Soutenance HDR Source Sismique - Physique et Perspective pour Aléa -

mercredi 13 mai 2009

Soutenance HDRSource Sismique

- Physique et Perspective pour Aléa -

Aochi Hideo

BRGM, Service Risques Naturels et Sécurité du Stockage CO2

Memory of HDR


HDR - Paris VII/IPGP

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mercredi 13 mai 2009 > 2

Outlines

> Introduction / Historical background• The University of Tokyo (1995 – 2000)

• ENS Paris (2000 – 2003)

• IRSN (2003 – 2004)

• BRGM (2004 – current)

> Previous Studies• Numerical methods

• Earthquake generation process

• Seismic hazard

> Perspective• Earthquake source : Physics and perspective to seismic hazard

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Introduction / Historical background

> University of Tokyo (1995 – 2000) … PhD Student• Slip- and time-dependent fault constitutive law and earthquake

rupture process (M. Sc in 1997)

• Theoretical studies on dynamic rupture propagation along a 3D non-planar fault system (PhD in 2000)

• M. Matsu’ura … Friction law, scaling law, quasi-static nucleation process

• E. Fukuyama (NIED) … BIEM, dynamic rupture

• APEC Cooperation for Earthquake Simulation (ACES), 1999 – 2004.



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> ENS Paris (2000 – 2003) … postdoc • Theoretical study on rupture processes of interacting

complex fault systems, (JSPS Fellow, 2000-2002).

• R. Madariaga … dynamic rupture, wave radiation, FDM

• K. B. Olsen (UCSB in 2002) … strong ground motion

• Invited researcher at UCSB (2002) and at ERI (2003)



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> IRSN (2003 – 2004) … postdoc• Seismic hazard analysis in the Moyenne Durance

fault, south-eastern France, based on dynamic rupture process

• C. Berge-Thierry … Seismic hazard study methodology

• O. Scotti … Seismic hazard study methodology

• M. Cushing … Tectonics, structure geology

• Japanese traduction of « Quantitative seismology » by Aki and Richards (2004)



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> BRGM (2004 – current) … project leader, senior researcher• Seismic hazard and risk studies.

• J. Douglas … earthquake engineering

• F. De Martin (thesis in progress) … wave propagation, non-linear site effect

• A. Ducellier… wave propagation, numerical development

• F. Dupros (thesis in proress) … high performance computing

• G. Bertrand … tectonics, seismic hazard methodology

• M. De Michele (thesis in progress), D. Racoules … InSAR analysis, fault observation

• J. Salichon (postdoc), A. Lemoine … teleseismic inversion, empirical green function

• M. Delatre … high frequency generation

• S. Bernardie, B. Possion … fault dynamics



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> BRGM• V. Cruz-Atienza (Géoscience Azur, PhD in 2006) … Curved fault

dynamics with BIEM and FDM

• J. Le Puth (UJF, master 2P in 2005) … hybrid simulation of accelerograms in the Nice region

• E. Manglou (Polytech Paris, master 2P in 2006) … rupture dynamics using SEM

• M. Urvoy (ENS Paris, master 2S in 2007) … Seismic hazard evaluation methodology

• W. Imperatori (Univ Trieste, master in 2007) … ground motion simulation in the Friuli region

• M. Yoshimi (GSJ, chercheur invité in 2009) … strong ground motion of the 2009 L’Aquila earthquake



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> BRGM• S. Ide (Univ Tokyo) … fault heterogeneity and earthquake dynamcs

• P. Suhadolc, G. Costa (Univ Trieste) … ground motion simulations

• D. Komatitsch (Univ Pau) … art of wave propagation

• K. Nobuki (Univ Tokyo) … hybrid method for earthquake dynamics

• A. Kato (Univ Tokyo) … the 2007 Niigata-ken Chuetsu-oki earthquake

• ANR SEISMULATORS (2006 – 2008) … Seismic simulation of complex source-site contexts (BRGM, IPGP, ENS, ECP, IRSN).

• ANR DEBATE (2009 – 2011) … Development of broadband acceleration time histories for engineers (BRGM, ENS, IRSN, private company)



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Previous studies

>Numerical methods

>Earthquake generation process

>Seismic hazard



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22 Feb 2006 > 11

1. Initial Condition Fault Geometry, Tectonic Stress Rupture Criterion

2. Dynamic Rupture Propagation

3. Seismic Wave Propagation

4. (Non-linear) Soil Behavior

Simulation Strategy from Source to SiteThe 1992 Landers, CA (M7.3)

Boundary Integral Equation Method

Finite Difference Method

Finite Element Method

Aochi et al. (2000a)

Aochi and Madariaga (2003), Cruz-Atienza et al. (2007), Dupros et al. (2008)

De Martin et al. (2007a, b)Ducellier and Aochi (2009)

Numerical Methods• Boundary Integral Equation Method (BIEM)

• Finite Difference Method (FDM)

• Hybrid finite Difference – Boundary integral Method (HDBM)



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Thrust faulting with free surface using HDBM.

