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Systematic Estimation of Earthquake Source Parameters for Continental Australia. Attenuation and Stress Drop

Created 17/10/2025

Updated 19/11/2025

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A new continental-scale Fourier spectral attenuation model is developed to resolve source parameters for well-recorded earthquakes occurring within Australian continental crust since 1994. The attenuation model uses almost 6,200 individual earthquake recordings and is valid for hypocentral distances up to 2,000 km. Assuming the Brune (1970) f-2 model, source parameters are derived for over 290 earthquakes from moment magnitude 3.1 ≤ M ≤ 6.6. The stress drop parameter (Δσ) is log-normally distributed with a median estimate of 1.90 MPa, ranging from less than 0.1 MPa to greater than 60 MPa. The estimates of Δσ suggest significant regional variability in earthquake source characteristics for different seismotectonic regions, with earthquakes in Australia’s northwest and Flinders Ranges regions demonstrating stress drops consistently higher than the median value relative to other areas. Given Australia’s sparse monitoring network, it is difficult to attribute a physical justification (e.g., source depth) for this observation. Nevertheless, the regional variations in source parameters will have utility for the selection and development of ground-motion models for national-scale and site-specific seismic hazard assessments in Australia. Importantly, the earthquake source parameters presented herein are explicitly anchored to the attenuation model developed in this study. Citation: Allen, T.I., 2025. Systematic estimation of earthquake source parameters for continental Australia: attenuation and stress drop. Bulletin of the Seismological Society of America. https://doi.org/10.1785/0120250054

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Field Value
Title Systematic Estimation of Earthquake Source Parameters for Continental Australia. Attenuation and Stress Drop
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/efec8728-329f-4235-ac0b-f85d2c0118dc
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        112.0,
        -44.0
      ],
      [
        154.0,
        -44.0
      ],
      [
        154.0,
        -9.0
      ],
      [
        112.0,
        -9.0
      ],
      [
        112.0,
        -44.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Systematic Estimation of Earthquake Source Parameters for Continental Australia. Attenuation and Stress Drop". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/systematic-estimation-of-earthquake-source-parameters-for-continental-australia-attenuation-and