Australian National Gravity Grids With 400-Meter Cell Resolution

2019 gravity grids combine over 1.4 million suitable ground observations from the 1940s onward with satellite and airborne data. Geoscience Australia and GNS Science produced these grids, which include Free Air Anomaly, Complete Bouguer Anomaly, and De-trended Global Isostatic Residual values at a 400-meter cell size.

Use Cases

• Model crustal thickness and density variations by analyzing Complete Bouguer Anomaly (CBA) values.
• Identify local geological structures and mineral targets using De-trended Global Isostatic Residual (DGIR) grids.
• Correlate Free Air Anomaly (FAA) data with offshore bathymetry and onshore topography for tectonic studies.
• Integrate the 400-meter resolution grids with seismic or magnetic datasets for enhanced geophysical interpretation.

Strengths

• Derived from over 1.4 million quality-controlled gravity observations.
• Integrates 345,000 line km of airborne gravity gradiometry for improved resolution.
• Features a 400-meter cell size, improved from previous 800-meter grids.

Limitations

• Station spacing is uneven, varying from 1 km to 11 km across the continent.
• Some grids (DGIR) required correction for artefacts, indicating initial processing errors.
• Specific row counts and data volumes for individual grids are not provided.

Provenance

Source

Geoscience Australia and GNS Science.

Collection Method

Combination of ground observations from the Australian National Gravity Database, airborne surveys, and the NOAA Global Gravity Grid.

Time Range

1940s to 2019.

Freshness

Grids represent data as of September 2019, with a metadata update in 2026.

Geography

Australia, including onshore and offshore regions.