Kame and Aochi (AGU, 2008)

Fault element view in FDM

Cruz-Atienza et al. (2007)

Numerical Methods

> Wave propagation with topography (FD/FE hybrid method)



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Ducellier and Aochi (Waves, 2009)

Semi-infinite A hill A series of hillsFE elements

Earthquake Generation Process



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> Role of fault surface irregularity

microscopic

macroscopic

Aochi and Matsu’ura (2002)

Aochi and Ide (2004, 2009)Ide and Aochi (2005)

Aochi et al. (2000a, b, 2002, 2003, 2005, 2006),Aochi and Fukuyama (2002), Aochi and Madariaga (2003), Cruz-Atienza et al. (2007)


> Dynamic rupture process along 3D nonplanar fault system



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Aochi and Fukuyama (JGR, 2002)Aochi et al. (G3, 2003)


> Wave radiation from dynamic rupture propagation



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Aochi and Fukuyama (JGR, 2002)Aochi et al. (G3, 2003)


> Multi-scale heterogeneity and earthquake scaling law• Much more small asperities (Fractal

law).

• Each asperity has Dc according to its size L.

> Where does the rupture begin?

• On one of the smallest asperities.



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Dn nN r

Dc L

Ide and Aochi (JGR, 2005)




> 18Ide and Aochi (JGR, 2005)




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Dc scaling with earthquake size but cascade-like earthquake rupture

Ide and Aochi (JGR, 2005)

Seismic Hazard



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> Mechanical approach vs statistical approach

Earthquake Scenario

Ground Motion Simulation

Aochi et al. (2006)

Aochi and Douglas (2006)Douglas et al. (2007),Imperatori et al. (2009)

Aochi et al. (2003), Aochi and Madariaga (2003),Aochi and Olsen (2004)

Seismic Hazard> Earthquake scenario likelihood based on dynamic rupture simulation

> Kinematic description• Earthquake magnitude

• Rupture area

• Rupture directivity

> Dynamic simulation• Spontaneous rupture process



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Aochi et al. (GJI, 2006)

Seismic Hazard



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• Logic tree taken into account


Seismic Hazard

> Rupture scenario with probability



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Seismic Hazard



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Seismic Hazard

> 1D/2D/3D ground motion simulation in Friuli, north-easteran Italy• poorly constrained 3D model

• good 2D cross section

• 1D regional model

• 1D model at receiver position

• 1D averaged model between source-receiver



> 25Imperatori et al. (BGTA, in press, 2009)

Seismic Hazard

> 1D/2D/3D ground motion simulation in Friuli, north-easteran Italy• poorly constrained 3D model

• good 2D cross section

• 1D regional model

• 1D model at receiver position

• 1D averaged model between source-receiver




Seismic Hazard

• Point source (M5)

• Large amplification due to basin edge (X = 50 km)

• Wrong amplification at distance (X = 110 km)




Seismic Hazard

> 2D vs 1D in attenuation relation with distance



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Source (I) Source (II) Source (III)

Imperatori et al. (BGTA, in press, 2009)

Publication List1. Imperatori, W., H. Aochi, P. Suhadolc, J. Douglas, A. Ducellier and G. Costa, 2D versus 1D ground-motion modelling

for the Friuli region, north-eastern Italy, accepted in Bollettino di Geofisica Teorica ed Applicata, 2009.

2. Aochi, H. and R. Ando, Numerical simulations on faulting: Microscopic evolution, macroscopic interaction and rupture process of earthquakes, in press, J. Seism. Soc. Japan, 2009.(review paper in Japanese)

3. Aochi, H. and S. Ide, Complexity in earthquake sequences controlled by multi-scale heterogeneity in fault fracture energy, J. Geophys. Res., 114, B03305, doi:10.1029/2008JB006034, 2009.

4. Douglas, J. and H. Aochi, A survey of techniques for predicting earthquake ground motions for engineering purposes, Survey in Geophysics, 29, 187-220, 2008.

5. De Michele, M., D. Raucoules, H. Aochi, N. Baghadadi, C. Carnec, Measuring coseismic deformation on the northern segment of the Bam Naravat escarpment associated with the 2003 Bam (Iran) earthquake, by correlation of very high resolution satellite imagery., Geophys. J. Int., 173,doi:10.1111/j.1365-246X2008.03743.x, 2008.

6. Cruz-Atienza, V., J. Virieux and H. Aochi, 3D Finite-Difference Dynamic-Rupture Modelling Along Non-Planar Fault, Geophysics, 72(5), SM123--SM137, 2007.

