Australian Gravity Anomaly Tilt Image Derived From 1.8 Million Observations

Nearly 1.4 million gravity stations from the Australian National Gravity Database, supplemented by marine data, were used to generate this grid. The image visualizes the tilt of de-trended global isostatic residual anomalies over Australia and its continental margins, processed by Geoscience Australia from data collected from the 1940s to September 2019. The underlying grid has a cell size of approximately 435 meters.

Use Cases

• Detect edges of geological units by interpreting the tilt filter applied to the DGIR grid.
• Model subsurface rock density variations using the de-trended global isostatic residual anomalies.
• Integrate gravity anomaly data with other geophysical datasets for continental-scale geological mapping.
• Assess regional geological structure for mineral exploration using the 435-meter resolution grid.

Strengths

• Derived from nearly 1.4 million gravity stations and marine data, sourced from approximately 1.8 million total observations.
• Grid resolution of 0.00417 degrees (approximately 435 meters) provides continent-scale detail.
• Data quality was checked by Geoscience Australia geophysicists to ensure fitness for purpose.
• Incorporates ground observations with station spacing as dense as less than 1 km in parts of the continent.

Limitations

• Ground station spacing is inconsistent, varying from 11 km to less than 1 km across the continent.
• The dataset is a processed derivative (tilt image) of underlying gravity grids, not the raw observations.
• Temporal coverage is broad (1940s to 2019), potentially mixing data from different measurement standards.

Provenance

Source

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

Collection Method

Ground and marine gravity observations processed via standard methods, with a tilt filter applied using a fast Fourier transform (FFT) process.

Time Range

1940s to September 2019.

Freshness

Based on data current as of September 2019, with metadata last updated in April 2026.

Geography

Australia and its continental margins.