Imperial College London
Alternate

ProfessorJoannaMorgan

Faculty of Engineering, Department of Earth Science & Engineering

Emeritus Professor of Geophysics
 
 
 
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Contact

 

+44 (0)20 7594 6423j.v.morgan

 
 
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Location

 

1.46CRoyal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Davy:2017:gji/ggx415,
author = {Davy, RG and Morgan, JV and Minshull, TA and Bayrakci, G and Bull, JM and Klaeschen, D and Reston, TJ and Sawyer, DS and Lymer, G and Cresswell, D},
doi = {gji/ggx415},
journal = {Geophysical Journal International},
pages = {244--263},
title = {Resolving the fine-scale velocity structure of continental hyperextension at the Deep Galicia Margin using full-waveform inversion},
url = {http://dx.doi.org/10.1093/gji/ggx415},
volume = {212},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Continental hyperextension during magma-poor rifting at the Deep Galicia Margin is characterized by a complex pattern of faulting, thin continental fault blocks and the serpentinization, with local exhumation, of mantle peridotites along the S-reflector, interpreted as a detachment surface. In order to understand fully the evolution of these features, it is important to image seismically the structure and to model the velocity structure to the greatest resolution possible. Traveltime tomography models have revealed the long-wavelength velocity structure of this hyperextended domain, but are often insufficient to match accurately the short-wavelength structure observed in reflection seismic imaging. Here, we demonstrate the application of 2-D time-domain acoustic full-waveform inversion (FWI) to deep-water seismic data collected at the Deep Galicia Margin, in order to attain a high-resolution velocity model of continental hyperextension. We have used several quality assurance procedures to assess the velocity model, including comparison of the observed and modeled waveforms, checkerboard tests, testing of parameter and inversion strategy and comparison with the migrated reflection image. Our final model exhibits an increase in the resolution of subsurface velocities, with particular improvement observed in the westernmost continental fault blocks, with a clear rotation of the velocity field to match steeply dipping reflectors. Across the S-reflector, there is a sharpening in the velocity contrast, with lower velocities beneath S indicative of preferential mantle serpentinization. This study supports the hypothesis that normal faulting acts to hydrate the upper-mantle peridotite, observed as a systematic decrease in seismic velocities, consistent with increased serpentinization. Our results confirm the feasibility of applying the FWI method to sparse, deep-water crustal data sets.
AU  - Davy,RG
AU  - Morgan,JV
AU  - Minshull,TA
AU  - Bayrakci,G
AU  - Bull,JM
AU  - Klaeschen,D
AU  - Reston,TJ
AU  - Sawyer,DS
AU  - Lymer,G
AU  - Cresswell,D
DO  - gji/ggx415
EP  - 263
PY  - 2017///
SN  - 0956-540X
SP  - 244
TI  - Resolving the fine-scale velocity structure of continental hyperextension at the Deep Galicia Margin using full-waveform inversion
T2  - Geophysical Journal International
UR  - http://dx.doi.org/10.1093/gji/ggx415
UR  - http://hdl.handle.net/10044/1/51241
VL  - 212
ER  -
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