development of earthquake early warning
DESCRIPTION
Development of Earthquake Early Warning. Yih-Min Wu Dept. of Geosciences, National Taiwan University. 如何降低地震災害?. 長期 土地利用規劃 中期 耐震設計 短期 地震預測 地震發生. Earthquake Early Waning. Before Occurrence Earthquake Prediction – Predicts Earthquake Before Strong Ground motion - PowerPoint PPT PresentationTRANSCRIPT
Development of Earthquake Development of Earthquake Early WarningEarly Warning
Yih-Min Wu
Dept. of Geosciences, National Taiwan University
如何降低地震災害?如何降低地震災害?
長期– 土地利用規劃中期– 耐震設計短期– 地震預測地震發生
Earthquake Early WaningEarthquake Early Waning
Before Occurrence Before Occurrence – Earthquake Prediction – Predicts EarthquakeEarthquake Prediction – Predicts Earthquake
Before Strong Ground motionBefore Strong Ground motion– Seismic Early Waning System (EWS)Seismic Early Waning System (EWS)– Predicts Shaking Predicts Shaking
Before Damage is DiscoveredBefore Damage is Discovered– Seismic Rapid Reporting System (RRS)Seismic Rapid Reporting System (RRS)– Predicts DamagePredicts Damage– Focusing seismic rescue effortsFocusing seismic rescue efforts
Philosophy
Currently precise prediction of earthquake process is difficult.However, once seismic waves are excited, the process is governed by known “Elasticity theory” and “Earth structure”, and the behavior is more predictable, and we can respond to ever-changing situation associated with an earthquake and its aftermath.
Environment is Changing
Large cities, high-rise buildings, bridges, tunnels, airport, gas, telephone, electricity, etc.
But, developments in modern engineering (e.g., structural control) will allow effective use of rapid seismic information to mitigate seismic hazards.
地震預警地震預警應用範圍應用範圍學校學童躲入桌子底下尋求保護及心理應變。墨西哥市的學校學童躲入桌子底下尋求保護及心理應變。墨西哥市的預警系統研究成果顯示,接受地震預警訊息的學童,在心預警系統研究成果顯示,接受地震預警訊息的學童,在心理上大幅降低對地震之恐懼。 理上大幅降低對地震之恐懼。 工人能離開危險的工作位置。 工人能離開危險的工作位置。 醫院進行的手術能暫時停止或調整精細及關鍵的操作,例醫院進行的手術能暫時停止或調整精細及關鍵的操作,例如如 :: 眼科手術等。 眼科手術等。 運輸系統能自動停止或減速,例如運輸系統能自動停止或減速,例如 :: 高速鐵路列車減速以高速鐵路列車減速以降低翻車之風險。 降低翻車之風險。 維生管線及通訊網路能自動調整、重組或關閉,例如維生管線及通訊網路能自動調整、重組或關閉,例如 :: 關關閉瓦斯及供水管線,減少地震所引起之火災及其他災害。 閉瓦斯及供水管線,減少地震所引起之火災及其他災害。 工廠能及時進行緊急應變,保護振動敏感之設備,例如工廠能及時進行緊急應變,保護振動敏感之設備,例如 ::晶元製造廠。晶元製造廠。
Earthquake early warning (EEW)Earthquake early warning (EEW)
Before Strong Ground MotionBefore Strong Ground Motion– Earthquake Early Waning SystemEarthquake Early Waning System– Predict Shaking Predict Shaking
Regional Warning & Onsite WarningRegional Warning & Onsite Warning
119 120 121 122Longitude (E)
2 2
2 3
2 4
2 5
La
titu
de
(N)
VSN no warning area
1 0 sec
2 0 sec
3 0 sec
Warning tim e
Early Warning T im e of the Earthquake of Sep. 2 0 , 1 9 9 9 (M w7 .6 )
0 sec
Blind zone of on-site warning
Regional Warning v.s. Onsite Warning
- 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
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).
Nakamura and Saita (2006)
A concept of the Regional warning
The first successful case The first successful case
The Mexico City Seismic Alert System The Mexico City Seismic Alert System successfully 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-Aranda (Espinosa-Aranda et al.et al., 1995). , 1995).
To public systemTo public system
(Espinosa-Aranda (Espinosa-Aranda et al.et al., 1995), 1995)
Successful case in Taiwan Successful case in Taiwan
102 sec after the 102 sec after the 19991999 Chi-Chi Chi-Chi earthquake, 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 an reporting time after the occurrence of an earthquake (Wu and Teng, 2002). earthquake (Wu and Teng, 2002).
0 10 20 30 40 50 60 70
Tim e (sec)
-1000
-750
-500
-250
0
250
500
750
1000
-100
-75
-50
-25
0
25
50
75
100
AC
C.
