An Updated Fourier Spectral Attenuation Model for Southwestern Western Australia

<div>Earthquake ground-motion data recorded on the South-West Australia (seismic) Network (SWAN) are augmented to existing ground-motion datasets for the southwest Western Australian region. These data are used to develop an updated Fourier amplitude attenuation model for the region. The model is applicable for the moment magnitude range of 2.5 ≤ <em>M</em>W < 5.3, hypocentral distances less than 500 km, and for 150 logarithmically spaced frequencies from 0.1 ≤ <em>f</em> < 36 Hz. The data collected through the SWAN improves the constraint on the near-source attenuation of Fourier spectral amplitudes and will enable improved characterisation of earthquake source characteristics. Site-specific amplification effects are evaluated, and these will be used in concert with measurements of the seismic site properties to develop an attenuation model for a reference seismic site class. Stochastic simulations using the Fourier attenuation model will be used to improve ground-motion models for large-magnitude earthquakes that are applied in probabilistic seismic hazard analyses for the region. <b>Citation:</b> Allen, TI 2024, Site classification and VS30 determination for seismic hazard evaluation in the SWAN seismic network, Western Australia, in South West Australia Network (SWAN): passive seismic imaging and hazard analysis compiled by RE Murdie and MS Miller: Geological Survey of Western Australia, Report 255, p. 68-75