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Earthquake early warning and Earthquake early warning and seismotectonicsseismotectonics in Taiwan regionsin Taiwan regions

YihYih--Min WuMin Wu

Dept. Geosciences, NTUDept. Geosciences, NTU

Earthquake Early WarningEarthquake Early Warning Profs. Profs. HirooHiroo KanamoriKanamori (Caltech), Ta(Caltech), Ta--Liang Liang TengTeng

(USC), Willie H. K. Lee (USGS), Yi(USC), Willie H. K. Lee (USGS), Yi--Ben Tsai Ben Tsai (PG&E), (PG&E), TzayTzay--ChynChyn Shin (CWB), Shin (CWB), Aldo Aldo ZolloZollo(INGV, Italy),Richard (INGV, Italy),Richard Allen (UC Berkeley) Allen (UC Berkeley)

Drs. Drs. NaiNai--Chi Hsiao (CWB), Chi Hsiao (CWB), ChienChien--HsinHsin Chang Chang (CWB), (CWB), TingTing--Li Lin (NTU), Li Lin (NTU), ChienChien--Fu Wu (CWB), Fu Wu (CWB), Li Li Zhao (IES), Yamada Masumi (Kyoto Univ.), Zhao (IES), Yamada Masumi (Kyoto Univ.), Barry Barry HirshornHirshorn (PWTC(PWTC))

Mrs. Mrs. DaDa--Yi Yi Chen (CWB), JangChen (CWB), Jang--TianTian ShiehShieh (NTU)(NTU)

Central Weather Bureau, Central Weather Bureau, Taiwan.Taiwan.

NIED, NIED, Japan; SCECJapan; SCEC, , USA.USA.

ChiaChia--ChingChing Lin, Lin, SanlienSanlien Company.Company.

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MotivationMotivation

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Earthquake early warning (EEW)Earthquake early warning (EEW)

Before Strong Ground MotionBefore Strong Ground MotionEarthq ake Earl Waning S stemEarthq ake Earl Waning S stem Earthquake Early Waning SystemEarthquake Early Waning System

Predict Shaking Predict Shaking

Regional Warning & Onsite WarningRegional Warning & Onsite Warning

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4

25

Early Warning Time of the Earthquake of Sep. 20, 1999 (Mw7.6)

Blind zone of on-site warning

Regional Warning v.s. Onsite Warning

-200

0

200

400

Ac

ce

lera

tio

n (

ga

l) PGA Mw6.6, focal depth 10 kmKnet Station NIG018Epicentral distance 14 km

23

24

La

titu

de

(N)

10 sec

20 sec

0 sec

-4

0

4

8

ce

me

nt

(cm

)

-20

-10

0

10

20

Ve

loci

ty (c

m/s

ec

)

-200A

Pd

PGV

c

0.5 cm

119 120 121 122Longitude (E)

22

VSN no warning area

30 sec

Warning time-3 0 3 6 9 12 15 18 21

Time after P arrival (second)

-12

-8

Dis

pla

PGDPd threshold warning

BackgroundBackground

Cooper (1868) proposed EEW conceptCooper (1868) proposed EEW concept“arrange a very simple mechanical contrivance “arrange a very simple mechanical contrivance

at various points from 10 to 100 miles from at various points from 10 to 100 miles from San Francisco” & “instantaneously ring an San Francisco” & “instantaneously ring an alarm bell… near the center of the city”alarm bell… near the center of the city”

A hundred years later, Japan Railways A hundred years later, Japan Railways designed an EEW system in 1965 and designed an EEW system in 1965 and started to operate in 1966 (Nakamura, started to operate in 1966 (Nakamura, 1988).1988).

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A concept of the Regional warning

Nakamura and Saita (2006)

The first successful case The first successful case

The Mexico City Seismic Alert System The Mexico City Seismic Alert System f ll id d b t 70 ff ll id d b t 70 fsuccessfully provided about 70 sec of successfully provided about 70 sec of

advanced warning of the 14 September, advanced warning of the 14 September, 19951995, Copala (Guerrero, Mexico) , Copala (Guerrero, Mexico) earthquake to the citizens of Mexico City earthquake to the citizens of Mexico City (Espinosa(Espinosa--Aranda Aranda et al.et al., 1995). , 1995).

