National Gravity Compilation with Airborne Tilt Image for Australia

A gravity anomaly grid derived from approximately 1.8 million gravity observations, including 1.4 million ground stations and airborne surveys totaling 451,000 line kilometers. The dataset, processed by Geoscience Australia, uses a cell size of 0.00417 degrees (approximately 435m) to reveal subsurface geological structure across Australia and its continental margins.

Use Cases

• Model subsurface density variations using the complete Bouguer anomaly grid to infer geological structures.
• Integrate airborne tilt image data with ground gravity observations to improve resolution in areas with sparse ground data.
• Apply terrain corrections using offshore bathymetry and onshore topography data to refine gravity anomaly calculations.
• Analyze the national gravity grid's B series to map continental margins and identify potential mineral resources.

Strengths

• Integrates approximately 1.8 million gravity observations from multiple sources.
• Combines 1.4 million ground stations with 451,000 line km of airborne gravity and gradiometry surveys.
• Provides a consistent national grid with a cell size of 0.00417 degrees (approx. 435m).
• Data quality is checked by GA geophysicists and spans acquisitions from the 1940s to present.

Limitations

• Station and line spacing varies significantly (ground: 1-11 km, airborne: 0.5-2.5 km), creating uneven resolution.
• Offshore data is sourced from a global grid (v28.1), which may have different accuracy and resolution than the primary Australian data.

Provenance

Source

Geoscience Australia, incorporating data from Commonwealth, State/Territory Governments, industry, universities, and global sources.

Collection Method

Processed from the Australian National Gravity Database and airborne surveys, with terrain corrections applied using bathymetry and topography data.

Time Range

Ground data acquired from the 1940s to present; compilation date is 2019.

Freshness

Grid derived from data as of September 2019; metadata last updated March 2026.

Geography

Australia and its continental margins.