Submarine Landslides On The South-Eastern Australian Margin

High-spatial resolution bathymetric data acquired during two recent RV Southern Surveyor voyages have identified several distinct large sediment slides varying in volume from <0.5 km3 to 20 km3 on the upper continental slope of the southeastern Australian margin. Gravity cores, up to 5 m long, have been obtained from areas within and outside the identified slide features, and are believed to intersect the slide planes in some cases at depths of between 85 cm and 220 cm below the present-day seabed. The paper will provide a brief review of the factors believed responsible for submarine landslides, and discuss the relevance of these factors to the southeastern Australian margin. The paper will use the data from the recent ship surveys (SS2008/12 off the southern Queensland / northern New South Wales coastline and SS2006/10 off the mid New South Wales coastline) to show the size and magnitude of submarine landslides that have been identified, present results from soil characterisation studies of the recovered cores, and present the results of mechanical tests. These data will be used to consider the stability of the continental shelf sediments and to consider the tsunami risk that they pose.