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Comparison of 2-D and 3-D full waveform inversion imaging using wide-angle seismic data from the Deep Galicia Margin

Comparison of 2-D and 3-D full waveform inversion imaging using wide-angle seismic data from the Deep Galicia Margin
Comparison of 2-D and 3-D full waveform inversion imaging using wide-angle seismic data from the Deep Galicia Margin

Full waveform inversion (FWI) is a data-fitting technique capable of generating high-resolution velocity models with a resolution down to half the seismic wavelength. FWI is applied typically to densely sampled seismic data. In this study, we applied FWI to 3-D wide-angle seismic data acquired using sparsely spaced ocean bottom seismometers (OBSs) from the Deep Galicia Margin west of Iberia. Our data set samples the S-reflector, a low-angle detachment present in this area. Here we highlight differences between 2-D, 2.5-D and 3-D-FWI performances using a real sparsely spaced data set. We performed 3-D FWI in the time domain and compared the results with 2-D and 2.5-D FWI results from a profile through the 3-D model. When overlaid on multichannel seismic images, the 3-D FWI results constrain better the complex faulting within the pre- A nd syn-rift sediments and crystalline crust compared to the 2-D result. Furthermore, we estimate variable serpentinization of the upper mantle below the S-reflector along the profile using 3-D FWI, reaching a maximum of 45 per cent. Differences in the data residuals of the 2-D, 2.5-D and 3-D inversions suggest that 2-D inversion can be prone to overfitting when using a sparse data set. To validate our results, we performed tests to recover the anomalies introduced by the inversions in the final models using synthetic data sets. Based on our comparison of the velocity models, we conclude that the use of 3-D data can partially mitigate the problem of receiver sparsity in FWI.

Controlled source seismology, Crustal imaging, Waveform inversion
0956-540X
228-256
Boddupalli, Bhargav
20ded581-d378-4ab3-862e-c6f54a717701
Minshull, Tim A
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Morgan, Joanna
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Bayrakci, Gaye
e0b89aa5-d514-4ecb-91b1-8ed8bd472eda
Klaeschen, Dirk
6f4c994a-036e-44cc-b35e-c85e894f1bac
Boddupalli, Bhargav
20ded581-d378-4ab3-862e-c6f54a717701
Minshull, Tim A
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Morgan, Joanna
87d72bd4-2fda-4070-849a-6cf9dadf8cbb
Bayrakci, Gaye
e0b89aa5-d514-4ecb-91b1-8ed8bd472eda
Klaeschen, Dirk
6f4c994a-036e-44cc-b35e-c85e894f1bac

Boddupalli, Bhargav, Minshull, Tim A, Morgan, Joanna, Bayrakci, Gaye and Klaeschen, Dirk (2021) Comparison of 2-D and 3-D full waveform inversion imaging using wide-angle seismic data from the Deep Galicia Margin. Geophysical Journal International, 227 (1), 228-256. (doi:10.1093/gji/ggab164).

Record type: Article

Abstract

Full waveform inversion (FWI) is a data-fitting technique capable of generating high-resolution velocity models with a resolution down to half the seismic wavelength. FWI is applied typically to densely sampled seismic data. In this study, we applied FWI to 3-D wide-angle seismic data acquired using sparsely spaced ocean bottom seismometers (OBSs) from the Deep Galicia Margin west of Iberia. Our data set samples the S-reflector, a low-angle detachment present in this area. Here we highlight differences between 2-D, 2.5-D and 3-D-FWI performances using a real sparsely spaced data set. We performed 3-D FWI in the time domain and compared the results with 2-D and 2.5-D FWI results from a profile through the 3-D model. When overlaid on multichannel seismic images, the 3-D FWI results constrain better the complex faulting within the pre- A nd syn-rift sediments and crystalline crust compared to the 2-D result. Furthermore, we estimate variable serpentinization of the upper mantle below the S-reflector along the profile using 3-D FWI, reaching a maximum of 45 per cent. Differences in the data residuals of the 2-D, 2.5-D and 3-D inversions suggest that 2-D inversion can be prone to overfitting when using a sparse data set. To validate our results, we performed tests to recover the anomalies introduced by the inversions in the final models using synthetic data sets. Based on our comparison of the velocity models, we conclude that the use of 3-D data can partially mitigate the problem of receiver sparsity in FWI.

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Accepted/In Press date: 11 May 2021
e-pub ahead of print date: 11 May 2021
Published date: 1 October 2021
Additional Information: Publisher Copyright: © 2021 Crown copyright.
Keywords: Controlled source seismology, Crustal imaging, Waveform inversion

Identifiers

Local EPrints ID: 449590
URI: http://eprints.soton.ac.uk/id/eprint/449590
ISSN: 0956-540X
PURE UUID: fb10eb54-6a19-45c6-9463-85bd2ce8504e
ORCID for Tim A Minshull: ORCID iD orcid.org/0000-0002-8202-1379

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Date deposited: 08 Jun 2021 16:32
Last modified: 22 Nov 2022 02:34

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Contributors

Author: Bhargav Boddupalli
Author: Tim A Minshull ORCID iD
Author: Joanna Morgan
Author: Gaye Bayrakci
Author: Dirk Klaeschen

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