Development of Earthquake Early Warning System using initial P - - PowerPoint PPT Presentation

Development of Earthquake Early Warning System using initial P waves

Yih-Min Wu (NTU) Hiroo Kanamori (Caltech)

Earthquake early warning (EEW)

 Before Strong Ground Motion

 Earthquake Early Waning System  Predict Shaking

 Regional Warning & Onsite Warning

119 120 121 122

Longitude (E)

22 23 24 25

Latitude (N)

VSN no warning area

10 sec 20 sec 30 sec

Warning time

Early Warning Time of the Earthquake

• f Sep. 20, 1999 (Mw7.6)

0 sec

Blind zone of on-site warning

There is no warning time for VSN method within the distance 70 km from epicenter.

Regional warning v.s. onsite warning

τc & Pd Methods

 τc average period parameter of the initial three

seconds P waves

 Pd 0.075Hz high pass peak displacement

amplitude of the initial three seconds P waves

 τc for magnitude determination

 Kanamori (2005), Wu & Kanamori (2005A,2008a,b)

 Pd for intensity estimation

 Wu & Kanamori (2005B,2008a,b), Wu et al. (2007)

 Pd for magnitude determination

 Wu & Zhao (2006), Wu et al. (2007)

• 3

3 6 9 12 15 18 21

Time after P arrival (second)

• 12
• 8
• 4

4 8

Displacement (cm)

• 20
• 10

10 20

Velocity (cm/sec)

• 200

200 400 Acceleration (gal)

Pd PGA PGV PGD

c

Mw6.6, focal depth 10 km Knet Station NIG018 Epicentral distance 14 km

0.5 cm Pd threshold warning

3 6 9 12

Time (sec)

• 1

1

• 4

4

Displacement (cm)

• 1

1

• 2

2

• 0.5

0.5

c measured 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 Epicentral Distance

71 km 8 km 70 km 13 km 13 km

Station Code Depth

HKD112 42 km TCU079 8 km MYG011 42 km TTR007 11 km NIG020 9 km Japan Japan Japan Japan Taiwan

4 5 6 7 8

Mw

0.1 1 10

c (sec)

Taiwan 11 events Southern California 26 events Japan 17 events

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

Filter problem

0.2 0.4 0.6 0.8 1

SDV of Error in Mw Determination

1 2 3 4 5 6

Pole (A) c

0.2 0.4 0.6 0.8 1 1 2 3 4 5 6

Pole (B) p

Std 0.27 for usingboth

Simple Pd for onsite EEW

0.01 0.1 1 10

Pd, Displacement (cm)

0.1 1 10 100

Filtered PGD (cm)

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

0.5 cm 4 cm

Chi-Chi

0.001 0.01 0.1 1 10

Pd (cm)

0.1 1 10 100

PGV (cm/sec)

Taiwan 507 records Southern California 199 records Japan 74 records

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

• 2
• 1

1 2 3 4

Time after P arrival (sec)

• 4
• 2

2 4 6

• 2
• 1

1 2

Displacement (cm) 2007/03/25 Noto Mw6.7 earthquake

ISK006 =7 km ISK005 =19 km

3 6 9 12

Time of Pd 0.5 cm (sec)

1 10

2 3 4 5 6 7 8 9 20

Time of PGV (sec)

PGV < 20 cm/s 20 cm/s  PGV < 40 cm/s 40 cm/s  PGV

No warning

Pd for regional EEW

Pd for magnitude determination

10 100

Hypocentral Distance (km)

0.001 0.01 0.1 1

Pd (cm)

M7.1 M6.7 5 < M < 6 4 < 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 7

M

4 5 6 7

MPd MPd = M +- 0.18

Near Source effect!

5 6 7 8

Mw

0.01 0.1 1 10

c*Pd (sec*cm)

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

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.c Historical SAC Records

Iwate ate earthquake thquake 2008/06/14 08:43:45.36 Lat.=39.0298 Long.=140.8807 Depth =7.77 km JMA magnitude 7.2 4 stati tion

• ns

6.8 sec afte ter 38.9905 140.8262 5.65 km Mpd=7.45 Mtc=7.72 7 stati tion

• ns

7.4 sec afte ter 39.0804 140.9413 4.38 km Mpd=7.10 Mtc=7.53 11 stati tions

• ns

8.3 sec afte ter 39.0393 140.8726 13.92km Mpd=7.29 Mtc=7.30

Summary

 Parameters from initial three seconds P waves

 Average period, τc can be used for magnitude

determination

 Pd can be used for predicting shaking intensity  Pd and τc can be used to identify damage event  10 sec EEW is possible depends on telemetry, dense

array in operation, and instrumentation.

 Will be useful onsite type EEW system (structure

control, chip manufacture, eyes surgical operation…)

 This concept is testing in Taiwan, PWTC, and Kyoto

Univ.

Thanks to

 Profs. Ta-Liang Teng (USC), Willie H. K. Lee

(USGS), Yi-Ben Tsai (PG&E), Tzay-Chyn Shin (CWB), Richard Allen (UC Berkeley)

 Drs. Nai-Chi Hsiao (CWB), Chien-Hsin Chang

(CWB), Li Zhao (IES), Yamada Masumi (Kyoto Univ.), Barry Hirshorn (PWTC)

 Da-Yi Chen (CWB), Jang-Tian Shieh (NTU)  Central Weather Bureau, Taiwan  NIED, Japan  SCEC, USA