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Broad-band 3-D Physics-Based Simulation of Earthquake-induced Wave-Field at the Kashiwazaki-Kariwa Nuclear Power Plant (Japan): an All-Embracing Source-to-Site Approach.

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The influence of the regional 3-D geology on the synthetic earthquake ground motion prediction is herein assessed, studying the seismic response of Kashiwazaki-Kariwa nuclear power plant (KKNPP), during the 2007 Niigata seismic sequence (west Japan), so to explore the potentiality and practicability of the innovative computational tools available. This applicative case study was chosen within the framework of the SINAPS@ project, the first French research project which aims to propose a continuous approach from the fault to the structure and equipment’s, accounting explicitly for the uncertainties related to the databases and the models. A source-to-site numerical model of the region (≈ 60 km wide) is built-up and calibrated for small aftershocks including surface topography, Japan sea and complex 3-D underground foldings. The impact of complex 3-D geology in terms of seismic response at KKNPP is quantified, by comparison with the simplified transverse isotropic geology. This validation stresses the importance of the 3-D geology and explicates the observed high ground motion spatial variability, as well as the strong dependence of the site response on the incident wave obliquity. The synthetic wave-field (0-5 Hz) is obtained by employing SEM3D, a high-scalable software tailored based on the Spectral Element Method. This high-fidelity code performs efficiently (thanks to its high scalability on parallel supercomputers) when refining the model spatial discretization and increasing the bedrock-to-sediment shear wave velocity gradient. The synthetic wave-motion simulated was exploited as input motion for a Soil-Structure Interaction numerical model (Finite Element Method - Boundary Element Method, Code_Aster-MISS3D) of the standard reactor building at KKNPP. The impact of the 3-D geology is assessed therefore on the structural components, highlighting a considerable amplification compared to the case of layered one.
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Broad-band 3-D physics-based
simulation of earthquake-induced
wave-field at the Kashiwazaki-Kariwa
Nuclear Power Plant (Japan): an
all-embracing source-to-site approach
F. Gatti1
F. Lopez-Caballero1-D.Clouteau1-R.Paolucci2
1Lab. MSSMat UMR CNRS 8579 - CentraleSup´
elec
2DICA - Politecnico di Milano
1 / 24
An excursus on SINAPS@
An excursus on SINAPS@
2 / 24
S´
eisme et Installations Nucl´
eaires, Am´
eliorer et P´
erenniser la Sˆ
uret´
e
Improvement in Seismic Risk & Vulnerability assessment of
French Nuclear Facilities
Which were the open issues back in 2012 ?
IUncertainty quantification : Numerical vs Experimental modelling
ISafety Margins Estimation : Deterministic vs Probabilistic assessment
ICritical Perspective on current Design Standards : Risk & Vulnerability
An excursus on SINAPS@
An excursus on SINAPS@
2 / 24
S´
eisme et Installations Nucl´
eaires, Am´
eliorer et P´
erenniser la Sˆ
uret´
e
Improvement in Seismic Risk & Vulnerability assessment of
French Nuclear Facilities
Which were the open issues back in 2012 ?
IUncertainty quantification : Numerical vs Experimental modelling
ISafety Margins Estimation : Deterministic vs Probabilistic assessment
ICritical Perspective on current Design Standards : Risk & Vulnerability
Which were the open issues now in 2018 ?
IUncertainty quantification : How to integrate data and synthetics ?
ISafety Margins Estimation :
Span the scenario’s space with numerical simulations ?
ICritical Perspective on current Design Standards : Risk & Vulnerability
Improved broad-band physics-based numerical modelling
Improved broad-band physics-based numerical modelling
3 / 24
A new horizon
IRegional scale deterministic numerical simulation : SKY IS THE LIMIT !
+Fu et al. (2017) 18.9-Pflops Nonlinear Earthquake Simulation on Sunway
TaihuLight : Enabling Depiction of 18-Hz and 8-Meter Scenarios. Proceedings
of the International Conference for High Performance Computing,
Networking, Storage and Analysis, ACM, 2 :1-2 :12
IStudy the accuracy of numerical analysis !
