Hybrid Simulations of Ground Motions for the Earthquake Scenarios of Shanchiao and Hengchun faults

Transcription

1 Hybrid Simulations of Ground Motions for the Earthquake Scenarios of Shanchiao and Hengchun faults 顏銀桐 Yin Tung Yen Sinotech Engineering Consultants, Inc. Institute of Nuclear Energy Research 1

2 Questions What are the useful measures of ground motion for earthquake engineering or seismology engineering? What factors control the level of ground motion? What can we simulate ground motion for a scenario case of specific earthquake(fault) and how? 2

3 Fault type (Normal, Reverse, Strike slip) Strike, dip, rake Source Path Site Fault dimension Rupture behavior Slip pattern Velocity structure Attenuation Shallow velocity, V s30, Engineering&Seismic bedrock (270 or 360, 760 m/s, 3 km/s) Engineering bedrock Seismic bedrock 3

4 Broadband waveform (Ground motion time history) OR GMPEs 4

5 Measures of ground motion for engineering purposes PGA (peak ground acceleration) PGV (peak ground velocity) Response spectral acceleration (elastic, inelastic) at periods of engineering interest Intensity (Be related to PGA and PGV) (ground acceleration time-history) 5

6 Or Empirical relation Characterized Slip Model GMPEs (Irikura and Miyake, 2010) Seismic Hazard 6

7 1 Headquarters of Earthquake Research Promotion in Japan

8 2 1 Characterized Source Model for scenario simulation (Fault geometry Geophysical and Geological survey) Magnitude Fault length Fault width Dip angle Seismogenic depth Characterized Source Model Asperity (number, location, dimension) Rise time (Source time function) Rake ( strike 0,180; normal 90; reverse 90) Starting point 8

9 3 Parameter table Mo to S Mo to Tr Mo to A Sa to A Path structure Shallow structure ( < Vs ~ 3km/s) Deep structure Q structure 9

10 4 Strong ground motion of scenario simulation Hybrid simulation Theoretical method ( < 1 Hz) Empirical or Stochastic method ( > 1Hz) 5 GMPEs (Ground motion prediction equations) Magnitude Distance metric Fault type Site condition 10

11 Recipe of ground motion simulation in Japan fault source 活斷層調查地震觀測等巨視的震源特性 約 22% (Somerville et al., 1999) 特徵震源模型 微視的震源特性 活斷層上的滑移 最近的活斷層發生地震的解析結果等 規模 M 震源斷層形狀 Asperity 的位置 數量 (4) 式 長大斷層 Asperity 的總面積 S a 地震矩規模 M 0 (7) 式 震源斷層模型面積 S model 經驗式 (2), (3) 式 震源斷層面積 S 地震矩規模 M 0 (12) 式 (20-2) 式 (20-1) 式 Asperity 的應力降 σ a σ=3.1 Mpa (Fujii and Matsu ura, 2000) Madariaga (1979) 分配率 (9), (10) 式 M 0 (11) 式 加速度震源反應譜短周期水準 A 各 Asperity 的應力降 σ ai 各 Asperity 的面積 S ai 平均滑移量 D (5) 式 (15) ~ (19) 式 (24) 式 地震發生層的 S 波速度 β 地震發生層的密度 ρ 其它的震源特性 震源斷層的形狀等 各 Asperity 的實效應力 σ ai σ ai = σ ai 背景領域的實效應力 σ b (22), (23) 式 (25) ~ (28) 式 滑移速率函數 各 Asperity 及背景領域的平均滑移量 D ai,d b 破壞傳播速度 破壞開始點 f max 破壞傳播樣式 距離衰減式驗證 YES 強地動評估結束 (The Headquarters for Earthquake Research Promotion, 2008) NO 改善特徵地震模型 11

12 Scheme of hybrid ground motion simulation for a scenario case Stochastic method (freq. > 1 Hz ) Theoretical method (freq. < 1 Hz ) Hybrid Green s Function Matched pair of filters Combine both Green s functions in time domain Broadband waveform using Hybrid Green s Function with Characterized Source Model (Modified from Kamae et al., 1998) 12

13 Low frequency simulation Theoretical method for point sources (FK) Point source with unit moment Mw 4.4 (rise time: 0.10sec trapezoid shape function) (Zhu and Rivera, 2002) Circular rupture with a constant propagating velocity 13

14 Low frequency simulation (Hengchun fault) Thickness(km) Vs(km/s) Vp(km/s) Density(g/cm 3 ) Qs Qp Velocity (Wu et al, 2009) Density Birch's Law (Birch 1961) Qp, Qs Empirical relation (Brocher, 2008) 14

15 High frequency simulation Stochastic method for point sources (Boore, 1983; Motazedian and Atkinson, 2005) P, SH, SV to three geographical coordinates components A test case M7.0 (Hypo Dis. = 11 km) Strike Dip Depth of fault Fault length and width, subfault length and width

