Australian National Gravity Anomaly Grid 2019

Geoscience Australia's 2019 National Gravity Compilation is a processed gravity anomaly grid derived from approximately 1.8 million ground and airborne observations. The grid has a cell size of 0.00417 degrees (approximately 435m) and includes data acquired from the 1940s to 2019, supplemented by offshore global gravity data.

Use Cases

• Interpret the half vertical derivative (0.5VD) grid to reveal geological structures for sub-surface mapping.
• Analyze the complete Bouguer anomaly grid to model changes in rock density beneath the Earth's surface.
• Use the gravity anomaly data with its 435m cell size for regional geophysical exploration and targeting.
• Integrate airborne gravity gradiometry line data (106,000 line km) to improve resolution in areas with sparse ground stations.

Strengths

• Derived from a substantial foundation of nearly 1.4 million ground gravity stations and 345,000 line km of airborne gravity surveys.
• Incorporates data from multiple sources including Commonwealth, State, and industry surveys spanning from the 1940s to present.
• Processed with terrain corrections using both offshore bathymetry and onshore topography data.

Limitations

• Station and line spacing is variable, ranging from less than 1 km to 11 km, which may affect resolution consistency.
• The grid is a derivative product (half vertical derivative of Bouguer anomalies), not the raw observation data.
• Primary update was in 2019, with older historical data included; newer surveys may not be represented.

Provenance

Source

Geoscience Australia Data

Collection Method

Data processed via standard methods and FFT from the Australian National Gravity Database and global grids, quality-checked by GA geophysicists.

Time Range

1940s to 2019

Freshness

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Geography

Australia and its continental margins