IWithin the basin :
VSmin =650 m/s
IHeterogeneous ρ:
I`C,h=90 m
I`C,v=40 m
ItCPU =1487 h (30
sec)
I216 MPI cores
Mygdonian basin(7 Hz) Gatti, Touhami, Lopez-Caballero, Pitilakis NUMGE2018
Improved broad-band physics-based numerical modelling
Improved broad-band physics-based numerical modelling
3 / 24
A new horizon
IIntegrate data and numerical simulations
+Paolucci, Gatti, Infantino, Ozcebe, Smerzini & Stupazzini (2018)
Broad-band ground motions from 3D physics-based
numerical simulations using Artificial Neural Networks. BSSA
IHolistic approach : wave-propagation & structural vibration
http://news.mit.edu/sites/mit.edu.newsoce/ les/images/2013/20130906170823-0_0_0.jpg
IWithin the basin :
VSmin =650 m/s
IHeterogeneous ρ:
I`C,h=90 m
I`C,v=40 m
ItCPU =1487 h (30
sec)
I216 MPI cores
Improved broad-band physics-based numerical modelling
Improved broad-band physics-based numerical modelling
4 / 24
HPC platform for broad-band modelling
LEGO approach
Andrianov et al. (2011) (c)
A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
Outline
1A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
23-D numerical simulation of the NCO earthquake
3Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
4Conclusions and Perspectives
5 / 24
A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
Niigata-Ken Ch¯
uetsu-Oki Earthquake 16/07/2007
Niigata-Ken Ch¯
uetsu-Oki Earthquake 16/07/2007
5 / 24
Figure 1–Map of the surroundings of KKNPP and epicenters’
locations.
IMagnitude
IMw 6.6 - MJMA 6.8
IDepth
IHypocenter : 9 km
Max. 17 km
IFault mechanism
IBuried reverse-slip
A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
Niigata-Ken Ch¯
uetsu-Oki Earthquake 16/07/2007
Niigata-Ken Ch¯
uetsu-Oki Earthquake 16/07/2007
5 / 24
Figure 1–Map of the KKNPP site
IKashiwazaki-Kariwa Nuclear
Power Plant (KKNPP)
I7 reactors
I1st threshold : Operating Basis
Earthquake (OBE)
I2nd threshold : Safe Shutdown
Earthquake (SSE)
IDISTANCE
I15-20 km
IPGA SSE
Iground settlements 15cm
Ifire & damage to pipelines
Ipartial shut down till 2011
Gatti et al. Bull. Earthquake Eng. 2018 10.1007/s10518-017-0255-y
IHigh spatial variability
INear-field conditions
ILarge non-linear site effects (a few cases of liquefaction)
3-D numerical simulation of the NCO earthquake
Outline
1A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
23-D numerical simulation of the NCO earthquake
3Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
4Conclusions and Perspectives
6 / 24
3-D numerical simulation of the NCO earthquake
Construction of earthquake scenario
Construction of earthquake scenario
6 / 24
Targets
ICharacterize geology of Niigata area
ICharacterize geology in KK-NPP surroundings
Modelling features
IModel 1 : 90 km ×83 km ×83 km
1. Aftershock AS1 (MW4.4)
2. fmax = 3.75Hz
3. VS,min = 1000m/s
4. LAYERED geology
5. Topography
3-D numerical simulation of the NCO earthquake
Construction of earthquake scenario
Construction of earthquake scenario
6 / 24
Targets
ICharacterize geology of Niigata area
ICharacterize geology in KK-NPP surroundings
Modelling features
IModel 2 : 68 km ×50 km ×50 km
1. Aftershocks :
?AS1 (MW4.4)
?AS2 (MW4.2)
2. fmax = 5.07.0Hz
3. VS,min = 700m/s
4. FOLDED geology
5. Topography
6. Japan sea
3-D numerical simulation of the NCO earthquake Computational 3-D wave-propagation
Outline
