Australian National Gravity Grids: Free Air and Bouguer Anomalies, 400 m Resolution

A 2019 series of gravity grids for Australia, combining over 1.4 million ground observations from the 1940s onward with satellite and airborne data. The grids, produced by Geoscience Australia and GNS Science, feature a 400-metre cell size and include Free Air Anomaly, Complete Bouguer Anomaly, and De-trended Global Isostatic Residual values. Offshore data from a global gravity model provides context to the onshore measurements.

Use Cases

• Modeling crustal thickness and density variations based on Complete Bouguer Anomaly values.
• Identifying subsurface geological structures for mineral exploration using the De-trended Global Isostatic Residual grid.
• Integrating onshore and offshore gravity data for continental-scale geophysical studies.
• Calibrating regional gravity surveys against a national standard dataset.

Strengths

• Integrates over 1.4 million quality-controlled gravity observations from a national database.
• Improved 400-metre cell resolution, enhanced from previous 800-metre versions.
• Combines onshore ground data with offshore satellite-derived gravity and over 450,000 line km of airborne surveys for broader coverage.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Data may reflect geographic and temporal bias inherent to the collection methods spanning from the 1940s.

Provenance

Source

Geoscience Australia and the Institute of Geological and Nuclear Sciences Limited (GNS Science).

Collection Method

Grids combine data from the Australian National Gravity Database, airborne surveys, and the NOAA Global Gravity Grid.

Time Range

Observations from the 1940s to 2019.

Freshness

Last updated 2026-06-05 06:46:21.416924; freshness should be verified.

Geography

Australia, including onshore and offshore regions.