National Gravity Compilation 2019: Free Air Anomaly Grid for Australia

Nearly 1.4 million ground gravity stations, 345,000 line km of airborne gravity data, and 106,000 line km of gravity gradiometry data were combined to create this free air anomaly grid. The grid, with a cell size of approximately 435 meters, reveals geological structures beneath Australia and its continental margins. Geoscience Australia compiled this dataset from observations dating from the 1940s to 2019, supplemented with global offshore data.

Use Cases

• Modeling subsurface geological structures based on free air gravity anomaly values.
• Integrating ground and airborne gravity data for regional geological mapping.
• Calibrating or supplementing other geophysical surveys using the detailed 435m resolution grid.

Strengths

• Integrates a large volume of data, including nearly 1.4 million ground stations and over 450,000 line km of airborne surveys.
• Provides high-resolution coverage with a grid cell size of approximately 435 meters.
• Data quality is explicitly checked by Geoscience Australia geophysicists to be fit-for-purpose.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Data density is variable, with station spacing ranging from 11 km to less than 1 km across the continent.

Provenance

Source

Geoscience Australia Data, supplemented with data from Scripps Institution of Oceanography, NOAA, and NGA.

Collection Method

Processed from ground observations in the Australian National Gravity Database and airborne surveys, using standard geophysical methods.

Time Range

1940s to 2019 (data collection period).

Freshness

Last updated 2026-03-25 17:16:27.152658; freshness should be verified.

Geography

Australia and its continental margins.