Gravity and Magnetic Filtering

The Grav/Mag extension to Oasis montaj provides a Continuous Reduction to the Pole function for creating a grid that is reduced to the pole everywhere.

The extension also enables you to calculate Total Magnetic Field from Measured Horizontal Gradients.

The software was developed by Paterson, Grant & Watson Limited (PGW). Geosoft licenses Grav/Mag Filtering as a montaj plus™ extension to Oasis montaj.

Use the Grav/Mag Filering extension to:

• Vary the Earth’s magnetic inclination and declination to produce a grid that is reduced to the pole everywhere. The local inclination and declination of the earth’s magnetic field can vary quite dramatically over large regional surveys. One value of inclination and declination will not satisfy the reduction to the pole operator at all places on the grid.
• Calculate a total magnetic field grid from two horizontal gradient Hx and Hy grids (see technical reference below).
• Highlight anomalies (e.g. kimberlites) with high gradients Reduce the survey cost by eliminating the need to collect tie lines

Technical reference

Nelson, J. Bradley, Leveling - total field aeromagnetic data with measured horizontal gradients, Geophysics, vol.59, no.8 July, 1994, p.1166-1170.