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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Seismic wave Propagation and Imaging inComplex media: a European network
Yilong Qin
Early Stage Researcher
Host Institution: IPG, Paris
Place of Origin: Beijing, China
Appointment Time: Jan. 2005
Project: A SPICE synthetic dataset to benchmark globaltomographic methods
Task Groups: Planetary Scales
Cooperation: Universitetet I Oslo, Norway
University of Utrecht, Netherlands
Yilong Qin
Early Stage Researcher
Host Institution: IPG, Paris
Place of Origin: Beijing, China
Appointment Time: Jan. 2005
Project: A SPICE synthetic dataset to benchmark globaltomographic methods
Task Groups: Planetary Scales
Cooperation: Universitetet I Oslo, Norway
University of Utrecht, Netherlands
www.spice-rtn.org
SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Content
•Project Scope
•Benchmark of benchmark
•Final benchmark
•Conclusions
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Project Scope
There is general agreement about the location of long-wavelengthstructure. But the small-scale features still vary considerably fromauthor to author
From The Reference Earth Model Website (http://mahi.ucsd.edu/Gabi/rem.html)
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
The benchmark of benchmark
•Model build
•Acquisition geometry
•Computation
•Synthetic data
•Inversion results
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Model build
1D model (red) and PREMmodel (black)
3D model (Vs). Depth-independent
Large-, medium- and samll-scaleanomaly.
Model parameters: isotropic Vp, Vsand density, gravity, attenuation
1D reference model and 3D model
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Acquisition geometry
27 events
256 receivers
Distribution of events and station
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
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
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Upper: comparison between CSEM and Normal-mode
Lower: Source wavelet (left) and its spectrum (right) (minimum period 50s)
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Synthetic data
Comparison seismograms between 1D and 3D model
FFC
COYC
XMAS
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
InversionAutomated multimode inversion based on time-frequency partition of waveform (Lebedev et al., 2005)
Courtesy of S. Lebedev
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Inversion results (Sergei Lebedev)
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
The final benchmark
•Acquisition geometry
• Model build
•Computation
•Synthetic data
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Distribution of stations and events.Near the location of red beach ball,three events are calculated.
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
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 andeta) and the orientation of the crystal
•1D model
•3D variation
•Crustal model
•Topography and bathmetry
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
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.
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Comparison of Eigenfrequency for 1D Valerie model and PREM
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
P, S and density variation(release after blind test)
•Random part: defined as spherical harmoniccomponent. we have added mixture ofadjacent layers over a depth interval of250km.
•The deterministic part: medium- and small-scale variation
•S-wave and density variation are coupledwith P-wave variation
•Crystal with variable orientation of symmetry
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Crustal model for Vs
Crustal model for density
The crust has a significant impact on the observed seismic data but, at thesame time, is too thin to be resolved by them.
Crustal model (smoothed CRUST2.0)
Constant depth=26km
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Topography and bathmetry (ETOPO5)
The ocean are incorporated in the CSEM by introducing an equivalentload a the ocean floor( Dimitri Komatitsch and Jeroen Tromp, 2002)
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
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 dispersionand computation cost.
•Implementation
•IPGP (Institut de physique du globe de Paris)
•IDRIS (Institut du Développement et des Ressources enInformatique Scientifique)
•CINES (Centre Informatique National de l'EnseignementSupérieur)
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Courtesy of Capdeville
Coupling Spectral-elementmethod (CSEM)
Mesh
topography
Ocean
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Source wavelet
An heavis wavelet with frequency up to 0.031Hz (minimumperiod 32s )
wavelet
spectrum
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Derivative of source wavelet andthe corresponding spectrum
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Comparison between normal-mode (black) and CSEM (redfor 0.2s of time step , green for 0.4s time step) for minimumperiod of 32s.
Numerical dispersion for maximum period 32s
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
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
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Station PAYG for event 09 (coupling between T, L and Z) for Valerie1D model
spectrum
synthetic
T
L
Z
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Z component for station PAYG of event 09
Blue (3D model) and red (1D model)
Filtered ( >200s)
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
L component for station PAYG of event 09
Blue (3D model) and red (1D model)
Filtered (>200s)
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
T component for station PAYG of event 09
Blue (3D model) and red (1D model)
Filtered >200s
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Seismic noise for GEOSCOPE station TAM
E and N component of noise is much stronger than Z component
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
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
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
Conclusions
•Perform benchmark of benchmark
•A complex 3D global anisotropicelastic model has been created
•A high quality anisotropic elasticdataset has been created
•Data and model (after blind test) arefreely available
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
uses
•phase velocity inversion
•Waveform inversion
•CMT inversion
Limitations
•Minimum period 32s
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SPICE Research and Training Workshop III, July 22-28, Kinsale, Ireland
acknowledgement
•SPICE
•Service de Calcul Parallèle, inInstitut de Physique du Globe deParis
•Sergei Lebedev (University ofUtrecht)