Regional Workshop on Essential Knowledge of Site Evaluation Report for Nuclear Power Plants.

Transcription

1 Regional Workshop on Essential Knowledge of Site Evaluation Report for Nuclear Power Plants. Development of seismotectonic models Ramon Secanell Kuala Lumpur, August 2013

2 Overview of Presentation Main concepts about seismotectonic model in SSG-9 Regional seismotectonic model Local seismotectonic model Seismic characterization of seismotectonic sources Treatment of uncertainties associated to seismotectonic model Example of regional and local seismotectonic model 2

3 Overview of Presentation Main concepts about seismotectonic model in SSG-9 Regional seismotectonic model Local seismotectonic model Seismic characterization of seismotectonic sources Treatment of uncertainties associated to seismotectonic model Example of regional and local seismotectonic model 3

4 Necessary Information for the construction of the seismotectonic model. a) Geological, geophysical, geotechnical and seismological database. b) 4 spatial scales: a) Regional (300 km) b) Near regional (25 km) c) Site vicinity (5 km) d) Site area (1 km) c) Data compiled in a SIG 4

5 Seismotectonic model a) Introduction: 1. Link between geological, geophysical and geotechnical database and seismological database. 2. Identification of seismogenic structures: faults or systems of faults and zones of diffuse seismicity. 3. Evaluation and characterization of seismic sources and its uncertainty (Characteristic model, Poissonian model). 4. Epistemic uncertainty should be considered and weighted. Alternative models should be used. 5. Use of palaeoseismology. 6. Magnitude of the catalogue should be the same as the magnitude of the attenuation relationship used (Mw preferred due to the non saturation). 5

6 Seismotectonic model a) Introduction: 7. The magnitude-frequency should identify the parameters describing the seismic exceedance rate in function of magnitude and the maximum magnitude for each source (Typically, b-value, a-value and Mmax). 8. Uncertainty in seismic parameters should be considered. 9. Attention to the definition of Mmax (key parameter for long return periods). 10. Use of paleoseismicity in order to: a) Identification of seismogenic structures b) Improvement of the completeness (large events, high magnitudes) c) Definition of Mmax 6

7 Seismotectonic model b) Seismogenic structures: Safety Guide (SSG-9) Identification and characterization: 1. Consideration of seismogenic sources able to produce a ground motion in the site (in the frequency range of interest). 2. Analysis of surface faulting and fault displacement. 3. Identification of seismogenic sources using: geological, geophysical, geotechnical and seismological data. 4. Identification of the geometry, segmentation, branching, focal mechanism, etc. and its uncertainty. 5. Identification of Mmax. 6. Identification of a magnitude-frequency relationship (typically characteristic or exponential) and its uncertainties 7

8 Regional seismotectonic model c) Zones of diffuse seismicity: 1. Identification of the diffuse zones taking into account depth of the earthquakes, rates of earthquakes, etc. 2. Depth and its uncertainty are a key parameter in PSHA. 3. Identification of Mmax with historical and instrumental data., comparison with similar regions, etc. 4. Determination of the magnitude-frequency relation. Attention should be paid to the definition of b-value. 8

9 Overview of Presentation Main concepts about seismotectonic model in SSG-9 Regional seismotectonic model Local seismotectonic model Seismic characterization of seismotectonic sources Treatment of uncertainties associated to seismotectonic model Example of regional and local seismotectonic model 9

10 Example of Regional Seismotectonic zonation: The geometry of zones should be justified 10

11 Example of Regional Seismotectonic Zonation: The geometry of zones should be justified with data 11

12 Overview of Presentation Main concepts about seismotectonic model in SSG-9 Regional seismotectonic model Local seismotectonic model Seismic characterization of seismotectonic sources Treatment of uncertainties associated to seismotectonic model Example of regional and local seismotectonic model 12

13 The objective if to defined the geometry and seismic parameters of a fault: 13

14 Example of Local Seismotectonic Zonation. Use of existing data

15 Example of Local Seismotectonic Zonation Use of existing data

16 Example of local seismotectonic zonation: seismic reflexion profiles. Use of existing data Seismic reflexion profiles

17 Example of local seismotectonic zonation: aerial photographies Use of existing data

18 Example of Local Seismotectonic Zonation Possible capable fault. Bibliographic evidences: geological cross-sections, geological maps, etc.

19 Example of seismotectonic zonation: local scale Generation of new data High resolution seismic reflexion profiles gives us a good image of the sub-surface

20 Example of seismotectonic zonation: local scale High resolution seismic reflexion Profiles: characterization of geometry and location of faults

21 Example of seismotectonic zonation: local scale High resolution seismic reflexion Profiles: characterization of geometry and location of faults

22 Overview of Presentation Main concepts about seismotectonic model in SSG-9 Regional seismotectonic model Local seismotectonic model Seismic characterization of seismotectonic sources Treatment of uncertainties associated to seismotectonic model Example of regional and local seismotectonic model 22

23 Characterization of the seismic sources: seismic distribution Poisson model: GR law, log10(n)=a+bm. Parameters: a, b,, β, (a), (b), ( ), (β), Mmax, Mmin Characteristic model. Parameters: Tc, Mc and Elapsed time from last earthquake 23

24 Characterization of the seismic sources 24

25 Methods to fit the GR law: Safety Guide (SSG-9) Least squares (old methodology) Maximum likelihood methods Weichter method (1980), free code Kijko method (2002, 2012), commercial code The maximum likelihood methods are preferred because they allow to take into account the periods of completeness and a better consideration of the number of earthquakes Par range of magnitude 25