To public systemTo public system

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(Espinosa(Espinosa--Aranda Aranda et al.et al., 1995), 1995)

Successful case in Taiwan Successful case in Taiwan

102 sec after the 102 sec after the 19991999 ChiChi--Chi Chi th k th CWB f T i t dth k th CWB f T i t dearthquake, the CWB of Taiwan reported earthquake, the CWB of Taiwan reported

the hypocenter, magnitude (M7.3), and the hypocenter, magnitude (M7.3), and shaking map to public (Wu et al, 2000). shaking map to public (Wu et al, 2000).

In In 20022002, the CWB achieved 22 sec , the CWB achieved 22 sec reporting time after the occurrence of anreporting time after the occurrence of anreporting time after the occurrence of an reporting time after the occurrence of an earthquake (Wu and Teng, 2002). earthquake (Wu and Teng, 2002).

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-1000

-750

-500

-250

0

250

500

750

1000 Td Tpr

T < 0

Sun Moon Lake ( = 9 km)

09/20/1999 17:47 Mw 7.6

S arrival

P arrival

1000

-100

-75

-50

-25

0

25

50

75

100

AC

C.

(gal

)

75

100

S arrival

Tw < 0

Tw > 0

Taichung( = 35 km)

Taipei( = 145 km)

P arrival

0 10 20 30 40 50 60 70

Time (sec)

-100

-75

-50

-25

0

25

50

S arrival

Reporting time

P arrival

Successful case in Japan Successful case in Japan

Urgent Earthquake Detection and Alarm Urgent Earthquake Detection and Alarm S t (U EDAS) thi t k dS t (U EDAS) thi t k dSystem (UrEDAS), this system worked System (UrEDAS), this system worked during the Niigata Chutsu earthquake in during the Niigata Chutsu earthquake in 20042004. It immediately detected the P. It immediately detected the P--wave wave arrival and shut off the train’s power in less arrival and shut off the train’s power in less than 3 seconds after P arrival (Nakamura than 3 seconds after P arrival (Nakamura et al., 2006).et al., 2006).

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Nakamura (2009)

Big progress in Japan 2007Big progress in Japan 2007

JMA JMA startedstarted officialofficial distribution of early warning distribution of early warning information to a limited number of organizationsinformation to a limited number of organizationsinformation to a limited number of organizationsinformation to a limited number of organizationsin August, 2006, and plans to distribute it to the in August, 2006, and plans to distribute it to the public in the fall of 2007. public in the fall of 2007.

System was successfully activated during the System was successfully activated during the 2007 2007 NotoNoto HantoHanto and Niigata Chuetsuand Niigata Chuetsu--Oki Oki earthquakes and provided accurate informationearthquakes and provided accurate informationearthquakes, and provided accurate information earthquakes, and provided accurate information regarding the source location, magnitude and regarding the source location, magnitude and intensity at about 3.8 s after the arrival of P wave intensity at about 3.8 s after the arrival of P wave at nearby stations. at nearby stations.

Odaka et al. (2003) & Kamigaichi (2004)

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Doi (2009)

Doi (2009)

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Doi (2009)

TaiwanTaiwan

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Real-time strong-motion networkAccelerometer - 102 stations (20km averaged

spacing)

16 bits resolution 16 bits resolution

± 2g Max. amplitude

Telemetry - Real-time data stream (RTD)

4.8K dedicated telephone line

Sampling rate 50 sps 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 16 bits resolution

± 2g Max. amplitude

Telemetry - Real-time data stream (RTD)

4.8K dedicated telephone line

Sampling rate 50 sps 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

Performances for VSNPerformances for VSN

0.28

5 46 6 41 k

24

~17 sec

5.46 6.41 km

4.66 4.73 km

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Network triggered

Compute Pd

Pd > 0.1Estimate M

from

M > 6.0Create

shakemap

yes

M

VSN algorithmfrom coming signals

yes

g g

M 6.4M 6.4

2006/4/1 M 6.5Taitung earthquake

Our approachOur approach

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For onsite case, an earthquake For onsite case, an earthquake occurs, you may think aboutoccurs, you may think about

Large earthquake?Large earthquake?

