Ambient Noise Tomography of The Australian Continent Using 40 Years of Passive Seismic Records in Australia

The Australian continental crust has a rich and complex tectonic history, reflected in seismic tomography by sharp velocity contrasts. In this study, we utilise data from all available temporary seismic deployments in Australia through AusPass (https://auspass.edu.au/), the Australian Permanent Seismic Network (ANSN), and the AusArray network (https://www.eftf.ga.gov.au/ausarray), which covers the continent in a 2° × 2° array. AusArray, initially funded through the Exploring for the Future program continues with an expanded deployment as part of the Resourcing Australia's Prosperity initiative. We compute hourly cross-correlations and stack them to generate noise correlation functions (NCFs) for each station pair. Dispersion curves are extracted from NCF spectra using an automated workflow, enabling us to perform ambient noise tomography (ANT) across the Australian continent. Our ANT model, constructed from surface wave velocity maps from 60s to 2s periods, resolves well-known major sedimentary basins as well as several recently discovered smaller basins. We validate our model against deep-crustal active seismic profiles in Australia and observe remarkable agreement between the two datasets. Additionally, we compare our results with borehole data, interpreted basin analysis from gravity, magnetic, and active seismic surveys, revealing the lateral extent and depth of major basins such as the Canning, Officer, and Great Artesian basins. In the Great Artesian Basin, we detect extremely low velocities in regions with significant water saturation. These findings highlight ANT as a robust tool for imaging first-order, large-scale crustal structures, offering valuable insights into Australia’s geological framework. Presented at the 2025 IAGA/IASPEI Joint Scientific Meeting