Yih-Min Wu National Taiwan UniversityHiroo Kanamori CaltechNai-Chi HsiaoCentral Weather Bureau, Taiwan

Topics

P waves method for earthquake early warning

Progress on earthquake early warning system in Taiwan

Earthquake occurs, you may think about

Large earthquake? Cause damage? Is this place safe?

τc & Pd Methods

ττcc average period parameter of the initial three seconds P waves For magnitude determination

PPdd 0.075Hz high pass peak displacement amplitude of the initial three seconds P waves For intensity estimation & damage

identification

- 3 0 3 6 9 1 2 1 5 1 8 2 1

Tim e after P arrival (second)

-12

-8

-4

0

4

8

Dis

pla

ce

me

nt

(cm

)

-20

-10

0

10

20

Ve

loci

ty (

cm

/se

c)

-200

0

200

400

Ac

ce

lera

tio

n (

ga

l)

Pd

PGA

PGV

PGD

c

M w6.6, focal depth 10 kmKnet Station NIG018Epicentral distance 14 km

0.5 cm

Pd threshold warning

Earthquake size could be determined by τc!

4 5 6 7 8

M w

0 . 1

1

1 0

c (

sec)

Taiwan 11 eventsSouthern California 26 eventsJapan 17 events

log (c) = 0.296 M w - 1.716Sdv=0.122, R=0.933

Pd large than 0.5 cm following shakings may cause damage

0.01 0.1 1 10

Pd, Displacem ent (cm )

0.1

1

10

100

Fil

tere

d P

GD

(cm

)

No dam age records (168)No dam age events average (21)Damage records (40)Damage events average (5)

0.5 cm

4 cm

Chi-Chi

PGV could be predicted by Pd and then Shaking Intensity could

be predicted!

0.001 0.01 0.1 1 10Pd (cm)

0 . 1

1

1 0

1 0 0

PG

V (

cm/s

ec)

Taiwan 507 recordsSouthern California 199 recordsJapan 74 records

Linear regression over 780 recordslog(PGV)=0.920 log(Pd) + 1.642SDV = 0.326

Pd for regional EEWfor regional EEW

Pd for magnitude determination

1 0 1 0 0Hypocentral Distance (km)

0.001

0.01

0.1

1

Pd

(cm

)

M7.1M6.75 < M < 64 < M < 5

log(Pd) = -3.463 + 0.729 M - 1.374 log(R), S.D.V. = 0.305

M4.5

M5.5

M6.5

4 5 6 7M

4

5

6

7

MP

d

M Pd = M +- 0.18

Near Source effect!

τc & Pd for damaging event identification!

5 6 7 8

Mw

0.01

0.1

1

10 c

*Pd

(se

c*c

m)

No damage records (168)No damage events average (21)Damage records (40)Damage events average (5)

Damage

No Damage

1999 Chi-Chi

2003Chengkung

1998Reuyli

1999Chiayi

1994Nanoa

Warning could be given within one second after P arrival!

- 2 - 1 0 1 2 3 4Tim e after P arrival (sec)

- 4

- 2

0

2

4

6

- 2

- 1

0

1

2

Dis

pla

cem

ent

(cm

)

2007/03/25 Noto Mw6.7 earthquake

ISK006=7 km

ISK005=19 km

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.

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 200808_evts.txt

Earthworm

sniffwave4eew

Sniffwave4eew.c

SimuSac.cHistorical SAC Records

Iwate earthquake2008/06/14 08:43:45.36 Lat.=39.0298Long.=140.8807 Depth =7.77 kmJMA magnitude 7.2

4 stations6.8 sec after38.9905140.8262 5.65 kmMpd=7.45Mtc=7.72

7 stations7.4 sec after39.0804140.9413 4.38 kmMpd=7.10Mtc=7.53

11 stations8.3 sec after39.0393140.8726 13.92kmMpd=7.29Mtc=7.30

Progress on earthquake early warning system in Taiwan

Real-time strong-motion networkAccelerometer - 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

Real-time strong-motion networkAccelerometer - 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

Virtual sub-network approach

29

Performances for VSN

0.28

~17 sec

5.46 6.41 km

4.66 4.73 km

30

Pd discriminator

3 sec P wave

31

Magnitude estimationc

max

p M

Network triggered

Compute Pd

Pd > 0.1Estimate M

from

M > 6.0Create

shakemap

yes

M

VSN algorithmfrom coming signals

yes

M 7.1

2002/3/31 M 7.0Offshore Hualien earthquake

Network triggered

Compute Pd

Pd > 0.1Estimate M

from

M > 6.0Create

shakemap

yes

M

VSN algorithmfrom coming signals

yes

M 6.4

2006/4/1 M 6.5Taitung 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

c

35

CWB seismographic network

New established stations

36

Preliminary test for new system

0.48 0.34

12.01 13.01 km

20.2 4.9 sec

37

Promotion plan in Taiwan Establish the

promotion mechanismand policy

Construct the prototype systems and testing

Launch formal systems and deploy applications

2011 2012 20132009 2010 2014 2015

PolicyRatification

TechnologyDevelopment

ApplicationDeployment

Development and integrationof key technology

Concentrated Investment

Establish associated measures for application

System integration and product certificationTechnology transfer and industry promotion

Education, training, and drillsRelated regulation draft

First stage

Second stage

2016

• Regional EEW technology• On-site EEW technology• Evaluation of communication

channels• Investigation of user demands

School: Regional EEW, On-site EEW, Alarms, Broadcasting system

Emergency response institutions: Regional EEW, Alarms, Broadcasting system

Transportation system: Regional EEW, On-site EEW, Alarms, Broadcasting system, Automatic control

Apply the regional EEW systemDevelop the on-site EEW system

Develop the regional EEW and on-site EEW systems at the same time

Hospital: Regional EEW, On-site EEW, Alarms, Broadcasting system, Automatic control

Elevator: Regional EEW, On-site EEW, Automatic controlBuilding: Regional EEW, On-site EEW, Alarms,

Broadcasting system, Automatic controlHigh-tech factory: Regional EEW, On-site EEW, Alarms,

Broadcasting system, Automatic control

Integration of regional and on-site EEW systems

Thanks for your attention!