Progress on Early Warning Research in Taiwan

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Progress on Early Warning Research in Taiwan

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

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Topics

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

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Earthquake occurs, you may think about

• Large earthquake?
• Cause damage?
• Is this place safe?

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tc Pd Methods

• tc 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

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Earthquake size could be determined by tc!
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Pd large than 0.5 cm following shakings may cause
damage
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PGV could be predicted by Pd and then Shaking
Intensity could be predicted!
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Pd for regional EEW
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Pd for magnitude determination
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Near Source effect!
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tc Pd for damaging event identification!
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1999 Chi-Chi
2003 Chengkung
1999 Chiayi
1998 Reuyli
1994 Nanoa
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Warning could be given within one second after P
arrival!
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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.
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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 200808_evts.txt
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Iwate earthquake 2008/06/14 084345.36 Lat.39.0298 Long.140.8807 Depth 7.77 km JMA magnitude 7.2 4 stations 6.8 sec after 38.9905 140.8262 5.65 km Mpd7.45 Mtc7.72 7 stations 7.4 sec after 39.0804 140.9413 4.38 km Mpd7.10 Mtc7.53 11 stations 8.3 sec after 39.0393 140.8726 13.92km Mpd7.29 Mtc7.30
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Progress on earthquake early warning system in
Taiwan
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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

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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

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Virtual sub-network approach
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Performances for VSN
0.28
5.46 ? 6.41 km
17 sec
4.66 ? 4.73 km
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Pd discriminator
3 sec P wave
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Magnitude estimation
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M 7.1
2002/3/31 M 7.0 Offshore Hualien earthquake
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M 6.4
2006/4/1 M 6.5 Taitung earthquake
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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

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CWB seismographic network
New established stations
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Preliminary test for new system
0.48 ? 0.34
12.01 ? 13.01 km
20.2 ? 4.9 sec
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Promotion plan in Taiwan
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Thanks for your attention!