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Yih-Min Wu National Taiwan University Hiroo Kanamori Caltech Nai-Chi Hsiao Central Weather Bureau, Taiwan.

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Presentation on theme: "Yih-Min Wu National Taiwan University Hiroo Kanamori Caltech Nai-Chi Hsiao Central Weather Bureau, Taiwan."— Presentation transcript:

1 Yih-Min Wu National Taiwan University Hiroo Kanamori Caltech Nai-Chi Hsiao Central Weather Bureau, Taiwan

2 Topics P waves method for earthquake early warning Progress on earthquake early warning system in Taiwan

3 Earthquake occurs, you may think about Large earthquake? Cause damage? Is this place safe?

4 τ c & P d Methods τ c τ c average period parameter of the initial three seconds P waves For magnitude determination P d P d 0.075Hz high pass peak displacement amplitude of the initial three seconds P waves For intensity estimation & damage identification

5

6 Earthquake size could be determined by τ c !

7

8 Pd large than 0.5 cm following shakings may cause damage

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10 PGV could be predicted by Pd and then Shaking Intensity could be predicted!

11

12 for regional EEW P d for regional EEW

13 Pd for magnitude determination

14

15 Near Source effect!

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17 τ c & Pd for damaging event identification!

18 1999 Chi-Chi 2003 Chengkung 1998 Reuyli 1999 Chiayi 1994 Nanoa

19 Warning could be given within one second after P arrival!

20

21 Combination with modern MEMS sensor. Cheaper device may install to every building to give warning within three seconds after P arrival after a large earthquake occurs.

22

23 Imports Picks Scream2ew-BB PICK_RING WAVE_RING1 Import_Wave Import_Smart24 WAVE_RING2 WAVE_RING3 Scn2scnl WAVE_RING4 Sniffring4eew.c sniffwave4eew Share Memory TcPd.c Report _evts.txt Earthworm sniffwave4eew Sniffwave4eew.c SimuSac.c Historical SAC Records

24 Iwate earthquake 2008/06/14 08:43:45.36 Lat.= Long.= Depth =7.77 km JMA magnitude stations 6.8 sec after km Mpd=7.45 Mtc= stations 7.4 sec after km Mpd=7.10 Mtc= stations 8.3 sec after km Mpd=7.29 Mtc=7.30

25 Progress on earthquake early warning system in Taiwan

26 Real-time strong-motion network Accelerometer stations (20km averaged spacing) 16 bits resolution ± 2g Max. amplitude Telemetry - Real-time data stream (RTD) 4.8K dedicated telephone line Sampling rate 50 sps 0.2 sec averaged delay Data processing - Taipei data center Windows-based workstation

27 Real-time strong-motion network Accelerometer stations (20km averaged spacing) 16 bits resolution ± 2g Max. amplitude Telemetry - Real-time data stream (RTD) 4.8K dedicated telephone line Sampling rate 50 sps 0.2 sec averaged delay Data processing - Taipei data center Windows-based workstation

28 Virtual sub-network approach

29 29 Performances for VSN 0.28 ~17 sec km km

30 30 Pd discriminator 3 sec P wave

31 31 Magnitude estimation

32 Network triggered Compute Pd Pd > 0.1 Estimate M from M > 6.0 Create shakemap yes VSN algorithm from coming signals yes M /3/31 M 7.0 Offshore Hualien earthquake

33 Network triggered Compute Pd Pd > 0.1 Estimate M from M > 6.0 Create shakemap yes VSN algorithm from coming signals yes M /4/1 M 6.5 Taitung earthquake

34 34 New proposed EEW system All seismographs installed by CWB are included for EEW evaluation Use the Earthworm as the platform of different seismic data format integration Both VSN and P waves methods

35 35 CWB seismographic network New established stations

36 36 Preliminary test for new system km sec

37 37 Promotion plan in Taiwan

38 Thanks for your attention!


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