s eismic wave p ropagation and i maging in c omplex media: a e uropean network

www.spice-rtn.orgSPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland

Seismic wave Propagation and Imaging in

Complex media: a European network

Yilong Qin Early Stage Researcher

Host Institution: IPG, ParisPlace of Origin: Beijing, ChinaAppointment Time: Jan. 2005

Project: A SPICE synthetic dataset to benchmark global tomographic methods

Task Groups: Planetary Scales

Cooperation: Universitetet I Oslo, Norway University of Utrecht, Netherlands

Yilong Qin Early Stage Researcher

Host Institution: IPG, ParisPlace of Origin: Beijing, ChinaAppointment Time: Jan. 2005

Project: A SPICE synthetic dataset to benchmark global tomographic methods

Task Groups: Planetary Scales

Cooperation: Universitetet I Oslo, Norway University of Utrecht, Netherlands


Content

• Project Scope

• Benchmark of benchmark

• Final benchmark

• Conclusions


Project Scope

There is general agreement about the location of long-wavelength structure. But the small-scale features still vary considerably from author to author

From The Reference Earth Model Website (http://mahi.ucsd.edu/Gabi/rem.html)


The benchmark of benchmark

• Model build

• Acquisition geometry

• Computation

• Synthetic data

• Inversion results


Model build

0 1 e+ 06 2 e+ 0 6 3e + 06 4 e+ 06 5e + 06 6 e+ 06 7 e+ 06R ad ius ( km )

0

5 0 00

1 00 00

1 50 00

-0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08

1D model (red) and PREM model (black)

3D model (Vs). Depth-independent

Large-, medium- and samll-scale anomaly.

Model parameters: isotropic Vp, Vs and density, gravity, attenuation

1D reference model and 3D model


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1 1 1 2

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Acquisition geometry

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XMAS_PSI

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DBIC

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CTAOMBWA_RER _RAR BRAS_LVCLB TB PTCNWARB CPUP_RPN

_LCONRFK _RAO TR INARM AWOOL STKA_SUR BBOO_CAN

TR IS_A IS TRQA

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_PA F

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ORCD

PMSACASY _DRV_M AW_SYO

DGAR _UGM ASCN

SNAA_TNV_DCC

QSPA

MARQ_PMG _HNR

_SPA

27 events

256 receivers

Distribution of events and station


Computation

• 3D Coupling Spectral Elements and Modal Solution (CSEM) (Capdeville et al., )

• Z, N-S and E-W velocity component

• Not consider the effect of ellipticity, crust, topography, ocean and rotation of real Earth.

• 10500s records


Time (s) Frequency (Hz)

0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0-3 e + 1 2

-2 e + 1 2

-1 e + 1 2

0

1 e + 1 2

2 e + 1 2

3 e + 1 2

Tim e (s)

Am

plit

ud

e

Upper: comparison between CSEM and Normal-mode

Lower: Source wavelet (left) and its spectrum (right) (minimum period 50s)


Synthetic data

Comparison seismograms between 1D and 3D model

-0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08

0 90 180 270-90

0

90

0 90 180 270-90

0

90

FFC

C OYC

XMAS

FFC COYC

XMAS


InversionAutomated multimode inversion based on time-frequency partition of waveform (Lebedev et al.,

2005)

Courtesy of S. Lebedev


Inversion results (Sergei Lebedev)


The final benchmark

• Acquisition geometry

• Model build

• Computation

• Synthetic data


Distribution of stations and events. Near the location of red beach ball, three events are calculated.

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_ H D C_ K O D_ A G D

G U M O_ T G Y _ M B O K O W A_ F D F_ T P X S A C VP N IGJ O H N_ H Y B _ S J G_ S R RC H T O _ Q I Z C O L MW A K E P O H A

X M A S_ P S I

T E IGL Y U BA B U S_ T A M W S A RR AY N M C S J_ K M I N A G O

_ O G S _ H 2 O_ E VN D W P F_ M D Y_ N D I _ T B TS IW A _K B D _L T X_E IL _ H K T_ Q U E _ E N H _ S S E _ TK AG H A R _ TU C _ B E CM A R J _B A R _ M D TN H S C_ H C H_ N I L _O X FW M O K_ A L Q_C S SK R IS _K S H _ T T T_ W D D_ T H R _ P K D_ L Z H_ M E B _ TJ N _ K N B_ S S Y E R I P

C M L A_ TA B _ A O BM A L T G W D E_G A R_ V S L

_ B N G B O C O _ C AY

_ B J T A C S O_ B M N_ A R C_ W U S_ T I R_ C A D G I G S _ H R VA H ID J F W S_ N M R_ W M Q_ K IV R S S D_ M D J _ H A LS A D O_ B N I _ R B N_ M L R R A ION E 5 6 M A K Z _ C B M

_ U L N_ P S Z E Y M N_ F U R _ N E WD R L N_ H I A K A P OA K T K _ S B D_ P H CK U R K_ G S H_ B H M _ T L Y _ A D KN E 5 4 _ S M Y_ V O S _ P ET M O BC _ E D M

_U V AB S E G_ F F C S C H Q_ N V S_ M H V _ E K BP R YA B M B C_A R U _ S IT_ K D CN E 5 2 D L B C _ F C C

_ M A 2K O N O _ U P P

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_ S C O _ J M IT I X I

_ R E S_ M B C _ D A G

_ K B S

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_ A L E

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_ P P T_ P V CF I T Z VA V AA B P OT S U M_ W R A

K N T N_J A Y

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B R A S_ L V C

LB T B P T C NW A R B C P U P_ R P N

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_ C A NT R I S_ A I S T R Q A

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C O Y CC R Z F

_ PA F

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_ M AW_ S Y O

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_ T N V_ D C C

Q S P A

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90 180

0.

