Seismic diffraction imaging to better characterise mass-transport complexes: examples from the Gulf of Cadiz, south west Iberian Margin

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Authors

Jonathan Ford , Roger Urgeles, Angelo Camerlenghi, Eulàlia Gràcia

Abstract

Mass-transport complexes are characterised by complex, laterally discontinuous internal structure, such as pressure ridges, local shear zones and intact translated blocks. Their internal structure is often poorly imaged by seismic reflection techniques, which are fundamentally limited in lateral resolution by the bandwidth of the seismic source. Diffraction imaging, instead, directly images subsurface heterogeneity by primarily imaging the diffracted part of the seismic wavefield. We apply seismic diffraction imaging to two marine multi-channel seismic profiles containing mass-transport complexes from the Gulf of Cadiz (south west Iberian Margin). We observe that mass-transport complexes generate a large amount of diffracted energy relative to the un-failed sediments. We demonstrate that, in combination with conventional seismic reflection images, diffraction images can be used to better discriminate the lateral extent (runout) of mass-transport complexes, particularly for thin bodies that are not well-resolved using conventional imaging. We suggest that diffraction imaging may have similar applications for marine geohazard assessment to seismic discontinuity attributes, such as the similarity attribute, with the advantage of being closer to a true image of the heterogeneous subsurface. Applying diffraction imaging to image mass-transport complexes from 2-D seismic data is challenging, but may provide some unique insights that are not available from conventional reflection images.

DOI

https://doi.org/10.31223/osf.io/5kvnx

Subjects

Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Keywords

marine geophysics, mass-transport complex, seismic reflection, submarine landslides

Dates

Published: 2020-08-03 17:26

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License

CC BY Attribution 4.0 International

Additional Metadata

Data Availability (Reason not available):
Pre-stack seismic data used for this study will be archived with Zenodo (or another FAIR compliant repository) prior to acceptance.

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