Lithospheric Structure of the Australasian Region Using Full Waveform Inversion of Broadband Data from Permanent Networks and AusArray deployment

Lithospheric structure is fundamental to understanding Earth's dynamic processes and geological systems. While existing tomographic models of the Australian lithosphere effectively capture large-scale features, discrepancies persist at finer scales. To address this, we are developing a fully verifiable lithospheric model, ensuring transparency by sharing all datasets and results. In this study, we present initial results from a full waveform inversion tomography model of the Australian lithosphere, resolving structures down to a period of 70 seconds. This model is constructed using seismic data from the Australian National Seismograph Network (ANSN), legacy datasets, and new records from the AusArray 2° × 2° deployment, which has significantly improved coverage in previously unsampled regions. We begin with seismic waveforms from 193 earthquakes (moment magnitude, MW 6.2–7.5) and subsequently incorporate 165 additional events (MW >5.0) as the model extends to 70-second periods. The AusArray project, commenced during the Australian Government’s recently completed Exploring for the Future Program, is funded to continue under the new Resourcing Australia’s Prosperity initiative. With the continued availability of new data and computational refinements, the model resolution will improve over time. Expanding the inversion to higher frequencies will allow for better constraints using body waves, enhancing tomographic models at periods of 40 seconds and shorter. Our results confirm previously identified large-scale lithospheric structures while revealing new, finer-scale variations across continental Australia, offering deeper insights into the region's geological framework. Presented at the 2025 IAGA/IASPEI Joint Scientific Meeting