Cause damage?Cause damage?

Is this place safe?Is this place safe?

ττcc & & PPdd MethodsMethods ττcc average period parameter of the initial three initial three

seconds P wavesseconds P waves For magnitude determinationFor magnitude determination

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

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-200

0

200

400

Ac

ce

lera

tio

n (

ga

l) PGA

PGV

Mw6.6, focal depth 10 kmKnet Station NIG018Epicentral distance 14 km

4

8

(cm

)

-20

-10

0

10

20

Ve

loc

ity

(c

m/s

ec

)

Pd

PGV

c

-3 0 3 6 9 12 15 18 21

Time after P arrival (second)

-12

-8

-4

0

Dis

pla

ce

me

nt Pd

PGD

0.5 cm

Pd threshold warning

-0.5

0

0.5

c measured

c 4.4s, Mw8.3

EpicentralDistance

71 km

Station CodeDepth

HKD11242 km Japan

1-4

0

4

Dis

pla

cem

ent

(cm

)

-1

0

1-2

0

20.5

c 3.8s, Mw7.6

c 3.2s, Mw7.2

c 2.4s, Mw6.7

8 km

70 km

13 km

13 km

TCU0798 km

MYG01142 km

TTR00711 km

Japan

Japan

Taiwan

0 3 6 9 12

Time (sec)

-1

0

1c 1.3s, Mw6.1

13 kmNIG0209 km Japan

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E th k i ldEarthquake size could be determined by τc!

10Taiwan 11 eventsSouthern California 26 eventsJapan 17 events

1

c (

sec)

4 5 6 7 8

Mw

0.1

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

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Pd large than 0.5 cm following shakings may cause damage

10

100

m)

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

Chi-Chi

1

Fil

tere

d P

GD

(c

4 cm

0.01 0.1 1 10

Pd, Displacement (cm)

0.1

0.5 cm

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PGV ld b di t d b PdPGV could be predicted by Pd and then Shaking Intensity could

be predicted!

10

100

ec)

Taiwan 507 recordsSouthern California 199 recordsJapan 74 records

1

PG

V (

cm/s

e

0.001 0.01 0.1 1 10Pd (cm)

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

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τc & Pd for damaging event identification!

10

)

1999 Chi-Chi

2003Chengkung

1998Reuyli

1999Chiayi

1994Nanoa

0.1

1

c*P

d (

sec*

cm Damage

No Damage

5 6 7 8

Mw

0.01

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

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Near Source effect!Near Source effect!

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Warning could be given within one second after P arrival!

0

2

4

6

t (c

m)

2007/03/25 Noto Mw6.7 earthquake

ISK006=7 km

-4

-2

0

1

2

Dis

pla

cem

ent

ISK005=19 km

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

-2

-1

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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.

Palert ‐ Features

• Pd technology embedded

PGA PGV PGD t t• PGA PGV PGD output

• Network streaming ability

• NTP time synchronize

• Four kinds of trig modes– PD, PGA, STA/LTA, DisplacementPD, PGA, STA/LTA, Displacement

• Support both TCP server and client

• Noise performance < 0.1 gal

• Intensity meter

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iiTouch for Touch for backup power backup power

(4 hrs)(4 hrs)(4 hrs), (4 hrs), display and display and

sound sound warningwarninggg

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Palert EEW Networking SystemPalert EEW Networking System

Industrial HMI

NTP Server

Modbus TCP

Industrial HMI

EEW Server 1

RS-485Modbus RTU

DO

Palert

Router HubEEW Server 2

Internet

Intensity 3‐17 seconds

Intensity 5‐5 seconds

Standard Equipment

P Wave &Pd > 0.5cm Intensity 4

‐10 seconds

Intensity 4‐12 seconds

Intensity 4‐11 seconds

Intensity 5‐5 seconds

Intensity 3‐15 seconds

PC Utility & DemoPC Utility & DemoPalert Install location

http://www.cwb.gov.tw/eng/seismic/quake_index.htm?

