Australian National Magnetic Data Collection

This data collection are comprised of magnetic surveys acquired across Australia by Commonwealth, State and Northern Territory governments and the private sector with project management and quality control undertaken by Geoscience Australia. Magnetic surveying is a geophysical method for measuring the intensity (or strength) of the Earth's magnetic field, which includes the fields associated with the Earth's core and the magnetism of rocks in the Earth's crust. Measuring the magnetism of rocks, in particular, provides a means for the direct detection of several different types of mineral deposits and for geological mapping. The magnetism of rocks depends on the volume, orientation and distribution of their constituent magnetic minerals (namely magnetite, monoclinic pyrrhotite, maghaemite and ilmenite). The instrument used in magnetic surveys is a magnetometer, which can measure the intensity of the magnetic field in nanoteslas (nT). Magnetic surveys in this collection have been acquired using aircraft or ship-mounted magnetometers and are a non-invasive method for investigating subsurface geology.

How Magnetotelluric (MT) Surveys Work

This animation shows how Magnetotelluric (MT) Surveys Work. It is part of a series of Field Activity Technique Engagement Animations. The target audience are the communities that are impacted by our data acquisition activities. There is no sound or voice over. The 2D animation includes a simplified view of what magnetotelluric (MT) stations and equipment looks like what the equipment measures and how the survey works.

Australian Geomagnetic Reference Field 2025 Revision (AGRF25)

<div>AGRF25 is a regional magnetic field model for Australia covering the interval 2020-2030. </div><div>The Australian Geomagnetic Reference Field (AGRF) is a set of numerical models of the geomagnetic field for Australia and near-neighbouring regions. It represents a combination of the Earth's main field originating from the core and the broad-scale crustal field. AGRF describes the geomagnetic field on a regional scale, intermediate between the global scale of the International Geomagnetic Reference Field (IGRF) and the local scale provided by detailed ground and aeromagnetic surveys.</div><div><br></div><div>Included with the dataset is evaluation software:</div><div>README.TXT: This text file of information</div><div><br></div><div>AGRF25S.FOR: Source code of a main program for generating AGRF25 values</div><div>    at a sequence of single sites. The program may also be used to</div><div>    generate values of the International Geomagnetic Reference Field, </div><div>    revision 14 for epochs after 2025.0</div><div><br></div><div>AGRF25S.EXE: A Windows console application of program AGRF25S</div><div><br></div><div>AGRF25G.FOR: Source code of a main program for generating AGRF25 values</div><div>    for a single field element on a latitude-longitude grid at </div><div>    a constant altitude</div><div><br></div><div>AGRF25G.EXE: A Windows console application of program AGRF25G</div><div><br></div><div>AGRF25LB.FOR: Source code for subroutines called by the main programs.</div><div><br></div><div>COEF25:  A data file of model coefficients and parameters.</div><div><br></div><div>GRID2GEO.FOR: Source code of a program to convert Universal Transverse</div><div>    Mercator Easting and Northings to geodetic latitude and longitude</div><div><br></div><div>GRID2GEO.EXE: A Windows console application of GRID2GEO</div><div><br></div><div>GEO2GRID.FOR: Source code of a program to convert geodetic latitude and </div><div>    longitude to UTM Easting and Northings</div><div><br></div><div>GEO2GRID.EXE: A Windows console application of GEO2GRID</div><div><br></div><div>SPHEROID.TXT: A text data file of geodetic spheroid parameters, </div><div>    used by GRID2GEO and GEO2GRID</div>