7. Douglas, J., H. Aochi, P. Suhadolc and G. Costa, The importance of crustal structure in explaining the observed uncertainties in ground motion estimation, Bull. Earthq. Engineering, 5, 17--26, 2007.

8. Aochi, H. and J. Douglas, Testing the validity of simulated strong ground motion from the dynamic rupture of a fault system, by using empirical equations, Bull. Earthq. Engineering, 4, 211--229, 2006.

9. Aochi, H., M. Cushing, O. Scotti, and C. Berge-Thierry, Estimating rupture scenario likelihood based on dynamic rupture simulations: the example of the segmented Middle Durance fault, southeastern France, Geophys. J. Int., 165, 436-446, 2006.

10. Ide, S. and H. Aochi, Earthquakes as multiscale dynamic ruptures with heterogeneous fracture surface energy, J. Geophys. Res., 110, B11303, doi:10.1029/2004JB003591, 2005.



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Publication List11. Aochi, H., O. Scotti, and C. Berge-Thierry, 3D dynamic rupture propagation along complex segments with

different mechanisms, Geophys. Res. Lett., 32, L21304, doi:10.1029/2005GL024158, 2005.

12. Aochi, H. and K. B. Olsen, On the effects of non-planar geometry for blind thrust faults on strong ground motion, Pure appl. Geophys., 161, 2139-2153, 2004.

13. Aochi, H. and S. Ide, Numerical Study on Multi-Scaling Earthquake Rupture, Geophys. Res. Lett., 31(2), 10.1029/2003GL018708, 2004.

14. Aochi, H. and R. Madariaga, The 1999 Izmit, Turkey, earthquake: Non-planar fault structure, dynamic rupture process and strong ground motion, Bull. Seism. Soc. Am., 93, 1249-1266, 2003.

15. Aochi, H. and E. Fukuyama and R. Madariaga, Constraints of Fault Constitutive Parameters Inferred from Non-planar Fault Modeling, Geichemistry, Geophysics, Geosystems, 4(2), 10.1029/2001GC000207, 2003.

16. Aochi, H. and M. Matsu'ura, Slip- and time-dependent fault constitutive law and its significance in earthquake generation cycles, Pure appl. Geophys., 159, 2029-2044, 2002.

17. Aochi, H., R. Madariaga and E. Fukuyama, Effect of Normal Stress During Rupture Propagation along Non-planar Fault, J. Geophys. Res., 107(B2), 10.1029/2001JB000500, 2002.

18. Aochi, H. and E. Fukuyama, Three-dimensional nonplanar simulation of the 1992 Landers earthquake, J. Geophys. Res., 107(B2), 10.1029/2000JB000061, 2002.

19. Aochi, H., E. Fukuyama and M. Matsu'ura, Selectivity of spontaneous rupture propagation on a branched fault, Geophys. Res. Lett., 27, 3635-3638, 2000b.

20. Aochi, H., E. Fukuyama and M. Matsu'ura, Spontaneous Rupture Propagation on a Non-planar Fault in 3D Elastic Medium, Pure appl. Geophys., 157, 2003-2027, 2000a.

> Proceedings of Conferences (13)



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Perspective

> Earthquake source : Physics and perspective to seismic hazard



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Earthquake Source Fundamental, pluri-disciplinary

problem seismology, fracture mechanics, tribology,

geochemistry, geodynamics

1. Governing physical equation2. Uncertainty of field information

Prediction of Strong Ground Motion

Prediction of (Large) Earthquakes

Perspective

> How does earthquake rupture evolve in a complex fault system?

> How does geological structure influence the earthquake generation or vice versa?

> Why and how are large and small earthquakes different? (Frequency contents)

> How does friction law evolve during seismic cycle? (intrinsic or evolutional)

> How does the environement (fluid etc. ) influence the earthquake?

> How is stress built up before earthquakes?



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Perspective

> Can a single numerical method model all the seismic phenomena?

> How can we answer the demands of engineers?

> How can we explain the extremity of hazard?

> How should we integrate observation into seismic hazard study?



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Perspective

> ANR DEBATE (2009 – 2011)• Development of Broadband Acceleration

Time histories for Engineers



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The 2007 Niigata-ken Chuetsu Oki earthquake by Aoi et al. (2008)

Perspective

> Contribution of earthquake source on the extremity of strong ground motion at near field.

> We are responsible to provide reliable « physical » source model, and then near-field broadband acceleration.

> The only way is to learn from earthquakes.



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Acknowledgement

> 9 years-experience in France

> 5 years-experience in Japan

> (2 months in California)

> I thank all the colleagues (University of Tokyo, ENS, IRSN, BRGM, …) for their encouraging, discussing, criticizing, and so on.

> I also thank all the people supporting me.



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Soutenance HDR Source Sismique - Physique et Perspective pour Aléa -

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