1. Progress on Early Warning Research in Taiwan
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. τc & Pd Methods
τc average period parameter of the initial three seconds P waves
For magnitude determination
Pd 0.075Hz high pass peak displacement amplitude of the initial three seconds P waves
For intensity estimation & damage identification

6. Earthquake size could be determined by τc!

8. Pd large than 0.5 cm following shakings may cause damage

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

12. Pd for regional EEW

13. Pd for magnitude determination

15. Near Source effect!

17. τc & Pd for damaging event identification!

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

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

21. Combination with modern MEMS sensor
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.

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

24. Iwate earthquake
2008/06/14 08:43:45.36
Lat.=
Long.=
Depth =7.77 km
JMA magnitude 7.2
4 stations
6.8 sec after
5.65 km
Mpd=7.45
Mtc=7.72
7 stations
7.4 sec after
4.38 km
Mpd=7.10
Mtc=7.53
11 stations
8.3 sec after
13.92km
Mpd=7.29
Mtc=7.30

25. Progress on earthquake early warning system in Taiwan

26. Real-time strong-motion network
Accelerometer -
102 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 -
102 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. Performances for VSN
0.28
5.46  6.41 km
~17 sec
4.66  4.73 km 29

30. Pd discriminator
3 sec P wave 30

31. Magnitude estimation 31

32. M 7.1 Network triggered Compute Pd Estimate M from Create shakemap
yes
VSN algorithm
from coming signals
M 7.1
2002/3/31 M 7.0
Offshore Hualien earthquake

33. M 6.4 Network triggered Compute Pd Estimate M from Create shakemap
yes
VSN algorithm
from coming signals
M 6.4
2006/4/1 M 6.5
Taitung earthquake

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 34

35. CWB seismographic network
New established stations 35

36. Preliminary test for new system
0.48  0.34
12.01  km
20.2  4.9 sec 36

37. Promotion plan in Taiwan37

38. Thanks for your attention!