1A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
23-D numerical simulation of the NCO earthquake
Computational 3-D wave-propagation
NCO wave-field in the Niigata region : Model 1
Include local geology at KK-NPP : Model 2
3Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
4Conclusions and Perspectives
7 / 24
3-D numerical simulation of the NCO earthquake Computational 3-D wave-propagation
SEM3D
SEM3D
7 / 24
Solve 3D Wave Propagation at Regional Scale
Spectral Element Method
High order FEM for 3D Solid and Fluid media
(Faccioli et al., 1997; Komatitsch, 1997)
ILagrange polynomials
IGauss-Lobatto-Legendre (GLL)
INaturally diagonal Mass matrix
ILeap-Frog solver
ISpectral Convergence (in p)
IABC : Perfectly Matched Layers (PML)
Efficiency and low numerical dispersion
IMassively parallel implementation
Moulon M´esocentre (Paris Saclay University)
3-D numerical simulation of the NCO earthquake NCO wave-field in the Niigata region : Model 1
Outline
1A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
23-D numerical simulation of the NCO earthquake
Computational 3-D wave-propagation
NCO wave-field in the Niigata region : Model 1
Include local geology at KK-NPP : Model 2
3Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
4Conclusions and Perspectives
8 / 24
3-D numerical simulation of the NCO earthquake NCO wave-field in the Niigata region : Model 1
Using aftershock to calibrate geological profile
Using aftershock to calibrate geological profile
8 / 24
Aftershocks AS1 : 07/16/2007 - MW4.4 ($$)
IPoint-wise double couple source
IMethodology
IWNI method ($$$) -fmax =0.5 Hz
ISEM3D analysis - fmax =3.75 Hz
3-D numerical simulation of the NCO earthquake NCO wave-field in the Niigata region : Model 1
Predict regional wave-field
Predict regional wave-field
9 / 24
Figure 2–Mesh of the Niigata region :
220988 nodes - 211410 elements - 3.7·108GLL.
12h on FUSION (Universit´
e Paris-Saclay) - 192 MPI cores.
7
3-D numerical simulation of the NCO earthquake NCO wave-field in the Niigata region : Model 1
Predict regional wave-field (0.1-3.75 Hz)
Predict regional wave-field (0.1-3.75 Hz)
10 / 24
10 20 30 40 50 60
10-1
100
101
102
103
PGAH[cm/s/s]
AS: Mj 4.4 2007-07-16 21:08
[km]
10 20 30 40 50 60
10-1
100
101
102
103
PGAH[cm/s/s]
[km]
AS: Mj 4.4 2007-07-16 21:08
Rise time estimation
Dreger et al. (2007)
Duputel et al. (2013)
0 0.4 0.8 1.2 1.6
t[s]
0
4
8
12
16
20 SVF
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
Outline
1A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
23-D numerical simulation of the NCO earthquake
Computational 3-D wave-propagation
NCO wave-field in the Niigata region : Model 1
Include local geology at KK-NPP : Model 2
3Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
4Conclusions and Perspectives
11 / 24
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
Coupling regional model with local geological structures
Coupling regional model with local geological structures
11 / 24
Tsuda et al. (2011) geological model
Figure 3–Folded geology beneath KK-NPP Tsuda et al. (2011)
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
Improved geological model : from 1D to 3D structure
Improved geological model : from 1D to 3D structure
12 / 24
SW
Mj4.4 - 16/07/2007-21:08
KKNPP
(a)
SC
Mj4.4 - 16/07/2007-21:08
KKNPP
(b)
SC
SW
Folding
Smoothing bands
SE
