection if necessary.

The data integration centercan make the accuracy of the earthquake information higher with integrating the multiple UrEDAS
data and it will be useful for the response after the earthquake. And the center does not need toanalyze large amount of the waveform data so even small computer system can integrate manyobservation sites.

The EEW by JMA is issued from the integrated system of the multi station system of NIED and thesingle station system of JMA.

According to the process time, 5.4 seconds in average, andtelecommunication time, 1-2 seconds, it is almost impossible to issue the EEW by JMA for thepossible epicentral damaged area before the large earthquake motion of the close earthquake
including epicentral earthquake.

Exact earthquake information is the critical information to estimate the serious damaged area andalso the information to realize the rational and quick response just after the event.

Earthquake

observation system for the scientific research will be useful for the estimation of the exact locationof the events like CUBE. The reason that UrEDAS estimates roughly the earthquake parameter isThe 2nd International Workshop on Earthquake Early Warning- 2009 in Kyoto, Japan -for the rational dissolving of the warning and the response reasonably after the earthquake.
However the information included in the EEW by JMA is only the forecast so it is impossible toapply as the information for the response after the event.

Public organizations should deliver theinformation on the earthquake parameters of not only the main shock but also aftershocks in realtime.
From the viewpoint of the earthquake disaster prevention, it is more important to deliver the accurate
earthquake information rather than to deliver the “later” early warning.

For the rational and quick

response after the earthquake, the actual observed seismic intensity, not the estimated value, must be
the important information.

The earthquake early warning is not information for disaster prevention to be provided exclusively
as a national project. The earthquake information can be realized in diverse ways and should berealized.

There is a high possibility for the catastrophic damaged area in focal region to be required

the rescue activities of the local government around there and of national organizations.

Hence,

what to do for national organizations is to estimate the catastrophic damaged area accurately and to
go to rescue, and the responsible organizations must issue the information for this purpose in
realtime.

The source of the information is not limited to JMA, and local universities and research

institutes must be considerd.

Several regulations by JMA under a law for providing the earthquake

Processing Time for Alarm in seconds

information must be reconsidered from the viewpoints of the useful disaster mitigation.

10

RTRI: prototype UrEDAS

JMA:Realtime Process
4 sIntermitting
Process
5.4 s
in average
2 s
at the minimum

SDR:
1Realtime Process
for actual use
UrEDAS: 3 sCompact UrEDAS: 1 s
FREQL: New Generation EEW
1s for UrEDAS function since 2005
minimum 0.1 sfor Compact UrEDAS function
since April of 2009

0.1
1980

1985

1990

1995

2000

2005

2010

AD (year)
Comparison of Processing Times for Warning by several Institutes

2015