Australian Gravity Anomaly Grid with Airborne Survey Integration

Over 1.8 million gravity observations underpin this 0.5 vertical derivative grid of Australia. Data integrates 1.4 million ground stations with 345,000 line km of airborne gravity and 106,000 line km of airborne gradiometry surveys. The grid was compiled by Geoscience Australia using data from government, industry, and academia, with observations spanning from the 1940s to 2019.

Use Cases

• Map subsurface geological structures by interpreting the half vertical derivative (0.5VD) gravity anomaly values.
• Identify density contrasts for mineral exploration using the spherical cap Bouguer anomaly grid cell values.
• Assess regional crustal thickness variations by analyzing the terrain-corrected gravity data across the continent.
• Calibrate airborne survey methodologies by comparing line-spacing data (0.5 km to 2.5 km) with ground station spacing (1 km to 11 km).
• Model offshore continental margins by integrating the Global Gravity grid v28.1 data with onshore observations.

Strengths

• Integrates approximately 1.8 million gravity observations from multiple sources.
• Combines 1.4 million ground stations with 451,000 total line kilometers of airborne gravity and gradiometry data.
• Grid cell resolution is 0.00417 degrees (approximately 435 meters).
• Data collection spans over seven decades, from the 1940s to present day.

Limitations

• Ground station spacing is irregular, varying from less than 1 km to 11 km, creating resolution inconsistencies.
• The core observational data is from September 2019, with newer surveys not included.
• Specific error metrics or uncertainty estimates for individual grid cells are not provided in the description.

Provenance

Source

Australian National Gravity Database (ANGD) and Global Gravity grid v28.1 from Scripps Institution of Oceanography, NOAA, and NGA.

Collection Method

Data processed from ground and airborne surveys using terrain corrections and a Fast Fourier Transform (FFT) to calculate the first vertical derivative.

Time Range

Observations from the 1940s to September 2019.

Freshness

Grid compilation is based on data as of September 2019; metadata was last updated in April 2026.

Geography

Australia and its continental margins.