Show simple item record

dc.contributor.authorDjebbi, Ramzi
dc.contributor.authorAlkhalifah, Tariq Ali
dc.date.accessioned2015-05-21T07:00:44Z
dc.date.available2015-05-21T07:00:44Z
dc.date.issued2014-02-18
dc.identifier.citationTraveltime sensitivity kernels for wave equation tomography using the unwrapped phase 2014, 197 (2):975 Geophysical Journal International
dc.identifier.issn0956-540X
dc.identifier.issn1365-246X
dc.identifier.doi10.1093/gji/ggu025
dc.identifier.urihttp://hdl.handle.net/10754/554371
dc.description.abstractWave equation tomography attempts to improve on traveltime tomography, by better adhering to the requirements of our finite-frequency data. Conventional wave equation tomography, based on the first-order Born approximation followed by cross-correlation traveltime lag measurement, or on the Rytov approximation for the phase, yields the popular hollow banana sensitivity kernel indicating that the measured traveltime at a point is insensitive to perturbations along the ray theoretical path at certain finite frequencies. Using the instantaneous traveltime, which is able to unwrap the phase of the signal, instead of the cross-correlation lag, we derive new finite-frequency traveltime sensitivity kernels. The kernel reflects more the model-data dependency, we typically encounter in full waveform inversion. This result confirms that the hollow banana shape is borne of the cross-correlation lag measurement, which exposes the Born approximations weakness in representing transmitted waves. The instantaneous traveltime can thus mitigate the additional component of nonlinearity introduced by the hollow banana sensitivity kernels in finite-frequency traveltime tomography. The instantaneous traveltime simply represents the unwrapped phase of Rytov approximation, and thus is a good alternative to Born and Rytov to compute the misfit function for wave equation tomography. We show the limitations of the cross-correlation associated with Born approximation for traveltime lag measurement when the source signatures of the measured and modelled data are different. The instantaneous traveltime is proven to be less sensitive to the distortions in the data signature. The unwrapped phase full banana shape of the sensitivity kernels shows smoother update compared to the banana–doughnut kernels. The measurement of the traveltime delay caused by a small spherical anomaly, embedded into a 3-D homogeneous model, supports the full banana sensitivity assertion for the unwrapped phase.
dc.publisherOxford University Press (OUP)
dc.relation.urlhttp://gji.oxfordjournals.org/cgi/doi/10.1093/gji/ggu025
dc.rightsArchived with thanks to Geophysical Journal International © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
dc.subjectInverse theory
dc.subjectSeismic tomography
dc.subjectWave propagation
dc.titleTraveltime sensitivity kernels for wave equation tomography using the unwrapped phase
dc.typeArticle
dc.contributor.departmentEarth Science and Engineering Program
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Division
dc.identifier.journalGeophysical Journal International
dc.eprint.versionPublisher's Version/PDF
kaust.personAlkhalifah, Tariq Ali
kaust.personDjebbi, Ramzi
refterms.dateFOA2018-06-13T14:52:29Z
dc.date.published-online2014-02-18
dc.date.published-print2014-05-01


Files in this item

Thumbnail
Name:
Geophys. J. Int.-2014-Djebbi-975-86.pdf
Size:
3.626Mb
Format:
PDF
Description:
Main article

This item appears in the following Collection(s)

Show simple item record