8823aec2-2a7a-4a4b-9547-43255475ddf1 urn:uuid eng UTF-8 nonGeographicDataset nonGeographicDataset 2025-10-16T08:00:42 creation ISO 19115 2016 Ambient noise tomography of Australia: Application to AusArray deployment - Update 8823aec2-2a7a-4a4b-9547-43255475ddf1 As part of the first phase (2016-2020) of the Exploring for the Future (EFTF) program, Geoscience Australia deployed 119 broad band seismic stations in northern Australia. This deployment was part of the Australian Passive Seismic Array (AusArray) Project. Data from these stations were used to image the seismic structure using various techniques, including ambient noise tomography (ANT). The first ANT model (Hejrani et al, 2020) was focused on a narrow range of frequencies and used the Hawkins and Sambridge (2019) approach to estimate dispersion curves. This new approach starts from the original work by Aki (1957) to estimate phase velocity in the frequency domain, and then takes a step further to ensure a smooth curve is achieved. In Hejrani et al., (2022), using minimum Signal-to-Noise-Ratio (SNR) threshold of 2, about 4,000 data points (out of 7,000+) were used to generate surface wave velocity maps at a resolution of 1 degree at four frequencies (sensitive to different depths). This model was subsequently updated in September 2021 by using all 7,000+ data points (no SNR threshold) of phase velocity measurements across AusArray year one to provide a 0.25 degree resolution model. All dispersion curves regardless of their quality were utilized. A number of artefacts were identified in that model, which motivated further investigations. During 2022, I developed a new automated and scalable approach to estimate dispersion curves, which was completed in December 2022. This new method starts from the original idea by Aki (1957), but takes a different approach to stabilize the dispersion curves and to avoid cycle skipping. This record represents the preferred 2D velocity models for AusArray year one data based on the newly estimated dispersion curves and a comparison with previous models and interpretations; is an update from Hejrani et al. (2020) and should be read in conjunction. Work is currently under way to invert these 2D surface wave models to obtain 3D velocity models for the crust and mantle. Such 3D velocity models would be suitable for joint interpretations with other data such active seismic, gravity and magnetic. The code will be made publicly available at the conclusion of EFTF. {"type": "Polygon", "coordinates": [[[112.92, -54.75], [159.11, -54.75], [159.11, -9.2402], [112.92, -9.2402], [112.92, -54.75]]]} 112.92 159.11 -54.75 -9.2402 Ambient Noise Tomography AusArray Australia’s Resources Framework EFTF – Exploring for the Future Published_External Seismology Seismology and Seismic Exploration Download Report (pdf) [1.9 MB] documentDigital Download Report (pdf) [1.9 MB] PDF Download Model Package (xyz) [5.0 MB] documentDigital Download Model Package (xyz) [5.0 MB] ZIP Link to GA Portal documentDigital Link to GA Portal HTML National Geophysical Grids WMS documentDigital National Geophysical Grids WMS WMS National Geophysical Grids WCS documentDigital National Geophysical Grids WCS WCS