Australian Gravity Anomaly Grid With First Vertical Derivative

A geospatial grid representing the first vertical derivative of de-trended global isostatic residual gravity anomalies across Australia and its continental margins. The compilation integrates approximately 1.8 million ground and airborne gravity observations, including 1.4 million ground stations and over 450,000 line kilometers of airborne surveys, processed by Geoscience Australia from data collected from the 1940s to 2019. It is derived from the 2019 Australian National Gravity Grids B series.

Use Cases

• Map subsurface geological structures by interpreting the first vertical derivative of DGIR anomalies across the 0.00417-degree resolution grid.
• Identify regions of high-density rock formations by analyzing gravity anomaly patterns, particularly in areas supplemented by 345,000 line km of airborne gravity data.
• Integrate offshore gravity data from the Scripps v28.1 global grid with terrestrial observations to model continental margin geology.
• Assess data coverage and resolution for exploration planning using station spacing metrics ranging from 11 km to less than 1 km for ground observations.
• Calibrate new airborne gravity surveys by comparing results against this foundational 2019 national compilation grid.

Strengths

• Integrates a large volume of observations, including nearly 1.4 million ground stations and over 450,000 line km of airborne surveys.
• Provides continent-wide coverage of Australia and its margins at a consistent grid cell size of approximately 435 meters.
• Combines multi-source data from government, industry, and research organizations collected over eight decades.

Limitations

• Ground station density is uneven, with spacing varying from 11 km to less than 1 km, potentially creating resolution gaps.
• The core data snapshot is from September 2019, making it temporally stale for analyses requiring recent measurements.
• Airborne data inclusion was selective, primarily for areas where ground data quality was insufficient, which may introduce methodological inconsistencies.

Provenance

Source

Geoscience Australia (GA), Australian Ocean Data Network.

Collection Method

Grid generated from the Australian National Gravity Database and global grids, processed via standard geophysical methods including isostatic correction and Fast Fourier Transform.

Time Range

1940s to 2019.

Freshness

The underlying data compilation is from 2019, though the platform record was updated in April 2026.

Geography

Australia and its continental margins.