Department of Civil and Environmental EngineeringTokyo Institute of Technology, Tokyo, JAPAN

Lee Boon HonMasachika Tanigawa

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Outline

1. Earthquakes and the impacts in Japan

2. Methods of prediction

3. Emergency Early Warning (EEW) System

4. Summary and conclusions2

1. Earthquakes and the impacts in Japan

Many major earthquakes have occurred at plate boundaries.

1.1. Map of tectonic plates

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1.2. Examples of recent major earthquakes in Japan

Great Hanshin

Earthquake (1995)

Mid Niigata Prefecture Earthquake

(2004)

Iwate-Miyagi Nairiku

Earthquake (2008)

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Great Hanshin earthquake

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Hanshin EXPWY

Hanshin line

1.3. Details of the earthquakes

Great Hanshin

Earthquake (1995)

Mid Niigata Prefecture Earthquake

(2004)

Iwate-Miyagi Nairiku

Earthquake (2008)

JMA magnitude

M7.3 M6.8 M7.2

Fatalities 6,437 68 12

Disappearances

3 --- 12

Casualties 43,792 4,805 433

Evacuees > 300,000 > 103,000 Not available

Damage (Yen)

10 trillion 3 trillion 0.14 trillion

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2. Methods of prediction

2.1. Non technical methods

2.2. Seismicity pattern

2.3. Earthquake early warning (EEW) system

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2.1. Non technical methods (1/2)

Abnormal animal behavior

Unusual phenomena in weather and the earth ‘s

crust

• Snakes came out from hibernation• Usually unseen bats flew in a group• Huge number of bream being caught (Awaji-island)

• Milky water came out from hot spring source• Orange and blue flash shined like aurora for around 4 seconds and noise from earth is heard (west area of Kobe)

Predicting earthquakes by observing abnormal events in nature

For example, during the Great Hanshin Earthquake, following events have been observed:

2.1. Non technical methods (2/2) 1975 Haicheng earthquake in China : M7.2 ~

1,300 fatalities Abnormal events were observed and earthquake

warning had been sent out 9 hours before the real event.

(large group of rats running together, chickens flew in a group, water spilled out from wells)

BUT 1976 Tangshan Earthquake in China : M7.8 ~

242,419 fatalities Failed prediction causing a large number of fatalities.

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Number of fatalities can be hugely reduced if earthquake can be successfully predicted

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Seismicity pattern of Kanto area

Seismologists believe that earthquakes occur in a cyclic pattern

As the time span is too large, the exact time cannot be predicted

2.3 Emergency early warning (EEW) system

Predicting earthquake after receiving some early signals from ground movement

Send out real time early warning Japan is now applying EEW system Similar kind of projects

Mexico, Taiwan, California, SAFER (Seismic eArly warning For EuRope) project at Europe

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Information before strong ground shaking

3. Emergency Early Warning (EEW) system

3.1 Concept of EEW

3.2 Brief history of EEW

3.3 Information system of EEW

3.4 Examples 0f EEW application

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3.1. Concept of EEW

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Predicting earthquakes by detecting primary waves

3.1. Concept of EEW

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●： JMA 、●： Hi-net (NIED) >1000 stations with a spacing of 20km

NIED: National Research Institute for Earth Science and Disaster Prevention

Stations used for EEW

3.2. Brief history of EEW

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1992- Development of EEW technology ( with Railway Technical Research Institute )

Feb 2004 Start of trial provision ( for Kanto area )

Mar 2005 Expansion of trial provision area ( for North-Japan area )

Jun 2005Integrated use of ‘Not Yet Arrived Data Method’ ( Algorithm Developed at NIED into EEW )

Mar 2006 Expansion of trial provision area ( for whole country )

Aug 2006 Start of interim provision to registered corporations

Oct 2007 Start of provision to the public

3.3. Information system of EEW

Announcement through TV and Radio

Announcement by local authorities

Announcement at public places (shopping mall etc)

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3.4. Example of EEW application

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3.4. Examples of EEW application

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3.5. Pros and cons of EEW

ReliableConsistent

Short warning time

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4. Summary and conclusions

Study of animal behavior is not dependable

Seismicity pattern is not accurate

Prediction and warning can save many lives, but accurate prediction is difficult

Insufficient time to evacuate in EEW system

Knowledge on earthquake mechanism is not enough

World’s largest shaking table in Miki City, Hyogo-prefecture, JAPAN

More research is essential20

Thank you for your attention

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