Australian Gravity Anomaly Map from 1.4 Million Observations

Australia's 2019 B-Series gravity map visualizes de-trended global isostatic residual (DGIR) data as a Hue-Saturation-Intensity image. It combines over 1.4 million ground observations, 345,000 line km of airborne gravity, and 106,000 line km of gravity gradiometry data collected from the 1940s onward by government, industry, and research bodies. The primary data source is the Australian National Gravity Grids.

Use Cases

• Analyze subsurface density contrasts using the DGIR gravity anomaly values ranging from -500 to +500 µm.s-2.
• Correlate gravity anomaly patterns from the HSI image with known geological features for regional mapping.
• Validate airborne gravity survey data (345,000 line km) against ground-based observations for quality assessment.
• Study long-term geophysical trends by integrating data collected from the 1940s to 2019.
• Use the linear color scale from blue (-500 µm.s-2) to red (+500 µm.s-2) for standardized visual interpretation of anomaly intensity.

Strengths

• Integrates a large volume of source data, including 1.4 million ground gravity observations.
• Combines multiple survey types: ground, airborne gravity (345,000 line km), and gravity gradiometry (106,000 line km).
• Data collection spans a long temporal range, from the 1940s to 2019, providing historical context.

Limitations

• The primary deliverable is a static PDF image, limiting direct quantitative analysis of the underlying grid data.
• The dataset's recency is unclear as it is based on a 2019 grid compilation, though the platform record was updated in 2026.
• Specific metadata regarding data precision, interpolation methods, or uncertainty estimates for the final grid is not provided in the description.

Provenance

Source

Australian National Gravity Database (ANGD) and National Australian Geophysical Database (NAGD), integrated with the Scripps Institution of Oceanography Global Gravity Grid.

Collection Method

Combination and processing of ground, airborne, and satellite-derived gravity observations.

Time Range

1940s to 2019 (for source data collection); grid represents a 2019 compilation.

Freshness

Based on the 2019 Australian National Gravity Grids; platform record last updated 2026-04-04.

Geography

Australia