Gigantic submarine landslide offshore western Tasmania

Voyage Number

IN2023_V02

Voyage Dates

24 Mar, 2023 to 30 Apr, 2023

Voyage Location

Hobart to Hobart

Chief Scientist

Dr Martin Jutzeler

Institution

University of Tasmania

View the full voyage

Voyage summary

Research voyage out of Hobart, travelling to the west coast of Tasmania to investigate a gigantic submarine (underwater) landslide on the continental shelf.

The continental shelf off the west coast of Tasmania consists of a smooth, 20-40 km wide shelf, indented by numerous small canyons. However, over 50 km of continental shelf shows an abrupt headscarp failure (collapse) associated with a gigantic submarine (underwater) landslide deposit. Scientists will survey the surface and sub-surface of the failed and unfailed deposits to understand how, when and why this underwater landslide happened. These data will be used to identify if such an event could occur nearby or in other places on the Australian shelf and establish hazard mitigation maps for Australia.

These data will be supplemented by seafloor habitat and biology surveys to increase understanding of marine biodiversity in the region and factors controlling its distribution. In addition, scientists will investigate the composition of the continental shelf to infer onshore prospective rock formations.

This research will help in risk assessment and mitigation for shelf-derived tsunami that could impact Australian coastal communities.

There are two other projects on this voyage:

• Argo float deployments: deployment of 2 standard Argo floats (Dr Gabriela Pilo, CSIRO). 
• Investigation of unidentified shipwreck: systematic (bathymetric) mapping and camera inspection of an unidentified shipwreck in region (Mr Craig Davey, CSIRO).

The voyage will be led by Chief Scientist Dr Martin Jutzeler from the University of Tasmania’s Centre for Ore Deposit and Earth Sciences (CODES). It is being delivered in collaboration with the University of Sydney along with several other universities and research bodies.

The voyage has 30 science participants from 8 institutions, including 4 Australian and one international university (Utrecht University, Netherlands) and Minerals Resources Tasmania (Tasmanian Government).

COVID Protocols

To safeguard the health and well-being of participants, strict COVID protocols apply to all activities on this voyage. This includes 2-phase PCR testing of all participants for COVID prior to boarding the vessel.

Voyage outcomes

The voyage successfully surveyed, in its entirety, the gigantic submarine landslide on the continental slope of southwestern Tasmania and gathered data to assess the mechanisms of shelf failure and to model tsunami formation. These data will be used to assess how, when and why this event happened, and determine if there are risks for further landslides in this area. Important data about seabird, marine mammal and seafloor biodiversity was also collected during the voyage, significantly increasing our knowledge of species distribution and abundance in the region.

As a result of this voyage, we have a better understanding of the past landslides that affected the southwestern coast of Tasmania and have collected data to study their dispersal on the deep seafloor. Data and samples collected will lead to improved modelling of shelf failure, sediment transport to the deep sea and tsunami initiation. Such knowledge is applicable to other locations in Australia and his project will provide critical information to inform a national strategy on natural hazard mitigation and risk reduction.

Significantly, the location of the MV Blythe Star, a shipwreck of national significance, was also confirmed during this voyage, bringing closure to a 50-year mystery. The project, which was delivered as a piggyback project alongside the primary research project, demonstrates the wide capacity for multidisciplinary research that can be accommodated on voyages of RV Investigator.