0 9 0 1 8 0 2 7 0 3 6 0-9 0

0

9 0


Model build

• Model parameters: P-wave isotropic average velocity, S-wave isotropic average velocity, Density, quality factor(Qmu), anisotropic parameter for vertically transverse anisotropic (xi, phi and eta) and the orientation of the crystal

• 1D model

• 3D variation

• Crustal model

• Topography and bathmetry


1D Valerie model

• Anisotropic model (D” layer, upper mantle and transition zone)

• Six layer (D’’, lower lower mantle, upper lower mantle, transition zone, upper mantle and crust)

• boundary is 3480.0km, 3780.0km, 4700.0km, 5701.0km, 5971.0km, 6345.0km, 6371.0km.

0 1 e + 0 6 2 e + 0 6 3 e+ 0 6 4 e + 0 6 5e + 06 6 e + 0 6 7 e+ 0 6R a d iu s ( k m )

0

5 0 0 0

1 0 0 0 0

1 5 0 0 0


0 100 200 300 400angular order

0

10

20

30an

gula

r fr

eque

ncy

(mH

z) PREMValerie-1D

Comparison of Eigenfrequency for 1D Valerie model and PREM


P, S and density variation(release after blind test)

• Random part: defined as spherical harmonic component. we have added mixture of adjacent layers over a depth interval of 250km.

• The deterministic part: medium- and small-scale variation

• S-wave and density variation are coupled with P-wave variation

• Crystal with variable orientation of symmetry


-0.08 0.00 0.08 0.16 0.24

0 90 180 270 360-90

0

90

Crustal model for Vs

-0.08 0.00 0.08 0.16 0.24

0 90 180 270 360-90

0

90

Crustal model for density

The crust has a significant impact on the observed seismic data but, at the same time, is too thin to be resolved by them.

Crustal model (smoothed CRUST2.0)

Constant depth=26km


-50 -25 0 25 50

Topography and bathmetry (ETOPO5)

The ocean are incorporated in the CSEM by introducing an equivalent load a the ocean floor( Dimitri Komatitsch and Jeroen Tromp, 2002)


Computation• Algorithm• coupling spectral element method (including the effect of anisotropy,

gravity, attenuation, rotation, ocean, ellipticity, topography)

• Computation time• Total hours is about 70000 CPU hours• Time step 0.35s, a compromise between numerical dispersion

and computation cost.

• Implementation• IPGP (Institut de physique du globe de Paris)• IDRIS (Institut du Développement et des Ressources en

Informatique Scientifique) • CINES (Centre Informatique National de l'Enseignement

Supérieur)


Courtesy of Capdeville

Coupling Spectral-element method (CSEM)

Meshtopography

Ocean


Source wavelet

Tim e(s)

An heavis wavelet with frequency up to 0.031Hz (minimum period 32s )

wavelet spectrum


Time (s)

Derivative of source wavelet and the corresponding spectrum


3980 3990 4000 4010 4020

-5e-08

0

5e-08

1e-07

Time (s)

Comparison between normal-mode (black) and CSEM (red for 0.2s of time step , green for 0.4s time step) for minimum period of 32s.

Numerical dispersion for maximum period 32s


Synthetic data

• Three component (Z, N-S, E-W) velocity wavefield• Record length 10500s• Sampling rate is 1s• Format AH• No instrutment response • Add real noise from GEOSCOPE TAM


Time (S)

Station PAYG for event 09 (coupling between T, L and Z) for Valerie 1D model

Frequency (Hz)

spectrum

synthetic

T

L

Z


Time (s)

Frequency (Hz)

Time (s)

Z component for station PAYG of event 09

Blue (3D model) and red (1D model)

Filtered ( >200s)


Time (s)

Time (s)

Frequency (Hz)

L component for station PAYG of event 09


Filtered (>200s)


Time (s)

Time (s)

Frequency (Hz)

T component for station PAYG of event 09


Filtered >200s


Seismic noise for GEOSCOPE station TAM

E and N component of noise is much stronger than Z component

Time (s)Frequecy (Hz)


download

• http://www.ipgp.jussieu.fr/~qyl/benchmark_no_noise (about 1G) • http://www.ipgp.jussieu.fr/~qyl/benchmark_with_noise (about 1G) • README, 1D reference model, Source wavelet and dataset


Conclusions

• Perform benchmark of benchmark

• A complex 3D global anisotropic elastic model has been created

• A high quality anisotropic elastic dataset has been created

• Data and model (after blind test) are freely available


uses• phase velocity inversion• Waveform inversion• CMT inversion

Limitations• Minimum period 32s


acknowledgement

• SPICE

• Service de Calcul Parallèle, in Institut de Physique du Globe de Paris

• Sergei Lebedev (University of Utrecht)

s eismic wave p ropagation and i maging in c omplex media: a e uropean network

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