16 Average radiation pattern coefficients (Boore, 1984) The function of Q factor (Roumelioti and Beresnev, 2003) High frequency simulation Three types of body waves (P, SV, and SH waves) evaluated from a point source by the stochastic Green s function method and convert to three component (NS, EW, and UD). (Onishi et al., 2004) 16

17 Match filter for hybrid simulation National Research Institute for Earth Science and Disaster Prevention(NIED),

18 18 Scheme of finite fault ground motion simulation

19 Japan

20 20

21 Flow of Seismic Reevaluation According to New Seismic Regulatory Guide A. Geological survey, evaluation of active faults B. Evaluation of design basis ground motion Ss Site specific ground motion by identifying earthquake source Ground motion without identifying earthquake source Evaluate ground motions Ground motions by response spectra Ground motions by fault model method Define design basis ground motion C. Evaluation of seismic safety of facilities Refer Exceedance prob. Items to be reflected to seismic safety reevaluation based on the findings from the 2007 Chuuetsu oki Earthquake Classification of importance Evaluation of seismic safety of important structures Evaluation of important components and piping Stability evaluation of basemat Accompanying events (Stability of surrounding slope) Accompanying events (Safety against Tsunami) 21

22 Source model of the 2007 Chuetsu oki earthquake Best-fit source model Asp1 Asp2 Asp3 Hypocenter (Hi net) with three asperities (ASP1, ASP2 and ASP3) is estimated from comparison between observed and simulated motions using the Empirical Green s Function Method. Kashiwazaki Kariwa Nuclear Power Plant ( 柏崎刈羽原子力発電所 ) 22

23 23

24 Source model of the 2006 Pingtung earthquake Best-fit source model with one asperity (20x20 km 2 ) is estimated from comparison between observed and simulated motions using the Empirical Green s Function Method. 24

25 Hybrid simulation vs. Observations The procedure of Recipe has been evaluated by an actual event. 25

26 Shanchiao Fault ( 山腳斷層 ) Strike South(N33 o E), North(N59.3 o E) Dip 60 o Rake -90 o (Normal type) Land LiDAR (Digital Terrain Model,DTM) Geology map seismic reflection Offshore Multi-Beam Side-Scan Sonar Sub-Bottom Profile Multi-Channel Seismic Reflection 26

27 27 Characterized Source Model of Shanchiao fault

28 Hengchun Fault ( 恆春斷層 ) Strike N25.2 o W Dip 45 o Rake 75 o (Reverse-Strike type) Land LiDAR (Digital Terrain Model,DTM) Geology map seismic reflection Offshore Multi-Beam Side-Scan Sonar Sub-Bottom Profile Multi-Channel Seismic Reflection 28

29 29 Characterized Source Model of Hengchun fault

30 Scenario earthquake of Shanchiao fault waveforms and spectra Case 1 30

31 Scenario earthquake of Shanchiao fault waveforms and spectra Case 2 31

32 Scenario earthquake of Shanchiao fault waveforms and spectra Case 3 32

33 33 Scenario earthquake of Hengchun fault waveforms and spectra

34 34 Howe about historical earthquakes?

35 The 1920 Hualien Earthquake Characterized Source model & parameters Seismicity Structure model 1920 Earthquake Dcument 35

36 Recipe of ground motion simulation in Japan subduction earthquake source 海溝型震源模型 過去地震震源區域 地震觀測記錄基盤等深線 過去的海溝型地震解析結果等 巨視的震源特性 微視的震源特性 震源斷層形狀 Asperity 的位置 數量 震源斷層面積 S (29) 式 (12) 式 (20-2) 式 Asperity 的總面積 S a 分配率 地震矩規模 M 0 Asperity 的應力降 σ a (11) 式 加速度震源反應譜短周期水準 A 各 Asperity 的應力降 σ ai 各 Asperity 的面積 S ai (9) 式 平均滑移量 D (15) ~ (19) 式 地震發生層的 S 波速度 (28) 式 過去地震震源 各 Asperity 的實效應力 σ ai σ ai = σ ai 背景領域的實效應力 σ b (22), (23) 式 (24) ~ (27) 式 滑移速率函數 各 Asperity 及背景領域的平均滑移量 D ai,d b 其它的震源特性 f max 破壞傳播速度 破壞開始點 破壞傳播樣式 距離衰減式驗證 YES 強地動評估結束 NO 改善特徵地震模型 36

37 Summary Geophysical and geological survey are helpful to provide macro parameters of characterized source models. Micro parameters of characterized source models could be built up by the recipe (a serious of empirical relations). Reliability of the Recipe for hybrid simulation has been proofed by the pre-inspection for real earthquakes For the scenario cases of Shanchiao and Hengchun faults, ground acceleration time histories from hybrid simulation could provide the evaluation of seismic safety of NPP facilities. Scenario simulations for historical of future earthquakes could provide important measures of ground-motion for engineering purposes. 37

38 38 Thank you for your attention