N
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
Assess the effect of local foldings
Assess the effect of local foldings
13 / 24
SG1-G.L. -2.4 m
SG4-G.L. -250 m
1G1-G.L. 0 m
5G1-G.L. 0 m
1G1
[cm/s/s]
5G1
SH
0.01 0.1 1 23
0
20
40
60
80
100 EW
0.01 0.1 1 23
0
20
40
60
80
100 NS
0.01 0.1 1 23
0
20
40
60
80
100 EW
0.01 0.1 1 23
0
20
40
60
80
100 NS
0.01 0.1 1 23
0
20
40
60
80
100 EW
0.01 0.1 1 23
0
20
40
60
80
100 NS
0.01 0.1 1 23
0
20
40
60
80
100 EW
0.01 0.1 1 23
0
20
40
60
80
100 NS
LAYERED vs FOLDED
fmax 5 Hz
Gatti et al. (2018) GJI 213, 1073-1092. doi : 10.1093/gji/ggy027
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
Assess the effect of local foldings
Assess the effect of local foldings
13 / 24
SG1-G.L. -2.4 m
SG4-G.L. -250 m
1G1-G.L. 0 m
5G1-G.L. 0 m
1G1
[cm/s/s]
5G1
SH
0.01 0.1 1 23
0
20
40
60
80
100 EW
0.01 0.1 1 23
0
20
40
60
80
100 NS
0.01 0.1 1 23
0
20
40
60
80
100 EW
0.01 0.1 1 23
0
20
40
60
80
100 NS
0.01 0.1 1 23
0
20
40
60
80
100 EW
0.01 0.1 1 23
0
20
40
60
80
100 NS
0.01 0.1 1 23
0
20
40
60
80
100 EW
0.01 0.1 1 23
0
20
40
60
80
100 NS
AS1
LAYERED vs FOLDED
fmax 5 Hz
Gatti et al. (2018) GJI 213, 1073-1092. doi : 10.1093/gji/ggy027
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
Assess the effect of local foldings
14 / 24
EW
NS
AS - 07/16/07 - 17:42 - Mw 4.2
AS - 07/16/07 - 21:08 - Mw 4.4
SG1-G.L. -2.4 m
SG4-G.L. -250 m
1G1-G.L. 0 m
5G1-G.L. 0 m
1G1
[cm/s/s]
5G1
SH
0.01 0.1 1 23
0
10
20
30
40
50 EW
0.01 0.1 1 23
0
10
20
30
40
50 NS
0.01 0.1 1 2
3
0
10
20
30
40
50 EW
0.01 0.1 1 23
0
10
20
30
40
50 NS
0.01 0.1 1 23
0
10
20
30
40
50 EW
0.01 0.1 1 23
0
10
20
30
40
50 NS
0.01 0.1 1 23
0
10
20
30
40
50 NS
0.01 0.1 1 23
0
10
20
30
40
50 EW
LAYERED vs FOLDED
fmax 5 Hz
Gatti et al. (2018) GJI 213, 1073-1092. doi : 10.1093/gji/ggy027
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
Assess the effect of local foldings
14 / 24
EW
NS
AS - 07/16/07 - 17:42 - Mw 4.2
AS - 07/16/07 - 21:08 - Mw 4.4
SG1-G.L. -2.4 m
SG4-G.L. -250 m
1G1-G.L. 0 m
5G1-G.L. 0 m
1G1
[cm/s/s]
5G1
SH
0.01 0.1 1 23
0
10
20
30
40
50 EW
0.01 0.1 1 23
0
10
20
30
40
50 NS
0.01 0.1 1 23
0
10
20
30
40
50 EW
0.01 0.1 1 23
0
10
20
30
40
50 NS
0.01 0.1 1 23
0
10
20
30
40
50 EW
0.01 0.1 1 23
0
10
20
30
40
50 NS
0.01 0.1 1 23
0
10
20
30
40
50 NS
0.01 0.1 1 23
0
10
20
30
40
50 EW
AS2
LAYERED vs FOLDED
fmax 5 Hz
Gatti et al. (2018) GJI 213, 1073-1092. doi : 10.1093/gji/ggy027
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
Assess the effect of local foldings (fmax = 5 Hz)
Assess the effect of local foldings (fmax = 5 Hz)
15 / 24
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8
t[s]
-2.4
-1.6
-0.8
0
0.8
1.6
2.4
vFN (t) [cm/s]
Mj 4.4 2007/07/16-21:08
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8
t[s]
-2.4
-1.6
-0.8
0
0.8
1.6
2.4
vFN (t) [cm/s]
Mj 4.4 2007/07/16-21:08
Figure 4–Velocigrams along FN direction @ 1G1 (Unit 1 - Free-Field)
3-D numerical simulation of the NCO earthquake Include local geology at KK-NPP : Model 2
On the accuracy of 3D physics-based model
On the accuracy of 3D physics-based model
16 / 24
0.01 0.1 0.5 1
T [s]
1
1.2
1.4
1.6
1.8
2
2.2
2.4
log 10 Sa [cm/s/s]
Mj 4.4 2007/07/16-21:08@1G1
0.01 0.1 0.5 1
T [s]
1
1.2
1.4
1.6
1.8
2
2.2
2.4
log 10 Sa [cm/s/s]
Mj 4.4 2007/07/16-21:08@5G1
All time-histories filtered at 7 Hz
0.01 0.1 1 2 3
T [s]
0
50
