Imperial College London
Portrait Picture

DrRebeccaBell

Faculty of Engineering, Department of Earth Science & Engineering

Reader in Tectonics
 
 
 
//

Contact

 

+44 (0)20 7594 0903rebecca.bell

 
 
//

Location

 

2.37aRoyal School of MinesSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@article{Gray:2019:10.1029/2019JB017793,
author = {Gray, M and Bell, R and Morgan, J and Henrys, S and Barker, D and IODP, Expedition 372 scientists and IODP, Expedition 375 scientists},
doi = {10.1029/2019JB017793},
journal = {Journal of Geophysical Research. Solid Earth},
pages = {9049--9074},
title = {Imaging the shallow subsurface structure of the North Hikurangi subduction zone, New Zealand, using 2-D full-waveform inversion},
url = {http://dx.doi.org/10.1029/2019JB017793},
volume = {124},
year = {2019}
}
Download

RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The northern Hikurangi plate boundary fault hosts a range of seismic behaviors, of which the physical mechanisms controlling seismicity are poorly understood, but often related to high pore fluid pressures and conditionally stable frictional conditions. Using 2D marine seismic streamer data, we employ full-waveform inversion (FWI) to obtain a high-resolution 2D P-wave velocity model across the Hikurangi margin down to depths of ~2 km. The validity of the FWI velocity model is investigated through comparison with the pre-stack depth migrated seismic reflection image, sonic well data, and the match between observed and synthetic waveforms. Our model reveals the shallow structure of the overriding plate, including the fault plumbing system above the zone of SSEs to theoretical resolution of a half seismic wavelength. We find that the hanging walls of thrust faults often have substantially higher velocities than footwalls, consistent with higher compaction. In some cases, intra-wedge faults identified from reflection data are associated with low-velocity anomalies, which may suggest they are high-porosity zones acting as conduits for fluid flow. The continuity of velocity structure away from IODP drill site U1520 suggests that lithological variations in the incoming sedimentary stratigraphy observed at this site continue to the deformation front and are likely important in controlling seismic behavior. This investigation provides a high-resolution insight into the shallow parts of subduction zones, which shows promise for the extension of modeling to 3D using a recently-acquired, longer-offset, seismic dataset.
AU  - Gray,M
AU  - Bell,R
AU  - Morgan,J
AU  - Henrys,S
AU  - Barker,D
AU  - IODP,Expedition 372 scientists
AU  - IODP,Expedition 375 scientists
DO  - 10.1029/2019JB017793
EP  - 9074
PY  - 2019///
SN  - 2169-9356
SP  - 9049
TI  - Imaging the shallow subsurface structure of the North Hikurangi subduction zone, New Zealand, using 2-D full-waveform inversion
T2  - Journal of Geophysical Research. Solid Earth
UR  - http://dx.doi.org/10.1029/2019JB017793
UR  - https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JB017793
UR  - http://hdl.handle.net/10044/1/72074
VL  - 124
ER  -
Download