multiscale seismology: the future of inversion w. menke lamont-doherty earth observatory columbia...
Post on 19-Dec-2015
215 views
TRANSCRIPT
![Page 1: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/1.jpg)
Multiscale Seismology:
the future of inversion
W. MENKELamont-Doherty Earth Observatory
Columbia University
E. CHESNOKOV and R.L. BROWNInstitute for Theoretical Geophysics
University of Oklahoma
![Page 2: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/2.jpg)
Thesis
The past 15 years has seen a tremendous improvement in the fidelity of many types of seismic images.
This improvement was driven by, more and higher quality seismometers, faster computers, better data archiving and processing methodologies.
But our ability tointegrate knowledge from multiple data types
hasn’t kept up. Often different data types are telling us seemingly-contradictory things.
![Page 3: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/3.jpg)
Example:
Surface Wave Tomography
e.g. of North America
![Page 4: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/4.jpg)
Woodward and Snieder, 1993
275 seismograms
![Page 5: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/5.jpg)
Zhang & Tanimoto, 1993
18,000 seismograms globally, about 324 prorated for area
![Page 6: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/6.jpg)
685 seismograms
![Page 7: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/7.jpg)
400,000 seismograms globally, about 7,200 prorated for area
note inversion includes transverse anisotropy
![Page 8: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/8.jpg)
“Exponential”
growth
of
data !
Images better & better in evolutionary
way
![Page 9: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/9.jpg)
But how do these impressive images
connect with
other things we know about the earth?
![Page 10: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/10.jpg)
Connection 1
Continental Scale Body Wave Traveltimes
![Page 11: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/11.jpg)
Surface wave models have big asthenospheric LVZ’s that imply very large
shadow zones
Are such shadows actually observed in continental-scale P or S waves?
![Page 12: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/12.jpg)
Connection 2
SKS Shear Wave Splitting
![Page 13: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/13.jpg)
From Gaherty
North America has large amount of transverse anisotropy
![Page 14: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/14.jpg)
Predicts
Correctly predicts large Love-Rayleigh discrepancy along paths
parallel to MOMA Array
![Page 15: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/15.jpg)
But inconsistent with SKS splitting results along MOMA array
Fouch’s splitting data as plotted by Gaherty
No plausible anisotropic material can have fast-axis parallel to array and have large Love-Rayleigh discrepancy parallel to the array, too
![Page 16: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/16.jpg)
More overlap in parameters than length scale !
![Page 17: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/17.jpg)
Hypothesis:
differentlength scales
strongly influence interpretation
![Page 18: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/18.jpg)
EARTH OBSERVATION
INVERSION
StrongSpooky
Interactions
(seismic waves)
Length scale ofLength scale of
Length scale of
![Page 19: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/19.jpg)
we understand this interactionpretty well
(but only in very idealized media)
strong spooky interactionsOBSERVATION
(seismic waves)EARTHLength scale of
Length scale of
![Page 20: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/20.jpg)
WHAT IS THE STRUCURE OF THIS MEDIUM ?
,, ρμ
,, ρμ
bulk modulus 1
shear modulus 1,
density 1
thickness 1
bulk modulus 2
shear modulus 2
density 2
thickness 2
![Page 21: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/21.jpg)
WHAT IS THE STRUCTURE OF THIS MEDIUM ?
Inhomogenous with various properties of
isotropic layers?
YES !when <<thickness
![Page 22: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/22.jpg)
WHAT IS THE STRUCTURE OF THIS MEDIUM ?
Strongly Scattering?
YES !when ~thickness
![Page 23: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/23.jpg)
WHAT IS THE STRUCURE OF THIS MEDIUM ?
Effectively homogeneous and anisotropic?
YES !when >>thickness
![Page 24: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/24.jpg)
Theory for understanding this effectin 3-D media with random heterogeneitiesis well developed …
Elasticity and density written in terms of average and deviation from average
![Page 25: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/25.jpg)
• Chesnokov et al. 2000
weird! effective density is a tensor ..
1. elasticity and density are frequency-dependent
2. integrals embody interaction of wavefield with scale length of heterogeneities …
3. … through correlation functions
![Page 26: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/26.jpg)
![Page 27: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/27.jpg)
“UPSCALING” ExampleReconciling Sonic Log with VSP
Collect Sonic Logs (500 Hz) of Vp, Vs1, Vs2, density
Infer all components of Cijkl(f=500 Hz)
Compute Correlation Functions
Predict Cijkl(f=50 Hz)
Compare with VSP (50 Hz) experiment
Is this Inversion?
Not quite …
![Page 28: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/28.jpg)
Sonic Log
Result for C55
Predicted VSPVSP
![Page 29: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/29.jpg)
theorycan be
extendedto include
more complicated
micro-physics
e.g.fluid/rock
interactions
![Page 30: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/30.jpg)
There’s been some interesting efforts on this side of the triangle, too
stro
ng s
pook
y in
tera
ctio
ns
OBSERVATIONLength scale of
INVERSIONLength scale of
![Page 31: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/31.jpg)
True Slip on Hypothetical Fault
ThreeInversionsThatFit the DataEquallyWell
Results of Slip Inversions Highly Dependent onScale of Model Representation
Courtesy of Morgan Page
![Page 32: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/32.jpg)
A Challenge of the Future
Create
Earth knowledge
that
practitioners using
different techniques
AGREE UPON
!
![Page 33: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/33.jpg)
EARTH
INVERSION
Joint Inversions thathandle multiple scales
in a Physics-Based way
OBSERVATION(seismic waves)
Length scale ofLength scale of
Length scale of
![Page 34: Multiscale Seismology: the future of inversion W. MENKE Lamont-Doherty Earth Observatory Columbia University E. CHESNOKOV and R.L. BROWN Institute for](https://reader035.vdocuments.us/reader035/viewer/2022062421/56649d395503460f94a13165/html5/thumbnails/34.jpg)
The Future ?
Scale1 Data
physics-based parameterization
1
Assessment of underlying physics
Scale2 Data
Business as Usual
Scale1 Data
Ad-hoc parameterization
1
Ad-hoc parameterization
2
Speculative attempts to integrate and reconcile results
Scale2 Data
feedback
confusion ?!Improved knowledge of earth