Department of Civil and Environmental Engineering Tokyo Institute of Technology, Tokyo, JAPAN Lee Boon Hon Masachika Tanigawa 1

Outline 1. Earthquakes and the impacts in Japan 2. Methods of prediction 3. Emergency Early Warning (EEW) System 4. Summary and conclusions 2

1. Earthquakes and the impacts in Japan  Many major earthquakes have occurred at plate boundaries Map of tectonic plates 3

1.2. Examples of recent major earthquakes in Japan Great Hanshin Earthquake (1995) Mid Niigata Prefecture Earthquake (2004) Iwate-Miyagi Nairiku Earthquake (2008) 4

Great Hanshin earthquake 5 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 magnitudeM7.3M6.8M7.2 Fatalities6, Disappearances Casualties43,7924, Evacuees> 300,000> 103,000Not available Damage (Yen)10 trillion3 trillion0.14 trillion 6

2. Methods of prediction 2.1. Non technical methods 2.2. Seismicity pattern 2.3. Earthquake early warning (EEW) system 7

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

10 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 11 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 12

3.1. Concept of EEW 13 Predicting earthquakes by detecting primary waves

3.1. Concept of EEW 14 ● ： 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 Development of EEW technology ( with Railway Technical Research Institute ) Feb 2004Start of trial provision ( for Kanto area ) Mar 2005Expansion of trial provision area ( for North-Japan area ) Jun 2005 Integrated use of ‘Not Yet Arrived Data Method’ ( Algorithm Developed at NIED into EEW ) Mar 2006Expansion of trial provision area ( for whole country ) Aug 2006Start of interim provision to registered corporations Oct 2007Start 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) 16

3.4. Example of EEW application 17

3.4. Examples of EEW application 18

3.5. Pros and cons of EEW Reliable Consistent Short warning time 19

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 essential 20

Thank you for your attention 21