100
150
200
SaGMH [cm/s/s]
Mj 4.4 2007/07/16-21:08@1G1
5! GL L
7! GL L
10 ! GLL
3 4 5 6 7 8 9 10 11 12
GLL [1]
5
10
50
100
200
300
400
500
CPU-Time [1e6 s]
Figure 5 – f5GLL
max 3.5Hz ;f7GLL
max 5.0Hz ;f10GLL
max 7.0Hz
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
Outline
1A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
23-D numerical simulation of the NCO earthquake
3Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
4Conclusions and Perspectives
17 / 24
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
Broadband modelling : hybrid approach
17 / 24
Broadband modelling
IModelling challenge
IDeal with computational burden
IHF/SP is Deterministic ?
Stochastic
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
Broadband modelling : hybrid approach
17 / 24
NUMERICAL
SIMULATION
HYBRID
Numerical Simulations:
Range of applicability
f [Hz]
[1]
STOCHASTIC/EMPIRICAL
ACCURACY?
Broadband modelling
IModelling challenge
IDeal with computational burden
IHF/SP is Deterministic ?
Stochastic
LF/HF Hybridization
Graves and Pitarka (2004)
ILow-Frequency :
3D Physics-Based Simulation
IHigh-Frequency :
Empirical
(Semi-)Stochastic
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
Broadband modelling : hybrid approach
17 / 24
Paolucci et al. (2018) BSSA.
doi : 10.1785/0120170293
Broadband modelling
IModelling challenge
IDeal with computational burden
IHF/SP is Deterministic ?
Stochastic
LF/HF Hybridization
Graves and Pitarka (2004)
ILow-Frequency :
3D Physics-Based Simulation
IHigh-Frequency :
Empirical
(Semi-)Stochastic
Alternative Approach...
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
Alternative Hybrid Broadband modelling : ANN2BB
Alternative Hybrid Broadband modelling : ANN2BB
18 / 24
NUMERICAL
SIMULATION
HYBRID
ANN
Numerical Simulations:
Range of applicability
SPEED
SEM3D
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB Weak coupling with structural model
Outline
1A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
23-D numerical simulation of the NCO earthquake
3Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
Weak coupling with structural model
4Conclusions and Perspectives
19 / 24
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB Weak coupling with structural model
From source to the structure
From source to the structure
19 / 24
SEM3D+MISS3D+CODE ASTER
7-R2
7-R1
E
W
SEM3D
MISS3D
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB Weak coupling with structural model
ANN2BB to SEM3D simulations
ANN2BB to SEM3D simulations
20 / 24
0.01 0.1 1 2 3
T [s]
0
80
160
240
320
Sa GMH [cm/s/s]
AS1 @SG1
0.01 0.1 1 2 3
T [s]
0
80
160
240
320
Sa GMH [cm/s/s]
AS1 @1G1
Figure 6–ANN2BB pseudo-acceleration spectra (T?=0.75 s)
IImproved outcrop motion prediction
ISEM3D records filtered at fmax =5 Hz
IRecords and ANN2BB synthetics are
filtered at fmax =30 Hz
Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB Weak coupling with structural model
Response at reactor building basement
Response at reactor building basement
21 / 24
SEM3D+MISS3D+CODE ASTER
0.01 0.1 1 2 3
T[s]
0
20
40
60
80
100
Sa(T)[cm/s/s]
7R2
7-R2
7-R1
E
W
SEM3D
MISS3D
Conclusions and Perspectives
Outline
1A complex test case : the 2007 NCO earthquake and the KK-NPP seismic site
response
23-D numerical simulation of the NCO earthquake
