Australian Gravity Anomaly Map with Airborne Data

Nearly 1.8 million gravity observations, including 1.4 million ground stations and 451,000 line kilometers of airborne surveys, underpin this national compilation. The Australian Ocean Data Network released this processed grid, derived from data collected from the 1940s to 2019, to reveal sub-surface geological structures. It represents the half vertical derivative of de-trended global isostatic residual anomalies across Australia and its continental margins.

Use Cases

• Model crustal thickness and lithospheric structure using the de-trended global isostatic residual (DGIR) anomaly grid.
• Identify geological boundaries and fault systems from the half vertical derivative image which highlights density contrasts.
• Integrate airborne gravity gradiometry line data (106,000 line km) with ground station data to improve resolution in under-sampled regions.
• Calibrate regional geodynamic models by analyzing the Complete Bouguer Anomaly (CBA) data after removal of near-field, far-field, and trend corrections.

Strengths

• Combines approximately 1.8 million observations from ground, airborne gravity, and airborne gradiometry surveys
• Integrates data from a 70+ year time range (1940s to 2019) for long-term geological analysis
• Provides high-resolution with ground station spacing as dense as 1 km and airborne line spacing as tight as 0.5 km in some areas

Limitations

• Primary data source (ANGD) was last updated as of September 2019, limiting recency
• Station density is variable, with some continental areas having spacing between 2.5 and 7 km, which may be coarse for local studies
• Offshore data is sourced from a global model (v28.1) which may have lower resolution than the terrestrial data

Provenance

Source

Australian National Gravity Database (ANGD), Global Gravity grid from Scripps Institution of Oceanography/NOAA/NGA, and Commonwealth/State/Territory Government and industry surveys.

Collection Method

Data processed via standard geophysical methods, quality-checked by GA geophysicists, and gridded using a Fast Fourier Transform (FFT) process.

Time Range

1940s to 2019

Freshness

Grid compilation is from 2019; metadata was updated in April 2026.

Geography

Australia and its continental margins