Seismic Examples of Composite Slope Failures (Offshore North West Shelf, Australia)

Scarselli, Nicola; McClay, K. R.; Elders, Chris

doi:10.1002/9781119500513.ch16

Cited by 6 publications

(1 citation statement)

References 45 publications

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“…The digital elevation model provides the full picture of modern sedimentary systems, from the source of the sediments (e.g., fluvial and carbonate systems) to their accumulation grounds along the shelf and in the basin. Parts of these modern systems can be used to better understand past sedimentary record (Paumard et al, 2020;Nyberg and Howell, 2016;Ainsworth et al, 2019), the geotechnical properties of marine sediments (Beemer et al, 2019;Beemer et al, 2018;Senders et al, 2013) or the geohazards affecting the area (Lane and Tyler, 2015;Hogan et al, 2017;Scarselli et al, 2019;Hengesh et al, 2013). Therefore, the integration of regional high-resolution bathymetry can constitute a step change and allow researchers to ponder their results with regard to the regional context and hence support the development of more reliable interpretations and models.…”

Section: Discussionmentioning

confidence: 99%

Towards a regional high-resolution bathymetry of the North West Shelf of Australia based on Sentinel-2 satellite images, 3D seismic surveys and historical datasets

Lebrec¹,

Paumard²,

O’Leary³

et al. 2021

Preprint

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Abstract. High-resolution bathymetry is a critical dataset for marine geoscientists. It can be used to characterize the seafloor and its marine habitats, to understand past sedimentary records and even to support the development of offshore engineering projects. Most methods to acquire bathymetry data are costly and can only be practically deployed on relatively small areas. It is therefore critical to develop cost-effective and advanced techniques to produce large-scale bathymetry datasets. This paper presents an integrated workflow that builds on satellites images and 3D seismic surveys, integrated with historical depth soundings, to generate a regional high-resolution digital elevation model. The method was applied to the southern half of Australia's North West Shelf and led to the creation of a new high-resolution bathymetry, with a resolution of 10 × 10 m in nearshore areas and 30 × 30 m elsewhere. The vertical and spatial accuracy of the datasets have been thoroughly assessed using open source Laser Airborne Depth Sounder (LADS) and Multi Beam Echo Sounder (MBES) surveys as a reference. The comparison of the datasets indicates that the seismic-derived bathymetry has a vertical accuracy better than 1 m + 2 % of the absolute water depths, while the satellite-derived bathymetry has a depth accuracy better than 1 m + 5 % of the absolute water depths. This dataset constitutes a significant improvement of the pre-existing regional 250 × 250 m grid and will support the onset of research projects on costal morphologies, marine habitats, archaeology, and sedimentology. All datasets used as inputs are publicly available and the method is fully integrated in Python scripts making it readily applicable elsewhere in Australia and around the world. The workflow as well as the resulting bathymetry have been independently reviewed and approved for release by a technical committee from the AusSeabed Community (Geoscience Australia). The regional digital elevation model as well as the underlying datasets can be accessed at: https://doi.org/10.26186/144600.

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Section: Discussionmentioning

confidence: 99%

Towards a regional high-resolution bathymetry of the North West Shelf of Australia based on Sentinel-2 satellite images, 3D seismic surveys and historical datasets

Lebrec¹,

Paumard²,

O’Leary³

et al. 2021

Preprint

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A guide to recognising slow-moving subaqueous landslides in seismic and bathymetry datasets

Couvin,

Georgiopoulou,

Amy

2024

Earth-Science Reviews

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The formation and implications of giant blocks and fluid escape structures in submarine lateral spreads

Jackson

Johnson

et al. 2021

Basin Research

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Lateral spread (or 'spreading') and submarine creep are processes that occur near the headwalls of both terrestrial landslides and submarine mass-transport complexes (MTCs).Both submarine creep and spread deposits may contain giant (km-scale) coherent blocks, but their transport processes remain poorly constrained. Here we use 2D and 3D seismic reflection data to determine the geometry, scale, and origin of an ancient (Late Miocene) mass-transport complex (MTC) located in the Kangaroo Syncline, offshore NW Australia. We show that this large remobilised mass of carbonate ooze is c. 170-300 m thick and covers an area of at least c. 1050 km 2 . The deposit is defined internally by two distinct seismic facies: (i) large, upward-tapering blocks (up to 210-300 m thick, 170-210 m wide, and 800-1200 m long) with negligible internal deformation, which decrease in height and spacing along the transport direction (identical, but in situ, seismic facies forms undeformed slope material immediately updip of the deposit headwall); and (ii) troughs (160-260 m thick, 190-230 m wide and 800-1200 m long) comprising moderately deformed strata, which contain 'v'-shaped, pipe-like structures that extend upwards from the inferred basal shear surface to the top surface of the MTC. The lack of deformation within the blocks, and their correlation to adjacent in-situ deposits, suggests they underwent very limited transport (c. 50 m-70 m). The relatively high degree of deformation within the intervening troughs is attributed to the vertical expulsion of fluids and sediment during hydraulic failure of the sediment mass. We present a hydraulic failure model that accounts for the styles and patterns of intra-MTC deformation process. This model invokes evacuation of the lower slope by a pre-cursor MTC that formed the space to trigger the lateral spread event. Our study provides new insights into the genesis and rheology of subaqueous lateral spreads, enabling improved assessments of the threats posed to critical seafloor infrastructure. The genetic links identified between mass wasting and spatially-focused fluid flow indicate that, as well as disturbing the deep seafloor, submarine landslides may also create important deep-sea biodiversity hotspots.

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Seismic Examples of Composite Slope Failures (Offshore North West Shelf, Australia)

Cited by 6 publications

References 45 publications

Towards a regional high-resolution bathymetry of the North West Shelf of Australia based on Sentinel-2 satellite images, 3D seismic surveys and historical datasets

Towards a regional high-resolution bathymetry of the North West Shelf of Australia based on Sentinel-2 satellite images, 3D seismic surveys and historical datasets

A guide to recognising slow-moving subaqueous landslides in seismic and bathymetry datasets

The formation and implications of giant blocks and fluid escape structures in submarine lateral spreads

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