Bouguer Gravity Anomaly Grid of Onshore Australia 2016

Full description

This gravity anomaly grid is derived from observations stored in the Australian National Gravity Database (ANGD) as at February 2016 as well as data from the 2013 New South Wales Riverina gravity survey. Out of the almost 1.8 million records in the ANGD approximately 1.4 million stations together with 19,558 stations from the Riverina survey were used to generate this grid. This product shows spherical cap Bouguer anomalies over onshore continental Australia. The data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. The spherical cap Bouguer anomalies in this grid are the combination of Bullard A and B corrections to the Free Air anomaly values using a density of 2670 kg/m^3.

Lineage

Maintenance and Update Frequency: asNeeded

Statement: This grid is derived from gravity observations stored in the Australian National Gravity Database (ANGD) as at February 2016 as well as data from the 2013 New South Wales Riverina gravity survey. Out of the approximately 1.8 million gravity observations 1,372,131 gravity stations in the ANGD together with 19,558 stations from the Riverina survey were used to generate this grid. The grid shows spherical cap Bouguer anomalies over onshore continental Australia. The data used in this grid have been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. Continental Australia has a base coverage of 11 kilometres, with South Australia, Tasmania and part of New South Wales covered with gravity stations at a spacing of 7 kilometres. Victoria has station coverage of approximately 1.5 kilometres. Federal, State and Territory Government initiatives have systematically infilled at a station spacing of 2 to 4 kilometres to improve coverage in areas of scientific or economic interest. Other areas of detailed coverage have been surveyed by private companies for exploration purposes. Only open file data held in the ANGD at February 2016 were used in the creation of the grid. The 2013 Riverina survey was added to the gridding process as this survey was not in the ANGD. The spherical cap Bouguer anomalies here are the combination of Bullard A and B corrections to the Free Air anomaly values using a density of 2670 kg/m^3. The data was gridded using the Nearest Neighbour algorithm using software from Intrepid Geophysics. The units of Spherical Cap Bouguer Anomaly in this grid are µm/s^2 (micrometres per second squared) and are referenced to the Australian Absolute Gravity Datum (AAGD07). The original grid was converted from ERMapper (.ers) format to netCDF4_classic format using GDAL1.11.1. The main purpose of this conversion is to enable access to the data by relevant open source tools and software. The netCDF grid was created on 2016-08-04. 20170906 NetCDF file restructured to be indexed Southward-positive for improved performance and interoperability