Taming waveform inversion non-linearity through phase unwrapping of the model and objective functions

Handle URI:
http://hdl.handle.net/10754/555750
Title:
Taming waveform inversion non-linearity through phase unwrapping of the model and objective functions
Authors:
Alkhalifah, Tariq Ali ( 0000-0002-9363-9799 ) ; Choi, Yun Seok
Abstract:
Traveltime inversion focuses on the geometrical features of the waveform (traveltimes), which is generally smooth, and thus, tends to provide averaged (smoothed) information of the model. On other hand, general waveform inversion uses additional elements of the wavefield including amplitudes to extract higher resolution information, but this comes at the cost of introducing non-linearity to the inversion operator, complicating the convergence process. We use unwrapped phase-based objective functions in waveform inversion as a link between the two general types of inversions in a domain in which such contributions to the inversion process can be easily identified and controlled. The instantaneous traveltime is a measure of the average traveltime of the energy in a trace as a function of frequency. It unwraps the phase of wavefields yielding far less non-linearity in the objective function than that experienced with conventional wavefields, yet it still holds most of the critical wavefield information in its frequency dependency. However, it suffers from non-linearity introduced by the model (or reflectivity), as reflections from independent events in our model interact with each other. Unwrapping the phase of such a model can mitigate this non-linearity as well. Specifically, a simple modification to the inverted domain (or model), can reduce the effect of the model-induced non-linearity and, thus, make the inversion more convergent. Simple numerical examples demonstrate these assertions.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Alkhalifah, Tariq, and Yunseok Choi. "Taming waveform inversion non-linearity through phase unwrapping of the model and objective functions." Geophysical Journal International 191, no. 3 (2012): 1171-1178.
Publisher:
Oxford University Press (OUP)
Journal:
Geophysical Journal International
Issue Date:
25-Sep-2012
DOI:
10.1111/j.1365-246X.2012.05699.x
Type:
Article
Additional Links:
http://gji.oxfordjournals.org/content/191/3/1171.short
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorAlkhalifah, Tariq Alien
dc.contributor.authorChoi, Yun Seoken
dc.date.accessioned2015-05-26T07:08:46Zen
dc.date.available2015-05-26T07:08:46Zen
dc.date.issued2012-09-25en
dc.identifier.citationAlkhalifah, Tariq, and Yunseok Choi. "Taming waveform inversion non-linearity through phase unwrapping of the model and objective functions." Geophysical Journal International 191, no. 3 (2012): 1171-1178.en
dc.identifier.doi10.1111/j.1365-246X.2012.05699.xen
dc.identifier.urihttp://hdl.handle.net/10754/555750en
dc.description.abstractTraveltime inversion focuses on the geometrical features of the waveform (traveltimes), which is generally smooth, and thus, tends to provide averaged (smoothed) information of the model. On other hand, general waveform inversion uses additional elements of the wavefield including amplitudes to extract higher resolution information, but this comes at the cost of introducing non-linearity to the inversion operator, complicating the convergence process. We use unwrapped phase-based objective functions in waveform inversion as a link between the two general types of inversions in a domain in which such contributions to the inversion process can be easily identified and controlled. The instantaneous traveltime is a measure of the average traveltime of the energy in a trace as a function of frequency. It unwraps the phase of wavefields yielding far less non-linearity in the objective function than that experienced with conventional wavefields, yet it still holds most of the critical wavefield information in its frequency dependency. However, it suffers from non-linearity introduced by the model (or reflectivity), as reflections from independent events in our model interact with each other. Unwrapping the phase of such a model can mitigate this non-linearity as well. Specifically, a simple modification to the inverted domain (or model), can reduce the effect of the model-induced non-linearity and, thus, make the inversion more convergent. Simple numerical examples demonstrate these assertions.en
dc.publisherOxford University Press (OUP)en
dc.relation.urlhttp://gji.oxfordjournals.org/content/191/3/1171.shorten
dc.rightsArchived with thanks to Geophysical Journal International © 2012 The Authors Geophysical Journal International © 2012 RASen
dc.subjectTime series analysisen
dc.subjectInverse theoryen
dc.subjectSeismic tomographyen
dc.titleTaming waveform inversion non-linearity through phase unwrapping of the model and objective functionsen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalGeophysical Journal Internationalen
dc.eprint.versionPublisher's Version/PDFen
kaust.authorAlkhalifah, Tariq Alien
kaust.authorChoi, Yun Seoken
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