3Broad-band earthquake simulations via Artificial Neural Networks : ANN2BB
4Conclusions and Perspectives
22 / 24
Conclusions and Perspectives
So far, so good
So far, so good
22 / 24
Large scale S2S analysis
towards fmax =10 Hz
Progressive refinement of regional/near wave-field
Small heterogeneities in the Earth’s crust
Site effects
Include complex soil rheology (non-linearity) and buried topography
(basin)
Conclusions and Perspectives
So far, so good
So far, so good
22 / 24
Large scale S2S analysis
towards fmax =10 Hz
Progressive refinement of regional/near wave-field
Small heterogeneities in the Earth’s crust
Site effects
Include complex soil rheology (non-linearity) and buried topography
(basin)
Hybrid modelling
ANN2BB to reach 30 Hz
Coherent distribution of peak values at HF
Structural analysis
Conclusions and Perspectives
Future Perspectives
Future Perspectives
23 / 24
Main shock simulation
include kinematic fault modelling (fractal model fmax =10 Hz)
dynamic rupture
(Ruiz et al., 2011)
Conclusions and Perspectives
Future Perspectives
Future Perspectives
23 / 24
Main shock simulation
include kinematic fault modelling (fractal model fmax =10 Hz)
dynamic rupture
Modelling site effects
Refine non-linear rheology
Include complex heterogeneous structure (von Karman, anisotropic)
SSI : SEM3D-SEM3D Domain Reduction Method
Pe
Ωext
Ω0
ue
ub
ui
Γb
Γe
-Pb
Pb
0
0
0
0
0
Conclusions and Perspectives
Future Perspectives
Future Perspectives
23 / 24
Main shock simulation
include kinematic fault modelling (fractal model fmax =10 Hz)
dynamic rupture
Modelling site effects
Refine non-linear rheology
Include complex heterogeneous structure (von Karman, anisotropic)
SSI : SEM3D-SEM3D Domain Reduction Method
Pe
Ωext
Ωint
ue
ub
ui
Γb
Γe
-Pb
Pb
(Bielak et al., 2003)
Conclusions and Perspectives
24 / 24
Make CivEng Great Again !
Filippo Gatti
filippo.gatti@centralesupelec.fr
filippo.gatti@polimi.it
https://github.com/FilLTP89
Science has limits : A few things that science does not do
No moral judgment
No aesthetic judgment
No rules in how to use it
No conclusions on supernatural phenomena
http://undsci.berkeley.edu/article/0 0 0/whatisscience 12
Andrianov, S., Ivanov, A., and Podzyvalov, E. (2011). A LEGO Paradigm For Virtual Accelerator Cocept. In ICALEPCS2011, volume 3, pages
728–730.
Bielak, J., Loukakis, K., Hisada, Y., Yoshimura, C., Chiaki, Y., Ferna, A., Bielak, J., Hisada, Y., and Ferna, A. (2003). Domain Reduction Method for
Three-Dimensional Earthquake Modeling in Localized Regions. Part 1 : Theory. Bulletin of the Seismological Society of America, 93(2) :817–840.
Dreger, D., Hurtado, G., Chopra, A. K., and Larsen, S. (2007). Near-Fault Seismic Ground Motions. Technical Report 59A0435, California
Department of Transportation.
Duputel, Z., Tsai, V. C., Rivera, L., and Kanamori, H. (2013). Using centroid time-delays to characterize source durations and identify earthquakes
with unique characteristics. Earth and Planetary Science Letters, 374 :92–100.
Faccioli, E., Maggio, F., Paolucci, R., and Quarteroni, A. (1997). 2D and 3D elastic wave propagation by a pseudo-spectral domain decomposition
method. Journal of Seismology, 1(3) :237–251.
Graves, R. W. and Pitarka, A. (2004). Broadband time history simulation using a hybrid approach. In 13th World Conference on Earthquake
Engineering, Vancouver, B.C., Canada.