26 Methods to fit the characteristic model: Needed parameters are: Characteristic earthquake. It is determined using physical equations or paleoseismicity Wells & Coppersmith (1994) Todorovska (2007) Others Return period of characteristic earthquake. It is determined using paleoseismicity or using the slip rate methods. Elapsed time since the last earthquake 26

27 Slip rate method Fast slip rate & big fault Slow slip rate & small fault 27

28 Seismic characterization of seismic sources. Depth and Mmax 28

29 Seismic characterization of seismic sources : Depth Depth can be estimated using instrumental data and/or geological information 29

30 Seismic characterization of seismic sources: Mmax Mmax can be estimated taking into account some methods to propagate the uncertainties 30

31 Example of seismic parameters of a seismotectonic model. Input data for a PSHA Zone a b a b b Mmin ajust Data fitted b Mmin ajust Mmax Obs. Step mag. SEISMIC PARAMETERS. CATALOGUE Mw File Per. Comp. Mmin / km² * 10E6 Data recalculated from a and b for a new Mmin b Mmin Mmin calc. b H Hmoy Mmax periodes_mw.dbf à à periodes_mw.dbf à à periodes_mw.dbf à à periodes_mw.dbf à à Mmax moy surface (km) 31

32 Overview of Presentation Main concepts about seismotectonic model in SSG-9 Regional seismotectonic model Local seismotectonic model Seismic characterization of seismotectonic sources Treatment of uncertainties associated to seismotectonic model Example of regional and local seismotectonic model 32

33 Why do we introduce faults in a PSHA? PSHA study in Provence: example of fault treatment Seismicity models Gutenberg-Richter based on earthquake catalogue Characteristic earthquake based on moment rate distribution Objectives Compare faults models with zone models Include these models in the logic tree Impact on the hazard assessment. 33

34 New Seismotectonic zonation 1773 RÉGION TRICASTIN DIOIS-BARONNIES 1866 CHAINES SUBALP MÉRIDIONALE PROVENCE OCCIDENTALE PROVENCE ORIENTALE GOLFE DU LION-CAMARGUE Kilomètres Old Seismotectonic zonation 34

35 Western Provence fault model for PSHA UNCERTAINTIES Geometry trace segmentation dip depth Slip rate Single/multi segment rupture Recurrence model Background seismicity 35

36 Probabilistic logic tree Epistemic uncertainties Aleatory uncertainties Seismotectonic model Seismicity distribution Attenuation model Source parameters RFS & catalogue Ms [0.33], b, H, Mmax (zones) Regional zonation [0.33] Gutenberg-Richter [1] Campbell & Bozorgnia (2003) & catalogue Mw [0.33], b, H, Mmax (zones) Sabetta & Pugliese (1996) & catalogue MLLDG [0.33], b, H, Mmax (zones) Probabilistic Logic tree RFS & catalogue Ms [0.33], b, H, Mmax, b, H, Mmax (faults) (zones) Single segment rupture [0.75] Gutenberg-Richter [0.5] Campbell & Bozorgnia (2003) & catalogue Mw [0.33], b, H, Mmax, b, H, Mmax (faults) (zones) Fault model + Regional zonation [0.66] Multi segment rupture [0.25] Characteristic model (faults) + Gutenberg-Richter (zones) [0.5] Sabetta & Pugliese (1996) & catalogue MLLDG [0.33] RFS & catalogue Ms [0.33] Campbell & Bozorgnia (2003) & catalogue Mw [0.33] Sabetta & Pugliese (1996) & catalogue MLLDG [0.33], b, H, Mmax, b, H, Mmax (faults) (zones) H, V, Mca r, T car (faults), b, H, Mmax (zones) H, V, Mca r, T car (faults), b, H, Mmax (zones) H, V, Mca r, T car (faults), b, H, Mmax (zones) 36

37 Total Logic tree : Seismic hazard map 475 years Negligible contribution of faults 37

38 Total Logic tree : Seismic hazard map 1975 years Low contribution of faults 38

39 Total Logic tree : Seismic hazard map 5000 years Conclusion: Uncertainties in PSHA can be reduced using new data Significant contribution of faults 39

40 Overview of Presentation Main concepts about seismotectonic model in SSG-9 Regional seismotectonic model Local seismotectonic model Seismic characterization of seismotectonic sources Treatment of uncertainties associated to seismotectonic model Example of regional and local seismotectonic model 40

41 Geological, geophysical, seismological database of Peru-Chilean region Seismicity, geological cross-sections, etc 41

42 Geological, geophysical, seismological database of Peru-Chilean region Morphology, tectonic units, geological cross-section 42

43 Regional shallow seismic zonation of the Chilean-Peru region Summary of the characteristics of the zones 43

44 Regional shallow seismic zonation of the Chilean-Peru region Seismic and Geological parameters of the zones 44

45 Regional shallow seismic zonation of the Chilean-Peru region with seismic catalogue Seismic parameters needed in a PSHA 45

46 Regional subduction seismic zonation of the Chilean-Peru region with cross section 46

47 Regional subduction seismic zonation of the Chilean-Peru region with depth of the subduction 47

48 Regional subduction seismic zonation of the Chilean-Peru region with seismic catalogue Seismic parameters needed in a PSHA 48

49 Local seismotectonic zonation: consideration of faults 49

50 Thank you for your attention This activity is conducted by the IAEA, with funding by the European Union. The views expressed in this presentation do not necessarily reflect the views of the European Union.