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![Page 1: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/1.jpg)
Coherence-weighted Wavepath Coherence-weighted Wavepath Migration for Teleseismic Data Migration for Teleseismic Data
J. Sheng, G. T. Schuster, K. L. Pankow, J. Sheng, G. T. Schuster, K. L. Pankow, J. C. Pechmann, and R. L. Nowack J. C. Pechmann, and R. L. Nowack
University of UtahUniversity of Utah
Feb. 5, 2004Feb. 5, 2004
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MotivationMotivation
Given: Teleseismic dataGiven: Teleseismic dataGoal: Local crustal structureGoal: Local crustal structure
Solution I: Receiver function (RF)Solution I: Receiver function (RF)
![Page 3: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/3.jpg)
Principle of RFPrinciple of RF
(Langston, 1977, 1979)(Langston, 1977, 1979)
PP
PPPSPS
MohoMoho
P
Ps
Ps
P
G
G
V
R
iGsR
iGsV
Vertical Comp.Vertical Comp.
RadialRadial
Source historySource historyGreen’s fun.Green’s fun.
InstrumentInstrument
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ProblemsProblems
• Other phases generate artifactsOther phases generate artifacts
MohoMoho
pPspPs pSspSs pPppPp
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MotivationMotivation
Given: teleseismic dataGiven: teleseismic dataGoal: local crustal structureGoal: local crustal structure
Solution I: Receiver function (RF)Solution I: Receiver function (RF)
Solution II: Xcorrelogram mig. (Xmig)Solution II: Xcorrelogram mig. (Xmig)
![Page 6: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/6.jpg)
Principle of XmigPrinciple of Xmig
GhostGhostP-waveP-wave
Direct Direct P-waveP-wave
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ProblemsProblems
• Incident angle usually > 30 deg.Incident angle usually > 30 deg.• Irregular spacing Irregular spacing • Low frequency and long source Low frequency and long source historyhistory
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MotivationMotivation
Given: teleseismic dataGiven: teleseismic dataGoal: local crustal structureGoal: local crustal structure
Solution I: Receiver function (RF)Solution I: Receiver function (RF)
Solution II: Xcorrelogram mig. (Xmig)Solution II: Xcorrelogram mig. (Xmig)
Solution III: Coherence-weighted WM Solution III: Coherence-weighted WM
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Coherence-weighted WMCoherence-weighted WM
OutlineOutline
Synthetic TestSynthetic Test
Earthquake DataEarthquake Data
SummarySummary
![Page 10: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/10.jpg)
Coherence-weighted WM Coherence-weighted WM
Step 1:Step 1: Calculate radial and vertical RFCalculate radial and vertical RF
a.a. zero-phase traces zero-phase traces vvv *
b. source wavelet b. source wavelet vN
s1
c. deconvolution c. deconvolution s
v'
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Coherence-weighted WM Coherence-weighted WM
Step 2:Step 2: Migrate RF and obtain Migrate RF and obtain ps, pPs, and pPp imagesps, pPs, and pPp images
Step 1:Step 1: Calculate radial and vertical RFCalculate radial and vertical RF
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Wavepath MigrationWavepath Migration
Plane wavePlane wave
MMpsps(x)=RRF(T(x)=RRF(TSS-T-TPP))
RR
X’X’XX
X’X’XX
X’X’XX
PP
SS
MMpPspPs(x)=RRF(T(x)=RRF(TSS+T+TPP))
MMpPppPp(x)=VRF(2T(x)=VRF(2TPP))
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Coherence-weighted WM Coherence-weighted WM
Step 2:Step 2: Migrate RF and obtain Migrate RF and obtain ps, pPs, and pPp imagesps, pPs, and pPp images
Step 1:Step 1: Calculate radial and vertical RFCalculate radial and vertical RF
Step 3:Step 3: Coherence weight Coherence weight
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Coherence-weighted WM Coherence-weighted WM
MMCWCW=W*Mps=W*Mps
00
606000 220220
Dep
th (
km)
Dep
th (
km)
Distances (km)Distances (km)
psps pPspPs pPppPp
00 220220Distances (km)Distances (km)00 220220Distances (km)Distances (km)
00
6060
Dep
th (
km)
Dep
th (
km)
00 220220Distances (km)Distances (km)
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Coherence-weighted WMCoherence-weighted WM
OutlineOutline
Synthetic TestSynthetic Test
Earthquake DataEarthquake Data
SummarySummary
![Page 16: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/16.jpg)
00
606000 220220
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
Synthetic ModelSynthetic Model
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Parameters (Synthetic)Parameters (Synthetic)
• Plane P-wave incident at 40 deg.Plane P-wave incident at 40 deg.• 221 Stations with 1km spacing 221 Stations with 1km spacing • Source peak frequency 0.6 Hz Source peak frequency 0.6 Hz
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00
7070
Synthetic SeismogramSynthetic SeismogramT
rave
ltim
e (s
ec.)
