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

Regional warning v.s. onsite warning Early Warning Time of the Earthquake of Sep. 20, 1999 (Mw7.6) 25 There is no warning Blind zone of on-site warning time for VSN method within the distance 70 km from epicenter. 24 0 sec Latitude (N) 10 sec 20 sec 23 30 sec Warning time 22 VSN no warning area 119 120 121 122 Longitude (E)

τ c & P d Methods  τ c average period parameter of the initial three seconds P waves  P d 0.075Hz high pass peak displacement amplitude of the initial three seconds P waves  τ c for magnitude determination  Kanamori (2005), Wu & Kanamori (2005A,2008a,b)  P d for intensity estimation  Wu & Kanamori (2005B,2008a,b), Wu et al. (2007)  P d for magnitude determination  Wu & Zhao (2006), Wu et al. (2007)

400 M w 6.6, focal depth 10 km PGA Acceleration (gal) Knet Station NIG018 Epicentral distance 14 km 200 0 -200 PGV Velocity (cm/sec) 20 10 0 -10  c -20 8 Displacement (cm) 4 Pd 0 0.5 cm -4 -8 Pd threshold warning PGD -12 -3 0 3 6 9 12 15 18 21 Time after P arrival (second)

Epicentral  c measured Station Code Distance Depth 0.5 HKD112  c 4.4s, Mw8.3 71 km 42 km Japan 0 -0.5 2 8 km TCU079  c 3.8s, Mw7.6 8 km 0 Taiwan -2 Displacement (cm) 1 MYG011  c 3.2s, Mw7.2 70 km Japan 42 km 0 -1 4 TTR007  c 2.4s, Mw6.7 13 km Japan 11 km 0 -4 13 km 1  c 1.3s, Mw6.1 NIG020 Japan 9 km 0 -1 0 3 6 9 12 Time (sec)

10 Taiwan 11 events Southern California 26 events Japan 17 events  c (sec) 1 log (  c ) = 0.296 M w - 1.716 Sdv=0.122, R=0.933 0.1 4 5 6 7 8 M w

Filter problem

(A)  c (B)  p 1 1 SDV of Error in Mw Determination 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0 0 1 2 3 4 5 6 1 2 3 4 5 6 Pole Pole Std 0.27 for usingboth

Simple Pd for onsite EEW

100 No damage records (168) No damage events average (21) Damage records (40) Damage events average (5) Chi-Chi 10 Filtered PGD (cm) 4 cm 1 0.1 0.5 cm 0.01 0.1 1 10 Pd, Displacement (cm)

Taiwan 507 records Southern California 199 records 100 Japan 74 records PGV (cm/sec) 10 1 0.1 Linear regression over 780 records log( PGV )=0.920 log( Pd ) + 1.642 SDV = 0.326 0.001 0.01 0.1 1 10 Pd (cm)

2007/03/25 Noto Mw6.7 earthquake 6 ISK006 4  =7 km Displacement (cm) 2 0 -2 -4 2 ISK005  =19 km 1 0 -1 -2 -2 -1 0 1 2 3 4 Time after P arrival (sec)

20 10 Time of PGV (sec) 9 8 7 6 5 4 3 No warning 2 PGV < 20 cm/s 20 cm/s  PGV < 40 cm/s 40 cm/s  PGV 1 0 3 6 9 12 Time of Pd  0.5 cm (sec)

P d for regional EEW

Pd for magnitude determination log(Pd) = -3.463 + 0.729 M - 1.374 log(R), S.D.V. = 0.305 1 0.1 Pd (cm) M 6.5 0.01 M 5.5 0.001 M7.1 M 4.5 M6.7 5 < M < 6 4 < M < 5 10 100 Hypocentral Distance (km)

M Pd = M +- 0.18 7 6 M Pd 5 4 4 5 6 7 M

Near Source effect!

10  c *Pd (sec*cm) Damage 1 No Damage 0.1 No damage records (168) No damage events average (21) 0.01 Damage records (40) Damage events average (5) 5 6 7 8 Mw

SimuSac.c Historical SAC Records Earthworm Sniffring4eew.c Imports Picks PICK_RING Share Memory Sniffwave4eew.c WAVE_RING1 Scream2ew-BB sniffwave4eew WAVE_RING2 Import_Smart24 sniffwave4eew Import_Wave WAVE_RING3 WAVE_RING4 TcPd.c Scn2scnl Report 200808_evts.txt

Iwate ate earthquake thquake 4 stati tion ons 7 stati tion ons 11 stati tions ons 2008/06/14 08:43:45.36 6.8 sec afte ter 7.4 sec afte ter 8.3 sec afte ter Lat.=39.0298 38.9905 39.0804 39.0393 Long.=140.8807 140.8262 140.9413 140.8726 Depth =7.77 km 5.65 km 4.38 km 13.92km JMA magnitude 7.2 Mpd=7.45 Mpd=7.10 Mpd=7.29 Mtc=7.72 Mtc=7.53 Mtc=7.30

Summary  Parameters from initial three seconds P waves  Average period, τ c can be used for magnitude determination  Pd can be used for predicting shaking intensity  Pd and τ c 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