The Australian Passive Seismic Array Project (AusArray) is a collaborative, national survey between government and academia that acquires passive seismic data.
The project started in 2016 through the Exploring for the Future program and continues through the support of the State and Territory geological surveys and academia.
AusArray focuses on the creation of an updatable 3D model of the sub-surface seismic velocity variations. This model constrains local and regional Earth structures useful for the assessment of resource potential and natural hazards.
Past AusArray surveys have covered smaller areas of the continent at 50 km grid spacing. From 2016 to 2020, the Exploring for the Future program supported deployment of an array of broadband seismic instruments at more than 200 sites across the Northern Territory and Queensland on a 50 km spaced grid.
The broadband seismic instruments are currently arranged in a grid pattern spaced ~200 km apart across the entire continent, complemented by 12 semi-permanent higher sensitivity broadband seismic instruments. These instruments measure small natural vibrations that travel through the Earth caused by local and distant earthquakes, waves breaking on the shore and even wind.
These data help scientists to understand the variation in seismic velocity across the continent and, based on that, the composition of rocks beneath the surface. Results from the 2016-2020 deployment revealed new subsurface features that helped explain the geological evolution of northern Australia. It revealed a new sedimentary basin and provided explorers with insights into the potential for discovering new mineral and energy resources. Data from 50 km spaced AusArray deployments also allowed for better characterisation of Australian earthquakes, which is improving our natural hazard modelling and making our communities safer.
Key activities and outcomes from 2020 to March 2023 include:
- Deployment of broadband seismic instruments at ~200 km spacing across most of Australia (see the map). These instruments are left in the ground for approximately one year in order to collect sufficient data. Instruments are expected to be collected by May 2024, with data processing and modelling to follow.
- Processing of data collected between 2016 and 2020 across parts of the Northern Territory and Queensland. These data have identified and refined the mapping of key geological features in the sub-surface, including the presence of sedimentary basins.
- Processing all legacy data collected by government and academia. These data enabled the building of preliminary models over the entire Australian continent.
Key activities and outcomes in the Northern Australia region between Tennant Creek and Mount Isa from 2016 to 2020:
- two deployments of a constellation of 130 broadband seismic instruments in a grid pattern in 2 adjoining areas, with each deployment lasting for one year
- improved national 3D seismic velocity models of the Australian plate focused on northern Australia
- higher resolution 3D seismic models in areas covered by the transportable array from which physical properties of the lithosphere can be inferred from depths of a few metres to hundreds of kilometres.
AusArray is a collaboration initiated by academia with support from and . Geoscience Australia leads and funds this project activity in collaboration with State and Territory geological surveys, universities, particularly the Australian National University, Macquarie University, the University of Tasmania and other research organisations.
Legacy AusArray data has been kindly supplied to Geoscience Australia by researchers through the repository of legacy academia AusArray data housed by the Research School of Earth Sciences at the Australian National University.
Resource potential of the Proterozoic−Paleozoic Carrara depocentre, South Nicholson region, Australia
Grosjean, E., Jarrett, A.J.M, Boreham, C.J., Wang, L., Johnson, L., Hope, J.M., Ranasinghe, P., Brocks, J.J., Bailey, A. H. E., Butcher, G.A., Carson, C.J. (2023)
South Nicholson National Drilling Initiative
The South Nicholson National Drilling Initiative (NDI) Carrara 1 stratigraphic drill hole was completed in late 2020, as a collaboration between Geoscience Australia, the Northern Territory Geological Survey (NTGS) and the MinEx CRC. NDI Carrara 1 is the first drill hole to intersect the as yet undifferentiated Proterozoic rocks of the newly discovered Carrara Sub-basin.
Rock geochemistry from the Curnamona Province and Delamerian Orogen
Schroder, I., Taylor, H., Champion, D., Doublier, M., Gilmore, P., Clark, A., Main, P., Cheng, Y., Ashley, P., Cairns, C., Cayley, R., Byass, J., Gilmore, S., Long, I. (2023)