(gal
)
-100
-75
-50
-25
0
25
50
75
100
Td Tpr
S arrival
Tw < 0
S arrival
Tw > 0
Sun Moon Lake ( = 9 km )
Reporting time
Taichung( = 35 km)
Taipei( = 145 km )
09/20/1999 17:47 M w 7.6
S arrival
P arrival
P arrival
P arrival
Successful case in Japan Successful case in Japan
Urgent Earthquake Detection and Alarm Urgent Earthquake Detection and Alarm System (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-wave . It immediately detected the P-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).
Nakamura (2009)
Big progress in Japan 2007Big progress in Japan 2007
JMA started official distribution of early warning JMA started official distribution of early warning information to a limited number of organizations information to a limited number of organizations in 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 Noto Hanto and Niigata Chuetsu-Oki 2007 Noto Hanto and Niigata Chuetsu-Oki earthquakes, 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 intensity at about 3.8 s after the arrival of P wave at nearby stations. wave at nearby stations.
Odaka et al. (2003) & Kamigaichi (2004)
Doi (2009)
Doi (2009)
Doi (2009)
Motivation in TaiwanMotivation in Taiwan
EWS in TaiwanEWS in TaiwanUsing the telemetered signals from Using the telemetered signals from strong-motion instruments.strong-motion instruments.Since 2000Since 2000Virtual Sub-Network Approach Virtual Sub-Network Approach (VSN)(VSN)
MML10L10
Wu et al., BSSA, 1998; Wu and Teng, BSSA, 2002.
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
28
Performances for VSNPerformances for VSN
0.28
~17 sec
119 120 121 122
Longitude (E)
2 2
2 3
2 4
2 5
Lat
itu
de
(N)
VSN no warning area
1 0 sec
2 0 sec
3 0 sec
Warning tim e
Expected Early W arning Time of the Earthquake of Sep. 20, 1999 (Mw7.6)
0 sec
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 Methods Methods
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
Wu and Kanamori (2005a,b; 2008a,b)
- 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
0 3 6 9 12
Tim e (sec)
- 1
0
1- 4
0
4
Dis
pla
cem
ent
(cm
)
- 1
0
1- 2
0
2- 0 . 5
0
0 . 5
c m easured
c 4.4s, Mw8.3
c 3.8s, Mw7.6
c 3.2s, Mw7.2
c 2.4s, Mw6.7
c 1.3s, Mw6.1
EpicentralDistance
71 km
8 km
70 km
13 km
13 km
Station CodeDepth
HKD11242 km
TCU0798 km
MYG01142 km
TTR00711 km
NIG0209 km
Japan
Japan
Japan
Japan
Taiwan
2 2 2 2
2 20
2 2
0
2
ˆ( ) 4 | ( ) |4
ˆ( ) | ( ) |
1 2
W
W
C
u t dt f u f dfr f
u t dt u f df
rf
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
PGV
(cm
/se
c)
Taiwan 507 recordsSouthern California 199 recordsJapan 74 records
Linear regression over 780 recordslog(PGV)=0.920 log(Pd) + 1.642SDV = 0.326
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.
An examination using building array records from a damage building
0.1 1 10
PG V (cm/s)
0
0.5
1
1.5
2
Pd
(cm
)
Ch03: Free-field
Ch11: F1
Ch18: RF
Ch21: RF
Ch22: RF
Taitung EQ
Chengkung EQChi-Chi EQ
Pd=0.5 cm
Applications on the EEW Information
uncontrolled
controlled
Kh
Kanamori (2005)
0.5 g
8 feet
controlled
Kanamori (2005)
Nakamura (2009)
Doi (2009)
Takamatsu (2009)
Takamatsu (2009)
Takamatsu (2009)
Takamatsu (2009)
Takamatsu (2009)
Motosaka (2009)
Motosaka (2009)
Motosaka (2009)
Motosaka (2009)
Sugano (2009)
Sugano (2009)
Sugano (2009)
Sugano (2009)
Sugano (2009)
Human SensorHuman Sensor
Thanks toThanks toProfs. Ta-Liang Teng (USC), Willie H. K. Lee Profs. Ta-Liang Teng (USC), Willie H. K. Lee (USGS), Yi-Ben Tsai (PG&E), Tzay-Chyn Shin (USGS), Yi-Ben Tsai (PG&E), Tzay-Chyn Shin (CWB), Richard Allen (UC Berkeley) (CWB), Richard Allen (UC Berkeley)
Drs. Nai-Chi Hsiao (CWB), Chien-Hsin Chang Drs. Nai-Chi Hsiao (CWB), Chien-Hsin Chang (CWB), Chien-Fu Wu (CWB), Li Zhao (IES), (CWB), Chien-Fu Wu (CWB), Li Zhao (IES), Yamada Masumi (Kyoto Univ.), Barry Hirshorn Yamada Masumi (Kyoto Univ.), Barry Hirshorn (PWTC)(PWTC)
Mrs. Da-Yi Chen (CWB), Jang-Tian Shieh (NTU)Mrs. Da-Yi Chen (CWB), Jang-Tian Shieh (NTU)
Central Weather Bureau, TaiwanCentral Weather Bureau, Taiwan
NIED, JapanNIED, Japan
SCEC, USASCEC, USA