- Title
- Submarine landslides on the upper southeast Australian passive continental margin - Preliminary findings
- Creator
- Clarke, Samantha; Hubble, Thomas; Airey, David; Yu, Phyllis; Boyd, Ron; Keene, John; Exon, Neville; Gardner, James; Shipboard Party SS12/2008
- Relation
- Submarine Mass Movements and Their Consequences. 5th International Symposium p. 55-66
- Relation
- Advances in Natural and Technological Hazards Research 31
- Publisher Link
- http://dx.doi.org/10.1007/978-94-007-2162-3_5
- Publisher
- Springer Netherlands
- Resource Type
- book chapter
- Date
- 2012
- Description
- The southeast Australian passive continental margin is narrow, steep and sediment-deficient, and characterized by relatively low rates of modern sedimentation. Upper slope (<1,200 m) sediments comprise mixtures of calcareous and terrigenous sand and mud. Three of twelve sediment cores recovered from geologically-recent, submarine landslides located offshore New South Wales/Queensland (NSW/QLD) are interpreted to have sampled failure surfaces at depths of between 85 and 220 cm below the present-day seabed. Differences in sediment physical properties are recorded above and below the three slide-plane boundaries. Sediment taken directly above the inferred submarine landslide failure surfaces and presumed to be post-landslide, returned radiocarbon ages of 15.8, 20.7 and 20.1 ka. The last two ages correspond to adjacent slide features, which are inferred to be consistent with their being triggered by a single event such as an earthquake. Slope stability models based on classical soil mechanics and measured sediment shear-strengths indicate that the upper slope sediments should be stable. However, multibeam sonar data reveal that many upper slope landslides occur across the margin and that submarine landsliding is a common process. We infer from these results that: (a) an unidentified mechanism regularly acts to reduce the shear resistance of these sediments to the very low values required to enable slope failure, and/or (b) the margin experiences seismic events that act to destabilise the slope sediments.
- Subject
- mass-failure; multibeam; seafloor geomorphology; continental slope
- Identifier
- http://hdl.handle.net/1959.13/1336734
- Identifier
- uon:27688
- Identifier
- ISBN:9789400721616
- Language
- eng
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