Tra
velt
ime
(sec
.)
VerticalVertical RadialRadial
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00
2020
Tra
velt
ime
(sec
.)T
rave
ltim
e (s
ec.)
Radial RF (Synthetic)Radial RF (Synthetic)
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00
2020
Tra
velt
ime
(sec
.)T
rave
ltim
e (s
ec.)
Vertical RF (Synthetic)Vertical RF (Synthetic)
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ps Image (Synthetic)ps Image (Synthetic)
00
606000 220220
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
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pPs Image (Synthetic)pPs Image (Synthetic)
00
606000 220220
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
![Page 23: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/23.jpg)
pPp Image (Synthetic)pPp Image (Synthetic)
00
606000 220220
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
![Page 24: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/24.jpg)
CW Image (Synthetic)CW Image (Synthetic)
00
606000 220220
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
![Page 25: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/25.jpg)
Coherence-weighted WMCoherence-weighted WM
OutlineOutline
Synthetic TestSynthetic Test
Earthquake DataEarthquake Data
SummarySummary
![Page 26: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/26.jpg)
Earthquake Data Earthquake Data
![Page 27: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/27.jpg)
Great Salt Lake
Great Salt Lake
41.841.8
39.839.8
-113.5-113.5 -110.5-110.5
Lat
itu
de
(deg
.)L
atit
ud
e (d
eg.)
Longitude (deg.)Longitude (deg.)
Station MapStation Map
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Processing ParametersProcessing Parameters
120120
5050
270270
200200Tim
e (s
ec.)
Tim
e (s
ec.)
50 sec.50 sec.
50 sec.50 sec.
Passband:Passband:0.2~0.6 Hz0.2~0.6 Hz
Water-level:Water-level:0.0010.001
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Radial RF Radial RF
00
202000 200200
Tim
e (s
ec.)
Tim
e (s
ec.)
Distances (km)Distances (km)
![Page 30: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/30.jpg)
00
202000 200200
Tim
e (s
ec.)
Tim
e (s
ec.)
Distances (km)Distances (km)
Vertical RF Vertical RF
![Page 31: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/31.jpg)
00
606000 200200
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
ps Image ps Image
![Page 32: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/32.jpg)
00
606000 200200
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
pPs Image pPs Image
![Page 33: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/33.jpg)
00
606000 200200
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
pPp Image pPp Image
![Page 34: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/34.jpg)
00
606000 200200
Dep
th (
km
)D
epth
(k
m)
Distances (km)Distances (km)
CW Image CW Image
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Coherence-weighted WMCoherence-weighted WM
OutlineOutline
Synthetic TestSynthetic Test
Earthquake DataEarthquake Data
SummarySummary
![Page 36: Coherence-weighted Wavepath Migration for Teleseismic Data Coherence-weighted Wavepath Migration for Teleseismic Data J. Sheng, G. T. Schuster, K. L. Pankow,](https://reader035.fdocuments.net/reader035/viewer/2022062721/56649f1c5503460f94c31c77/html5/thumbnails/36.jpg)
SummarySummary
• ps, pPs, and pPp arrivals in RF can be migrated ps, pPs, and pPp arrivals in RF can be migrated to provide a different perspective. to provide a different perspective.
• CWWM can combine three images to correctly CWWM can combine three images to correctly image the reflector with attenuated artifacts. image the reflector with attenuated artifacts.
• This method can image the Moho at the depth This method can image the Moho at the depth consistent with previous studies. consistent with previous studies.
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AcknowledgmentAcknowledgment
I thank the sponsors of the 2003 UTAM I thank the sponsors of the 2003 UTAM Consortium for their financial support . Consortium for their financial support .