Australian Gravity Anomaly Tilt Image Derived From 2019 National Grid

Gravity tilt anomaly data reveals geological structures beneath the Earth's surface across Australia. The compilation integrates nearly 1.4 million ground and marine gravity stations from a national database updated to September 2019. Geoscience Australia processed the data, applying a de-trended global isostatic residual (DGIR) calculation and a tilt filter to highlight geological edges.

Use Cases

• Map subsurface geological unit edges by interpreting the DGIR tilt filter values.
• Model crustal density variations by analyzing the de-trended global isostatic residual (DGIR) anomalies.
• Correlate gravity anomaly features with other geophysical data for mineral prospectivity mapping.
• Study continental margin structures using the integrated offshore gravity data from the Scripps global grid.

Strengths

• Integrates approximately 1.4 million gravity stations from a national database.
• Ground station spacing is detailed, ranging from 11 km down to less than 1 km across major parts of the continent.
• Data quality was checked by Geoscience Australia geophysicists to ensure it is fit-for-purpose.

Limitations

• The underlying gravity observations have variable density, with station spacing ranging from less than 1 km to 11 km, creating resolution inconsistencies.
• The grid cell size of approximately 435m may smooth over finer-scale geological features present in the raw data.
• The dataset is a 2019 compilation, so it does not include gravity surveys conducted after September 2019.

Provenance

Source

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

Collection Method

Data acquired from ground and marine surveys, processed via standard methods including DGIR calculation and a Fast Fourier Transform (FFT) tilt filter.

Time Range

Gravity observations range from the 1940s to September 2019.

Freshness

The compilation is based on data as of September 2019, though the metadata record was updated in April 2026.

Geography

Australia and its continental margins.