Australian Gravity Anomaly Grid with First Vertical Derivative

Australia and its continental margins are covered by a processed gravity anomaly grid with a 435-meter cell size. The compilation integrates nearly 1.4 million ground stations and over 450,000 line-kilometers of airborne surveys collected from the 1940s to 2019. Geoscience Australia produced this grid, representing the first vertical derivative of de-trended global isostatic residual anomalies.

Use Cases

• Map subsurface density contrasts and geological structures using the first vertical derivative (1VD) of de-trended global isostatic residual (DGIR) anomalies.
• Integrate ground station gravity data with airborne gravity gradiometry line data to improve resolution in under-sampled regions.
• Analyze the Complete Bouguer Anomaly (CBA) grid after removal of near-field, far-field isostatic, and trend corrections for crustal studies.
• Compare station spacing, ranging from 11 km to less than 1 km for ground data and 0.5 km to 2.5 km for airborne lines, to assess regional data density.

Strengths

• Integrates approximately 1.8 million gravity observations from ground and airborne sources.
• Combines 1.4 million ground stations with 345,000 line km of airborne gravity and 106,000 line km of airborne gravity gradiometry.
• Provides continent-wide coverage of Australia and its continental margins at a consistent 435m grid cell size.

Limitations

• Ground data temporal coverage is broad (1940s to 2019), potentially introducing methodological inconsistencies over time.
• Station and line spacing varies significantly across the continent, creating regions of heterogeneous data resolution.

Provenance

Source

Geoscience Australia, utilizing the Australian National Gravity Database and global grids from Scripps Institution of Oceanography/NOAA/NGA.

Collection Method

Data acquired from government, industry, and research organizations, processed via standard methods and FFT to produce the derivative grid.

Time Range

1940s to 2019

Freshness

Grid is based on data current as of September 2019, though metadata was updated in 2026.

Geography

Australia and its continental margins