National Gravity Compilation 2019: First Vertical Derivative Grid of Australia

Geoscience Australia's National Gravity Compilation 2019 DGIR 1VD image is a processed geophysical grid derived from approximately 1.8 million gravity observations. The grid, with a cell size of about 435 meters, shows the first vertical derivative of de-trended global isostatic residual anomalies over Australia and its continental margins. It integrates ground data from the Australian National Gravity Database (as of September 2019) and offshore data from a global gravity grid.

Use Cases

• Model subsurface geological structures based on gravity anomaly data.
• Interpret crustal density variations for tectonic studies based on the processed isostatic residual grid.
• Support mineral and resource exploration by mapping basement features and sedimentary basins.
• Integrate with other geophysical datasets (e.g., magnetic, seismic) for comprehensive geological interpretation.

Strengths

• Integrates a large volume of observations, with nearly 1.4 million gravity stations from the Australian National Gravity Database used.
• Data quality is checked by GA geophysicists to ensure it is fit-for-purpose.
• Combines decades of ground data (from the 1940s onward) with modern offshore global gravity data.
• Provides a continent-wide view with a consistent grid cell size of approximately 435 meters.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Station spacing for the underlying ground observations is variable, ranging from 11 km to less than 1 km, which may affect local resolution.

Provenance

Source

Geoscience Australia Data, incorporating data from Commonwealth, State, Territory Governments, industry, universities, and global sources (Scripps Institution of Oceanography, NOAA, NGA).

Collection Method

Ground and marine gravity observations processed via standard methods, with a first vertical derivative calculated via a fast Fourier transform (FFT) process.

Time Range

Ground data collected from the 1940s to present, with the compilation snapshot as of September 2019.

Freshness

Last updated 2026-04-30 12:39:45.039545; freshness should be verified.

Geography

Australia and its continental margins.