Hisada, Y. (1994). An efficient method for computing Green’s Functions for layered half-space with sources and receivers at close depths. Bulletin of
the Seismological Society of America, 84(5) :1456–1472.
Komatitsch, D. (1997). ethodes spectrales et ´el´ements spectraux pour l’´equation de l’´elastodynamique 2D et 3D en milieu h´et´erog`ene (Spectral
and spectral-element methods for the 2D and 3D elastodynamics equations in heterogeneous media). PhD thesis, Institut de Physique du Globe,
Paris, France. 187 pages.
Ruiz, J. A., Baumont, D., Bernard, P., and Berge-Thierry, C. (2011). Modelling directivity of strong ground motion with a fractal, k-2, kinematic
source model. Geophysical Journal International, 186(1) :226.
Tsuda, K., Hayakawa, T., Uetake, T., Hikima, K., Tokimitsu, R., Nagumo, H., and Shiba, Y. (2011). Modeling 3D Velocity Structure in the Fault
Region of the 2007 Niigataken Chuetu-Oki Earthquake with Folding Structure. In 4th IASPEI/IAEE International Symposium-Effects of Surface
Geology on Seismic Motion, pages 1–11.
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There are many engineering applications that require an understanding of the nature of strong ground motions adjacent to and spanning across faults. Unfortunately, such near-field observations at distances less than 100 m of fault rupture are few and incomplete. In this study a 3D finite-difference method is used to simulate strong ground motions for a hypothetical M-w 6.5 earthquake at sites within a few tens of meters of the fault to document the nature of strong ground motion at pairs of sites across the fault as a first step toward providing ground-motion input for engineering design applications. We employ several distributed slip kinematic models to examine ground-motion variability. We also examine the ground motions for fault scenarios ranging from vertical strike-slip to low-angle thrust faulting. The results show that the motions have two primary components: (1) far-field waves that undergo focusing and amplification due to finite-source rupture directivity and (2) near-field waves that are sensitive to the tectonic rebound, or fling, of the closest section of the fault to the recording stations. Both the far-field and near-field controlled motions result in nonstationary pulse-like velocity waveforms that have many implications for the design of engineered structures located close to or spanning faults.
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A new numerical method is presented for propagating elastic waves in heterogeneous earth media, based on spectral approximations of the wavefield combined with domain decomposition techniques. The flexibility of finite element techniques in dealing with irregular geologic structures is preserved, together with the high accuracy of spectral methods. High computational efficiency can be achieved especially in 3D calculations, where the commonly used finite-difference approaches are limited both in the frequency range and in handling strongly irregular geometries. The treatment of the seismic source, introduced via a moment tensor distribution, is thoroughly discussed together with the aspects associated with its numerical implementation. The numerical results of the present method are successfully compared with analytical and numerical solutions, both in 2D and 3D.
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The relationship between M-0 and the rupture duration is often difficult to establish. This is particularly true for large earthquakes for which the moment rate functions (MRF) generally have complicated shapes, and the estimated durations can vary considerably depending on the methodology used to evaluate the MRF. In this work, we show that the centroid time-delay (tau(c)) provides an alternative estimate of the source duration. Inverted MRFs often end gradually, making the end of coseismic rupture difficult to detect. In such cases, when the rupture duration is not well defined, the time-delay tau(c) is a useful quantity to represent the first-order temporal characteristics of the rupture process. Variations in stress parameter Delta sigma can be investigated by assuming a standard scaling relationship between the seismic moment M-0 and tau(c). This simple scaling relationship can also be used to identify unusual earthquakes, with unique source properties, such as events involving complicated rupture processes or earthquakes characterized by unusual rupture velocities, stress drops or aspect ratios.
