Australian National Gravity Grid First Vertical Derivative 2019

Australia and its continental margins are covered by a gravity anomaly grid derived from approximately 1.8 million ground, airborne, and offshore observations. The grid has a cell size of 0.00417 degrees (approximately 435 meters) and integrates data from government surveys, industry, and research organizations dating from the 1940s to 2019. The Australian Ocean Data Network processed and released this compilation, which includes a first vertical derivative transformation of the complete spherical cap Bouguer anomaly.

Use Cases

• Enhance geological interpretation by analyzing the first vertical derivative grid to highlight shallow density contrasts.
• Map subsurface structures by correlating Bouguer anomaly patterns with known rock densities across the continent.
• Integrate airborne gravity gradiometry line data (106,000 line km) with ground stations to improve resolution in data-sparse regions.
• Calculate terrain corrections using the referenced offshore bathymetry and onshore topography data to refine gravity models.

Strengths

• Integrates nearly 1.4 million ground stations with 345,000 line km of airborne gravity and 106,000 line km of airborne gravity gradiometry data.
• Provides continent-wide coverage of Australia and its margins with a consistent 435-meter grid cell resolution.
• Uses data collected and quality-checked by government geophysicists over a temporal range from the 1940s to 2019.

Limitations

• Ground station density is variable, with spacing ranging from 11 km to less than 1 km, potentially creating resolution inconsistencies.
• The dataset's core observations are current only as of September 2019, with the grid derivative calculated from that snapshot.
• Specific data quality metrics for individual observation sources or error estimates are not provided in the description.

Provenance

Source

Australian National Gravity Database (ANGD), Global Gravity grid v28.1, and government/industry/academic airborne surveys.

Collection Method

Ground, airborne, and shipborne gravity measurements processed via standard methods, with terrain corrections and FFT-derived vertical derivative calculation.

Time Range

1940s to September 2019

Freshness

null

Geography

Australia and its continental margins