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TestingTestingJuneJune--AugustAugust

2010201020102010

System configurationSystem configuration

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An examination using buildingAn examination using building array records from a damage building

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1.5

2

Ch03: Free-field

Ch11: F1

Ch18: RF

Ch21: RF

Ch22: RF

Taitung EQ

0 5

1

Pd

(cm

)

Pd=0.5 cm

0.1 1 10

PGV (cm/s)

0

0.5

Chengkung EQChi-Chi EQ

Pd 0.5 cm

2010 2010 JiaSianJiaSian earthquakeearthquake

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A study of A study of seismotectonicsseismotectonics of of Taiwan regionsTaiwan regions

YihYih--Min WuMin Wu

D t f G i NTUD t f G i NTUDept. of Geosciences, NTUDept. of Geosciences, NTU

Thanks toThanks to

ChienChien--Hsin Chang (CWB, Taiwan)Hsin Chang (CWB, Taiwan)

Li Zhao, Yaru Hsu (IES, Taiwan)Li Zhao, Yaru Hsu (IES, Taiwan)

YueYue--Gau Chen, Bruce Shyu, LingGau Chen, Bruce Shyu, Ling--Ho Ho Chung, KuangChung, Kuang--Yin Lai, John Suppe, Yin Lai, John Suppe, Kamil Ustaszewski, HsinKamil Ustaszewski, Hsin--Hua Huang, Hua Huang, (NTU Taiwan)(NTU Taiwan)(NTU, Taiwan)(NTU, Taiwan)

Mamoru Nakamura (Univ. of the Ryukyus)Mamoru Nakamura (Univ. of the Ryukyus)

ShuShu--Kun Hsu (NCU, Taiwan)Kun Hsu (NCU, Taiwan)

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&& //VpVp & & VpVp/Vs results/Vs results

Wu et al. (JGR, 2007)

Vp

Vp/Vs

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Vp

Vp/Vs

Vp

Vp/Vs

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Focal mechanism determination Focal mechanism determination using Genetic Algorithmusing Genetic Algorithm

Wu, Y. M., L. Zhao, C. H. Chang, and Y. Wu, Y. M., L. Zhao, C. H. Chang, and Y. J. Hsu (2008). Focal mechanism J. Hsu (2008). Focal mechanism determination in Taiwan by genetic determination in Taiwan by genetic algorithm, algorithm, Bull. Seism. Soc. Am. Bull. Seism. Soc. Am. 9898, , 651651 661661651651––661661..

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600 800 1000 1200 1400 1600 1800 2000

Population

6000

8000

10000

8000

10000

0 1 2 3 4 5 6 7 8 9 10

Reproduction (%)

6000

6000

8000

10000

12000

14000

Se

arc

h t

imes

1 2 3 4 5 6 7 8 9 10

Mutation Bits

0 10 20 30 40 50 60 70 80 90 100

Mutation (%)

10000

100000

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Relocation of Relocation of EarthquakeEarthquakess in Taiwan in Taiwan from 1991 to 2005from 1991 to 2005

Wu, Y. M.Wu, Y. M., C. H. Chang, L. Zhao, T. L. , C. H. Chang, L. Zhao, T. L. Teng and M. Nakamura (2008). A Teng and M. Nakamura (2008). A Comprehensive Relocation of Comprehensive Relocation of Earthquakes in Taiwan from 1991 to Earthquakes in Taiwan from 1991 to 20052005 Bull Seism Soc AmBull Seism Soc Am 9898 14711471––2005, 2005, Bull. Seism. Soc. Am. Bull. Seism. Soc. Am. 9898, 1471, 1471––14811481 ..

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Northeastern subduction zoneNortheastern subduction zone

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Vp Vp/Vs

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Southern subduction zoneSouthern subduction zone

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Vp Vp/Vsp p

Forearc basin subductionForearc basin subduction

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Central TaiwanCentral Taiwan

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Possible Possible MohoMoho Shape of TaiwanShape of TaiwanByBy

KamilKamil UstaszewskiUstaszewski, , YihYih--Min Wu, John Min Wu, John SuppeSuppe, , HsinHsin--HuaHua HuangHuang, , ChienChien--HsinHsin Chang and Sara Chang and Sara CarenaCarena

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Thanks for your attentionThanks for your attention

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