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We propose an analytical method to compute efficiently the dis-placement and stress of static and dynamic Green's functions for viscoelastic layered half-spaces. When source and receiver depths are close, it is difficult to compute Green's functions of the layered half-space, because their inte-grands, whose variable of integration is the horizontal wavenumber, oscillate with only slowly decreasing amplitude. In particular, when the depths are equal, it is extremely difficult to compute the stress Green's functions, because their integrands oscillate with increasing amplitude. To remedy this problem, we first derive the asymptotic solutions, which converge to the integrands of Green's functions with increasing wavenumber. For this purpose, we modify the gen-eralized R/T (reflection and transmission) coefficient method (Luco and Apsel; 1983) to be completely free from growing exponential terms, which are the obstacles to finding the asymptotic solutions. By subtracting the asymptotic so-lutions from the integrands of the corresponding Green's functions, we obtain integrands that converge rapidly to zero. We can,. therefore, significantly reduce the range of wavenumber integration. Since the asymptotic solutions are ex-pressed by the products of Bessel functions and simple exponential functions, they are analytically integrable. Finally, we obtain accurate Green's functions by adding together numerical and analytical integrations. We first show this asymptotic technique for Green's functions due to point sources, and extend it to Green's functions due to dipole sources. Finally, we demonstrate the validity and efficiency of our method for various cases.
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The kinematic fractal source model presented in this study is able to simulate broad-band accelerograms with spectral amplitudes proportional to a fraction of the directivity coefficient Cd in the far-field approximation. This approach is based on a composite source description, where subevents are generated using a fractal distribution of sizes, and, by summation, produces k-square space distribution of the slip. Each elementary source is described as a crack-type slip model growing circularly from a nucleation point when the rupture front reaches it. In order to better control the directivity effect, the location of the nucleation point for an elementary source is assumed to be scale-dependent. For the larger sources, the nucleation point is located near the intercept of the crack with the rupture front, whereas for smaller sources, it is randomly chosen within the crack. For simplicity, a constant rupture velocity is assumed. Each subevent is set up with scale-dependent rise-time, assuming a boxcar source–time function, hence filtering out its own high frequency radiation. The resulting mean slip-velocity functions are very similar to the ones derived from dynamic rupture modelling. Ground motion synthetics are computed by convolving the slip-velocity functions with the Green's functions. It is demonstrated that, in the far-field approximation, accelerogram spectra follow the ω2 model with amplitudes controlled by the frequency-dependent directivity effects. In particular, spectral amplitudes at high-frequencies are proportional to a fraction of Cd. These results were verified for few earthquake magnitudes. In addition, a validation exercise was made in the near-fault region by modelling the complete wavefield of strong ground motion at a few receivers and for several rupture scenarios. The synthetic strong-motion parameters are compared to the ones predicted by empirical attenuation relationships. It is shown that calculated standard deviations are in good agreement with the empirical ones, as well as the ground-motion parameter amplitudes predicted as a function of distance for whole interval of source distance considered in modelling. Minor differences were found in peak ground-accelerations computed at large distance from the fault, a problem related to the simplified response of the medium.
A LEGO Paradigm For Virtual Accelerator Cocept
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  • A Ivanov
Andrianov, S., Ivanov, A., and Podzyvalov, E. (2011). A LEGO Paradigm For Virtual Accelerator Cocept. In ICALEPCS2011, volume 3, pages 728-730.
Broadband time history simulation using a hybrid approach
  • R W Graves
  • A Pitarka
Graves, R. W. and Pitarka, A. (2004). Broadband time history simulation using a hybrid approach. In 13 th World Conference on Earthquake Engineering, Vancouver, B.C., Canada.
Modeling 3D Velocity Structure in the Fault Region of the 2007 Niigataken Chuetu-Oki Earthquake with Folding Structure
  • K Tsuda
  • T Hayakawa
  • T Uetake
  • K Hikima
  • R Tokimitsu
  • H Nagumo
  • Y Shiba
Tsuda, K., Hayakawa, T., Uetake, T., Hikima, K., Tokimitsu, R., Nagumo, H., and Shiba, Y. (2011). Modeling 3D Velocity Structure in the Fault Region of the 2007 Niigataken Chuetu-Oki Earthquake with Folding Structure. In 4 th IASPEI/IAEE International Symposium-Effects of Surface Geology on Seismic Motion, pages 1-11.