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Variation of crustal mass over the Australian region

Created 16/10/2025

Updated 16/10/2025

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Seismic refraction surveys in Australia and nearby marine areas provide data on crustal velocities and layer thicknesses. The averages of these at various places have been used to estimate a density-depth structure. By applying corrections for average elevation and free-air gravity, a crustal mass deficiency (CMD) is calculated for each site; this characterizes a standard crustal column with zero elevation and zero free-air anomaly, which is considered to be in isostatic equilibrium over a mantle of uniform density 3.32 t/m^3. The CMD ranges from about 13 kt/m^2 in the south-west of the continent, to about 21 in parts of Queensland; marine values range from 15 to 17 kt/m^2. The variations imply that isostasy on a broad scale is not complete at the base of the crust. As the gravity field indicates that departures from isostasy are comparatively small, compensation must occur partly in the mantle.

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Additional Info

Field Value
Title Variation of crustal mass over the Australian region
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/635c1177-8f5e-40e3-a078-ce8f52e6bab4
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        110.0,
        -44.0
      ],
      [
        156.0,
        -44.0
      ],
      [
        156.0,
        -9.0
      ],
      [
        110.0,
        -9.0
      ],
      [
        110.0,
        -44.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Variation of crustal mass over the Australian region". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/variation-of-crustal-mass-over-the-australian-region