Field

Fixed

Earth’s magentic field is uniform over survey area

Variable

Earth’s magnetic field (declination and/or inclination and/or strength) varies linearly over survey area

Fixed

Inclination

The inclination of the Earths magnetic field at the location specified by XYZ coordinate in this window

Declination

The declination of the Earths magnetic field with respect to the North direction of the model at the location specified by XYZ coordinate in this window.

Intensity

The intensity of the Earths magnetic field at the location specified by XYZ coordinate in this window

X,Y,Z

Location of local origin for variable inclination, declination or intensity

Orient

Orientation of gradient in inclination, declination or intensity

Change

Gradient in inclination, declination or intensity (in units of degrees per km or nT per km as appropriate)

Field

Inclination

The inclination of the Earths magnetic field at the origin of the block.

Declination

The declination of the Earths magnetic field with respect to the North direction of the model.

Intensity

The intensity of the Earths magnetic field at the origin of the block

Calculation Altitude

Surface

Geophysical calculations carried out oforn Earth’s surface

Airborne/ Altitude

Geophysical calculations carried out for given altitude above EarthÕs surface

Draped Survey

If a topography has been read into the model, a draped survey may be performed at the height specified by the calculation altitude, if this option is not checked, but a topography has been loaded, a barometric survey will be calculated. This option is only available for spectral calculations. You must set the Upper NE corner Z value to the highest elevation of the topography for this option to function correctly!

Deform Fields

Remanence

This option changes the way remanent vectors are treated. If the vectors are deformable, the remanent vector the user provides is the orientation provided when the rock is created, and the final vector orientation depends on the deformation history. If remanent vectors are not deformable, the vector orientation is uniform for a given rock unit regardless of the subsequent.

Anisotropy

This option changes the way anisotropic susceptibility is treated. If the anisotropy is deformable, the anisotropic susceptibility the user provides is the orientation provided when the rock is created, and the final orientation depends on the deformation history. If anisotropic susceptibility is not deformable, the orientation is uniform for a given rock unit regardless of the subsequent deformation.

Sus Units

c.g.s.

c.g.s. units used for magnetic susceptibility

SI

SI units used for magnetic susceptibility

Draped Survey

Calculates survey at constant hieght above topography (should use Full Spatial calculations to get accurate solution)